Believe it or not, I was working on this post before I got massively distracted by the efficiency questions surrounding ethanol and gasoline. To some, I may seem to be a bit of a Jeckyll and Hyde with respect to ethanol. One day, I am bashing it. The next day, I am endorsing it. So what’s the deal?
I fully acknowledge the need to move away from fossil fuels, but most grain ethanol in this country is primarily recycled fossil fuels. I object to taking fossil fuels, converting them to ethanol, subsidizing the ethanol not on the basis of energy “created”, but instead on a per gallon basis, while mining our topsoil in the process.
However, ethanol does not have to be created in an unsustainable manner. I applaud ethanol producers who are trying to produce ethanol in a more sustainable manner. Previously, I wrote on E3 Biofuels efforts to create a closed-loop process, which they should be starting up soon. Last week I saw another headline that described an integrated bioenergy plant with a different twist from that of E3 Biofuels:
Some excerpts from the article:
An electric cooperative in southwest Kansas is reaching beyond coal to generate power. Sunflower Electric Power Corp. announced plans Wednesday to create a first-of-its-kind “integrated bioenergy center” on a 10,000-acre site four miles south of Holcomb, plugging an expected meat-processing operation, dairy, ethanol plant and biodiesel plant into the co-op’s plans for its own expanding coal-fired energy center.
Together, the independent operations would work together to generate electricity, produce ethanol, feed livestock and otherwise help one another succeed — through reductions in water use, lessening of emissions and a host of other spin-offs previously unrealized in a single project anywhere.
“We’re trying to do something that’s never been done before,” said Scott Miller, a spokesman for the electric co-op.
The project would convert manure to methane, which could fuel an ethanol plant. Flue gas from the coal-fired electric plant could feed into an algae reactor, whose water could be drained for boiling in the power plant — steam drives the turbines that produce electricity — while the algae could be used to feed dairy cattle or help produce biodiesel fuel. (1)
This is the kind of alternative energy effort we should all advocate. Some will not be enthusiastic about the use of coal as an energy source, but in my opinion this is inevitable. Ethanol that is highly dependent upon natural gas will rise and fall with the price of fossil fuels. Ethanol that is dependent on coal will be more insulated from the volatility of other fossil fuels. Besides, since methane will be derived from the manure, the coal-demand will be much lower than for a conventional ethanol plant. And conventional ethanol plants are turning to coal as an energy source anyway. (2)
While the integrated bioenergy center is not a fully sustainable solution, it is a big step in that direction. And steps toward sustainability are steps I support.
1. “Bioenergy effort under way” Lawrence Journal-World, August 24, 2006.
2. “Carbon cloud over a green fuel” Christian Science Monitor, March 23, 2006.
5 thoughts on “Integrated Bioenergy Center”
I agree wholeheartedly that this kind of ‘integrated’ approach to bioenergy facilities is exactly what we need to see. This particular configuration may not be the most sustainable, but the kind of thinking involved in planning a facility like this is exactly the kind that designers of industrial facilities should be doing.
Industrial facilities should be planned, whenever possible, like a sort of industrial ecosystem, where each part of the facility can utilize some or all of the waste-stream (be it solid waste, used water, co-products, waste heat or steam, even carbon dioxide, etc.) from the other parts of the facility. In this way, a number of loops are closed, or at least a number of outputs are recycled into useful inputs instead of heading straight to landfills, toxic waste dumps, wastewater facilties, or our rivers, oceans and atmosphere.
Bioenergy facilities in particular can benefit from this kind of ‘industrial ecosystem’ design as they often have a number of different outputs, co-products and inputs that can work well together.
One proposal I mentioned in a previous thread here at R-Squared was for an integrated bioenergy facility that produced both corn and cellulose-based ethanol. The facility would accept corn and corn-stover as inputs. The corn-stover would feed a gasification-based cellulosic ethanol process (like the one BRI is developing) which would produce both ethanol and quite a bit of waste heat. Some or all of the waste heat could then go towards process heat/steam for the corn ethanol side of the facility (with the remainder generating electricity for internal use and maybe some for export if there’s any left).
This would eliminate the need for coal or natural gas to run the corn ethanol facility. The distillers’ dried grains and solubles and other co-products produced by the ethanol process could also be fed into the cellulosic ethanol process and gasified if that was more economical than selling the co-products.
Further expanding on this idea, based on the ideas in the post above, the facility could also incorporate an animal feed operation, using the distiller’s dried grains and corn meal produced by the corn ethanol process. The manure from the animal feed operation could provide further process heat/steam/electricity for the ethanol facilities.
Burning the methane and gasifying the corn stover (and/or other cellulosic feedstocks) also produce a CO2 waste stream (although both processes are net carbon neutral, in the case of the gasification, or negative, in the case of the methane). This CO2 could be fed to algae bioreactors like the ones being developed by GreenFuels Tech. Corp. The algae can be used as either animal feed, or to make biodiesel in a co-located biodiesel facility. The wastewater from the algae process can be used to make process steam.
