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[Episode #188] – Getting to a 100% Clean Grid

How much of a role might wind, solar, nuclear, transmission, power plants equipped with carbon capture and sequestration (CCS) technology, or direct air capture of CO2 play on a 100% clean power grid? Which mix of those technologies would provide the cheapest pathways to a clean grid?

And once we have met 90% of the need for grid power with clean generation, what will we need to meet the last 10% of the demand for grid power? Will it be ‘overbuilt’ wind and solar? Dispatchable geothermal, hydropower, and bioenergy generators? Seasonal storage using hydrogen or batteries? Conventional fossil-fueled plants with CO2 capture? Or might it be some mix of flexible demand technologies? Or some or all of the above?

For that matter, how certain can we even be about modeling the possible solutions years or even decades ahead? Are there solutions that might play a large role in the future but that we can’t yet model very well? How confident should we be that whatever the solutions turn out to be, we will end up with not only a grid that is completely free of carbon emissions but also one that is fully reliable?

In this episode, we speak with a senior researcher at the US National Renewable Energy Laboratory (NREL) who has been researching and modeling grid power for many years. In this quite technical discussion, we review two new NREL reports that address these questions and show that producing a 100% clean power grid is not only technically feasible by a variety of pathways but also commercially feasible and ultimately, cheaper than continuing to run the fossil-fueled power grid we have today.


Paul Denholm is a member of the Transmission Group in the Grid Planning and Analysis Center and also a senior research fellow—the highest technical position at the National Renewable Energy Laboratory (NREL)—leading research in grid applications for energy storage and solar energy. He pioneered a variety of research methods for understanding the technical, economic, and environmental benefits and impacts of the large scale deployment of renewable electricity generation. He has delivered over 100 invited presentations to agencies including the National Science Foundation, the World Bank, and the International Energy Agency. He has co-authored over 100 articles related to renewable energy integration. While his official title is principal analyst, he is still an engineer at heart and in his free time he likes to build contraptions of dubious functionality, like a concentrating solar marshmallow cooker.

On the Web: Paul Denholm’s page at NREL

Recording date: November 29, 2022

Air date: December 21, 2022

Geek rating: 9