How Nuclear, Batteries and Energy Storage Can Build a Carbon-Free Future

Energy storage technologies—and batteries in particular—are often seen as the “holy grail” to fully decarbonizing our future electricity grid, along with renewables and nuclear energy—which provides more than 56 percent of America’s carbon-free electricity.

“I like to say that the future energy system is going to be a lot of nuclear and a lot of renewables,” said Idaho National Laboratory Director Mark Peters. “When I talk about a lot of nuclear and a lot of renewables, that would [mean] a lot of batteries—a lot of storage on the grid.”

But what is energy storage?

On the grid, electricity flows from power producers to consumers, moment-to-moment as it’s needed. Operators monitor the system so that electricity supply exactly equals demand. Well, what if you generated electricity now, but kept it ready for use when you need it? That’s energy storage in a nutshell.
There are many ways to store energy on the grid, each with their own advantages, including:

• Lithium-ion batteries. These are the most recognizable form of energy storage. A lithium battery functions the same as the battery for your smartphone, except on a scale large enough to power neighborhoods instead of just your Twitter habit: electricity is stored as chemical energy and discharged back onto the system when it is needed. While they’re still expensive and too small-scale to store bulk amounts of power, these batteries have a quick response time and can offer other necessary services to the grid in addition to storing energy.
• Pumped hydroelectric storage. This is actually the most common form of energy storage currently used on the grid, as it makes up 94 percent of all U.S. energy storage. Instead of holding electrical charge, these types of hydroelectric plants pump water uphill to a reservoir, and when energy is needed, release the water down the hill to turn turbines and generate electricity. It’s an effective and mature technology—meaning that everyone knows how it’s going to behave in a variety of circumstances, which is an asset to grid operators.
• Thermal storage. This option involves using electricity for heating or cooling. The process doesn’t store the electricity itself, but basically offsets its use. Thermal energy is stored usually in water—or as ice—and can be affordably insulated and used for air conditioning or heating needs when necessary. Google is looking into a system that would store electricity as heat in molten salt and be able to convert it back into electricity later.
• Hydrogen storage. Hydrogen offers a unique opportunity to decarbonize additional sectors of the economy. Once produced, by using electricity to split water molecules, it can be burned to generate electricity again or it can be fed into fuel cells, in buildings or on board vehicles. The fuel cells produce nothing but electricity and pure water. In cars or buses it would reduce carbon emissions by substituting for gasoline or diesel.

Energy storage benefits renewable energy sources, since it will be able to take the excess electricity from wind and solar during times of peak production and low demand—during the day for solar and in the evening for wind—and push it back onto the grid when the sun isn’t shining and wind isn’t blowing.

Once storage technologies are large enough scale, cost-effective and efficient, it will benefit variable renewables and baseload nuclear. Keeping supply and demand in balance is good for the grid.

Nuclear energy is essential to a clean energy future and can work to protect the climate alongside energy storage. When it comes to nuclear energy’s role, more climate advocates are realizing that any climate solution requires nuclear energy.

“We absolutely need nuclear power as part of the solution,” said NEI’s President and Chief Executive Officer Maria Korsnick at a recent Washington Post Live event.

Proponents of both nuclear and storage share a common goal of lowering carbon emissions; many power companies have been working to see how these technologies can complement each other:

• Exelon Corp. has partnered with the U.S. Department of Energy—through DOE’s national laboratories consortium, H2@Scale—to look into using power from its nuclear plants to produce hydrogen without carbon emissions. Exelon is also a founding member of Volta Energy Technologies, which is focused on investing in startups developing storage technologies.
• Duke Energy Corp. is currently looking into whether it’s feasible to use battery technology in nuclear plants to replace a diesel generator used for maintenance and potentially reduce the duration of maintenance outages.
• Additionally, energy storage has already been built with nuclear energy in mind. Ludington Pumped Hydro Storage Plant was originally built to help baseload sources in Michigan, like nuclear plants, run efficiently during off-peak hours and make the electricity more dispatchable.

“If you want to decarbonize the economy, nuclear is very important. Storage is also very important to be able to integrate other types of clean energy sources,” said Ugi Otgonbaatar, Exelon’s manager of corporate strategy.

Reaching a clean energy future will take every tool available. Developing energy storage and preserving nuclear plants provide a path forward to make that dream a reality.

[Photo: Shutterstock]