Executive Summary
If you don’t want to run through the calculations, here is the summary. I attempted a thought experiment in which I calculated whether it would be feasible to use solar power to generate enough energy to offset all U.S. gasoline consumption. My conclusion is that it will take about 444,000 megawatts of electrical generating capacity. Current U.S. generating capacity is over 900,000 megawatts, but there isn’t a whole lot of spare capacity in that number.
To generate 444,000 megawatts with solar PV would require just under 1,300 square miles (a 36 mile by 36 mile square) of just PV surface area. To generate that much power with solar thermal – including supporting infrastructure – would require 4,719 square miles (a 69 mile by 69 mile square). A large area, but not impossible to envision us eventually achieving this.
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Introduction
Having made an attempt to calculate the number of square miles to replace current U.S. electricity consumption via solar PV or solar thermal, I have been challenged to do the same exercise for replacing our gasoline usage. (In fact, I was told by someone that they had never seen this kind of calculation done, so I told them I would do it). I have no idea how this calculation is going to turn out, but I suspect it is going to be similar to the previous calculation for replacing electrical consumption. My guess is less than 100 miles by 100 miles. Note that this is a thought experiment, in which I try to get an idea of what it would take to achieve this.
First, some caveats. There are still technical obstacles that prevent this scenario from being realized. Those are, 1). Battery range is still too low (The plug-in Prius is only going to be able to go 7 miles on battery power).; and 2). Solar power can’t be adequately stored. However, that’s not the purpose of the exercise. The purpose is to satisfy my curiosity: If we were going to try to replace gasoline with solar power, are the land requirements prohibitive?
I am only going to do this calculation for gasoline, as I think it is unlikely that electricity will ever power long-haul trucks or airplanes.
How Much Do We Need?
The U.S. currently consumes 389 million gallons of gasoline per day. (Source: EIA). A gallon of gasoline contains about 115,000 BTUs. (Source: EPA). The energy content of this is equivalent to 45 trillion BTUs per day. The average efficiency of an internal combustion engine (ICE) – that is the percentage of those BTUs that actually go into moving the vehicle down the road – is about 15%. (Source: DOE). Therefore, the energy that goes toward actually moving the vehicles is 6.7 trillion BTUs per day.
The efficiency of electric infrastructure can be broken down into several steps. According to this source, the respective efficiencies for the transmission lines, charging, and the vehicle efficiency are 95%, 88%, and 88%, for an overall efficiency (after the electricity is produced) of 74%. To replace the gasoline BTUs that go toward moving the vehicle with electricity is going to require 6.7 trillion/0.74, or 9.1 trillion BTUs. To convert to electricity, we use 3,413 BTUs/kilowatt-hour (kWh). Thus, 9.1 trillion BTUs/day is equal to 2.7 billion kWh/day. That’s how much energy we need. To convert this to power, we need to multiply by 1 day/24 hours, and that gives us 111 million kilowatts, or 111,000 megawatts (MW) of power generation required.
Looking back at my Solar Thought Experiment, I calculated 2,531 square miles to replace our peak electrical demand of 746,470 MW (746 GW). However, the current calculation is a different sort of calculation than what I did previously. The previous calculation attempted to have enough installed solar PV to meet peak demand. In the case of replacing our transportation fuel, I need enough panels to produce the required transportation energy in 8 hours or so while the sun is shining. To be conservative, we can assume 6 hours, which means we will actually need four times the 111,000 MW, or 444,000 MW.
Using Solar PV
From the previous essay, I used a conservative value of 12.5 watts per square foot as the generating capacity of an actual GE PV panel. To get 444,000 MW is going to take an area of 35.5 billion square feet, which is 1274 square miles. This is an area of just under 36 miles by 36 miles. However, this is just the surface area required to generate the electricity. It does not include area required for supporting infrastructure.
Using Solar Thermal
Doing the same calculation based on the solar thermal output from Running the U.S. on Solar Power, the expectation was that 0.147 megawatts could be produced per acre. This did include all of the land associated with infrastructure. If we use that number, we find that to generate 444,000 MW is going to take a little over 3 million acres, or 4,719 square miles. This is a square of just under 69 miles by 69 miles.
The reality is that we would use a combination of the solar PV and solar thermal. We have a lot of available rooftops that can create electricity with solar PV, and there are large tracts of land in sunny Arizona and Nevada that can create electricity with solar thermal.
Conclusions
Clearly, a lot of area is required, but it isn’t impossibly large. Of course to achieve this, a couple of big problems need to be resolved. First, battery life needs to improve somewhat before people are going to embrace electric transport. According to this ABC News story, the average commute is 16 miles one-way, but the range of the plug-in Prius is only expected to be 7 miles. The Aptera, on the other hand, claims a range of 120 miles. Maybe we just need to change the way we think about what we drive. (On the other hand, not a lot of commuters are going to climb into an Aptera if they have to share the road with large SUVs).
Second, and the bigger issue, is that we still don’t have a good way to store excess solar power. We need to have a good storage mechanism so electric cars can be charged at night from solar electricity produced during the day. One idea for this that I have seen floated is to use peak solar energy to electrolyze water, and then store the hydrogen in centralized locations. The hydrogen would then be burned at night to run centralized electrical generators. Not the most efficient method for storing solar energy, but technically workable.
Finally, the current electrical grid couldn’t handle such a large increase, but the model I envision would generate and consume the electricity locally.
Note
I had delayed posting this for almost a week, because I was sure there was an error in the calculations. I finally found one (I had turned a kilowatt into a watt), but let me know if you find other errors or incorrect assumptions.
I haven’t looked closely at your calculations yet, but you should be looking at KWH per year, not peak capacity.
Those are the kinds of issues I want to work through. Let’s talk about that, as I am open to changing my assumptions. Why do you think that?
The reason I did it the way I did is that on any particular day, the demand has to be met. If a lot of kWh per year are produced, but they are concentrated at a particular time or in a particular season, that doesn’t necessarily meet demand on a particular day due to the issues with storage.
Cheers, RR
Looking closer, I see you did get to 2.7 billion kWh/day, and you assumed 8 hours of sunlight and called 6 hours conservative. Unfortunately not all 8 hours is as bright as noon. So 6 hours is not at all conservative for most parts of the US. Sun hours for various cities in the US are listed at:
http://www.solar4power.com/solar-power-insolation.html
Six is a reasonable number for the mohave desert and Arizona, so if you only use the deserts, your final numbers look right. But if you want to use all the rooftops in the US, 4 sun hours per day is probably a more reasonable number.
Note: solar insolation is given in KWH per square meter per day, and peak rated capacity of photovoltaic modules is measured at 1000 watts per square meter insolation. Thiis why solar insolation units are sometimes called sun hours.
For solar thermal, peak rated capacity has more to do with the size of the thermal (steam) plant they decide to attach to the solar field. Companies like Ausra plan to attach small steam plants to large fields so they can run the plants for more hours on stored heat.
If you want to make sure you get enough sun each day, then you have to look at the “low” values on that Solar insolation table, which is a little bit less than 6 sun hours in the Southwest deserts. Eyeballing the table, if you’re going to use all the rooftops in the US, 3 might be a better number to use considering winter conditions.
I don’t know how much you might want to adjust for summer driving season using more fuel than the rest of the year.
I don’t know how much you might want to adjust for summer driving season using more fuel than the rest of the year.
The good thing about that, though, is that peak driving season corresponds to peak solar output.
Instead of converting solar to hydrogen,then transmitting the electricity so consumers can store it again,why not just convert CO2 to gasoline? When carbon taxes come down the pike,industry will be paying to get rid of the stuff.
Oops. I gave a poor choice for the solar insolation table, if you really want to consider December insolation.
http://www.apricus.com/html/insolation_levels_usa.htm
Looks like the average sun hours in the US in December is less than 2! Even in Las Vegas it’s only 2.6, and the highest December number is in Miami at 3.5.Not very good if you don’t want to store electricity for more than a day.
Maury, We’re not talking about converting solar to hydrogen. Seems like a waste to add an extra step. Go straight from solar to electricity.
Robert mentioned it in his post clee. We need power 24/7. Here’s an article about solar CO2 to gasoline.
http://tinyurl.com/32ue3j
Thanks. I missed the mention of hydrogen. I’ve obviously been up too long. Solar thermal with thermal storage comes to mind, but that’s good for overnight…not as good for summer to winter storage. I’ll go to sleep now…before I say something else stupid. 🙂
Instead of converting solar to hydrogen,then transmitting the electricity so consumers can store it again,why not just convert CO2 to gasoline?
