ENERGY | ENERGY STORAGE (UTILITIES)
RANKING AND RESULTS BY 2050 #77
AN ENABLING TECHNOLOGY—COST AND SAVINGS
ARE EMBEDDED IN RENEWABLE ENERGY
About eleven thousand years ago, when we humans shifted from hunter-gatherer mode to permanent settlements and agriculture, we started learning about storage. We had no choice, really, because those first crops yielded temporary surpluses that had to be protected from mice and humidity. Earthen, wooden, then ceramic granaries were the early answers. Nowadays we excel at storage. If we make it, we contain it… with one notable exception. The most fundamental commodity in the industrialized world—electricity—is one for which storage in volume has not been considered. What is the hedge against brownouts, blackouts, and inefficiency. In the absence of large-scale energy storage, utilities rely on highly polluting “peaker” plants that they rev up to meet high demand. As we seek to reduce emissions from electricity production and enable the shift to variable renewable sources of power, storage is doubly vital.
How does a utility store large amounts of electricity? One option is pumping water from lower reservoirs into higher ones, ideally fifteen hundred feet higher. The water is released back down into the lower reservoir as needed and runs through power generation turbines. Utilities pump the water at night, when electrical power is in surplus, and bring it down again when demand and prices peak. IN an example, General Electric has teamed up with a German company to create energy when there is no wind. The project requires a sloping topography with four wind turbines working in concert to generate energy to pump water from a reservoir at a lower elevation to a reservoir at a higher elevation. When wind is lacking or demand is high, the water flowing downhill powers a conventional hydroelectric plant. All told, there are more than two hundred pumped storage systems in the world at present, accounting for 97 percent of global storage capacity. It is an opportunity that works when topography obliges.
Nevada is experimenting with energy storage by rail. Here where there is no water, gravity can still be enlisted.
Concentrated solar power plants are also at the forefront of energy storage, where molten salt is used to hold heat until it is needed to generate electricity.
Then, there are batteries at scale. Some utilities are installing banks of lithium-ion batteries to help meet peak demand. By 2021, Los Angeles plans to take it natural gas peaker plant off-line, replacing it with eighteen thousand batteries that will be charged by wind power at night and solar in the morning, while energy needs are low. And dozens of start-ups and established companies are racing to create low-cost, low-toxicity, and safe (no spontaneous ignition) batteries that will revolutionize energy storage from flashlights to utilities—batteries of the future.
IMPACT: Taken on its own, the production of energy storage does not reduce emissions; instead, energy storage enables adoption of wind and solar energy. No carbon impact numbers are included above in order to prevent double counting with the variable renewable energy solutions themselves. As with other forms of grid flexibility, the costs and total growth are not modeled directly.