Why are biofuels carbon neutral? They arent.

It's hard to believe that burning biomass is considered carbon neutral.

But under the current international rules for GHG emissions accounting, burning of biomass (plants, trees, etc) does not add to atmospheric carbon.* Wait, what? Burning anything in the presence of oxygen releases carbon dioxide. If an acre of trees is cut down and burned, the stored carbon is released into the atmosphere. Period. (The exception to this is anaerobic combustion, to make biochar, which I will write about later). Under these current accounting methods for GHG emissions, there seems to be NO requirement that the burned biomass should be replaced at all, let alone be replaced at the same rate that it's burned.

That's why power plants in the UK are shipping trees from the Congo and Amazon to be burned for electricity -- because it's considered "carbon neutral." So England gets a good carbon reduction report card because they're burning the most valuable forests in the world? No way! Burning trees is not carbon neutral; there's an overall net carbon emission. What gives?

The current emissions accounting assumes that trees that get cut down and burned are replaced with other trees that will get cut down and burned, thus making a nice closed-loop carbon system. But there are three problems with this assumption. The biggest problem: if you don't REQUIRE the trees to be replaced, you CANNOT assume that they will be replaced, and you can't assume that a third party will replace the trees. Just because a resource is renewable doesn't mean it renews itself at the same rate you use it.

Beyond making sure that the trees are replaced with saplings, there is another issue about carbon emissions. From the moment that the trees are cut down, we are missing out on carbon sequestration that those trees would have been doing if they were left alone. (In econ-speak this is called opportunity cost). Lastly, if additional energy is used to transport & process the trees being burned as fuel, the additional transportation emissions should count towards the total carbon impact of those burning branches.

I propose instead that burning biomass should be considered a carbon emission (since it is, duh). If replacement biomass is planted and grown at the same rate as the biomass is burned, then the company should get credit for doing so. Only then would the emissions be roughly considered "carbon neutral." Then companies who actually ensure that they replace what they use are rewarded for their efforts. Burning wood does release carbon and those emissions should count as an emission until the "replacement" trees have sequestered the same amount of carbon that the burned trees released.

Recent articles on trees, forests, carbon & energy production:
Tree Harvester Offers to Save Indonesian Rainforest, NYT, Norimitsu Onishi, 29 Nov 2009
Trees: Out of the Forest and Into the Oven, IPS, Stephen Leahy, 24 Sept 2009
Wood-Fired Powerplants are No Environmental Cure-all Boston Globe Editorial, 29 Nov 2009

*Intergovernmental Panel on Climate Change. Greenhouse Gas Inventory Reference Manual: Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories, Vol. 3, Pg. 6.28, (Paris France 1997)