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Southern Company embraces the only practical and affordable way to ‘capture’ emissions at a coal plant today — run it on biomass

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"Southern Company embraces the only practical and affordable way to ‘capture’ emissions at a coal plant today — run it on biomass"

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The best and cheapest near-term strategy for reducing coal plant CO2 emissions without forcing utilities to simply walk away from their entire capital investment is to replace that coal with biomass (see “If Obama stops dirty coal, as he must, what will replace it? Part 2: An intro to biomass cofiring“).

Today, Energy Daily (subs. req’d) reports on the huge — but little covered — news from one of the nation’s biggest carbon polluters:

The Georgia Public Service Commission gave the green light Tuesday to a Georgia Power request to convert the utility’s 155 megawatt coal-fired Plant Mitchell near Albany, Ga., to burn woody biomass, a move that will result in the first biomass plant in the vast generation fleet of Georgia Power parent Southern Co.

This will become “the largest biomass facility in the United States,” according to Southern Company COO Tom Fanning. And this is not the only biomass effort Southern Company is pursuing:

Alabama Power, another Southern affiliate, is studying co-firing woody biomass and switchgrass at its coal-fired Gadsden plant near Birmingham and co-firing woody biomass at its coal-fired Barry plant near Bucks, Ala. Southern affiliate Gulf Power is evaluating co-firing biomass at its coal-fired Plant Scholz near Marianna, Fla.

The huge advantage of biomass conversion or co-firing is that you don’t have to build an entire planet from scratch, thus lowering the capital costs. Plus you already have the powerplant sited and you have transmission sited and you have train lines and water supply. Plus this is new baseload renewable power — arguably the most valuable commodity in the entire power sector these days.

And since biomass captures carbon dioxide already in the atmosphere during the process of growing, it is the only form of carbon capture that is likely to lead to deliver significant kilowatt-hours for the next one to two decades (see “Is coal with CCS a core climate solution?“).

So, again, this is, in the near term, the most practical and affordable strategy for utilities with coal plants that want to reduce CO2 emissions without simply writing off the entire value of their plant. Hence, this is a crucial strategy for coal-intensive utilities in the Southeast and Midwest that have long opposed renewable energy standards and climate action:

Southern for years has spearheaded utility industry opposition to a national renewable electricity standard (RES) that would require power companies to obtain a percentage of their electricity from wind, solar power or other green resources, saying the mandate would discriminate against utilities in the Southeast, which lacks the abundant wind and solar resources found in the Midwest and Southwest, respectively.

If this is to be a scalable medium-term solution, then the country will need to make an all out effort to develop cellulosic biomass for use in power plants. Even today, the resource is significant in the key regions:

However, the Southeast has enormous quantities of woody biomass, a renewable fuel that utilities can use to meet the RES. Southern’s Web site states that 8 million acres of forest and timberlands lie within a 100-mile radius of Plant Mitchell, providing 12 million tons of surplus supply wood fuel annually. The converted Mitchell plant, which will have a capacity of 96 MW, is expected to consume about 1 million tons per year.

The conversion of the Mitchell plant to biomass may signal recognition by Southern Co. that–with stronger Democratic majorities in the House and Senate and President Obama a strong backer of a federal RES–developing its extensive biomass resource may be both politically and economically prudent. The converted Mitchell plant is expected to begin operation in June 2012.

Interestingly, the new biomass power plant will generate more electricity than the current coal-fired unit. Here are some interesting details from a 2008 story in Biomass magazine:

According to Lynn Wallace, a company spokeswoman for Georgia Power, the nameplate capacity for the converted wood biomass-powered unit would be 59 megawatts lower due to the different physical characteristics of wood in comparison to coal. Wood contains more moisture and produces only 4,000 British thermal units (Btu) to 5,000 Btu per pound compared to coal at 12,000 Btu per pound, she said.

As a wood biomass-powered unit, the facility would actually produce more electricity than it does as a coal-fired unit, Wallace said. The unit currently operates at low capacity and is not considered one of the company’s base-load power units; however, the biomass-powered unit would operate continuously and be part of the company’s base load.

