Governments across the world are issuing ambitious plans to decarbonize electric and transportation systems. This dual decarbonization effort to increase plug-in electric vehicles (EVs) and renewable generation will create challenges for electricity grids, but also presents an immense opportunity for electric vehicles, i.e. “energy storage on wheels,” to enable a more cost-effective, cleaner electricity grid, at a fraction of the cost than if supported solely by stationary energy storage. The convergence of these two market trends will transform the management of the electricity system, as renewable electricity is inflexible and intermittent, and the proliferation of electric cars will grow, alter and challenge historical patterns of electricity demand. However, smart EV charging, or V1G, can provide a range of grid services through intelligent modulation of unidirectional energy flows from the grid to the vehicle, such as real-time grid balancing, reducing energy costs, integrating intermittent renewable energy, reducing air pollutants and deferring expensive infrastructure upgrades.
The rise in everything electric & renewable
From electric scooters to cars, trucks, and buses, there is a growing appetite for electric vehicles from governments, businesses and consumers. According to Bloomberg, there will be more than 100 battery-powered electric car models available by next year, and BNEF forecasts that by 2022 EVs will cost the same as their internal combustion counterparts. This is anticipated to drive record sales growth and lead to an inevitable decline of internal combustion engine (ICE) vehicles.
In conjunction with ZEV mandates, many regions are setting ambitious renewable energy goals. China, which accounts for nearly half of the world’s electric car sales, has created a quota for automakers with annual vehicle sales of more than 30,000 to comply with a 10 percent plug-in vehicle sales quota in 2019, 12 percent in 2020, and at least 20 percent by 2025. China’s aggressive New Energy Vehicle (NEV) mandate attempts to curb local air pollution and clean up its streets, while simultaneously reducing its dependence on coal with a Renewable Portfolio Standard of at least 35 percent by 2030. Similarly, California, which represents the world’s fifth largest economy, has taken a three-pronged strategy by mandating a carbon-free electric grid by 2045 and setting goals of a decarbonized economy by 2045 and five million ZEVs by 2030, matched with 260,000 public charging ports by 2025. Already, California has over 490,000 registered electric vehicles and North America has over 1 million. Vehicle-grid integration in 2019 will serve as a key factor for California to achieve its longer-term decarbonization goals efficiently.
EV Smart Charging, A Large and Highly Flexible Load
In 2013, California mandaed the procurement of 1.3GW of stationary storage by 2025, in part, to address the resulting grid challenges from increasing intermittent solar and wind generation -- before the State increased its carbon-free electricity goals two-fold. It is even more critical for California’s electric grid to secure all low-cost sources of flexible demand to help balance supply and demand at every time scale needed. The growing fleet of EVs across the state, if dynamically managed, can supply this much-needed flexibility at a much lower cost than stationary energy storage. Good utility and regulatory practices call for first developing and utilizing lower cost resources on the supply curve of flexibility and reliability services before proceeding to higher cost sources.
The authors of a recent Lawrence Berkeley National Laboratory (LBNL) study found that with only one-way electric vehicle charging control, or V1G, “California can achieve much of the same benefit of its Storage Mandate, but at a small fraction of the cost. By displacing the need for construction of new stationary grid storage, EVs can provide a dual benefit of decarbonizing transportation while lowering the capital costs for widespread renewables integration.”
Solar and wind generation are intermittent, so maintaining a cost-effective balanced grid by matching electricity supply and demand is essential to “keeping the lights on” as an affordable and expected customer service. By increasing solar generation to meet California’s SB 100 commitment, the belly of the duck curve is expected to become more dramatic as more renewables are deployed. Mid-day over-generation and sharp evening ramps once the sun sets are considered to be the most severe challenges, and LBNL demonstrates how productive vehicle-grid integration could be for California. For example, a daytime solar glut leads to substantial problems with over-generation, but could be mitigated by shifting and managing electric vehicle charging to align with daytime solar generation.
LBNL examined how delaying and ramping charging could help with peak shaving, valley filling, and reducing steep changes in supply and demand. The authors found that in a V1G-only case, there are substantial benefits for ramping mitigation and day-time valley filling, while V1G residential charging can avoid exacerbating the evening peak of the duck curve. Specifically, a 1-gigawatt virtual battery consisting of 1.5 million smart charged electric vehicles could replace most of the grid-scale stationary storage and save $1.3 - 1.6B in renewables integration costs, while providing the same flexible capabilities as stationary storage.
