Mitigating renewables curtailment and carbon emissions in California through water sector demand flexibility

Increased renewable energy deployment in places like California have led to more frequent curtailment of these resources when their generation exceeds simultaneous demand for electricity, resulting in wasted opportunities for electric grid decarbonization. Public potable water distribution systems, which account for approximately 1.2% of statewide electricity demand, may be able to shift the timing of their operations by filling their storage tanks when renewable energy is prevalent to help the California energy grid reduce renewables curtailment, grid emissions, and peak energy demand. We simulate the water demand, pumping, and energy demands of 702 public water distribution systems serving 84% of Californian residents under eight different energy pricing and emissions minimization scenarios. We find that the potable water distribution sector in California has the flexibility to shift its energy demands by up to 1071 GWh annually, reduce renewable energy curtailment by up to 68%, reduce the net demand peak by up to 321 MW, and avoid 330,627mTCO2e of emissions. The scenarios that led to the greatest load shifting and emissions reductions included time-of-use energy rates that incentivize consumption during the middle of the day without a demand charge. The findings of this work not only highlight the potential of the water sector to help meet future energy and emissions goals, but also how the energy sector can best incentivize this shift.