A couple of immediate reasons come to mind. First, where are you going to get the CO2? Atmospheric concentrations are in the PPM range. So something like this would only be feasible at a coal-power plants or other large source of CO2.
But, the other thing is that the reactions are complex. Turning CO2 into CO is one thing. Turning that into gasoline is much more complex, requiring things like Fischer-Tropsch reactors.
Electrolyzing hydrogen from solar is simple by comparison.
Cheers, Robert
From the Tesla motors website:
How far can the Tesla Roadster drive between charges?
Actual range depends on driving style and conditions. During testing of prototypes cars, Tesla Motors has seen between 170 miles per charge for very spirited driving to 267 miles per charge for city driving that makes use of the Roadster’s regenerative braking. Our most recent EPA driving cycle tests, conducted November 26-30, 2007, at an EPA-certified facility, resulted in the following numbers:
* 230 mi EPA city
* 211 mi EPA highway
* 221 mi EPA combined (city/highway)
Blogger Robert Rapier said…
The good thing about that, though, is that peak driving season corresponds to peak solar output.
That’s true. But the problem I’ve come across in my own thought experiments on using solar energy for transportation is, that the power is being produced during the day when I’m most likely to be at work.
Why not charge the car at work, rather than at home? Then you would only need one energy storage system – the car batteries.
Of course charging both at home and at work would double the range, which might be necessary for the first plug-in hybrids.
How far can the Tesla Roadster drive between charges?
I thought about the Tesla as well when I was writing this, but left it out because the cost is going to be out of most people’s range.
Cheers, RR
If there’s room for a gas-powered generator in the Roadster’s trunk,wouldn’t that make it a plug-in hybrid with a 200 mile electric range?
Robert,I’m hung up on the conversion of CO2 to gasoline thing. Love the idea of recycling CO2. Besides,there’re 125 million cars on U.S. roads that will cost trillions to replace.
I thought about the Tesla as well when I was writing this, but left it out because the cost is going to be out of most people’s range.
It is now, but the Tesla is probably more indicative of the kind of range we’d be getting from EVs by the time this massive solar farm gets built.
Remember the Prius has to haul around that big old ICE and all the hi-tech trickery that make the ICE and electric motor work seamlessly. Future EVs should be simpler and lighter.
Hrmm, would this process change your calculations Robert?
http://www.greencarcongress.com/2007/12/sandia-applying.html
Also, what relative solar-efficiencies are you assuming for PV versus Thermal?
Infact, what type of solarthermal are you assuming? Trough? Tower? Dish?
Also part of this is largely because electrolysis prefers DC, where as the grid prefers AC.
http://greyfalcon.net/hydrogen4.png
Also, something to keep in mind here
http://ergosphere.blogspot.com/2005/07/why-hydrogen-is-no-route-to-renewables.html
A couple of points, I think the BTU content you used is a bit low. My figures are 121,000 BTU/gal for oxygenate blend and 126,000 for conventional (5.3 MM btu/bbl for old LP modelers).
Secondly, what would be the point? A gasoline engine is only 15-20% efficient compared to an electric motor at around 90%.
What you really want to know is how much solar power could replace the same amount of work done by electricity or an IC engine. That is a slightly different question.
Another way to think about this problem is to compare how much you are paying for gasoline in kWh.
At 121,000 BTU/gal and 15% efficiency, there are 5.32 kWh/gal of gasoline. With gasoline selling at $3.50/gallon that is like buying power for $0.66 /kWh.
Which is what got me thinking about “mild hybrids” or running the electrical systems in your car on plug power or solar instead of with the alternator.
Secondly, what would be the point? A gasoline engine is only 15-20% efficient compared to an electric motor at around 90%.
I factored that into the analysis – how much energy actually moved the vehicle down the road.
Cheers, RR
RR:
There is some good news out there — PHEVs are expected to recharge at night, when overall demand is well below grid capacity– not sure we need that much more electrical capacity….
the other goods news, that I see in my work, is in the architecture community. Buildings are going green. About 2/3rds or more of the built space in America will be new or rehabbed in the next 30 years. Look for electrical consumption to go down, not up. Green buildings use far less electricity. New lights use much less electricity than before.Look fro demand from buildings to go down, not up, in future years.
Also (as you know), not all power needs be solar. Nukes, wind, geothermal.
Going to PHEVs present few problems. I just hope the batteries work….
Also, what relative solar-efficiencies are you assuming for PV versus Thermal?
I based this on my previous essays in which I used the output of an actual solar thermal plant, and for PV I used a typical GE solar PV cell. References in the previous posts.
Cheers, RR
I factored that into the analysis
I missed that paragraph. We won’t run out of land for solar but will hit other limits long before then.
Just using your numbers, and estimating cost with these Kyocera 85 watt PV panels, the cost of this much capacity comes to $2.2 Trillion. That seems like a lot, but consider how much the US has already spent in Iraq and it sounds like a very wise investment.
Two points:
First, using the price of a commercially available PV panel is woefully inaccurate for an estimate, but I was more interested in finding out if the cost would be in the low trillions, the low tens of trillions, etc. While economy of scale and new technology may bring down the cost per watt, I don’t actually think this method is too bad, as I’m not accounting for cost of land purchase, cost of installation, associated grid development, or potential future increases in price of embodied raw materials or energy.
Second, my hesitation in recommending exactly this kind of program is that I’m unconvinced that the EROEI of solar panels over their lifetime is adequate to justify using fossil energy today to generate this power tomorrow. I have five concerns along these lines: 1) that, when a wide-boundary is considered for calculating the EROEI of PV the result is very near to 1:1; 2) that the energy required to build this system must come upfront (as in, taken out of our current production rate of fossil energy) whereas the return will come over the next 30+ years; 3) that using our limited fossil fuel endowment to build PV only seems rational if the EROEI still works out after we take enough energy out of the PV system over 30 years to build its replacement; 4) that scaling this kind of project this massively may encounter many unforeseen limiting factors in the form of diminishing raw materials; and 5) that the up-front cost compared to the long-term nature of benefits likely makes this kind of project unworkable from a political will standpoint due to the very short time-horizon of US politics.
That said, I think this is exactly the kind of thought experiment that we need. I’m just presenting some problems with implementation, but not suggesting that they can’t be solved. I am, however, confident that we won’t get to implementation until we 1) convince the public of the need for the short-term sacrifice required for something like this, and 2) identify the problems to implementation so that we can then get to the business of solving them…
King: “mild hybrids”
I am probably going to get slammed for even owning a motorhome with a 440cid engine, but I do and because we drive an S10 and a Saturn for the rest of the year, it’s actually a economical vacation when I look at our gasoline usage through the rest of the year and it beats owning a 3/4ton truck to tow a trailer and running it the rest of the year.
Anyway…
I have been restoring the old camper for several years and it didn’t have engine AC or roof AC originally. I installed a roof air unit a few years ago (120VAC shore power only) which was great for camping in a serviced site, but there were still times when it was very hot driving. There are a lot of windows that open and it really isn’t bad on a 30C day on the highway.
What I did was install a 3000w power inverter and 3 huge deep cycle batteries. I also upgraded the alternator to a 120amp one, but the 2 deep cycle batteries will run the roof AC unit through the inverter for about a 1/2 hour and with the large alternator it will stay ahead of the AC indefinitely.
I would think that it’s a realistic idea for someone who has a less than 1 hour commute to add a large 12V drive motor to the engine AC compressor, a couple of deep cycle batteries and charge the system with shore power at home and at work.
The question is going to be that by adding a 100 lbs of batteries and equipment to the car if it’s actually going to save anything over just running the AC off the engine when the shore power usage is factored in.
Vehicle-to-grid technologies could help out with the storage issue.
An AC-induction-powered EV can be turned into a bidirectional grid-connected energy storage system with about $300 worth of extra parts.
But I think we’ll also start seeing the end of the era of vehicles that weigh ten or twenty times as much as their occupants.
