Arizona Solar Power Project, Calculations

The following guest post was written by Tom Standing, a “semi-retired, part-time civil engineer for the City of San Francisco.” In Part 1, Tom takes on the calculations for a 280 MW solar thermal plant in Arizona that I looked at back in February. My conclusion from that essay was that the electrical demands of the U.S. could in theory be met on 10,000 square miles of land. Tom peels the onion a few more layers and puts the energy production into perspective.

While solar calculations are by no means second nature to me, I see no obvious errors in Tom’s calculations. But I consider peer review to be a very useful component of my blog, and I know that Tom would appreciate any constructive criticisms. Part II will delve into France’s solar ambitions.


Hello Robert,

You and I met at the Sacramento Peak Oil conference. Your presentations and discussions were most enlightening. I was heartened by your analysis of cellulosic ethanol. I have always been deeply skeptical of the notion that the U.S. might displace a meaningful portion of transportation fuel with biofuels from cellulose. I could give you some of my thoughts on this subject, but you have already covered the territory thoroughly.

I want to comment on your calculations you posted in TOD in February, regarding the proposed 280 MW solar thermal plant in Arizona. First, a bit about my background. I started my career as a chemical engineer, first in refinery operations, and then chemical processing design. But that was only about 4 years. Most of my career has been as a registered civil engineer in a variety of disciplines for the City and County of San Francisco. Over the years, I have become interested, maybe even fascinated about the prospect of utility-scale generation of electricity from qualified renewable sources.

Throughout North America and Europe, many people have focused on renewable energy as a means of reducing dependence on Middle East oil and reducing CO2 emissions. They see renewable energy as an important element to achieve emissions targets of the Kyoto Protocol. In the U.S., renewable energy from wind, solar, and biofuels appears to be a keystone for energy policy in the Obama Administration. In Texas, T. Boone Pickens is campaigning for a new American energy policy centered on major input from wind-generated energy to displace electricity generated from gas-fired power plants. Natural gas would then be redirected as CNG to power autos and trucks. In California, Governor Schwarzenegger sees his “Million Solar Roofs” program as leading other states to do likewise, thereby reducing CO2 emissions. California utilities are mandated to supply 20% of electricity from qualified renewable sources (wind, solar, bio/waste, geothermal, and small hydro) by 2015. Contributions from these sources have been stuck in the range of 10-11% since 2000. The 20% mandate appears to be a major challenge, maybe unrealistic.

Many questions come to mind in looking at the proposed Arizona plant. What precisely does the 280 MW refer to? Is it the plant’s output at capacity? Is it an annual average output? How much electricity will it generate annually? How will output vary during the day, or by season? How will output be affected by clouds?

There is important data available and a few fundamental design features that will answer these questions. Costs for construction, however, are not my strong suit. Other analysts will have much better information on costs. Cost of the plant will not change the results of my analysis.

1. Insolation Data

Reliable data for site-specific solar radiation (insolation) is critical to estimating solar capabilities. Fortunately, a massive database for insolation is posted on the National Renewable Energy Laboratory (NREL) website. In 2000, an engineer who designed solar facilities directed me to the site; I was utterly amazed at what was there. I had to be extremely selective to get the most useful data. I settled on 30-year (1961-1990) average insolation for 239 U.S. cities: monthly and annual average insolation in kWh per square meter per day. Readings for all 239 stations are given for all possible orientations of solar collectors, either fixed or tracking systems. Amazingly, insolation data is also tabulated for averages of each hour during the 30 years for all 239 stations (kW/m2), enough data to make your head spin! Data is also tabulated for insolation of all collector orientations at 239 locations above Earth’s atmosphere! For reference, I eventually copied pages that filled a binder weighing 10 lbs.

2. Site Coverage with Solar Collectors

A rough approximation for coverage of the 1,900-acre site with solar collectors is 50%. Space is needed for maintenance and control centers, electrical converter units, towers for power lines, and maybe a backup power facility fired by gas or oil. Proposed facilities to store electricity for release at night will also consume land.

In 2001, I toured a solar thermal plant at Kramer Junction in California’s Mojave Desert.

At one square mile, it is about 1/3 the size of the Arizona plant. I would say that close to half of the site is taken up by gravel roads for maintenance vehicles. At least weekly, wash trucks at night clean the collectors of dust that frequently blows around. The roads also provide necessary space between rows of collectors to prevent shading. Collectors tilted upward to gather more sunlight cast shadows at low sun angles. If the designers in Arizona are really stingy with land use, they may be able to cover 50% of the site with collectors, including facilities for power storage.

