Clean Dispatchable Power

Nuclear power already provides about 10 percent of the world’s electricity, and this figure could rise as nuclear technologies that are safer (including having a lower risk of proliferation), cheaper, faster to build, and produce less nuclear waste are developed.

Researchers are currently investigating a wide range of next-generation fission technologies that improve on today’s Generation III+ reactors. These advanced reactors are characterized by the coolant they use—such as gases (like helium), liquid metals, and molten salt—and offer varying trade-offs between size, safety, cost, and complexity. They can also be built to prioritize resiliency from extreme weather events and the health and safety of nearby communities. Policies to deploy advanced nuclear power must ensure adequate safeguards for low-income communities and communities of color.

Creating energy from controlled nuclear fusion—the fusing of two atomic nuclei—has long been considered a key priority of clean energy R&D. If we can accomplish this feat, we can generate substantial amounts of zero-carbon energy while alleviating some of the challenges around safety, waste, and weapons proliferation associated with nuclear fission.

But despite more than 60 years of research, we have yet to achieve controlled fusion for energy production. Even when we do, making fusion cost-effective will remain a significant challenge. That said, innovative new approaches in recent years have given rise to a fusion technology renaissance that may still open the way to cheap, reliable, emissions-free fusion energy for the world.

Geothermal electricity is generated by using an underground geothermal resource to heat water or another fluid, which then turns the turbine of a generator. If we can find a cost-effective way to tap into it, Earth’s vast reserves of deep geothermal heat present a huge opportunity to provide large amounts of zero-carbon power: experts estimate more than 1,000 GW are readily available in the U.S. alone.

Enhanced geothermal systems (EGS), which provide access to a wider range of temperatures and rock formations than conventional resources through new drilling and fracturing techniques, can open more parts of the U.S. to geothermal development. Advances in EGS will bring down costs and improve performance. New technologies for extracting heat at higher efficiencies from lower temperature resources can also expand the use of this vast, safe, and underutilized energy resource.

In a fuel cell, electrons are split from fuel and pass through an external circuit, creating a flow of electricity. A variety of fuels can be used: hydrogen is the most common, and its only byproduct is water. Fuel cell technologies can help offset the inherent variability of wind and solar power.

When coupled with a hydrogen electrolyzer with hydrogen storage, this system could act as energy storage for the electric grid. For fuel cells to truly provide cost-effective flexibility on the distribution grid, we need transformational advances that make them significantly more affordable. The production of hydrogen for these fuel cells also needs to be decarbonized for the technology to become a viable alternative to fossil fuel-based incumbents.

One of the most promising solutions for dramatically reducing CO₂ emissions from large-scale fossil fuel power plants lies in carbon capture technologies. CO₂ can be captured from the fuel before combustion via gasification or reforming, for example. It can also be captured from the exhaust gas of the plant, typically using a thermally regenerated amine-based process. The fuel can also be combusted in pure oxygen, resulting in a purer and easier to capture CO₂ stream. The captured CO₂ can then be put to a productive use or stored securely underground.

Further development of low-cost, highly efficient CO₂-capture technologies can make this potentially powerful emissions reduction solution a widespread commercial reality, provided it is paired with policies and technologies that address other pollutants from fossil fuel production and combustion. Carbon capture technologies have faced some criticism from environmental justice and other groups concerned with local air quality and land use impacts. Durable policy support for these technologies should include consideration of all air quality and economic impacts, especially those affecting low-income and historically disadvantaged communities.

Hydropower provided 6.5 percent of total electricity and 40 percent of renewable electricity in the U.S. in 2018. While this is a carbon-free electricity source, constructing new dams often generates resistance, large hydropower projects are subject to cost and schedule overruns, and many old dams are nearing the end of their current permits and face challenges in re-permitting.

Distributed, low-head hydropower could resolve many of these challenges, but costs remain prohibitive. At the same time, existing technologies do not mitigate many of the environmental concerns associated with large dams, such as fish passage and ecological disruption. New kinds of turbines could help mitigate these concerns and enable more hydropower development, while streamlined permitting can accelerate existing timelines.