RR:
The future is going to have to require a combination of curtailment (people staying put much more and cutting out any trips that aren’t really necessary, or making each trip do more – by having 2, 3 or 4 riders in a car instead of just 1, for example) and substitution (alternatives to what we’re using now for trips – mostly gasoline-fueled ICE automobiles). We should be able to reduce our VMT by at least 25-33% must by carpooling, trip consolidation, and elimination of unnecessary trips. For that travel that remains, in the future we will use a combination of modes. Walking is the obvious default mode – if we can’t get around any other way, we’ll get there on foot. The Swedes make 33% of their trips on foot, I am doubtful that we are going to do much more than that anytime soon. The Dutch are famous for their bicycles, but only use them for 28% of their trips; I don’t see us beating that anytime soon either. The Swiss use their fabulous mass transit systems 20% of the time; given that at present in the US we compare at 2%, given the massive investments required to ramp this up, and given the terrible political obstacles that stand in the way, I am very doubtful that we’re going to be able to do any better than the Swiss.
That leaves us with a 19% remainder. If that 20% mass transit figure can cover most of the essential long distance trips, then all that most people should really need for most of those trips that can’t be done on foot, on bike, or by mass transit is a NEV – either one they own, one they rent, or one they ride in (taxi cab).
When you start looking at the amount of solar panels that we would need to recharge enough NEVs to cover 19% of our passenger transport, then I believe that you will find it to be a considerably smaller numer than what you suggested in your article. I would be surprised if it added up to more than 20% of your total, maybe even less. That is arguably something that looks a lot more feasible.
WNC Observer
I think you guys are missing the point. The grid is close to adequate already. The grid has been built for peak power consumption, suually on hot summer days. The demand comes from a/c.There is no part of the country that suffers brownouts in the middle of the ngiht — when PHEVs are expected to be re-charging.
So, just a few mor nukes, geothermal, wind and solar plants is probably all we will need…and buildings will be using less, not more, power in years ahead.
This is not a proble, — the real problem is, can we build a PHEV that works for average consumers?
I don’t see the relevance of mentioning the Prius PHEV prototypes. It achieves the 7 mile range just by adding another of the regular Ni-MH batteries found in the Prius, which previously due to power demand and battery life weren’t fully depleted. Now with more powerful electric motors and an added power splitter (like the Lexus hybrids have) in the e-CVT it can do most operation all electric and uses a more aggressive charge depleting strategy. The Ni-MH batteries are proven by Toyota now, so they’ll make some good reliable public demonstrators while collecting useful data on the vehicle systems, but I doubt we’ll see many if any Ni-MH production Prius PHEV unless they are jumping the market with a low volume of them earlier than expected. High-volume higher range Prius PHEVs would almost certainly use lithium-ion, but that is probably 2 years off since they’ve backed off cobalt chemistries and are now working on something else apparently. I’d watch for lithium-ion application in Lexus hybrids to foretell lithium-ion application in regular Toyotas. With a Lexus Prius coming out, I could see low volumes of both Prius as PHEVs, with the Lexus having Li-ion and a longer range. So all I’m saying is the Prius PHEV prototypes are most likely NOT a good indication of the volume production plug-ins from Toyota.
Don’t use Ni-MH as the benchmark, Toyota & Panasonic are already looking at re-tooling a Ni-MH factory for lithium batteries, and surely will be competing against a Nissan PHEV using high-volume produced lithium batteries from their JV with NEC. BMW, Mercedes and Audi and many others are all making moves towards lithium batteries in next generation cars by 2012-2013.
I would think that it’s a realistic idea for someone who has a less than 1 hour commute to add a large 12V drive motor to the engine AC compressor, a couple of deep cycle batteries and charge the system with shore power at home and at work.
That is the situation I’m in. The weight thing has me bugged. Before I tackled the A/C I would think about converting the radiator fan to electric and fooling the voltage regulator into keeping the alternator off while I ran everything else on battery.
Installing a larger alternator to stay ahead of the A/C might be defeating the whole idea.
benny, the main problem with trying charging EV’s with solar power is that during the time that solar is available, people are using their cars. If people charge their cars during the day say while they are at work then we may have a problem because the grid now has to handle that extra load. The grid can easily handle people plugging in their cars at night to charge, but then you run into the problem of storing all that electricity generated by solar during the day.
robert, I wonder just how inefficient it would be to use solar to split water to generate hydrogen which we store and use at a later time to either charge cars or meet electrical demand. The appeal of this method, at least to me, is that because solar power is so variable that you want to match it to a variable load such as electrolysis. This also can be said of using wind power.
Robert:
I’m glad you did this. I have argued for a long time that solar and wind can solve our energy problems, particularly along with conservation(Germany and Japan use about half the energy per capita of the U.S.). If you consider how much area/state, the number becomes even more manageable. The NREL website shows “lower 48” states to have an average solar insolation of 1,800 watts/ sq meter +/- 25%.
The author of the Coyote Blog also has the Climate Skeptic blog. He recently did an analysis of Gore’s claim that 90 mile x 90 mile tract of land in the Southwest covered with a field of solar panels, would yield enough electricity to power the entire United States. There is a downloadble spread sheet, too. Here is the URL:
http://www.climate-skeptic.com/2008/05/solar-panel-cou.html
Terry:
In a way, that my point. The grid will not be overtaxed by PHEVs. They will be charging at night — when the grid is fat and happy. Solar can add to our current grid, and handle the summer time surges (demand from buildings and industry, not PHEVs). We can add solar, wind and nukes to phase out coal, for AGW reasons, or for other environmental reasons, but not for power-shortage reasons.
The $64,000 q is still: Can a PHEV be manufactured for the masses?
Forget about the grid — that problem is already solved.
For solar applications, it’s easiest to multiply the peak power output rating by some capacity factor c_f (0.18-0.23 depending on latitude and cloud cover) to find the equivalent continuous power output, 24 hours a day, 365 days a year.
Your assumption that the sun shines 6 hours a day at max insolation is maybe a little high (c_f = 0.25). Note that Retscreen (http://www.retscreen.net/) can give you a real value without a lot of effort.
Jeff Vail writes:
1) that, when a wide-boundary is considered for calculating the EROEI of PV the result is very near to 1:1;
How did you get that 1:1 number and just how wide are these boundaries? Are you including the fuel used by the guy driving to work to make the fertilizer to grow the wheat that is in the sandwich of the lunch of the person who washes the PV panels?
A 2003 study of ground mounted PV gave an EROEI of 7.5
http://db.world-nuclear.org/info/inf11.html
http://www.nrel.gov/docs/fy04osti/35489.pdf
What kinds of EROEI do you get for other energy plants if you hold them to the same wide-boundaries?
Just for the purposes of comparison, the total area on which corn is grown in the United States is apparently about 136,000 square miles. That’s the equivalent of a square 370 miles on its side.
Wheat and soybeans each represent an area of similar magnitude.
Compared to that – and given that the ideal land for solar panels is, well, desert – the land requirements are pretty trivial.
Looking at all of these square miles of solar panels, and all of these electric vehicles that don’t yet exist, seems a little, shall we say, unsustainable. I suggest another approach.
Robert, using your numbers of 115,000 BTU per gallon of gas, and an average vehicle MPG of 20, I get 5750 Btus per average vehicle mile driven with the existing vehicle fleet, or about 1.7 KWh per mile.
6 miles avoided per day therefore yields about 10 KWh less energy used. This is a good number to use as the average daily output of a 2KW Solar PV grid-tie system, at least in the southwest, at about 5 full sun hours per day. For less sunny areas, of course, YMMV. A 2KW system on average before incentives will cost about $15,000.
So every average vehicle driving six less miles per day yields the same energy supply/demand balance improvement as would be achieved by a 2KW rooftop solar power system on the owner’s house or apartment (assuming the owner could accommodate that many panels). And no resource-consumptive fleet conversion to electric vehicles is needed.
City folks tend to like EVs because they will push the resulting pollution from vehicle use out “somewhere else”, away from where they live. To me, EV’s are just kicking the can down the road, unless we really can power them with clean energy. Even if EVs turn out to be 5 times more efficient, for $15000 solar investment you get about 30 miles a day (vehicle not included). I don’t think it’s a very sellable proposition, I think I’ll just drive a bit less.
