Becoming Less of a Mere Dream
Please view this video of the algae incubators installed by GreenFuels Technologies at Arizona Public Service Company's Redhawk Power Generating Station, a natural gas burning power plant that creates electricity for 250,000 homes. Algae is grown in water and CO2 produced as a byproduct of natural gas burning. The algae produces crude oil which can be refined and used as fuel; starches from the algae can be made into ethanol; and the remaining algal mass can be incorporated into food.
Last October I took a tour of the bioDiesel refinery in Pittsboro, NC. They take leftover fat from a nearby chicken processing plant and turn it into Diesel fuel which they sell wholesale at market price. It's fantastic. It is not making them rich, though it does seem to be a viable business. Speaking to the larger issues of our nation's energy problems, the guide said that really, there is probably not enough waste fat and grease in this country to save us from our dependency on foreign oil or the world from our production of CO2.
Naturally, I asked the guide what he thought about algae farming as a source of crude oil. He said that algae has been everyone's dream, that lots of companies have been turning out press releases but nothing ever seems to come of it.
It's no secret to readers of this blog what a dreamer I am about algae farming. In a past post, I wrote about the press releases on this particular algae experiment. So, I'm especially glad when evidence of real progress emerges.
4 comments:
My thoughts on the video:
1. This algae farm uses a lot of water in the middle of the desert.
2. The video thinks of the algae farm as GHG abatement: if it's a money loser but cheaper than other ways of GHG abatement or sequestration, then it's economically feasible.
3. It the goal is to produce hydrocarbons from algae, I can see that having a CO2 feedstock can possibly boost productivity, but:
a. How does the cost of this method compare with growing algae where water's available? Land is available around many existing plants, so putting the land to this use seems to have little land cost (except clearing out vegetation at other sites has an environmental consequence).
b. If it is cheaper to grow algae elsewhere, then even for a CO2 abatement objective, it could still be cheaper for the power plants to pay for the construction of off-site algae farms.
c. This method would take 1000s of acres (2 acres per MW of NG plant=2000 acres for this 1000MW plant) to offset the CO2 output of this power plant. That's a lot of land. That seems to be much more than you cited in other algae farm material you've found. On the other hand, if the costs are favorable, then even doing a partial offset at each power plant could still be worthwhile. The plant in the video is NG. Coal would produce even more CO2 and need more land to offset the same percentage of CO2 emissions. Coal plants also produce mercury and some other things in their emissions, and I wonder what implications that has for the use of the algae grown in those emissions.
d. This appears more energy-intensive than other methods of algae-farming that I've seen. But if they can use waste heat for part of the energy needs, then that might not matter. As an economist, I ask is this as cheap as the other algae-farming methods? Even from an environmental processing perspective, does this method have a bigger (smaller) net CO2 reduction per dollar spent than alternative algae-farming methods?
e. I wonder whether using saltwater is possible? There are lots of algae in the ocean. I don't know whether they produce more oil than freshwater, or whether salt-water algae bioconcentrate the metals from the salt water, with implications for processing or emissions when the oil is burned.
The other algae-farmers are talking about growing algae to make money. Solazyme thinks their products could produce automobile fuel cheaper than oil-based products within a few years. I didn't get that impression from this operation; it just sounded like algae to abate CO2, not producing algal biofuels more cheaply than petroleum fuels. The other algal farms abate CO2 as well, so I just wonder whether this method really has long-term promise. Coal companies might push it just to keep burning coal (if coal-emission algae doesn't have heavy metal problems). The way that utility regulators and politicians--especially Congress--frame it can make this attractive even if it's not efficient, either with tax breaks or regulations that favor it over other types of algae farms.
I applaud the research but still question the wisdom of placing of a production process with high water in the middle of the desert. I know the water is recirculated, but a lot of water ends up embodied in the biomass. Perhaps proof of concept here would paave the way for production where water is more plentiful.
Regarding the issue of using water in the desert, the video says that water is a byproduct of burning natural gas. I gather they are getting some of their water from this. I don't know if they are getting all of it as a byproduct though.
. . . although, if they do expand the operation to recapture ALL of the CO2 they produce, then they will certainly need lots more water from somewhere.
This is my third try to post this comment.
Mass balance for methane:
CH4 + 2O2 = CO2 + 2H2O
Burning logs in your fireplace, coal in a power plant, or almost any other organic material will produce water as one end product. In a power plant, it's steam amid all those hot emissions. Power plants, even NG ones, use a lot of water for cooling. "Dry" cooling can use less water, but at a cost of lower efficiency (and thus more CO2 emissions per MWH of electricity.) Even if the algae are grown in the discharged cooling water, they are using water that would have gone back into the river or lake and so are an added burden on the scarce local water supply.
A reference from the
Northwest Power Planning Council on water usage:
The principal environmental concerns associated with gas-fired combined-cycle gas turbines are emissions of nitrogen oxides (NOx) and carbon monoxide (CO). Fuel oil operation may produce sulfur dioxide. Nitrogen oxide abatement is accomplished by use of “dry low-NOx” combustors and a selective catalytic reduction system within the HSRG. Limited quantities of ammonia are released by operation of the NOx SCR system. CO emissions are typically controlled by use of an oxidation catalyst within the HSRG. No special controls for particulates and sulfur oxides are used since only trace amounts are produced when operating on natural gas. Fairly significant quantities of water are required for cooling the steam condenser and may be an issue in arid areas. Water consumption can be reduced by use of dry (closed-cycle) cooling, though with cost and efficiency penalties. Gas-fired combined-cycle plants produce less carbon dioxide per unit energy output than other fossil fuel technologies because of the relatively high thermal efficiency of the technology and the high hydrogen-carbon ratio of methane (the primary constituent of natural gas).
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