Surplus wood fuel for Plant Mitchell would come from suppliers operating within an approximately 100-mile radius of the plant. Wallace said the wood primarily would be waste wood, such as tree limbs, tree tops, needles, and leaves, which is normally left behind by timber harvesting companies. “We wouldn’t be competing with their wood supply,” she said.

Wallace said consumers are asking to have more energy produced from feedstocks and from processes that produce lower emissions. She said the wood biomass-powered unit will produce less sulfur dioxide and nitrogen oxide emissions and will engender a net reduction in carbon emissions.

Wood biomass is also less expensive than coal, Wallace added. The new feedstock requirement for the unit is expected to create between 50 and 75 new jobs related to waste wood recovery. She said waste wood that is left on the forest floor also emits methane gas and can easily fuel forest fires if it’s not cleared away.

The key, of course, to make sure this is all done in the sustainable fashion. That will be the job of regulators and the Obama administration.

When I was at the Department of Energy, we were pursuing research into developing better fast-growing hybrid poplars, which are “the fastest growing hardwood trees available to homeowners and landowners in America and they are growing successfully from the Northern Gulf Coast to New England, throughout the Midwest and into the Northwest.” They are a high-energy crop that “grow well on marginal land, so they don’t take up valuable food-producing soil.”

The fundamental reason biomass conversion and co-firing are a core climate solution is that anyone who can deliver considerable amounts of low carbon power for under $0.15 a kilowatt hour — and especially if that is baseload power — will be a major player in the transition to a low carbon economy. And if you can do that in regions of the country that don’t have a vast solar resource suitable for concentrated solar thermal or wind — and especially if it is closer to $0.10 a kilowatt hour — then you will be doubly valuable.

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14 Responses to Southern Company embraces the only practical and affordable way to ‘capture’ emissions at a coal plant today — run it on biomass

  1. Bob Wallace says:

    “the wood primarily would be waste wood, such as tree limbs, tree tops, needles, and leaves, which is normally left behind by timber harvesting companies”

    That left behind waste decomposes and feeds the next crop of trees. What’s going to be the effect of removing nutrients from the forest?

  2. Joe says:

    Much of the stuff left behind by timber harvesting can also feed forest fires and generate methane — too big sources of CO2 emissions.

    Clearly, the only way to do this is in sustainable fashion. But, of course, it wouldn’t be much of a resource if you couldn’t do it sustainably.

    The fact is this is going to happen — once there is a serious price for carbon, biomass conversion and coal firing is a no-brainer.

    So the trick is to set up regulations now that ensure it is done sustainably.

    Another point that deserves mentioning is that the “waste” resource is a small compared to what you could do with dedicated fast-growing hybrid poplar plantations on marginal lands.

  3. lgcarey says:

    If the currently mythical CSS technology was actually developed and deployed for biomass fired plants, wouldn’t the plant actually be carbon negative, drawing down and storing the CO2 captured in the biomass in the first place?

  4. Len Ornstein says:

    Such use of ‘wood’ to replace coal requires that the wood ash (or its equivalent) be returned to the site of harvest AND that the rate of removal not exceed the rate of replacement (i.e., the net primary productivity (NPP) of the biomass source be maintained.

    With such caveats, replacing coal with wood can provide enormous mitigation benefits in the relatively short term.

    Without such caveats, it can lead to more rapid deforestation and even accelerate AGW!

  5. Bob Wallace says:

    Just some random thoughts…

    Around here, North Coast CA timber country the waste, we call is “slash”, is piled up and burned. Not necessarily the ideal way to deal with the leftovers, but it does take care of the increased fire danger and leave some of the nutrients in the woods.

    I’ve wondered if chipping wouldn’t be a better way to leave the organic material and reduce fire danger.

    No data, but I’ve heard some people in the timber business say that successive “crops” grow less well. Some of the problem, if it’s real, might well be from top soil erosion on our steep slopes. Might not have the same problem in the flat Georgia piney woods. Or it may have to do with the removal of most of the plants that have soaked up the nutrients when the logs climb on the trucks.

