The Case for Forest Biomass

Increasingly, renewable energy sources are coming under scrutiny. Ironically, the same activists responsible for the movement away from fossil fuels and toward renewables are now working to undermine planned renewable energy facilities. They are filing lawsuits to stop wind and solar farms, smart grid construction and biomass power plants.

As an environmentalist and someone who works in the forestry and bioenergy industries, my question is this:  once we eliminate everything we don’t want in our backyards, how will we meet our renewable portfolio standards?  How will we meet our energy needs?

I’m not the only one asking this question. Twenty-seven states currently have renewable portfolio standards. And because opposition to even the most benign energy sources is growing, these states are now struggling to figure out how to reach their renewable generation goals.

Environmental interest groups aren’t helping. They seem unable to work toward the only goal that will save the planet—the development of long-term sustainable paths to a secure, renewable and clean energy future. They are making the perfect the enemy of the essential.

I understand that developing a long-term sustainable path to a clean and renewable energy future is a difficult undertaking.  Every state, after all, has a unique mix of energy sources. Some have abundant sun, some have abundant wind, and some have abundant forest biomass. Biomass power plants may abound in the South, where forest resources are plentiful, but North Dakota will need to find other options. Solar energy may be all the rage in sunny California, but don’t expect to see solar farms on the outskirts of Seattle.

Further complicating the undertaking—and something we must all learn to accept—is the fact that perfect energy sources don’t exist. All of our options have benefits and risks. That’s why the value of all energy sources should be measured not in terms of an ideal, but in the context of all other available and practical sources of energy.

Universally considered the cleanest energy sources, solar and wind are at the top of the list if we look only at their carbon footprints. Because they are intermittent and opportunistic, however, they are not practical sources of baseload power. With today’s technology, for instance, if we are relying on solar energy on a cloudy day, we must accept blackouts. For baseload power, states would be better off looking at forest biomass, which can be produced on demand.

But is biomass clean enough? The status of forest biomass as carbon neutral has recently been called into question. A report from the Manomet Center for Conservation Sciences concluded that burning forest biomass (both logging waste and whole trees) in Massachusetts creates a larger carbon deficit than coal, a deficit that requires the replacement tree to grow for 20 years (or more) before it reabsorbs that excess carbon.

Because every forest is different, however, the number of years will vary by the species of tree and the region of the country. Burning just the logging residue will take just a few years. In the South, where many species are fast growing and the growing season is long, the number is in the 10-15 year range. In addition, larger, more expensive trees—the ones that take longer to grow—will not be used as a feedstock for biomass electricity plants; any whole trees that will be used are pulpwood size at best, ones with a 10- to 15-year rotation length.

(It should be noted that despite the publicity that has accompanied the Manomet study, the study does not look at life cycle emissions. Serious peer reviewed studies have shown that biomass is exponentially better than coal, emitting just 4 percent of the greenhouse gases than coal does. See my post on this life cycle analysis study.)

On the other end of the spectrum are fossil fuels. The amount of time required for the replenishment of oil, natural gas and coal supplies cannot be measured in decades or even centuries; they must be measured in geologic time.

By comparison, a worst case scenario of a 10-15 year re-sequestration period ought to be acceptable.  Essentially, the excess carbon emitted from a biomass power plant would be reabsorbed within a single generation.  If our goal is to protect and preserve the planet for future generations, accepting near-term carbon deficits for longer term carbon dividends seems a sensible trade-off.

If we are going to carve a path to a secure, renewable and clean energy future, states need to meet their renewable electricity standards.  But they can only do so with the sources that are available to them. Limiting these sources without evaluating the benefits and risks of each in comparison to other available and practical sources will force states to adjust their standards downward. And when this happens, we’ll be even further from our goal of reducing climate change.

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The Case for Forest Biomass | Forest Business Netw

10-10-2011

[...] Case for Forest Biomass   October 10, 2011 - 0 Comments   By Suz-Anne Kinney – Forest2Market Watch Photo by Aaron [...]

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Josh Schlossberg

10-17-2011

Almost all US citizens are united in advocating for appropriately sited, community scale, non-smokestack/non-nuke energy. The projects that get most resistance are the largest projects. Industrial energy is not anything anyone wants to live near, would you like to live near a power plant?

Your biomass power carbon arguments are hard to follow. It seems the point you are missing is that if these forests were left to grow they would continue storing CO2 and absorbing even more, not to mention the ecosystem services of clean air and water that are lost. Cutting forests for electricity does more harm than good.

Non-smokestack renewable energy can go a very long way to feed our energy needs—but not our energy “wants.”  The bottom line is we must reduce our energy demand, which means conservation, efficiency, relocalizing and scaling down our economies, and yes, changing our lifestyles.

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Suz-Anne Kinney

10-31-2011

I concur that reducing our demand for energy through efficiency and conservation and relocalizing, Josh.

As to changing our lifestyles, however, I’m not sure how realistic that is. It sounds great on the surface, but I’m not sure it’s something that is going to happen at a large enough scale to really make a difference.

To your earlier point: there is a difference between carbon being continuously absorbed by trees and carbon sequestered in trees.

Mature trees have sequestered a considerable amount of carbon within them, but they absorb carbon at a much slower rate than young trees. When you harvest these mature trees, the forest regrows (whether artificially through replanting or naturally through regeneration). This results in a higher number of young trees. Again, these younger trees absorb carbon much more quickly that the mature trees.

Now for the carbon that is sequestered in the mature trees that were harvested. Let’s be clear, carbon is not released when the trees are harvested. It is not released when they are used to make lumber or other wood products like furniture and trusses and floors. The carbon that is sequestered in these long-lived wood products continues to be sequestered.

Carbon is released only from that portion of the trees that are used to produce energy. In the vast majority of cases, this entails only the bark, limbs and branches of the trees (a much smaller store of carbon is in these parts of a tree). For any carbon that is released during this process, new growth will more quickly resequester that carbon than a mature tree would.

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