Updated: Jun 1, 2020
Energy analysts used power demand data from the Midwest’s January deep freeze and wind and solar conditions to find the gaps in an all-renewable power grid. In short, energy storage is critical for cities and states in a 100% renewable energy United States.
Almost every power plant in the United States was running during the polar vortex late January. Energy analysts used that week as an experiment for how 100% renewable energy would perform in extreme climates. How much battery power would be required?
Researchers used energy production data combined with power demand to show how a grid powered by 50% wind energy and 50% solar energy would be stretched from the limited sun and wind available. Their conclusion? A lot of storage would be needed.
"You would need a lot more batteries in a lot more places"
said Wade Schauer, a research director for Wood Mackenzie Power & Renewables, who co-wrote the report.
More Than Today's Storage is Needed
Currently, there is 11 GW of battery storage in the grid regions that include New England, New York, the Mid-Atlantic, the Midwest, and parts of the South. Schuaer's analysis shows that battery storage would need to be increased to 277.9 GW. That's about double Wood Mackenzie's forecast for battery storage nationwide by 2040.
Energy storage is key to the Green New Deal and its transition to 100% renewable energy. The country would need to transform the energy grid, increasing interstate power lines, renewable energy production, and storage. The grid needs to be able to meet demands on days with extreme swings in temperature, both hot and cold. This is expected to happen as fossil fuels recede, but not at the scale that the report deems necessary.
The report found that there would be gaps of up to 18 hours where wind and solar energy would not meet energy demand during the polar vortex. The grid would have to be designed to best use wind and solar when they're available and to store the excess when those resources are providing more electricity than needed, a fundamental shift from the way most of the system is managed today.
Visible on the graph, there is more time that storage is necessary, but when storage can recharge, it can do so in such large amounts that it can easily compensate for when storage is needed. The storage just needs to be put into place.
Battery systems account for much of the growth of energy storage, thanks to the falling prices of batteries. However, they don't make up the majority of the current energy storage mix. The majority of energy storage comes from decades-old pumped hydroelectric systems.
This Can Be Done
Cities and states are already working with utilities to get more energy storage. However, analysts project that the most challenging part of renewable energy and energy storage increases is politics. Politically, Mark Jacobson, a Standford University professor who has looked at how renewable energy and energy storage can meet the United States' needs, says that an 80% goal by 2030 might work better on opposers of the Green New Deal, and 100% coming shortly afterward.
Schauer said that local politics will be the greatest challenge in the transition to all-renewable energy. To handle a big increase in wind, solar, and storage, communities would need to be willing to host those projects along with the transmission lines that would move the electricity.
"I'm not  to say any of this is impossible, but there are some basic challenges to pull this off in a short period of time, mainly NIMBYism"
he said, referring to the not-in-by-backyard sentiment that fuels opposition to transmission lines.
The Wood Mackenzie report doesn't discuss managing electric demands, which is also a key part of 100% renewables. New technology would have to be introduced to control energy demand.
The report also found that nuclear energy would need less energy storage to provide for the needs, but it also carries with it a whole host of environmental hazards.
The report only focuses on a few cold days in the year. Schauer has done a similar analysis of 2018 as a whole, which gives similar lessons. He said,
"It gets even more challenging when you extrapolate to the entire year"