As with Kramer Junction, the entire site will be dedicated to industrial use, fenced off and completely secure. Areas covered by collectors are denuded of vegetation, graded, and compacted. There is hardly space for a rodent or a bird to live. Collectors are supported by steel columns embedded in reinforced concrete foundations designed to resist maximum wind forces upon the considerable surfaces of the collectors. These are real-world features that solar advocates overlook when they envision hundreds of square miles devoted to solar power.

3. Calculate Collector Area

We calculate the area of solar collectors in square meters to utilize NREL insolation data.

The 1,900 acres converts to 7.7 million sq m. With 50% for collectors, 3.8 million sq m are on the site.

4. Model the Collection Array

The Arizona plant is to be a concentrating system that tracks the sun. Surprisingly, NREL data shows that concentrating systems collect less sunlight per sq m than systems consisting of flat plates, one-axis tracking, tilted at an angle = to latitude of site. Thus to be generous, I will calculate the output based on flat plates, 1-axis tracking, tilt = latitude.

For Phoenix, NREL data gives average annual insolation for our model as 8.6 kWh per sq m per day (i.e. all days averaged for 30 years). For Tucson, insolation under our model is 8.7, with slight differences for each month.

5. Calculate Insolation Striking the Collectors

Here we convert solar energy striking collectors during one day, to the average rate during the day. Thus, for Phoenix (the nearest station with NREL data to the plant):

The average annual rate of solar power striking collectors

= [8.6 kWh/ (m2-day)] [one day/24 h]

= 358 watts/m2, say 360 watts/m2

Scaling up this power for the entire plant, average daily solar power striking all collectors

= (360 W/m2) (3.8 million m2)

= 1,370 megawatts

6. Assume 15% Conversion of Insolation to Useful Electricity

The solar thermal plant at Kramer Junction converts about 15% of insolation striking the collectors into electricity. Therefore, a decent assumption for the Arizona plant that would be consistent with our other assumptions is 15% conversion.

Average electrical power generated by the plant over the entire year

= (0.15) (1,370 MW)

= 205 MW

This power output is, of course, highly variable, depending on time of day, season, and cloud cover. To get an idea for seasonal changes, the NREL data tells us that plant output would average 257 MW for an average day in June, to 138 MW for an average day in December.

7. Maximum Electrical Power Output

What might be the maximum electrical power output of the plant? It would correspond to maximum insolation, which is roughly 1,000 watts/m2. Fifteen percent conversion gives a plant output of 150 W/m2, times 3.8 million m2, so maximum electricity generation = 570 MW.

According to NREL data for the desert, maximum insolation duration is about two hours a day under cloudless skies from late spring through early summer. The duration of maximum shortens with increasing time away from June 21. In early spring and late summer, maximum insolation slips below 1,000 W/m2.

Clouds have a widely variable effect, from a 10 or 15% reduction from thin cirrus clouds, to a 50-70% reduction from dense cumulus clouds (thunderheads). At Kramer Junction, operators adjust flows of the heat transfer fluid whenever a cloud drifts over the array. I seem to remember that operators engage small electric pumps to keep the fluid flowing in portions of the array that experience cooling. The Arizona array, with three times more area, will experience more frequent effects of cloud shadows.

8. Annual Energy Generated

One final simple calculation gives us the average annual electrical energy that the Arizona plant will generate. It is the product of four factors:

Insolation, average day (NREL data) = 8.6 kWh/ (m2-day)

15% conversion of insolation to electricity

Area of solar collectors = 3.8 million m2

365 days/year

Thus the 1,900-acre Arizona plant will generate roughly 1.8 billion kWh per year.

Let’s give this quantity some perspective. EIA statistics for renewable energy in 2007 show that wind-generated energy in Texas was 8.1 billion kWh. Thus it would take four and one-half plants the size of the Arizona plant to match Texas wind energy for 2007.

A more telling comparison is with the recent growth of electrical consumption in the U.S. EIA statistics show that the U.S. consumed 2,885 billion kWh of electricity in 1992; in 2002 consumption was 3,660 kWh. Average growth, then, was 77 billion kWh per year over the 10 years. Thus the electrical energy that would be generated by the Arizona plant would supply only 2.3% (1.8/77) of one year’s growth of U.S. electrical consumption. I do not have electrical consumption broken down by state, but I would guess that Arizona could build a solar plant of equal size every year, and they would barely cover their own growth in electrical consumption.

