The advantages of wood:
1) Although both coal and wood are renewable, wood renews in a much faster cycle (decades) while coal takes millions of years to fossilize. Still, the peat being deposited in our wetlands will one day become coal, unless it is dug up and dried and burned as biomass.
The disadvantages of wood:
1) Wood is much dirtier than coal. http://www.pfpi.net/wp-content/uploads/2014/04/PFPI-Biomass-is-the-New-Coal-April-2-2014.pdf
Comparison of permits from modern coal, biomass, and gas plants shows that a even the “cleanest” biomass plants can emit > 150% the nitrogen oxides, > 600% the volatile organic compounds, > 190% the particulate matter, and > 125% the carbon monoxide of a coal plant per megawatt-hour, although coal produces more sulfur dioxide (SO2). Emissions from a biomass plant exceed those from a natural gas plant by more than 800% for every major pollutant.
2) Burning wood causes Climate Change at a higher rate than burning coal. (same document as above)
Biomass power plants are also a danger to the climate, emitting nearly 50 percent more CO2 per megawatt generated than the next biggest carbon polluter, coal. Emissions of CO2 from biomass burning can theoretically be offset over time, but such offsets typically take decades to fully compensate for the CO2 rapidly injected into the atmosphere during plant operation.
Additionally, in the mistaken belief that burning wood is better for the environment that other fuels, wood and biomass plants are less regulated than coal plants. Some "biomass" plants actually burn construction and demolition debris, which emits uncontrolled amounts of HAPs (hazardous air pollutants) and more toxic heavy metals than does coal. The EPA allows this on the theory that debris represents a "minor" fuel and most of the actual fuel is "clean" biomass. There is no monitoring of the fuel sources, a plant licensed to burn mostly biomass may burn mostly polluting debris with no danger of being fined.
Because of this perfect storm of lax regulation and regulatory rollbacks, biomass power plants marketed as “clean” to host communities are increasingly likely to emit toxic compounds like dioxins; heavy metals including lead, arsenic, and mercury; and even emerging contaminants, like phthalates, which are found in the “waste-derived” fuel products that are being approved under new EPA rules. Permissive emission standards for biomass plants mean that these pollutants can be emitted at higher levels than allowed from actual waste incinerators. As such, it is not a stretch to conclude that biomass plants being permitted throughout the country combine some of the worst emissions characteristics of coal-fired power plants and waste incinerators, all the while professing to be clean and green.
If you are thinking of small scale wood burning, here in Silicon Valley we have our dirtiest air during the Winter cold when people are burning wood for space heat. I step outside and sometimes choke - and they declare "Spare the Air" days when burning wood is banned unless it is the only heat in a residence.
Biomass power plants are disproportionately polluting not just because of their low efficiency (in converting heat to electrical output) and high emissions inherent in burning wood for energy, but also because the bioenergy industry exploits and actually depends on important loopholes in the Clean Air Act and its enforcement, loopholes that make bioenergy far more polluting than it would be if it were regulated like fossil fuels. Our review of 88 air permits of biomass power plants tabulated information on facility size, fuel use, pollution control technology, and allowable emissions. Some of the facility permits were issued under the Prevention of Significant Deterioration (PSD) program in the Clean Air Act, which requires “major sources” of pollution to reduce emissions by conducting a the Best Available Control Technology (BACT) analysis, and also requires facilities to conduct air quality modeling that assesses whether they will violate EPA’s air quality standards and threaten health.
