Nuclear & Renewables, the Ultimate Power Couple? We Think So

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The challenge of achieving a carbon-free economy by 2050 is huge, and can sometimes seem overwhelming. We’ve already seen a massive and rapid scaling of proven renewable technologies like wind and solar, but realistically, a carbon free economy is not a mountain renewables can scale alone. That’s why, as the deadline for a carbon-free economy looms, we have to expand, rather than constrain, the carbon-free options that will team-up to put us on the path to zero. To some, nuclear and renewables may seem like strange bedfellows, but we think they could be the ultimate power couple. Here’s why:

Seeking: clean and flexible companion

One common misperception about nuclear energy is that it is inflexible, and thus inherently incompatible in a system comprised of variable renewables. But in reality, nuclear is already operating flexibly, and the next generation of advanced reactors will only expand this capability. There are 58 reactors in France that have been operating flexibly for more than 30 years, and that can vary their output between 20% and 100% in as little as 30 minutes. This level of flexibility balances generation and demand, allowing renewables to contribute to the grid intermittently without any additional support from emissions-producing sources like coal or natural gas.

There are also companies working to make the existing fleet and, more importantly, the next generation of reactors more flexible by allowing for even more rapid and efficient ramping. For example, the NuScale small modular reactor (SMR) design has 12 separate modules that can be individually dialed back throughout the day — or even taken offline for an afternoon — to maximize use of renewables during their peak hours and ensure energy demand is met. That means nuclear offers a great support system, giving renewables the space to shine when the sun is out and the wind is blowing, but it’s always there when it’s needed.

Seeking: a relationship worth investing in

There has been a stream of recent analyses concluding that a combination of low-carbon “firm” resources like nuclear energy, together with renewables, gets us to 0x50 at the lowest cost. A recent study concluded that a US transition to a 100% renewable grid by 2040 would require an investment of $4.5 trillion to install new wind and solar and build the transmission lines and storage to provide consistent electricity to all Americans. Aside from the challenge of building out this much infrastructure within such a tight timeframe, this would all come with a huge increase in cost borne by ratepayers. Including technologies like nuclear, however, could cut roughly $500 billion off the price tag — making decarbonization less burdensome on households and businesses, and more likely to overcome political opposition.

If wind and solar are already the lowest-cost resources in some regions (and keep getting cheaper), why does pairing it with a technology like nuclear improve the bottom line? Essentially because getting to a carbon-free grid with only variable renewables will require a significant excess of supply. You have to build enough wind or solar to meet the hour of greatest demand in a given year, even in less-than-optimal weather conditions. When demand is lower, much of the power produced by all this extra capacity goes to waste. Studies suggest the amount of power wasted in a 100% renewables scenario could be 60%-130% of total annual electricity demand. So you end up paying to build all the capacity, but you don’t get paid for half of what it produces. And in the hours when you shine brightest or spin fastest, so do all of your competitors — meaning an abundance of supply drives down the price you can charge.

It’s entirely possible to construct a mostly-renewables grid that avoids these economic pitfalls, but they intensify as wind and solar get closer and closer to 100% of supply. That’s why nuclear and renewables complement each other so well: by adding firm resources like nuclear that can generate power on command, much of the excess supply can be eliminated. When nuclear and renewables band together, the cost of reaching a carbon-free grid could fall by as much as 62%.

Seeking: a partner for new adventures

Decarbonizing the economy goes way beyond the power sector. The power sector is one of the nation’s largest sources of carbon pollution, accounting for 27% of total emissions in 2018. But, what about the other 73%? A significant portion of the remaining emissions can be eliminated by electrifying segments of transportation, industry, and building sectors. This will require new and flexible sources of carbon-free power. And as these sectors continue to ratchet-down their emissions, energy systems that integrate renewables and nuclear can produce multiple products that will help address some of the trickiest obstacles, beyond just power generation.

How, you ask, does this actually work? The National Renewable Energy Lab and Idaho National Lab have analyzed a number of scenarios in which energy systems generate electricity for the grid, but also electricity or heat for other purposes. An Arizona scenario combines nuclear and solar energy, using excess power or heat to run a desalination plant. A hypothetical system in Texas combines nuclear with wind, while directing energy to produce synthetic gasoline. When it comes to producing heat, nuclear can cover a range of needs from running industrial processes at places like chemical facilities, to heating buildings or even entire neighborhoods. Most importantly, in all these cases nuclear energy replaces fossil fuels and reduces emissions.

If the goal is to get to net-zero emissions as quickly as possible, we need to use all of the tools available to us. This includes a massive and rapid scaling of proven renewable technologies like wind and solar, integrating them with our existing carbon-free nuclear plants, and adding in new technologies like small modular and advanced reactors. When nuclear energy and renewables join forces, they offer cost-effective and versatile options for a carbon-free economy — outcomes that neither could fully achieve alone. That’s why we think nuclear and renewables are the ultimate power couple.

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