PV Potential

I have not touched on PV, but there is much to discuss. NREL data is so extensive that there is almost no limit to analyses that could be done. For now, I should only refer you to an article that I published in the Oil and Gas Journal, June 25, 2001 issue. I graphically displayed annual insolation curves for a wide range of locations. At a glance the reader can see how insolation varies with latitude, longitude, and collector orientations. I also ran through sample calculations to see how much energy can be generated. An important finding is that insolation for most of the eastern half of the U.S. stays within a narrow range: 4.6 to 5.2 kWh/ (m2-day), with fixed collectors facing south, tilted at latitude for maximal exposure.

The above calculations are purely rational, using insolation data and general assumptions in design. Actual practice shows that solar installations typically generate 10 to 15% less energy than what the calculations show.

17 thoughts on “Arizona Solar Power Project, Calculations”

  1. Deep thanks to Mr. Standing for writing this — and to you, Mr. Rapier, for posting it on your blog.

    Perhaps the most shocking point to the usual suspects will be Mr. Standing’s description of the sterile nature of the entire area of a solar power plant. Reality rarely matches environmentally-benign solar dreams.

    But the substantive point on energy supply has been clear for a long time, as Prof. Smil’s work on energy intensity has made clear. The point — to keep 6.5 Billion human beings supplied with the energy necessary for a comfortable life without fossil fuels, and using today’s technology, nuclear fission will have to be a major part of the solution.

    Now can we please get on with it!

  2. On that “discovery” re. scraped and denuded solar plants, beware false generalization. What was done may not be exactly the same as what was necessary.

    It’s of course parallel to someone pointing to bad oil or nuclear projects and claiming that they really are or would continue to be typical.

    (Compare 1940’s vintage oil or nuke practices to those today.)

    – odograph

  3. Solar thermal so far consists of inefficient combines cycle gas fired power plants surrounded by solar collectors. Before calculating how many square miles it would take supply the US with electricity, get the first one working in a reliable manner. Solar may be renewable energy but the equipment to collect the energy is not sustainable.

    Yes, you can not collect solar energy, turn water into steam, and run it through a turbine to drive a generator to make electricity. But why would you do it?

    “These are real-world features that solar advocates overlook when they envision hundreds of square miles devoted to solar power.”

    There are many like odograph who do not make electricity that think it is a good idea. While California is mandating solar, the same folks who design and run nuke and coal plants will continue to demonstrate the art of operating steam plants safely with insignificant environmental impact.

  4. So let’s review our options. In order to continue to supply our civilization with energy at our current rate, we can:

    – utterly devastate hundreds of thousands of acres of land to get at coal (on target for 1.4 million acres by 2010; compare to the acreage used for solar…)

    – create nuclear proliferation problems and leave a toxic legacy for the next thousand generations

    – kill birds with wind

    – scar rivers with hydro

    – denude land for solar thermal

    – spend ourselves into the poorhouse building massive amounts of PV

    Or, shockingly, we could actually try to USE LESS ENERGY. Our current level of energy consumption (at least of electricity) is the result of really crappy building industry design practice, starting with architects who believe that aesthetics trump physics.

    This analysis tells me two things:
    1) Industrial-scale energy from renewables is possible.

    2) Energy production on the scale to which we are accustomed is probably not possible using renewables or other capital-and-energy intensive generation technologies (looking at you, nuclear). If we try, the environmental impact will be massive, the cost will be enormous, and the maintenance overhead will be crippling. And we can’t possibly build facilities fast enough to keep up with historical growth rates, and supplant legacy fossil sources, at the same time.

    We can provide enough energy to run a high-tech civilization that has learned to be frugal with energy, rather than treating it like it is free. We cannot provide enough energy to continue to run the society with have, without relying almost exclusively on the incredible energy density of the distilled sunlight that is fossil fuel. And regardless of environmental considerations, we can’t match historical growth rates with finite supplies of fossil fuels.

    Sounds to me like we have one option. Well, OK, we have two: we could continue to squander what resources we have left in a vain attempt to find the “magic” energy source (ethanol, nuclear, whatever) that will let us continue as we have in the past.

    What I really mean is, if we want our grandchildren to have a high-tech civilization, then we have only one option.

  5. Heh, I’ve been in gas and coal plants in 4 or 5 states, in a past life working for an emissions monitoring firm.

    Plants differ. The difference between a 1930’s vintage coal plant re-worked for oil, and a 1990’s vintage coal plant, are quite wide.