Have I missed something with my numbers? I never see anyone doing unit-level solar/vehicle calculations, so I’m curious as to what others think.
the model for solar power generation locations and associated grid structure would create some interesting political turf battles on many fronts among states and fed[FERC like agencies]. also similar economic cost/revenue breakage among utilities and among states. i’d bet these more insoluable than the technical/cost challenges.
fran
Robert,
One minor thing you missed that improves the situation a bit is that, of the 15% of the energy actually applied to the drive wheels, 5.8% is used in braking (per the reference you cited). Electric vehicles can regenerate at least 30% of that energy (http://engineering.wikia.com/wiki/Regenerative_braking). I imagine that pure-electric vehicles would do even better, since they would have a larger motor/generator. So, you would have to supply only about 13% of the gasoline energy content as solar electricity, not 15% – your solar grid shrinks by 13% (13% = 13/15).
iftheshoefits writes:
I never see anyone doing unit-level solar/vehicle calculations,
I thought Tesla Motor’s comparison was interesting.
http://www.arb.ca.gov/msprog/zevprog/symposium/presentations/eberhard.pdf
Slide 21: 1 MWH of electricity will get you 1440 miles in a hydrogen fuel cell car, or 4900 miles in a battery electric car.
Slide 25: 1 acre of farm land will get you 58K miles in an ethanol ICE car, or 1 acre of desert land covered with PV will give you 1862K miles in an electric car.
Slide 28: 1 gallon of biodiesel will get you 38 miles in a diesel car, or if put through a diesel generator, will give you 89 miles an electric car. You push the pollution around, but only half the pollution.
Clee,
Thanks for the link. I realize that EVs will be significantly more efficient than today’s vehicles, and that’s good in and of itself. I’m not sure they will save enough to justify the additional cost, all things considered, at least not for quite a while.
Another question I have about the EVs is the life-cycle cost of the batteries. I install off-grid solar power systems for homes, and I have to deal with the battery cost issues all the time. A couple years ago I stopped touting the “free electricity after initial investement” of off-grid solar, because when I spread the cost of the typical flooded lead-acid deep cycle batteries over their expected lifetimes, the battery cost was about the same as what a homeowner’s typical electric bill would have been. That was before lead acid battery prices nearly doubled.
What are the expected number of deep discharge cycles for the EV battery technologies in deployment? Do they provide at least 80% of initial capacity for the expected life of the vehicle? I expect them to have some finite life-span, and I wonder about replacement costs. Lead acid batteries are recycled – can the NiMH and Lithium ion batteries be recycled in much the same way, reducing replacement costs?
On a small scale, we consume and use up great amounts of re-chargeable batteries, not thinking that much of it, because the capacities (and therefore the costs) are relatively small. As energy capacity scales, though, the life cycle costs of today’s technologies can become formidable. A 10 year lifespan, with two deep discharges per day, means about 7300 deep cycles. I would hope for sustainability purposes that EV’s will be designed for longer life cycles than that, with less moving parts and all. But I think 10 year vehicle life is a reasonable expectation.
Everyone always blames the batteries, but do they ever cite anything to back their fears?
Robert said, “Battery range is still too low (The plug-in Prius is only going to be able to go 7 miles on battery power)“. Ah yes, that proves it doesn’t it? I guess the existence of 40, 50, and 60 mile PHEVs, and 100, 120, 150, and 250 mile BEVs is irrelevant? What kind of reasoning is this?
Robert said, “Of course to achieve this, a couple of big problems need to be resolved. First, battery life needs to improve somewhat before people are going to embrace electric transport“: Our 2002 production Toyota pure EV has 79,000 miles on it, and it is going strong, and there are multiple cars in the 100,000 mile club, and and Southern California Edison’s fleet (based on an earlier model) is still doing well with only 0.5% battery problems. So where’s your data to suggest that lifetime is an issue? Sure, standard LiCo batteries have lifetime problems, but those aren’t the only choices (e.g. there’s LiFePO4 and Li4Ti5O12), and even LiCo might be fixable by the addition of Mn.
Li4Ti5O12 by the way was the battery chemistry that demonstrated a 10-minute recharge of a 150-mile range BEV one year ago. Fast recharge makes the BEV equal to a plug-in hybrid, once there are highway fast charging stations. (This is a ways off, but it is where things are headed.)
I am curious why you chose to use solar rather than wind to power a PHEV or BEV fleet? Wind seems like the natural choice, as it tends to produce the most at night, which when vehicles are more likely to be parked in the owner’s garage. The total area required by a wind farm is about 8x that required by a CSP farm, but only 5% of that is not dual use (e.g. 95% can be farmed or grazed), which means the land taken from other uses is about 0.4 times that of a CSP farm. Wind is also cheaper than CSP.
The American Wind Energy Association’s FAQ says (the rest of this is cut and paste from their FAQ entry):
How much land is needed for a utility-scale wind plant?
In open, flat terrain, a utility-scale wind plant will require about 60 acres per megawatt of installed capacity. However, only 5% (3 acres) or less of this area is actually occupied by turbines, access roads, and other equipment–95% remains free for other compatible uses such as farming or ranching. In California, Minnesota, Texas, and elsewhere, wind energy provides rural landowners and farmers with a supplementary source of income through leasing and royalty arrangements with wind power developers.
A wind plant located on a ridgeline in hilly terrain will require much less space, as little as two acres per megawatt.
I thought about the Tesla as well when I was writing this, but left it out because the cost is going to be out of most people’s range.
RR:
The Phoenix Motors EV gets close to the range (100+ miles) of the Tesla at half the price:
http://www.phoenixmotorcars.com/
It can be charged in 10 minutes with an off board charger, or 5-6 hours with the on-board charger.
How about we put charging outlets on every parking meter, and add an RFID chip to the car’s plug? It could pay for your parking and power with a single action.
This from WSJ
The U.S. can follow Denmark’s lead and get 20% of its electricity from wind by 2030, the Department of Energy said today. The only obstacles, according to the DOE report, are building the wind turbines, improving them, getting them in place, and getting their electricity to where it’s used. Piece of cake.
Okay, so it will be hard to get to 20 percent. Bt we don’t need 100 percent from solar. Geothermal too.
The point is, we can do it. The good news is that any technology that produces electricity, or reduces consumption of oil, can help.
Better mpg cars, wind, solar, nukes — we have so many solutions.
The only thing to fear is fear itself, and our political leadership.
I’ve had 3 kW of solar panels on my roof since 2004. They have generated slightly over 4500 kWh / year, which works out to 4.1 hours / day of “full sun”. I live near Silicon Valley (zip code 95014). You would get more in the Mojave desert, but less in most of the USA.
I did a quick search and I found the Kyocera 205 watt KD205GX for $905, or $4.41 / watt. To that you’d need to add a substantial amount for inverters (DC-AC conversion), mounting racks, etc.
I guess the existence of 40, 50, and 60 mile PHEVs, and 100, 120, 150, and 250 mile BEVs is irrelevant? What kind of reasoning is this?
A great deal of misunderstandings could be relieved if one only reads the entire article. I threw the Prius out as an example, but also noted “The Aptera, on the other hand, claims a range of 120 miles.”
Cheers, RR
The math and ideas circulating here are great, but has anyone thought of using one 3’x3’PV cell on our cars. That would store a tremendous amount of energy across the nation and would provide for charging all day long when the cars are sitting in parking lots at work (for those of us that park outside, anyway).
Solar land area required for EVs is an interesting exercise, but not terribly relevant. The big issues with PV are cost and nighttime output, not land area.
Solar is best suited for sunbelt peaking power because solar output correlates well with peak power demand. Peakers are our least efficient and most expensive powerplants. Fuel cost alone for NG peakers is above 10 cents/kWh before you include depreciation, O&M, etc. At 15-20 cents/kWh solar is nearly cost-competitive with peakers already and the next round of cost reductions driven by thin film, CPV/CSP and ending the polysilicon shortage should drive costs below 10 cents/kWh. Peaking deployments alone could keep the solar industry busy for over a decade.
Meanwhile, wind is by far the most cost-effective choice for EV/PHEVs. It’s around 5 cents/kWh and produces power at night. There is no need for storage (beyond the PHEV batteries) and the resource is plentiful. ND and TX alone have enough wind to replace gasoline.
We could supply all our electricity and 80% of our transport energy with a mix of nuclear, wind and solar. Add in existing hydro and minor contributions from biofuels, geothermal, waste-to-energy, etc. and we’re home free. This requires an intelligent grid (which we need anyway) and some demand management, but very little in the way of costly storage schemes or exotic new innovations. The economic cost is actually a little less than we pay today and the environmental cost is clearly much less.
