NREL Finds Potential Pathways to the Great Challenge Ahead: Achieving 100% Clean U.S. Electricity by 2035

By Juan Torres, Associate Laboratory Director for Energy Systems Integration, National Renewable Energy Laboratory

At the National Renewable Energy Laboratory (NREL), we like tackling the biggest challenges. And we like dreaming big too.

A recent study by our NREL energy analysts combines both of those traits to identify potential pathways to a decarbonized U.S. power sector by 2035. Titled “Examining Supply-Side Options to Achieve 100% Clean Electricity by 2035,” this latest report is notable for its wide-ranging examination of our energy choices and their potentially beneficial consequences.

I mentioned dreaming, but Examining Supply-Side Options to Achieve 100% Clean Electricity by 2035 is no pie-in-the-sky fable. It doesn’t pretend to paint a picture of an easy way forward during the next decade or so. There isn’t one. And it is not prescriptive: The exact energy technology mix to achieve 100% clean electricity by 2035 will largely depend on R&D over the next decade.

By considering several new factors in four main scenarios, the report presents costs, benefits, challenges, and opportunities for the United States to attain all of its electricity from clean sources by 2035 — defined as net-zero greenhouse gas (GHG) emissions. Achieving this could set the United States on a path to economywide net-zero emissions by 2050. As with any such ambitious endeavor, there are multiple variables that could change and determine the exact path the United States takes. I encourage those who want to take a deeper look to read the full report.

The new report comes on the heels of the enactment of the landmark Inflation Reduction Act (IRA), which — in tandem with the Bipartisan Infrastructure Law (BIL) — is estimated to reduce economywide greenhouse gas emissions in the United States to 40% below 2005 levels by 2030. The impact of the IRA and BIL energy provisions are expected to be most pronounced for the power sector, with initial analyses estimating that grid emissions could decline to 68%–78% below 2005 levels by 2030.

None of the scenarios presented in the report include the IRA and BIL energy provisions, but their enactment is not expected to significantly alter the 100% scenarios explored — and the study’s insights on the implications of achieving net-zero power sector decarbonization by 2035 are expected to still apply.

Here are some key takeaways: For starters, creating an electricity system without GHG emissions requires unprecedented clean energy deployment. Overall, we’ll have to commit to building up not only generation capacity, including generation from such sources as wind energy and solar energy, but also increasing our average annual installation rate of renewable technologies. In order for this to work, the authors foresee doubling or tripling the electricity transmission system — a truly eye-popping number. This increased transmission capacity could be especially significant to access renewable energy in the Midwest and West.

Further, achieving the 100% goal will require not only upgrading the current distribution system. It will also require building new pipelines and storage for hydrogen, as well as a pipeline and storage network for CO2 that is captured from power plants and other sources. Although wind and solar technologies will provide the most increases in clean energy, the report additionally considers deploying nuclear energy and various carbon management technologies.

The NREL analysis demonstrates the potentially important role of several technologies that have not yet been deployed at scale, including seasonal storage and several carbon capture and storage (CCS)-related technologies. The blend of these technologies varies significantly across the evaluated scenarios depending on technology cost and performance assumptions.

This study doesn’t simply assume that everything will fall in line. Indeed, differences in energy contribution among the four core scenarios of the report are largely driven by possible constraints in transmission and renewable siting. Not everything goes ideally in the real world. Our analysts understand that, and that’s why they examine the four scenarios capturing a range of possible uncertainties. One thing remains the same throughout: All of this expansion must be done with low environmental disturbance and in an equitable fashion to all communities.

It’s quite a balancing act, yet NREL’s expert analysts and leading-edge tools are up to the task. Across the scenarios, our team used NREL’s Regional Energy Deployment System (ReEDS) model.

This computer model allows us to identify the resulting least-cost investment portfolios from a range of different generation, storage, and transmission technologies. At the same time, ReEDS considers the significant geographical variation in demand and resource availability. Finally, this NREL computer model has the capacity to drill down into regional and temporal variations in the output of renewable resources — boosting the reliability of the conclusions.

As I mentioned, the main uncertainty in reaching 100% clean electricity is the mix of technologies that achieves this target at least cost — particularly when meeting peak demand periods or during periods of low wind energy and solar energy output.

That precise energy generation blend will develop over time. Obviously, there’s much more work to be done and more refinements to be calculated. Further study is needed to evaluate trade-offs among electrification, energy efficiency, distributed energy resource deployment, and other demand-side measures in reducing emissions. All this must be accomplished while ensuring the lowest cost for households and other energy consumers.

Down the road, I anticipate that the full range of benefits attributed to power sector decarbonization will be quantified. And we intend to continually address the intersection between power sector decarbonization and environmental justice. There’s a lot to do in a relatively short time. We are not there yet. But with Examining Supply-Side Options to Achieve 100% Clean Electricity by 2035 as a guide, we have a better understanding of what it will take to reach our destination and help curb the effects of climate change.