Mitigation options that pay for themselves over the lifetime of the option, so-called “zero cost” options, are available to some extent to all counties in the Northeast (see figure below from Carbon and Communities below). Rural areas have considerably more land-based zero-cost options available, which include most investments in wind power and in fuelwood harvest programs. All counties, regardless of land use or population density, can benefit from a long list of energy-efficiency upgrades that pay for themselves over the lifetime of the device or service, including installing compact fluorescent lights, improving insulation in buildings, upgrading to more efficient boilers and air conditioners, and encouraging residents to install Energy Star appliances.
Other carbon mitigation options may help counties offset their carbon emissions but come at a cost. It is difficult to say exactly how much these options will cost, particularly since many depend on the future price of fossil fuels. Several biofuels, for example, derived from willow, soybeans, and switchgrass, could be cost-effective investments for local communities, but only if fuel prices are high or if government policies exist to make these investments more attractive. Other examples of non-zero cost options include planting trees to sequester carbon, installing residential, commercial, and industrial solar panels, and investing in geothermal heat.
A handful of rural counties with both low population densities and a high percentage of forest cover are already net carbon sinks; many rural counties that are not already net sinks could likely become carbon neutral at a relatively low cost to its residents. Wind power represents the largest potential efficiency gain for those counties that are properly sited to take advantage of this alternative source of energy. Start-up costs will vary by location and site conditions, but in many cases initial investments in wind infrastructure will be repaid in energy savings over the lifetime of the technology. Fuelwood harvest represents another possible carbon-abating strategy for rural counties which may use the wood primarily as a heating source to replace oil and natural gas. Wood fuel will only provide a carbon benefit if the supply is used locally and does not require large amounts of fossil fuels to transport it or to convert it to other products such as wood pellets. Roughly 25 percent of most rural emissions could be eliminated with a variety of energy efficiencies.
Both suburban and urban counties will likely need to invest in non-zero cost options in order to lower their carbon emissions. Perhaps as much as a quarter of emissions for most urban counties could be offset at no cost. Installing compact-fluorescent lights, for example, could in itself reduce 10 percent of most counties’ emissions. Zero- or low-cost investments in boiler upgrades, programmable thermostats, more efficient appliances, and better insulation in homes and businesses might reduce another 20 percent of the emissions for the typical suburban or urban county. Solar photovoltaic installations for homes and businesses could reduce up to 20 percent of carbon emissions but require a non-zero cost investment; incentives vary by state, however, making it a much more attractive investment in some areas. Investments in geothermal and other alternative energy sources such as biofuels have the potential to reduce carbon emissions by as much as 10 percent but currently are expensive relative to other mitigation options. Combining both non-zero and zero costs could reduce between 60-80 percent of emissions for most suburban and urban counties. The figure below compares mitigation options in the counties studied in Carbon and Communities.
Carbon calculators at the local scale
In order to help communities assess which mitigation options may be most appropriate for their particular circumstances, we suggest the resources currently on-line at Clean Air-Cool Planet. Their Community Toolkit is designed to help planners, home owners, and businesspeople sort through the various mitigation options with an eye toward focusing on the most rewarding strategies first. This tool, which is free, presents a kind of “decision tree”—a good first step for a community trying to sort through its many options. Clean Air-Cool Planet is well known for its Campus Calculator, which has helped hundreds of schools analyze their carbon-mitigation choices.