Hi Robert
check out http://assets.panda.org/downloads/plugged_in_full_report___final.pdf
as they have quite a good analysis of well to wheel and plant to wheel stats.
Your methodology seems good, but the simplest thing to do, would be require everyone to have a smart meter, allow for G2V smart charging and charge at night mostly.
I consult for wind farm developments but the molten salt storage seems the best for solar thermal plants. I looked at H2 as backup for Wind Turbine Generators, but the compressed air design seems a more efficient way to go. http://www.mechanology.com/index-2.html
In any event distributed systems are the best way to go, and a mixture as well.
I also strongly urge you (USA) to look at retrofitting old coal and gas plants with pebble bed nuclear reactors, as they are small, modular, can’t melt down and would use the existing switchyards and generators already onsite. The ultimate in recycling! http://www.nuclearoil.com/
I expect peak gas soon, followed a few years later by peak coal.
David Glogau
New Zealand
According to this ABC News story, the average commute is 16 miles one-way, but the range of the plug-in Prius is only expected to be 7 miles. The Aptera, on the other hand, claims a range of 120 miles.
A 16 mile one-way commute suggests a design somewhere between the Prius PHEV-7 kludge and the goofy Aptera. The Chevy Volt’s 40 mile range hits a sweet spot — it covers normal commuting without the cost/weight issues of a full EV.
I doubt Toyota will damage their brand by sell Prius PHEV-7s. They’re simply using what they have in the parts bin to gather data. IMHO their first PHEV will be a real PHEV with a lithium battery. That said, we may see some PHEV-10s or -20s. Average commute is 16 miles but lots of people live less than 10 miles from work. By recharging at work these people could cut their gasoline consumption 80% over a normal car with no sacrifices.
A PHEV-10 or -20 duty cycle is very stressful on batteries. You need 2-4x the power density of a PHEV-40 and a life of 8000 +/- deep discharge cycles. Only ALTI has claimed that kind of cycle life, and they’re too flaky to believe.
robert rapier said, ‘A great deal of misunderstandings could be relieved if one only reads the entire article. I threw the Prius out as an example, but also noted “The Aptera, on the other hand, claims a range of 120 miles.”‘
I did read the entire post, and I did see the Aptera comment. I don’t think your response addresses my comment though. You wrote, in the introduction, “First, some caveats. There are still technical obstacles that prevent this scenario from being realized. Those are, 1). Battery range is still too low (The plug-in Prius is only going to be able to go 7 miles on battery power).; and 2). Solar power can’t be adequately stored.” The Aptera reference is in the Conclusion. You used the parenthetical comment about the 7-mile EV range of the plug-in Prius as the only justification for the introductory comment that “battery range is still too low“. You were being extremely sloppy in your reasoning. Once again, I ask for more substance than just taking cheap shots at batteries.
Once again, I ask for more substance than just taking cheap shots at batteries.
Again, it wasn’t a cheap shot. I mentioned the Prius because most people are familiar with it. Most of those cars getting lots of miles on batteries are not mainstream. People will embrace electric cars much faster if something like a Prius could reach the average commute distance with batteries.
People don’t want to give up things. They will eventually have to, but my only point is that better batteries would speed acceptance.
Cheers, RR
“The $64,000 q is still: Can a PHEV be manufactured for the masses? “
Can Tesla add a gas-powered generator Benny? They already have regenerative braking and a 200 mi. range. And lower priced Tesla’s are in the pipeline.
“Peakers are our least efficient and most expensive powerplants.”
Utility companies are excited about the possibility of PHEV’s doing their load balancing doggydogworld. I read an article recently about one utility road testing some PHEV Prius’s with load balancing on their agenda.
The U.S. installed a record 5200 megawatts of wind power capacity last year. Unfortunately,that was only 1/3 of the increased power demand the grid called for. If we need a 40 sq. mi. array of solar panels to replace our IC vehicles,then it should probably be a federal effort. The multi-trillion dollar cost could be spread over the life of the panels with 30-year bonds. Hell,we should be building it right now,and retiring coal generating plants as they come online.
Gentlemen:
This is a great and very thought provoking post. I would like your comments on one aspect of this. While taking a cruise in the Bahamas recently, I looked out over the ocean and realized how much wide-open space there is available, and thought, would it be possible to have fleets of tugs towing solar panels at sea during the day and returning stored energy to the mainland at night? On the ocean, space would not be an issue, nor would the price of land, etc. Storage and transmission would be still be an issue, of course, but I don’t think from an engineering perspective impossible. Also, it could put to work the many seafaring people who have been hurt by economic conditions? Does this add anything to the idea pool?
Robert,
Have you read the
Scientific American Grand Solar Plan article? This is a worthwhile read and I would love to hear your comments on it.
Doogydog and Maury-
Right. Our grid is adequate right now to handle PHEVs. They charge up at night. We can migrate towards a wind- and solar-powered grid (nukes too).
Such a grid, and PHEVs, would bring to us more energy security, and cleaner and quieter cities. Better air to breath.
Really, I don’t see a downside here.
“On the ocean, space would not be an issue, nor would the price of land, etc.”
Jeff,I’ve wondered about those oceans myself. There’s incredible wave energy out there,not to mention solar and wind. I’d bet giant platforms could capture all three forms of energy. I think it would be cool if those tugs you mentioned could haul CO2 out to the platforms and return with gasoline.
My bad. That was meant for Jack…
Clee-
Here’s a link to my calculations to arrive at a 1:1 EROEI for solar PV:
http://www.jeffvail.net/2006/11/energy-payback-from-photovoltaics.html
Here’s the gist: all existing EROEI methodologies create a boundary for inclusion at some point that makes accounting feasible. That, by definition, makes the resulting EROEI high. I argue that the non-accounted-for energy inputs are very significant, and suggest using a Price-estimated EROEI methodology to solve the problem. Admittedly, price-estimated EROEI has many problems of its own, but it does get around the boundary problem.
I’ve seen many claims for EROEI of PV between 5:1 and 30:1, but they all seem to include only the energy required to manufacture the panel in the plant and the energy required to refine the silicon or other primary raw material. When I see a number greater than 1:1 that even attempts to include things like the energy required to mine the raw materials, the energy required to transport the raw materials to the plant and the finished product to the field, the energy required to support the work force, the energy required to build the machines used in manufacturing, mining, transportation, the infrastructure required for transporting all the elements, etc., then I may change my tune, but to my knowledge there has never been an energy accounting performed on solar PV manufacture that includes these items (hence my suggestion that we look to price-estimation methods).
Here’s a link to my calculations to arrive at a 1:1 EROEI for solar PV:
Jeff,
I can see a number of problems from that methodology, all of which I am sure you are aware of.
I understand what Pimentel did when he calculated the EROEI of ethanol by going back and including the energy used to make the ethanol plant. But you can just keep going. We can calculate the energy that went into making the steel, and the energy that went into making the factory that made the steel, and the energy it took to feed the worker at that factory, and then step back to the iron mine and do it all again. I am not sure where one should draw the boundaries.
How about calibrating against some other metrics, like payback for a diesel-powered electrical generator? That probably isn’t the best example, but maybe there are some other examples to work through to see if they support or contradict what you have done.
What you may be seeing is a consequence of the abundance of coal, which helps provide cheap electricity. Double or triple the price of electricity, and I am sure that’s in the cards, and the EROEI based on the price-estimation method should start creeping up (I wouldn’t expect panel prices to double if electricity prices doubled).
Cheers, Robert
Maury,
Thanks for the comment. Great minds think alike. I had also thought of how to incorporate those three renewable “sources” into a consolidated energy production platform, mobile or fixed. It would seem that all three sources could feed one single distribution framework. It would seem to me (as an engineer) that the issues here are less technical than economic. In fact, nothing here proposed sounds the least technically prohibitive. What I can’t undestand though, is how coal or oil can be more competitive than these technologies economically. With coal/oil, you have initial capital costs, raw material costs, operating costs, and waste and pollution control costs. With these technologies you have (maybe?) higher capital costs, but then, woudldn’t your operating costs be minimal, and raw material, waste and pollution control costs be almost non-existent? Has anyone done a NPV valuation comparison throughout a lifecycle for a new coal plant vs. solar/wind/wave farm plants? What am I missing here?