So, in this facility, you take corn and corn-stover, plus animals as inputs and end up with ethanol, meat, corn co-products, biodiesel (perhaps) and maybe some electricity. The facility would have limited emissions, be carbon neutral or negative, should limit water use (relative to non-integrated facilities) and minimizes waste streams.
Obviously, I’m not sure quite how the mass/energy flows would break down, but I think a facility like this would be possible. Expense is also clearly an issue, although I would imagine that co-locating these facilities would limit capital expenses relative to the same facilities that weren’t co-located. Still it’s going to probably be more spendy than a non-integrated ethanol facility using coal for energy. Operating costs should be lower though as the integrated facility makes good use of several materials streams that what would otherwise simply be waste.
What do you all think?
The corn-stover would feed a gasification-based cellulosic ethanol process (like the one BRI is developing) which would produce both ethanol and quite a bit of waste heat.
I agree completely with the integrated approach, but I am skeptical of the wisdom of gasification followed by conversion to ethanol. I think it would be far more efficient to gasify and then produce diesel via Fischer-Tropsch. I don’t think people would consider ethanol to be a reasonable end-product if it were not for the subsidies.
I like biomass gasification, because you can convert all of the lignin and hard to digest cellulose that would otherwise wind up as waste in a purely biological process. I just think that once you have syngas, there are much better options for it.
Expense is also clearly an issue,….
I think this will be a limitation for a while. Those gasification reactors are expensive, and so are the biomass handling facilities. A regular POX reactor that runs on natural gas is expensive. A POX reactor that runs on coal is more expensive. But the one that runs on biomass is the most expensive (although the only one with a chance to offer a sustainable solution).
Current ethanol plants use a lot of fossil process energy, one way of looking at this is:
There’s lots of scope for improvement!
Rather than saying, current ethanol plants use too much fossil energy, this surely will always be so, therefore let’s give up on ethanol.
I think most of the process energy is for low grade process heat (eg drying) and for distillation. For the latter, I see great potential to substitute membrane processes with an order of magnitude lower energy consumption, and for the former I think waste heat and more efficient driers should also have large scope for lowering energy inputs.
And on top of these improvements, we can then use biomass.
when you mention top soil loss and subsidies, I think you capture the essence of why there’s opposition.
People are unhappy that fossil fuel production is subsidised via ethanol and they believe that little is gained compared to the environmental problems of farming.
Farmers and coal miners have a different perspective oftentimes. I see that in what Chirac has to say about French farming, and what the Social Democrats have to say about German coal. For them, these add to national culture, farmers are custodians of the rural landscape and a vibrant rural life is a national asset. They think they are making the environment (in a very broad sense of the word, a sense that includes French Parisians being proud of acres of wheat fields) better not worse.
when you mention top soil loss and subsidies, I think you capture the essence of why there’s opposition.
For myself, it is the agricultural side of the operation that concerns me the most. There are lots of ways to get process heat on a sustainable (or at least non-egregious basis). Solar concentrators, co-gen, tap waste heat from an existing source, etc.
Making the corn production process more sustainable is a much tougher nut to crack. Accurately accounting for the externalities associated with industrial corn production is also intrinsically much harder, because the damage is often to soil, water, or ecosystems, which is not as easy to measure as the amount of GHG emissions from a process.
Watthead said, “So, in this facility, you take corn and corn-stover, plus animals as inputs and end up with ethanol, meat, corn co-products, biodiesel (perhaps) and maybe some electricity.”
One problem with using the corn stover as a source of thermal energy instad of letting it decompose back into the soil is that would only increase the need for fertilizers made from natural gas.
The system you suggest would kill the soil, inceasing the dependence on synthetic fertilizers. In effect, you would be using the soil as only a sterile holding medium to transform natural gas-based fertilizers into corn. As Robert has said many times, it would be far more efficient to transform natural gas directly into a liquid fuel rather than to use the natural gas as a feedstock for fertilizer that is used to grow corn, and then use more natural gas (or coal) to transform the corn into ethanol.
Watthead said, “Further expanding on this idea, based on the ideas in the post above, the facility could also incorporate an animal feed operation, using the distiller’s dried grains and corn meal produced by the corn ethanol process.”
Making use of the distiller’s dried grains (DDG) works well on a micro-scale. But on a macro-scale such as will soon exist in Iowa where new ethanol plants are popping up like daisies after a spring rain, there will be far more DDG than cattle feeders need.
And that my friend is bad news since ethanol has a positive EROEI only because of the energy locked in that DDG.
There will come a day with hundreds of ethanol plants in each of the Corn Belt states and all of those ethanol plants will be surrounded by piles and piles of DDG far in excess of what cattle feeders can use, and that no one will want or need. Those ethanol plants will look like the old coal mines surrounded by huge slag heaps, only these slag heaps will be piles of DDG.
Instead of using corn stover for thermal energy, the ethanol plants may well have to begin burning the excess DDG as a source of thermal energy.
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