    – odograph

  6. Deep geothermal will have a much smaller footprint. And it’ll produce power 24/7. France has a working plant. Others will come online soon in Australia. I don’t see solar or wind…or coal or natural gas for that matter, competing with geothermal 20 years down the road. It’s not much more complicated than drilling a deep oil well.

  7. On several occasions I left comments noting that DUST would be problem. No one seemed interested, but there I read that in fact “At least weekly, wash trucks at night clean the collectors of dust that frequently blows around.” I wonder if the energy inputs for this and other maintenance are deducted from the energy produced when calculating the EROEI.

    Don’t get me wrong — I’m not opposed to renewables and I think projects should proceed while the window of opportunity is still open. But I am saying that we shouldn’t get our hearts set on living high as we have on oil.

    In the vein, Green Engineer makes an excellent point. Why not power down at the same time?

  8. How does the concentration of the collectors affect the efficiency and usable output? If we somehow assembled, say, 1900 acres scattered on the rooftops of Phoenix (making some reasonable assumption on distribution), how would that system compare with the one you describe? How realistic is this common idea?

    Also, curious as to the water requirements for a large installation, especially in a hot dry area with lots of dust. Is it significant?

  9. After reading Mr Standings article, it makes me wonder if maybe we should concentrate more on residential/commercial rooftop solar. A lot of these large solar projects all seem to be situated far away from the areas of power consumption requiring a build out of infrastructure to get the power to where it is used. With rooftop solar, the use is local so you don’t need to build new transmission lines and relay stations. Now granted rooftop solar will cost more per watt installed because the projects are much smaller but has anyone looked at all the other costs associated with these municipal solar projects and done a comparison?

  10. I’m on board with reduced consumption. I don’t think Green Engineer is wrong that efficiency and conservation are the easiest and most reasonable paths.

    But, I don’t see a lot of other people climbing on board. The high consumption lifestyle may have taken a hit recently, but reports of a “new frugality” are probably over reported.

    Which means we should probably find out what works. We have enough pilot plants of all types that we can survey them best of breed and the success of those in particular.

    I think geothermal is long proven, wind wins, solar thermal has a chance, and … rooftop PV has high costs and spotty results. But by all means don’t believe me. Find a survey or study of successes in the real world and believe those.

    – odograph

  11. BTW, do you think area-measures like acres are the best way to measure footprint in all environments? Why not tons of biomass or something like that?

    Surely an acre of mojave is a smaller loss than an acre of rainforest.

    – odograph

  12. Robert, thanks …

    I've posted this before, but I believe it deserves review: the one piece of dogma that MUST be retired is the notion that power-generating technologies need to be 24/7. They do not. We humans have a diurnal consumption cycle that happens to correlate to the daily insolation curve. Solar/thermal's "advantage" is always held out as "being able to store heat". The problems are many: Carnot cycle (maximum-thermodynamic efficiency) heat engines' efficiencies diminish as the 'hot' and 'cold' reservoirs become closer in temperature. It simply is not a requirement. Collect the photons, convert them to electricity, feed the grid, and use it up on the other end.

    Try this thought-experiment: you live on a medium sized island where there are only two power souces – a great dam, working beautifully but only supplying a quarter the power your civilisation needs, .. and a large photovoltaic array, which only can supply energy in the daytime. What would such a civilisation do to optimize power use?

    The obvious is that they would adjust their power use to COINCIDE with the power availability. If most of power is available during the day, then the would manufacture during the day, would charge up their elecric vehicles during the day, would find ways to utilize and/or temporarily store the CHEAP energy during the day.

    Similarly, 'use' can be economically encouraged to follow 'production', as is now commonplace through the industrialized world.

    NEXT UP – "rooftop" versus "municipal" power generation. It may be a personal pride thing to envision each person having a prosaic windmill pitched on top of their yurt, but municipal power generation makes much more sense – fewer, larger, and intrinsicially more efficient generators (efficiency almost always scales with dimension), semi-centralized maintenance, and best, WAY fewer parts to 'break'.

    I applaud those people here in my town who have erected whole-roof deep blue PV arrays. They've got stuff to TALK ABOUT at social occasions! That they feed power back into the grid. That their power bill is "zero". And so on. But in truth, theirs is an investmeent that will soon need maintenance, and more so as the years take their toll on the array. Oh well … in Iceland's capital no one shovels snow from their driveways or city streets. It melts because municipal enterprise pipes the huge oversupply of hydrothermal water in pipes … under each driveway, sidewalk, road and highway. Pretty amazing. Shows the power of "municipal thinking" over the iconoclast's I'm My Own Kingdom point of view.

