Today, Southern California Edison has close to 500 MW of energy storage either operating or under contract to be developed. We have energy storage operating in the desert (Tehachapi), in cities (Santa Ana), next to cow pastures (Ontario), and on an island (Catalina). And, along with California’s other investor-owned utilities, we are on track to surpass the state’s goal to have 1.5 GW of energy storage procured by 2024. But, as much as this is a good start, it is also a very small start.
In our roadmap paper, The Clean Power and Electrification Pathway, published in October 2017, we suggest that California will need up to 10 GW of energy storage by 2030 to meet its greenhouse gas reduction goals and to support a grid that is 80% carbon free. That is, we need close to seven times as much storage to come on line in the next 12 years as California currently requires through legislation and regulation. This storage will be integral to the supply and distribution of energy in California as traditional fossil-fired generation plants are retired or have restricted operations.
So we need to think more about energy storage conceptually. We are getting storage right when it is adaptive, flexible and scalable. In other words, when it is intelligent, and when it meets a specific need.
We have three tests for usefulness:
1. What is the utility use? Does it improve our performance, reduce our costs, fix a problem or help us to meet state mandates?
2. How do customers benefit? We are a sales “decoupled” utility, so anything that improves our power-supply bottom line flows through to our customers. Our customers are also increasingly interested in having choices—and energy storage can facilitate those choices. For instance, we are looking at how we pair energy storage, EV charging and rooftop PV to offer customers the ability to take advantage of the energy they generate to power their own vehicles. A clean energy win-win.
3. What are the societal benefits? Can an energy storage system harmonize different assets in order to help meet California’s GHG reduction goals? Can an energy storage system support California’s move (as mandated in recently passed legislation) to deliver 100% carbon-free energy?
Through this lens, we have some thoughts about where energy storage can provide solutions.
We potentially need long duration (i.e., multi-day) storage that can bridge the gap between solar and wind resources during significant weather events, to reduce the need to retain standby fossil-fired generation and protect against curtailments.
We need to figure out how to harness distributed solar, and to mitigate the large ramp up that happens in the late afternoon when demand for energy sharply increases and solar energy goes dark.
We need to consider how to pair transportation electrification, particularly fleet electrification, with storage to create beneficial synergies. We have a tremendous opportunity to reduce both GHG emissions and air pollution by electrifying medium and heavy duty fleets. But charging is a challenge—both for fleet owners, and for the grid. As the trucking industry is starting to plan for electrification, some have called for as much as 4.5MW of charging power per truck. This level would be impactful on local facilities and the grid if unmanaged.
Smart energy storage systems will be able to support grid reliability or fast-battery applications to improve power-quality on a circuit, and could participate in advanced applications such as battery networks that can collaborate at the circuit, substation and system level. Realizing this full potential of energy storage will require investing in energy storage systems that are connected, software configurable, cyber secure and accessible for customer, utility, and energy service providers.
At SCE, we have been working towards this concept of intelligent energy storage for more than a decade. Our 2017 Hybrid EGT projects pair existing gas-fired peaker plants with energy storage and a new control system. The batteries provide just enough storage –10MW/4.3MWh – to bridge the approximate 5 minute gap it takes for the peakers to come online, creating the equivalent of an instant-on system that enables non-spinning reserves to become spinning reserves. On the distribution grid, our new 2.8MW/5.6MWh Connolly energy storage system will demonstrate how to use storage to better integrate high solar penetration.
These projects, and all of the demonstrations, pilots and on-line projects now in our system demonstrate more than anything that we haven’t gotten here by ourselves. Our vendors have been our close partners. They have developed the control, communication and energy systems for our energy storage projects, and are continuing to invest in developing more interoperable, secure and network-centric solutions. Together, we are building out a rich, distributed energy ecosystem that will help us meet our sustainable energy goals.