Jack,there’s a ton of solar energy packed into that barrel of oil. It took millions of years to create,while a solar panel has to produce its yield instantly. It’s not really a fair competition,but renewables get more competitive every day.
On EROEI and solar vs. oil:
The price mechanism neatly sorts things out. That’s why Pimental’s studies are worthless. Let the price mechanism work.
The price mechanism fails, however, to address pollution and energy security. In such cases, the use of taxes or subsidies to mimic such external values may be warranted. This is nice on paper, but usually settles deeply into politics…still, it is nice to know to start….
Robert Rapier said, “Again, it wasn’t a cheap shot.” Well what was it then? Because it sure didn’t seem to have much substance to it. Just what is the technical obstacle you refer to, because I don’t see what it is. GM is building a plug-in hybrid with 40 miles of electric range. Dr. Andy Frank’s group at UC Davis built several with 60 miles of electric range, and that is what BYD is talking about too. Volvo’s plug-in hybrid also gets 60 miles of electric range. The Fisker gets 50 miles, and the AFS Trinity gets 40 of electric range. These designs don’t see a technical obstacle.
Robert Rapier said, “I mentioned the Prius because most people are familiar with it. Most of those cars getting lots of miles on batteries are not mainstream.” Robert, at that point you were writing about a technical obstacle, not marketing acceptance. Again I ask, what is this supposed technical obstacle?
Robert-
I agree, and the potential for a rise in the cost of coal-generated electricity is a key weakness (along with subsidies, comparing differing types of energy, etc.).
I think that, ultimately, the aggregate EROEI of society in total must be 1:1 + whatever our rate of growth. I’m still a bit unsure of how to proceed, and I’m not yet convinced by Prof. Hall’s proposals at TOD, but I do think the EROEI nut is a key one to crack. If we can’t address the “bootstrap-EROEI” issue (the fact that much of the infrastructure that current PV calculations are presuming were build on no-longer-available easy oil/coal/natural gas) and the need for any renewable energy source to produce, with unlimited boundaries for energy inputs, all the energy used for the production for its replacement plus enough surplus to keep powering society, then we’re just poking about in the dark. I wish I could propose a sound methodology, but I don’t have, and am not aware of, any options better than the very imperfect existing methods for calculating EROEI or the equally imperfect alternative that I’ve already proposed… and that concerns me a great deal.
eak,
The technical obsticle is the cost of the batteries and their expected useful life. You have a Rav EV, they were over $40,000 new for a vehicle with limited range and that takes hours to recharge. When the battery starts to fail, you are in for $26,000 to make your used car functional again.
You provided a link for owners who have over 100,000 mile on their batteries. That is fine, but how many will make 100,000 on their $26,000 batteries, maybe those four are on the high side of the curve. I need to see the whole distribution, not just the ouliers on the high side. What will the average life of the battery be for all vehicles?
At Tesla they say that the batteries will “maintain good performance for 100,000 miles or five years” They also say that 50,000 miles over 5 years should have about 70% of initial performance. They don’t say how much a new battery pack will cost. If I had to guess, I would say over $40,000. I would say that bringing that price down or bringing the performance or expected lifetime up is a technical obstacle.
The examples you offer are prototypes, what is the price, what are the specifications. Will the average Joe see a car on the lot, crunch the numbers and decide it is worth it?
I want electric vehicles to succeed. Everyone here understands the advantages of electric transport, but to ignore the clear technical obsticles of the battery is just delusional.
Robert Rapier said, “Again, it wasn’t a cheap shot.” Well what was it then? Because it sure didn’t seem to have much substance to it. Just what is the technical obstacle you refer to, because I don’t see what it is.
I already pointed this out, and Dennis reiterated above: The technical obstacle is in moving something mainstream over a decent range. That is a technical obstacle. To suggest that something more resembling a golf cart has a huge range isn’t particularly relevant; people want to drive a normal sized car (which is why the Prius example was used). So, the batteries need to get better before mass acceptance. And I consider that a technical obstacle. I think most people do.
RR
At Tesla they say that the batteries will “maintain good performance for 100,000 miles or five years” They also say that 50,000 miles over 5 years should have about 70% of initial performance. They don’t say how much a new battery pack will cost. If I had to guess, I would say over $40,000.
I attempted to calculate that once, based on the number of batteries required. I came up with $40,000, but thought you might get it down to $34,000 if you could assume some savings from buying the batteries in bulk.
RR
Dennis — one of the big CA utilities (PG&E or SoCal Edison) did a long-term study on five of their RAV4-EVs. Three made 100k miles no problem. One pack failed and was replaced. One pack was “reconditioned” by Toyota using a non-disclosed procedure. That failure rate is too high for retail, but not unusual for new technology fleet deployment.
JeffVail – one problem with price-based EROEI is most everything comes out 1:1. A barrel of oil costs $120 to produce and ship, as evidenced by the current market price and lo and behold, it provides $120 worth of energy. The bootstrap argument also has problems. Refineries use massive amounts of electricity, some of which comes from nuclear, hydro, wind, etc. Does this mean gasoline EROEI is below 1.0?
EROEI is not good for much, but it can help you figure out how well a process will scale. If you need 20k BTUs of fossil fuel to grow the corn and 50k BTUs of fossil-fueled process heat to create one gallon of ethanol with 80k BTUs, then even a massive ethanol plant will have problems. You have to figure out a way to reduce fossil-fuel inputs, such as burning corn cobs for process heat, before you scale up.
EROEI can also shed light on whether or not you’ll become cost-effective if competing energy prices rise. Again, if your fossil fuel requirements are 20k BTUs for corn and 50k BTUs for process heat you will gain no cost advantage as fossil fuel prices double.
Costs for PV and wind, on the other hand, have steadily declined as scale has increased. A detailed EROEI analysis would have helped you predict this, a market-price based EROEI would not. Similarly, PV and wind have shown almost zero sensitivity to the recent energy price spikes. This can only happen if EROEI is highly positive, quite the opposite of what market-price EROEI tells you.
I think that, ultimately, the aggregate EROEI of society in total must be 1:1 + whatever our rate of growth.
I think it’s got to be quite a bit better than 1:1. As you get closer to 1, the amount of energy required to secure the rest of the energy climbs exponentially, and the net energy falls rapidly.
RR
The technical obstacle is in moving something mainstream over a decent range.
The Volt is mainstream. Battery pack cost is estimated at $10k initially, falling to $6k over time.
Instead of the 7 mile Prius kludge (regular Prius with two battery packs instead of one), the $9995 A123/Hymotion pack makes for a better example. It turns a regular Prius into a PHEV-20. OEM price would be much less and an OEM would save another $1500 or so by eliminating the NIMH pack.
I attempted to calculate that once, based on the number of batteries required. I came up with $40,000, but thought you might get it down to $34,000 if you could assume some savings from buying the batteries in bulk.
This seems quite high. 6800 18650 cells should cost about $14,000 to a quantity purchaser. Tesla uses low Ah cells. 53 kWh pack divided by 6800 cells is 7.8 Wh/cell, and at 3.6V, that would be 2.2 Ah. This is quite low by modern 18650 standards. One advantage is that the lower Ah cells last much longer than the high Ah ones.
Of course, there’s a fair bit of work to remove the old 18650 cells and put in new ones, so I would guess the cost is about $20,000. Tesla has said as much in presentations. However, because 18650s are declining in price by 10% per year, the number should be much lower by the time a replacement is needed.
Maury said, “Robert,I’m hung up on the conversion of CO2 to gasoline thing. Love the idea of recycling CO2.“
That’s simple. It would take five times as much electricity to create gasoline as to drive on the electricity directly. It’s the difference between 3,000 mi^2 and 15,000 mi^2, and the cost per mile is more than a factor of five higher as well.
Maury said, “Besides,there’re 125 million cars on U.S. roads that will cost trillions to replace.“
Most solutions are going to take 30-40 years to implement completely. During that time the U.S. vehicle fleet will be replaced anyway. What’s important is to get new vehicle sales to be 50% of the replacement technology. Then wait 20 years and your fleet is pretty much replaced. It also takes time to build the solar and wind farms to power the plug-in vehicles, but spread out over 30-40 years, it is quite doable.
