Charles Landau, MPA, Staff Writer, Brief Policy Perspectives
The U.S. is increasingly investing in a future where more of our energy comes from renewable sources. Because these sources such as wind, solar, and hydroelectric power are intermittent and unreliable, energy innovators also need to invest in creating batteries that can store renewable energy when society’s needs outpace supply at a given moment. Higher quantities of better batteries are also needed for reasons beyond the need to store energy.
The Intermittent Power Issue
Currently, the U.S. plans its grid needs based on sources of reliable, consistent energy at “peak load.” Peak load is the maximum amount of energy demanded at a point on the grid over a given period of time. Of course, wind and solar energy sources can only create electricity based on the amount of wind blowing or sunlight received. If the U.S. is going to build a grid that can accept renewable energy at scale, policymakers will need to incentivize energy providers to find ways to create a consistent energy flow despite intermittent energy flows. The best way to accomplish this is by investing in batteries.
Charging the Business Proposition
The National Renewable Energy Laboratory (NREL) released a study in August that compared the economics of so called “solar plus batteries” installations to solely solar installations. They concluded that pure solar installations would have a lower cost of energy, but that solar plus battery installations would have an economic advantage by 2020. Because these installations have a long lifespan, that analysis informs decisions being made today.
Another extremely important way that batteries apply to the renewable energy industry is for load shifting. For example, there are some places where the busiest time of day for the energy grid occurs after the sun goes down, so energy providers could use a massive amount of batteries at too high of a cost to store solar-generated energy collected during the day and use it during the busy period hours later. Solar City’s “Gigafactory”, a massive (and headline-grabbing) lithium-ion battery factory in Nevada, is ramping up production, but those batteries are mainly used in electric cars. For grid applications, perhaps the more applicable batteries are “vanadium redox flow” batteries. These batteries, many based on a special molecule developed by the Pacific Northwest National Lab, are bigger, and have charging, capacity, and discharging behavior that is much better suited to grid-scale applications. For a comparison, see Figure 1 above. The best solution for load shifting may not involve cool-looking in-home batteries.
Even with new technologies, grid-scale battery-based load shifting would be difficult to execute. Up-front costs, inefficiencies in the storage medium, and the rate at which a given battery can discharge its stored energy all conspire to make the proposition costly or impractical. There are other, perhaps simpler applications for smaller scale load shifting with batteries. For example, providers can deploy and install batteries on substations to improve the reliability of the energy distribution system. Also, as electric vehicles become more popular, the energy demand at night will skyrocket as drivers returning home to charge their cars, l straining the grid. If providers couple residential battery installations and smart controllers, providers could stagger that energy demand into batches to prevent the residential load from spiking. For example, sending all the houses on block A a signal to only charge their car from batteries, then block B, and so on. Although the technology is still being developed, automakers could eventually connect electric vehicles to the grid to support electricity distribution, but this application may be too costly or technologically difficult. There are skeptics and supporters of each of these applications, but all concede that there are plenty more ways society could use batteries.
Watch This Space
It’s hard to predict how grid-supporting batteries will develop, but with so many potential applications being explored and analyzed, there’s a lot to be excited about. Policymakers should continuously evaluate the potential applications for battery deployment to support the grid, find ways to increase public and private sector investment in battery technologies, educate themselves on technological developments, and include battery deployment plans as part of their comprehensive energy strategies.