Summary

Biomass is regularly included in lists of green or renewable energy sources; We believe that this displays a lack of understanding about the carbon intensity of our energy systems. In practice, biomass powerplants not only do not have lower carbon emissions than fossil fuel powerplants but are often responsible for producing more. This is not to say that we are not in favor of policies that would reduce global carbon emissions, but allowing uninformed climate change ideologues to produce our energy policy will inevitably cause more harm than good.

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What is Biomass?

In the context of energy production, biomass refers to the burning of plant matter to produce energy. While there are numerous ways to produce energy from biomass, including chemical and thermochemical conversion — which turns the biomass into liquid fuel (ethanol) — the most common means for grid-scale power generation using biomass is through direct combustion (burning it). Most biomass for direct combustion takes the form of wood chips (or pellets), but theoretically, any kind of plant matter could be used. These wood pellets are then either burned in modified power plants that previously burned coal or co-fired with coal. In 2022 biomass accounted for about 5% of the total energy production in the United States (this does not include ethanol used as an additive to gasoline).

The energy density of biomass is considerably less than that of fossil fuels.

In comparison to fossil fuels, one has to burn a lot more biomass to produce the same amount of energy. The problem for biomass starts with emissions; burning a kilogram of biomass produces only a little less carbon dioxide (CO2) than burning a kilogram of coal. However, because of the energy density difference, one needs to burn substantially more biomass relative to coal to generate the same amount of energy. It’s because of this that biomass powerplants emit 150% of the carbon dioxide (CO2) produced by coal-burning powerplants and between 300%-400% produced by natural gas plants.

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The History of Biomass

Biomass was the first energy source that humans used, and it has been the primary energy source for most of human history, up until the Industrial Revolution in the mid-1800s, when humanity realized the incredible potential of coal. While the industrialized world adopted coal and later oil and natural gas for energy production, the poorest regions have continued to burn biomass for most of their energy needs (cooking fuel and lighting). This article doesn’t look to cover the over 2 billion people who use biomass as their only energy source, since that is simply a matter of poverty and access; if you provided them with a superior energy source, they would happily adopt it.

Enter the environmentalist movement: developed industrialized nations began to realize that the unabated burning of fossil fuels possibly had something to do with all this air pollution. Biomass was marketed by well-meaning but woefully misinformed people who wanted to reduce carbon emissions. Their reasoning seemed to amount to no more than “How could burning trees be worse for the environment than fossil fuels?” (Sadly, it turned out it was significantly worse).

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Second Order Impacts

Many arguments in favor of using biomass for energy generation argue that the trees that go into making the wood pellets are renewable; while this is technically true, by similar logic, one could also argue that fossil fuels are renewable sources as long as your time scale is measured in millions of years. While forests will be able to regrow within a lifetime, cutting down forests for fuel has more significant second-order impacts.

While many proponents of using biomass for grid-scale energy production would argue that environmentally sound forestry practices (not cutting down old-growth forests or only cutting down diseased trees) can be used to cultivate trees for biomass, the reality is different. Most biomass wood pellets are produced by environmentally harmful practices (such as clear-cutting); the fact is that if one is producing biomass on a small scale, sustainable forestry practices can be used to great effect; on an industrial scale (necessary for grid-scale energy production), the demand for biomass far exceeds the supply of sustainably sourced trees. Forests also play an important role as carbon sinks, absorbing CO2 from the atmosphere; in one year, a tree can absorb 48 pounds of CO2 from the atmosphere. Humanity already has a deforestation problem, with forests being cleared for use as cattle farms; there is really no need to exacerbate this trend for the sake of electricity production.

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Conclusion

So, we are burning trees to produce energy with a similar or worse carbon intensity to that of fossil fuels, the only difference being that the forests we cut down to produce our biomass actually would provide benefit environmental benefits for years to come if left alive, and by comparison, leaving fossil fuels in the ground would provide humanity no similar benefit.

It is mind-boggling how well-meaning environmentalists have endorsed an energy source that is so obviously harmful to the environment in almost every conceivable way. It displays that climate change has become so ideological and adversarial that no one is actually trying to provide any achievable path to addressing it. Environmentalists have villainized fossil fuels to such a degree that they cannot admit to themselves that their lifestyles would be impossible without them, and the conservatives that disregard the threat of climate change are not willing to admit that while fossil fuels have been an incredible resource responsible for unimaginable increases in our quality of life, there is a real need to reduce our carbon emission with less polluting energy sources. Our advice is to let some more engineers into the policy discussion; they’ll be able to draft achievable climate policy without ideological bias towards a particular energy source.