If you’re looking for data on insolation, consider the NREL maps:
http://www.nrel.gov/csp/maps.html
7.5 kWh / day / m^2 is reasonable (2700 kWh / year / m^2), and there are sites that are over 8.0 / day. For example, see
http://www.nrel.gov/csp/images/3pct_csp_sw.jpg
If you want to compare December and June insolation, consider these two maps:
http://www.nrel.gov/gis/images/us_csp_december_may2004.jpg
http://www.nrel.gov/gis/images/us_csp_june_may2004.jpg
Maury said, “Robert mentioned it in his post clee. We need power 24/7.“
Ausra has a solution for this. They claim they can provide 92% of the electrical demand for the U.S. 24×365 using CSP+TES:
http://www.ausra.com/pdfs/T_1_1_David_Mills_2049.pdf
http://www.ausra.com/pdfs/ausra_usgridsupply.pdf
This is actually better than baseload because it can follow load, instead of generating a fixed amount constantly. It is most efficient during the day when the load is highest.
dennis moore said, “You have a Rav EV, they were over $40,000 new for a vehicle with limited range and that takes hours to recharge. When the battery starts to fail, you are in for $26,000 to make your used car functional again. You provided a link for owners who have over 100,000 mile on their batteries. That is fine, but how many will make 100,000 on their $26,000 batteries, maybe those four are on the high side of the curve. I need to see the whole distribution, not just the ouliers on the high side. What will the average life of the battery be for all vehicles?“
Yes, it was $42,000 new ($29,000 after credits), but no I don’t think I am in for a $26,000 charge (and where did you get such a number?). For a vehicle that was produced in quantities of only hundreds per year and sold in a single state, $42,000 is remarkably low. Imagine what would happened if they had produced vehicles sufficient to meet the demand, instead of vehicles sufficient to earn the CARB credits required? What if they had sold it in 50 states? The learning curve on the EV-95 battery production would have lowered the pack cost over time as well. (It also doesn’t help that Chevron has ownership in the company with a critical NiMH U.S. battery patent and that company sued Toyota/Panasonic to block use of the EV-95 battery in the U.S.)
You suggest the car will need a new pack before the end of its life, but the data that exists suggests this will not be the case. Southern California Edison has had a fleet of 1998 and 1998 MY RAV4-EVs. Ed Kjaer from SCE wrote in response to an inquiry: “the majority of our EV fleet has consisted of ’98 and ’99 MY RAV4 vehicles. Of the almost 14,000 NiMH battery modules powering these EVs only a little less than 0.5% had to be replaced! A powerful testament to Toyota and Panasonic design, quality, durability and reliability. And what is even more impressive is the fact that these vehicles were from the 1990’s.”
I am not “ignor[ing] the clear technical obstacles of the battery” as you suggest at the end. I do think cost is an issue. I have written before suggesting that we need a business model that allows the lower lifetime total cost of EVs to offset the higher upfront cost. Using a 12-year transferable lease model would accomplish that for example. The lease payments plus the electricity cost would be less than the cost of gasoline, the owner would achieve a lower monthly cost out of the lot. 12-year leases are not the norm, however, which is why I talk about a change of business model being helpful.
Please know also that I don’t think BEVs are going to replace ICEs any time soon. I use BEV data because that is what is out there. I believe that PHEVs will solve the chicken/egg problem for battery costs. PHEVs with 20 mile range are not expensive, but they will begin to drive down battery pack costs so that 40 mile range will become more normal. That will in turn enable 60 mile range. Eventually the range extender ICE will become optional (just as an automatic transmission is today). A little further down the line, fast charge capability will make the ICE unnecessary in almost any application.
kingofkaty said, “A couple of points, I think the BTU content you used is a bit low. My figures are 121,000 BTU/gal for oxygenate blend and 126,000 for conventional (5.3 MM btu/bbl for old LP modelers). “
The LHV of gasoline is around 115,000 BTU/gal. The HHV is around 125,000 BUT/gal. You need to understand the difference between the lower and higher heating value. Robert is using the LHV, which is fairly typical in this sort of calculation.
“7.5 kWh / day / m^2 is reasonable”
No it isn’t. You won’t realize that level of insolation on a fixed flat plate collector, anywhere, except during peak days near summer solstice, with the panels tilted at optimum angle. And if the panels are tilted at optimum angle for summer conditions, they will be far from optimum in winter. The vast majority of solar installations do not use trackers for the obvious reliability problems, and most panels are not seasonally tilted unless they’re small arrays, on pole tops.
There are a lot of sites and programs that can calculate best tilt angles for year round performance, but best year round numbers in the US are in the range of 5.5-6.0 sun hours/per day, maybe 6.5 in a few places. A lot of locales only get 2-3. That’s before losses.
Did I mention losses? A 1KW rated array only produces rated power at 25C. At normal temperatures in full sun (~50C), figure on a temperature derating of 10-15% at full insolation. Then you’ve got wiring losses, contamination dust losses, inverter losses, good for another 10%. Battery charge/discharge, normally accounts for at least another 10% or more with lead acid. I see hopeful efficiencies promised for the EV battery technologies, I don’t know if they’re real or not.
I design and install solar systems for a living, and as such I’m a strong advocate of solar. But I spend so much of my time backing people down from hopelessly inflated expectations that just can’t be realized, and it gets tiresome. Everyone is praying for solar to really save us from the mess we’re in, but progress is slow. My bet is that these technologies will take a decade or two longer that the strongest advocates hope, to really make a difference.
iftheshoefits said, “No it isn’t. You won’t realize that level of insolation on a fixed flat plate collector,…“
I wasn’t talking about a fixed flat plate; I was talking about 2-axis tracking CSP (e.g. the Stirling dish). That is the proper way to generate a TWh/year for replacing gasoline. NREL estimates the cost is 5-7 cents per kWh.
iftheshoefits said, “Did I mention losses? A 1KW rated array only produces rated power at 25C.
We’re talking about 100-1000 MW here for a single farm. This is 5-6 orders of magnitude larger scale than you are talking about.
iftheshoefits said, “I design and install solar systems for a living,…“
I doubt you install Power Tower, Parabolic Trough, Stirling dish, etc. systems for a living. I realize that Robert used PV in his calculation, but I believe that was just to get an idea of the scale required, because PV is not the way to go to replace gasoline at the national level. Only a few companies (e.g. Nanosolar) are going for utility scale unconcentrated PV. (Besides CSP, there is also CPV, which might make some sense).
Look at what BrightSource, Ausra, Stirling Energy, eSolar, SkyFuel, Abengoa, Sungri, CoolEarthSolar, and Nanosolar are doing for utility scale solutions.
Robert Rapier said, “I already pointed this out, and Dennis reiterated above: The technical obstacle is in moving something mainstream over a decent range. That is a technical obstacle. To suggest that something more resembling a golf cart has a huge range isn’t particularly relevant; people want to drive a normal sized car (which is why the Prius example was used). So, the batteries need to get better before mass acceptance. And I consider that a technical obstacle. I think most people do.“
When did I suggest a golf cart? Most of the vehicles I referred to are larger and more functional than a Prius. Is the Toyota RAV4-EV a “golf cart”? If you intend to define it away because it is not mainstream (despite the mainstream form factor), you are splitting hairs because the point is whether the batteries can do the job, and the RAV4-EV proves they can. Are U.C. Davis’ Sequoia and Yosemite plug-ins hybrids golf carts? Are the AFS Trinity, BYD, and Volvo plug-in hybrid prototypes golf carts?
Again, where is the technical obstacle? The ability of old technology to do the job has been shown so many times. What more do you need? Is the only thing you’ll accept something currently on the floor of a showroom of a major automaker? That’s not about battery suitability; that’s about the marketing departments.
Big fan of your blog. Thanks for writing. First time posting, but why would we need to build so many solar farms when the current grid can handle 84% of the current car fleet going to plug in electric? I’m pro-alternatives and conservation, but this report makes me feel a transition is possible.
http://newswire.ascribe.org/cgi-bin/behold.pl?ascribeid=20061211.105149&time=11%2005%20PST&year=2006&public=0
You’re right, I’m looking strictly at solar PV. I wonder how many of these huge arrays out in the middle of the desert will ever get built, mainly due to environmental impacts.