    Lastly, there is NO COMPETITION between state-of-the-art PV and state-of-the-art Solar Thermal. The "value equation" of all technologies (not just ST & PV) absolutely must include cost-of-ownership, reliability-and-maintenance, and expected-lifetime (or "distributed cost of overhaul") figures. PV is simply a head and a should above all comers: almost no moving parts, 40+ year durability, increasingly compelling efficiency, and a "kilowatt" aquisition cost that is becoming very attractive.

    FINALLY, as to the above posters decrying the 'denuded' land, I must say – I have to laugh. Ever actually LIVED in a desert, oh bleeding hearts? I have. Tens of thousands of square miles of exactly the same stuff, all around. Deserts are not full of tiny microcosms sporting threatened species that merely walking over will drive to extinction. They are incredibly robust ecologies of hardy plants and animals that have a LOT MORE to deal with than a few shadows from a huge PV or ST array. Hundred-mile-per-hour winds. 150F (65C) surface heat. Zero humidity. No precipitation. Below-zero nights. Venomous predators. Poisonous plants.

    No, folks. We can cry our crocodile tears over the felled forests of the Pacific Northwest, and rivers of tears over the vanishing prairie, or over the logged rainforests, and the denuded beach dunes … but let's not shed too many tears over the 0.05% of the nation's deserts that could be employed to good use … better use in fact than many of those boreal forests, sand dunes and prairies.

    A national mandate to create 25 plants to manufacture multilayer single crystal, hetereojunction PV "exceeding 20% national average" would be the ticket. Coupled with a similar number of plants to manufacture the supporting "stuff" – sheet metal fabrication, electronic controls and inverters, insulators, specialized polymers, and so on. Create 5,000,000 new 1-square-meter panels a WEEK. A gigawatt (peak) a week, added to the power grid.

    Within 10 years, we will be generating 25% of our electricity from these PV arrays. Within 25 years, nearly all of it.

    And yes … it does take an equally forceful mandate to develop, install and use higher-efficiency ways of utilizing the power. But this is what this country and its partners can show the world: we do NOT have to depend on fossil fuels to keep a vibrant civilisation 'topped up' with cheap, useful, vital power.

  13. PS: I should have included the calculation for vehicular power demand: for light vehicles, about 1 megajoule per mile at highway speeds. Twice that for heavier vehicles (SUV, truck, large sedans). About 5 MJ/mi for bobtail trucks (inner-city delivery box trucks) and about 10 MJ/mi for interstate 18-wheelers.

    Assuming 250 miles/week for personal vehicles at mean(1,2)=1.5 MJ/mi is about 375 MJ/car/week. There are 200,000,000 cars say … (0.7/person) rounded, this would be 75,000,000,000 MJ/week (assuming 100% cars convert to PVE). If 50% of the fleet is by 2030 converted, then about 40,000,000,000 megajoules need to be generated.

    40,000,000,000 / 7 = 5,500,000,000 MJ/day. If a one square meter heterojunction panel can squeeze out 1.6 kWh = 5 MJ a day, then we’re talking 1 billion panels, to cover it the demand. That may sound large, but it is only a ‘square’ about 45 kilometers on a side (at 50% areal density) – spread out over tens of thousands of sites around the country.

    That is pretty compelling.

    THINK OF THE EMPLOYMENT TOO – as a country (and hemisphere!) we’re heading toward an era of chronically high unemployment. Construction projects such as this are an excellent way to not only keep many more people working, but to deliver GOOD to the country from their (our) enterprise.

    Get ‘er Done.

  14. Or, shockingly, we could actually try to USE LESS ENERGY.

    Let me try to be polite. If you, Mr. Green Engineer, wish to use less energy, then please consider emigrating to Bangladesh. The people there use much less energy than profligate Europeans or so-called "environmentalists" — very much less.

    Of course, there are consequences for the Bangladeshis from not using energy. Lack of internet access is probably the least of them — inadequate diet, poor shelter, polluted water supplies, no health care. There is a very long list of amenities that wealthy westerners take for granted which rely on an adequate supply of energy.

    Long before self-satisfied elitists started jetting off to distant resorts to attend conferences recommending cutting energy use, ordinary human beings were using their resources as best they could. Governments waste money & resources, but most individuals tend not to. You, Mr. Green Engineer, may not like their choices, but that is of no importance.

    There are more human beings in this world living today in energy poverty than living in high-consuming western countries. We have an energy supply side challenge.

