By Laura Wisland, Union of Concerned Scientists
On October 23, 2015, Southern California Gas Company employees discovered a massive natural gas leak at the Aliso Canyon storage facility, located 30 miles northwest of downtown Los Angeles. The leak was the largest human-caused release of methane in U.S. history.
In addition to releasing a tremendous quantity of a potent greenhouse gas into the atmosphere, the methane sickened nearby residents for weeks, causing headaches, nausea and severe nosebleeds.
The Aliso Canyon leak and its impacts on local residents is an unwelcome reminder of the many risks of California’s overreliance on natural gas. Overreliance on a single energy resource leaves communities vulnerable to supply shortages and price spikes. And, in addition to the ever-present prospects of gas leaks and explosions, the state’s dependence on natural gas is an increasingly large barrier to meeting its greenhouse gas reduction goals.
Despite the downsides, California’s natural gas fleet provides an important source of generation capacity and flexibility for when renewable energy is not readily available. Therefore, one of California’s biggest challenges is to figure out how to maintain grid flexibility and reliability while reducing dependence on natural gas and dramatically ramping up renewable energy power generation.
Fortunately, the tools are available to provide many of the renewable energy integration and grid reliability needs that natural gas plants currently provide, making us less vulnerable to gas supply shortages like the one caused by the Aliso Canyon leak. These include:
- A diverse renewable mix – Because different types of renewables generate power at different times, procuring a diverse set of renewables will create a more consistent flow of electricity, reducing the need to rely on gas to fill in gaps in generation.
- Increase coordination between grid operators – Pooling generation across a larger area makes it easier to obtain flexible generation reserves. This makes better use of existing natural gas assets, which means that more renewables can be integrated without building new plants.
- Target energy efficiency in evening hours – Implementing programs to save energy at night, when California’s world-class solar resource is not available, will reduce the need to ramp up natural gas plants.
- Deploy energy storage – Pumped hydropower, compressed air, and batteries can be used to store excess renewable generation. This helps extend the amount of time we depend on renewables–not gas–for energy needs. Storage can also provide some fast-ramping grid balancing services currently provided by gas.
- Shift electricity demand to align with peak renewable output – Demand response technologies, which enable electricity users to shift consumption toward times of the day when renewable generation is high and reduce the need for ramping up gas plants during other periods of the day. Load shifting can happen manually, or automatic signals can be sent to industrial equipment, home appliances, and electric vehicles so that the usage shifts happen imperceptibly (without affecting usability), avoiding the need for electricity users to make decisions. Demand response technologies can also be used to provide grid balancing services by adjusting levels of electricity demanded in smaller segments for shorter periods of time.
- Enable renewables to provide grid balancing services – As the state moves to a grid where the majority of the generation units are renewables, these facilities should have the option of providing some of their own grid balancing services. Providing some of these services with renewables will reduce the need to rely upon other forms of flexible generation, like natural gas.
As we contemplate the fallout from Aliso Canyon, the need to transition away from natural gas is crystal clear. The good news is that California has all of the tools it needs to achieve a much cleaner electricity supply while maintaining a consistent and affordable flow of electricity. By investing in low-carbon technologies that provide grid flexibility and reliability services, California will reduce its dependence on natural gas and ensure its renewable energy integration efforts succeed.