There’s this mentality we have of “stick it out in the desert”, that applies to coal plants, nuke waste storage, and now solar arrays. I live out in the remote desert, so I’m kind of sensitive to impacts of city consumption being pushed out here, whatever they are. PHEV’s in CA on a large scale mean dirtier skies in the morning to me. Dozens of square miles of solar arrays have got to have some unwanted environmental impacts, I’m not sure we know completely what they are at present.
There’s also transmission losses to bring the power where it can be used. Sure, those losses for large solar arrays are much the same as for other more traditional sources. With coal and nuke though, long transmission distances are the tradeoff that the has to be made to keep the environmental and aesthetic impact away from the populous areas. On the other hand solar can be just as easily scaled down and collected at point of use.
I prefer that approach, using the already existing hundreds of square miles of available commercial roof space. The major environmental impact has already occurred (perhaps some additional heat island effect) and much less transmission loss. But who knows, the resource impacts will have to balance against the relative efficiencies in each case.
iftheshoefits said, “You’re right, I’m looking strictly at solar PV. I wonder how many of these huge arrays out in the middle of the desert will ever get built, mainly due to environmental impacts.“
Here are the contracts signed that I know of:
500-850MW SCE with Stirling Energy Systems
300-900MW SDG&E with Stirling Energy Systems
177MW PG&E with Ausra
533MW PG&E with Solel
500MW PG&E with BrightSource
280MW APS with Abengoa
I don’t know if SkyFuel, eSolar, and others have signed utility contracts yet or not.
iftheshoefits said, “I live out in the remote desert, so I’m kind of sensitive to impacts of city consumption being pushed out here, whatever they are. PHEV’s in CA on a large scale mean dirtier skies in the morning to me.“
Dirty skys from solar? Also, we’re talking about sub 1% of the desert in most cases, and that is only if 100% of vehicle fuel came from solar. More likely the bulk of vehicle travel will come from wind.
iftheshoefits said, “I prefer that approach, using the already existing hundreds of square miles of available commercial roof space.“
This is OK, but the cost is about 8x that of mirrors in the desert. Of course you’re comparing the cost to th retail price of electricity instead of the wholesale price, but the markup is not that large. Even if the cost of the PV gets slashed dramatically, the cost of a custom install (every roof is different after all), will keep the system cost high.
eak quoted Ed Kjaer of SCE as writing,
“the majority of our EV fleet has consisted of ’98 and ’99 MY RAV4 vehicles. Of the almost 14,000 NiMH battery modules powering these EVs only a little less than 0.5% had to be replaced!“
Sounds impressive. Would you happen to know what was the maximum number of years any of those RAV4-EVs ran at SCE? 4? 9? Nine really would be nice. I haven’t been able to find evidence of more than 4 yet though.
First time posting, but why would we need to build so many solar farms when the current grid can handle 84% of the current car fleet going to plug in electric?
I don’t really think it’s going to play out quite like that, I was just trying to get a feel for how big of an undertaking this would be. If thin film solar is truly cost-competitive, then I suspect we will start putting those panels on lots of existing surfaces, and the plants that are built will be solar thermal.
Cheers, Robert
If what you bring to market is a vehicle that seems odd (aspect, range, durability of key parts, ease of recharge) to most people, then what you need to beat in terms of range and cost is a similarly odd vehicle with a normal IC engine. I’m thinking along the lines of Loremo here.
I’ve driven a smart fortwo for years, I like the idea of super efficient cars, but today the most believeable contender is the Loremo. No big ifs about its technology. “Just add lightness” and away you go. ~500 miles range with 2 minutes recharge. Even after 4 years. Even after 20 years.
26,000 for a rav 4 battery
DM
Here are the contracts signed that I know of:
500-850MW SCE with Stirling Energy Systems
300-900MW SDG&E with Stirling Energy Systems
Etc.
These are not construction contracts. The utilities contract to buy kWhs at a certain price. Stirling and others must still raise money and build the systems. It remains to be seen if they can convince investors their systems will make money at the contracted price. Stirling in particular has shown little progress in this area. Others, such as Brightsource (f/k/a Luz) and Solel have histories and Ausra seems well-backed (BTW they also have a deal with FPL). Still, it’s a little early to count any of these chickens.
Stirling in particular has shown little progress in this area.
Deciding to factcheck this after posting it, I went to their website and was surprised to see they got $100m from NTR a few weeks ago. Great news.
As Frank said I think V2G (vehicle to grid) has synergy with renewable like solar and grid because the fleet of EV provides distributed storage of energy.
When you think about it, car vendors will put 100+ miles of battery autonomy whereas average commuters will use 16 miles for one or two hours a day of driving, leaving 84 miles of capacity free. The rest of the time (22 hours per day) the vehicle can be plugged into the grid and will then help regulate intermitent sources of electricity like wind and solar.
Win win situation.
This has been linked to before, but is interesting to repeat. The Ausra guys found that a solar collector area of 211 km on a side is enough for 90+ percent of US grid plus auto fleet. They used different assumptions but the general conclusion is similar: this is very doable.
I also came to the conclusion that 10,000 sq mi of solar power towers would produce about 3 x USA electrical demand…
Check this out,
http://www.earth-policy.org/Alerts/Alert12_data2.htm says… This is about 50,000 sq miles consumed just for all roads in US. If that much land was devoted to FLAT MIRRORS and steam generators (along with some tracking chips, posts and other hardware of the late ’80s,) I will bet that ALL of our energy needs would be met. Now, noth’n cost less than flat mirrors and steam generators, so on with some math…
Consider that 50,000 sq mi will be only 10,000 square miles
actual collection after space for shadow, cleaning, habitat, beautiful rock formations, ect are accounted for. Further assume a 25% capacity factor = 2,500 sq mi, and 25% efficiency = 625 sq mi of pure 80 watts per sq ft electricity (constant production equivalent). = 5280 x 5280 x 625 * .08 (kWh per foot) * 8760 (hrs in year) = just over 12 Trillion kWh’s! (Way more than the 4,000 billion we use now).
As for costs, at $2.50 per installed watt, (which would be 12,000 trillion / 8760) is 1.369 trillion x 2.5 = about 3.4 trillion. Now, since we “must allow conventionals” to play out, we should just pay as we go, thus no finaince charges (only inflation). If just every household (105,000,000) was to pay over 30 years, then that cost would be… just $3 per day (32,400 per household) which is way less than what we paid even yesterday for fuel costs!
I know, we have to give it all up because some one out there will say ‘But we can’t afford the extra powerlines, and what about batteries, storage, ect.’
My reply is figure on a pack of cigs a day because energy generation always costs more than its storage… Funny how CIGS also stands for a promising new breakthrough solar printing technology that might become cheaper than all those moving mirrors (but not as efficient).
Also, (way) less co2, and positive albedo, (to make up for melting glaciers)!
As for charging, all places of work would have to be fitted with charging stations thus eliminating the need to store soooo much juice into the night.
Your calculation for Solar Thermal power is way off considering that ther eis new technology available to create a small footprint 1000 MW Solar Thermal Power plant – about the same size as a nuclear reactor. At 12.5 Watts/square foot is not really viable in comparison to Solar thermal – which is why Solar Thermal is being commercialized at a rapid pace in comparison.
new technology available to create a small footprint 1000 MW Solar Thermal Power plant
I am a big fan of technology, but unless a plant has actually been built such that we can measure the footprint and the output, then it isn’t relevant. Once those numbers are out there, I will update.
We have technology to do lots of cool things, but there are often problems as the technology scales up. That’s why I don’t spend much time doing calculations on what “might be”, as only a fraction of the “might bes” will end up panning out.
RR
Check out the PV version of Conserval's Solarwall. Combine this with seasonal heat storage – search on (annualized geo solar) and you use much more of the solar falling on a roof. This is good for single & two story buildings. I'm modifying my house for the AGS system gradually, and plan to add solarwall, then PV down the line, if God is willing. Note that everything doesn't need to be done at once.
The basic point is that solar powered transportation is doable. It will require changes. Since we've moved from railroads to jets as high speed transportation in a century, why not expect changes? But it is good to calculate beforehand. Erasing pencil is much less expensive than steel and silicon.
The Chinese Auto manufacturer BYD, in which Warren Buffet has invested, presently offers the pure electric e6 with a 300km range and 50% recharge in 10 minutes. As well as a plug-in hybrid (f3dm) with a 100km electric range.
Electric cars are available now, the question is who is going to make the money.