We would like to ask the City of Burlington to further develop its greenhouse gas accounting practices. For certain major energy sources, emissions not currently accounted for may completely change the carbon footprint.
In addition to (not instead of) the emissions estimates determined using the current greenhouse gas accounting practice for climate planning, we’d like for the City to estimate the lifecycle emissions (a.k.a. as cradle-to-grave emissions) for each energy source.
Estimating lifecycle emissions precisely can be difficult. Currently, there are large uncertainties in estimates for important parts of the lifecycle of many energy sources. Fugitive natural gas emissions are a stark example. Estimates of the amount of fugitive emissions and their impact range very widely. This means that the carbon footprint of natural gas – burned periodically, for instance, in the McNeil generating station — may not just be a few percent larger, but several-fold larger, than conventional estimates indicate.
Another example: the net greenhouse gas effects of bioenergy — woody biomass makes up the vast majority of the fuel for the McNeil station — also depend critically on non-combustion related factors, including the source of the biomass and the relevant land-use effects.
Because of these difficulties, the City of Burlington cannot, presumably, determine the precise lifecycle footprint of the natural gas used or resolve the question of how to account for land-use activities. That is not what we are asking for. But the City can take immediate steps to make carbon accounting more transparent by including an estimated range of lifecycle emissions for each relevant energy source.
We understand that the City needs to be able to measure its progress relative to other cities, using standard methods. This is important and needs to continue. But it is also critically important that we clearly contextualize conventional emissions estimates within a lifecycle analysis perspective. When lifecycle emissions may increase the carbon footprint by several hundred percent (relevant to conventional emissions estimates), the public needs to have access to this information, too.
We urge you to lead other cities by including in your climate planning a detailed explanation of (a) the conventional accounting metrics in the plan; (b) the actual carbon dioxide smokestack emissions from the McNeil Station, as calculated by the U.S. Environmental Protection Agency; and (c) the lifecycle factors currently known to potentially affect the relevance of the conventional estimates, with (d) estimated emission ranges / climate impact ranges for these effects.