    The heart-breaking fact is that we have the technology today to meet all the reasonable energy needs of the entire human race for millenia — but we are sitting on our hands, wasting our resources chasing sunbeams.

  15. Thank you, Kinuachdrach, for that display of ideologically-motivated ignorance.

    Energy consumption can be reduced by individual frugality, or it can be reduced by building infrastructure that is not inherently and egregiously wasteful.

    I believe there is a place for individual frugality, but beyond reducing air travel, industrial beef consumption, and regular commuting, there’s not much that an individual can do that is meaningful.

    The much more important part is to eliminate the wholesale waste of energy at the industrial and commercial levels. There are many opportunities.

    Agriculture: Vast energy goes into fertilizers, which are heavily applied and most of which wind up washing into waterways rather than growing food. This approach is not necessary, if the goal is simply to grow sufficient food. Non-industrial farming techniques can produce a higher yield per acre. They just don’t mechanize as well, so they don’t represent an appealing model to agribusiness. But make no mistake: we grow our food in an energy-intensive, pollution-intensive fashion only because it is economically convenient to the powers that be, not because it’s “the only way to feed the world”.

    Transportation: We’re still wedded to the inherently inefficient internal combustion engine. ‘Nuff said.

    Buildings: This is the area I know best, having worked on both design and on commissioning (post-construction QA process). It is absolutely technically possible to design buildings that use no, or very little, energy for space conditioning (which is the largest user in most places). There are a variety of reasons that this is not done; some of them are economic, a few are technical, but most of them are actually problems with the expectations embedded in the culture of the building industry.

    One other point: In many cases, the strategies that use less energy also produce a better result. A well-designed passive solar building is more comfortable than a conventionally designed one. Non-industrial food is higher quality, more nutritious, and tastes better than industrially-produced food. Electric cars aren’t necessarily a functional improvement over IC engine cars, in terms of the user experience, but at least they are quiet.

    Bottom line: Your assertion that humanity has an energy supply problem is absurd, in exactly the same way that it is absurd to say that world hunger is a result of insufficient food production. We produce PLENTY of food. Too much. It’s just very poorly allocated, for reasons that are largely political or economic (i.e. someone’s making a killing, by making a killing). Same exact deal with energy.

    In the West, we can absolutely have a standard of living as high, or higher, than what we currently enjoy while using a small amount of the energy we currently do. We simply have to make the decision that it is worthwhile to make the effort. While that effort could in theory be motivated by the desire to make a better building/car/farm/etc, it is in practice usually motivated by necessity. So the sooner we get over the illusion that we can infinitely expand our energy supply, or that we should even try, the sooner we will buckle down and figure out how to live well within our energy budget.

    Hell, the crowning irony in all of this is that the only reason I care, at all, about these issues is that I don’t want my descendants to be forced to live like Bangladeshi peasants. And that is the lifestyle that all but the ruling elite can look forward to, if we insist on blindly continuing down the same supply-side paradigm that you are so fond of.

  16. One other thing. Let’s suppose you are right. Let’s suppose that non-renewable, polluting energy sources are the only ones that can produce enough power to run the world. Let’s also suppose that the exponential growth of energy consumption is to be taken as a given, and that we simply must find enough coal/oil/gas/uranium to burn to provide for it.

    Great. That’s your paradigm. So what? Just because we have to do these things to survive, doesn’t mean that we actually CAN. Just because we need infinite supplies of non-solar energy doesn’t mean that the world will provide them. It doesn’t mean that we can continue to assault the world’s ecologies with pollution and destruction from our extraction and our generation activities without suffering the consequences. Even if we assume that “your way” is the only way, does not mean it will work.

    The world is finite. It contains limited resources, and has a limited to process pollutants. Further, in order to provide us with the necessities of even a pre-technical civilization — water, air, and fertile land — its various ecologies must function in a healthy fashion, which they cannot do when they are subject to our depredations at every turn.

    Our need does not change fundamental rules of metabolism: you can’t consume more than you produce indefinitely, and you can’t shit in your nest without paying the price. If we accept your paradigm without accepting your apparent delusion about the infinite nature of the world, then we must do so knowing that we are, at best, fighting a holding action against poverty and misery. In your world, we are fighting a battle that we must, necessarily, lose some time in the next century. Arguments from that perspective are just discussions of how to best manage the process of our decline and eventual failure as a technological species.

  17. July is the rainy season around here. I’m not convinced the output power goes down in July because of the shorter day although of course the days are getting shorter.

    Robert a Tucson

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