    Biomass might make sense for the short run. It could help us get off coal more quickly. But it might not be a good long term solution. Unless we can find ways to return nutrients to the forest soil we might end up with the sort of “burned out” soil that results from too much farming of heavy feeding crops.

    Switchgrass might be a better crop. As I recall it grows on very marginal land and improves the soil, even when the tops are cut and hauled off. It puts down a massive root system which creates lots of organic material underneath the surface.

  6. Harrier says:

    Could this move be a preemption of the EPA’s upcoming regulation of carbon dioxide emissions, much as the abandonment of several new coal-fired plants over the past few months seems to have been?

  7. athada says:

    “The huge advantage of biomass conversion or co-firing is that you don’t have to build an entire PLANET from scratch” (capitalization mine)

    Hopefully that won’t be the case! ;)

  8. David B. Benson says:

    Do not

    repeat, not,

    burn the needles or leaves, including the stem.

    Almost all the nutrients are there.

    Do not do that!

  9. 2012 is also when the 211MW Atikokan coal plant in Ontario will convert to 100 per cent wood pellets. It’s great to see momentum now with the Southern Company decision.

    Joe, I mentioned the 100 per cent option before and you downplayed it in favour of co-firing. But co-firing, while technically it reduces coal use and emissions, has other problems — primarily economic. You can’t resell the resulting fly ash blend (i.e. from pure coal it goes to cement industry; from pure biomass it can be used as fertilizer additive). The full burn option isn’t as difficult as you think, and it shouldn’t be viewed as the next stage after co-firing — some plants will be better suited to co-firing, some will be better for 100 per cent burn, based on location and burner type.

    See this PowerPoint from Ontario Power Generation, which goes over its Biomass Conversion Strategy. http://www.opg.com/power/fossil/Young%20Biomass%20Program%20at%20OPG.pdf

    Also, see Toronto Star stories: http://www.thestar.com/comment/columnists/article/574439
    http://www.thestar.com/comment/columnists/article/542152

    Either way, I completely agree that the biomass conversion option should be a top priority for coal plant owners.

  10. David B. Benson says:

    lgcarey — Depneds on the proportions when co-firing. Probably not, because co-fired operation typically are only up to 10% biomass.

    For a 100% biomass burner, then with CCS it certainly becomes carbon negative.

  11. Bob Wallace says:

    Something to throw into the discussion.

    From Science News….

    “During torrefaction, woodchips go through a machine – almost like an industrial-sized oven – to remove the moisture and toast the biomass. The machine, called a torrefier, changes more than just the appearance of the woody biomass. The chips become physically and chemically altered – through heat in a low-oxygen environment – to make them drier and easier to crush.

    The torrefied wood is lighter than the original woodchips but retains 80 percent of the original energy content in one-third the weight. That makes them an ideal feedstock for electric power plants that traditionally use coal to generate energy for businesses and residential neighborhoods.

    While the process of torrefaction is nothing new, NC State’s particular torrefier machine, called the Autothermic Transportable Torrefaction Machine (ATTM), is field portable and self-heated. Traditional torrefier machines are bulky and immobile, but the ATTM lends itself to field-based operations, which reduces the cost of transporting tons of woody biomass to and from the combustion facilities. The ATTM is also largely self-powered, producing a large energy return while also removing carbon from the atmosphere.”

    http://www.sciencedaily.com/releases/2009/03/090311134802.htm

  12. You probably expected that as a switchgrass grower I would be promoting that type of biomass, but actually I agree with Joe that short rotation woody crops like poplar have a lot of advantages.

    One advantage is that you don’t have to cut them each year, the amount of biomass continues to grow “on the stump”. Another is that you have more selection on times of harvest, a good thing to remember when trying to run a power plant 365 days a year while minimizing storage requirements. Lastly, wood chips can be handled with more typical walking floor tractor trailers and conveyors. Switchgrass and other warm season grasses generally need some form of intermediate densification to have that same capability.

  13. Theodore says:

    Bamboo grows fast in the south. Would it be better than wood?

  14. Nic Mulliez says:

    Any one familiar with Drax Power (UK) and the co-generation with Miscanthus?