Publications

Many states and other jurisdictions are grappling with how to value greenhouse gas emission reductions and trying to understand the rapidly developing climate economics and science involved in this task. Frequently, state governments and other jurisdictions value greenhouse gas emissions in policymaking using a tool known as the social cost of carbon.

While applying the social cost of carbon is conceptually simple, the appropriate value to place on the metric is in flux. In late 2022, the federal government released new, updated values of the social cost of carbon in draft form which, for now, remain unfinalized. So what estimates of the social cost of carbon should states and other entities use during this transition period? This policy brief explores the available options.

Nitrogen oxides (NOx) are a precursor to ground-level ozone, a pernicious pollutant that is harmful to human health and ecosystems. Despite decades of regulations and a sharp decline in NOx emissions, episodic high-ozone events prevent many areas from attaining air quality standards. Theoretically, spatially or temporally differentiated emissions prices could be more cost effective at reducing such events than a uniform price. To test this prediction, with data from EPA and NOAA spanning 2001–2019, this working paper uses novel empirical strategies to estimate (1) the link between hourly emissions and high-ozone events and (2) hourly marginal abatement costs. These estimates form the basis for simulations that compare uniform and differentiated emissions pricing. Consistent with economic theory, differentiated pricing is substantially more cost effective at reducing high-ozone events, but this advantage depends on the accuracy of the estimated NOx–ozone relationship.

In Massachusetts, achieving the state’s decarbonization target in a cost-effective manner will likely require the refusal of new gas service in addition to the termination of existing gas service in certain buildings and its replacement with electric service. The scope of utilities’ legal obligation to serve their customers will be central to those efforts. This brief analyzes the contours of this obligation by examining the relevant Massachusetts statutes, regulations, Public Utility Commission decisions, and case law.

In recent years, numerous federal agencies have made a controversial claim: that projects locking in fossil fuels over the long term will decrease aggregate greenhouse gas emissions, or that their effects on total emissions will be limited. In many of those cases, however, agencies have reached this counter-intuitive conclusion using a flawed consideration of energy substitution. This report identifies some of the recurring problems with agency analysis of energy substitution and offers best practices to apply moving forward.