While renewable energy sources have grabbed the spotlight, another crucial element in the development of a more sustainable electricity grid — large-scale energy storage — is demanding more attention. In the past, the lack of energy storage options has been a speedbump in the grid’s evolution. But technology is making a difference — as are policy shifts at the state and national levels.
California is an example of that progress. In Assembly Bill 2514, lawmakers required actionable plans from major private utilities for large-scale energy storage by 2020. When the legislation was passed five years ago, the technology to achieve that combined goal of 1,325 megawatts (MW) was a big reach for Southern California Edison, Pacific Gas & Electric and San Diego Gas & Electric.
But thanks to steady advances in the development of bigger, better and more affordable lithium-ion battery technology, those utilities are expected to meet that goal.
The Challenges of Large-Scale Energy Storage
Increasingly, energy from wind turbines, solar panels and other renewable sources are powering the nation’s grid. But these sources are intermittent, producing energy only when the sun shines or the wind blows. It’s a big handicap when it comes to power distribution.
How can this electricity be stored so that renewable energy can play a more meaningful role in delivering reliable power to the consumer? Scientists have been working toward a solution for energy storage for a long time, from pumped hydroelectric storage in the 1920s to Tesla’s recent launch of an energy-storage business.
From Pumped Hydro to Lithium-Ion Batteries
In pumped hydro energy storage systems, water is held in a reservoir at a high elevation. When released, it generates power by flowing through turbines on the way to a lower reservoir. Though the pump stations experience electrical losses from pumping, the technique can achieve 80 percent efficiency. Today, more than 22 gigawatts of pumped storage is installed on the grid.
Because of environmental concerns, pumped hydro fell out of favor in the 1970s, and no new facilities have been built in the past 30 years. The Sacramento Municipal Utility District recently won approval for a new facility, but only after a decade-long permitting process. Other technologies have emerged — including thermal storage, flywheels and compressed air — but none are yet suitable for widespread use.
Battery technology seems the most likely way to fulfill the need. But as recently as five years ago, lithium-ion batteries were too expensive and inefficient to satisfy utility capacity requirements. In the past few years that’s begun to change, thanks to a big push by the automotive industry into electric- and hybrid-powered vehicles coupled with interest from utilities. By 2017, lithium-ion batteries are expected to push over the capacity and cost barrier, developing into a $25 billion global market.
Moving Forward with the Tehachapi Demonstration Program
Southern California Edison is already moving forward. The utility has partnered with the U.S. Department of Energy to harness the power from wind turbines in the Tehachapi Wind Resource Area, which are expected to generate up 4,500 MW by 2016.
The two-year demonstration project consists of 604,832 lithium-ion batteries — the same type of cells used to power the Chevrolet Volt. Combined, the batteries can store 32 MW-hours of electricity, enough to power up to 2,400 homes for four hours. Ultimately, the widespread introduction of battery energy storage should help utilities hold down costs to consumers and provide a more reliable way to tap into renewable energy sources.
Webinar Examines Storage Mandate Challenge
At Burns & McDonnell, we’re paying attention to the advancements in battery storage — and the state policy shifts that support the trend. We recently hosted a webinar about Assembly Bill 2514, exploring how Southern California Edison responded to the challenge laid out by state officials. We provide engineering, procurement and construction (EPC) services to help utilities explore this new opportunity for energy storage. Check out the webinar or comment below to learn more.