The disunited state of American power generation

The overall carbon intensity of US electricity generation has declined by around one-third during the 21st Century, from 538 grams of CO₂ emitted per kilowatt-hour (gCO2 per kWh) in 2001 to 367 gCO2 per kWh in 2022. The US compares favourably to the global average (436 gCO2 per kWh), but still has some way to go to match that of the EU (277 gCO2 per kWh).¹

Although we often interpret developments in the United States in the aggregate (especially for analysts based elsewhere in the world), it’s important to look at developments on a state-by-state basis. Here the map below reveals a patchwork of progress towards the decarbonisation of power sector emissions. This map plus the one that follows was put together by

Sustainability by numbers

based on underlying data sourced from Ember Climate. I encourage you to check out the interactive maps and charts here.

The Northeast state of Vermont generated 100% of it’s electricity from renewable sources in 2022. Only three other states generated at least three-quarters of their electricity from renewables: South Dakota, Washington and Idaho. At the other end of the scale four states are barely edging towards 5%: Kentucky and West Virginia (70%-90% reliant on thermal coal), Delaware (~90% natural gas), and Puerto Rico (~50% oil fired generation).

Each state is blessed with certain resources - either below or above the ground - that make them more or less likely to burn coal (West Virginia), install solar panels (California), or build dams to harness the power of water (Vermont). Permitting, transmission infrastructure, and interconnection issues also play a major role in determining the speed at which renewable energy capacity can be rolled out, and these are often dealt with differently state-by-state.

Individual states are also subject to a certain basket of policy measures that play a major role in determining what generation type utilities are likely to pursue. For example, tax credits designed to encourage the growth in renewable capacity, feed-in-tariffs guaranteeing higher electricity prices for renewables, or cap-and-trade schemes that seek to price out carbon intensive generation. Despite this, almost half of the growth in renewable electricity generation since 2000 is thought to be due to one policy - Renewable Portfolio Standards (RPS).