(The following article summarizes a recently published report on the subject which can be found in the Reports section of this website (under the Resources tab).
The electricity supply mix in the US is changing. A large share of coal power plant capacity has already been replaced with new natural gas and also with renewable power plants in states less reliant on coal. Solar and battery power plant deployment is underway, thanks to Federal tax credits and manufacturing scale economies, especially in states that have predictably high annual solar radiation. Further deployment will be paced by the need to expand transmission capacity and so may in some cases not even keep pace with demand growth resulting from electrification of building and vehicle use.
Cumulative annual US utility scale solar capacity additions reached 30 Gigawatts in 2024. At this rate and assuming comparable rates of expansion of wind power capacity, full renewable decarbonization will require a century or much more. Near term acceleration of US utility scale deployment, while possible, is likely to be derailed by suspension or termination of renewable tax credits.
The Path Forward. As a result, timely solar decarbonization in the US will not be possible without pervasive local action. Review of California’s integrated plan for solar and battery power plant deployment confirms the need for parallel solar decarbonization along both centralized high voltage and decentralized lower voltage pathways. Fortunately, locally determined and financed solar decarbonization is being enabled globally by an expanding range of applications and funding sources, plus an expanding array of mature technologies, including, for example, solar PV panels that enable low grade heat capture to heat water.
Local Action. Solar decarbonization must be enabled by electric utilities and grid operators at least to an extent consistent with their business models and investor expectations. But it must also be enabled by 1) consumer and community adoption of products and systems, e.g., vehicle batteries, that are conveniently inter-operable with solar arrays and stationary batteries, and by 2) economically integrative local decision making and shared values of environmental and social responsibility.
Enabling Technologies. Removing roadblocks to solar decarbonization will be much easier and quicker when citizens and communities can fully exploit the economic, environmental and climate benefits of electric vehicles and zero carbon charging infrastructure. Local investment in microgrids that can operate independently of utility grids will also be necessary, at least until electric utilities can be induced to more proactively integrate their electricity distribution assets with locally owned solar supply and battery storage.
Roadblocks and Reform. Locally determined and financed solar decarbonization is impeded by utility rate regulation that fails to account for the major cost avoidance and environmental benefits of free “radiative” transport of solar energy directly to buildings and brownfield sites in or near communities.