Long Duration 200 kW Energy Storage with Aquifer Pumped Hydro
Antelope Valley Water Storage, LLC
Recipient
Lancaster, CA
Recipient Location
21st
Senate District
39th
Assembly District
$883,546
Amount Spent
Active
Project Status
Project Update
The 200 kW Aquifer Pumped Hydro (APH) system design and construction tasks are in progress, as well as production well retrofitting. Remaining site preparation tasks include: interconnection with the utility, installation of containers for housing equipment, microgrid construction, pipeline system connection, surface storage pond construction, and final inspection of equipment. A survey to assess the statewide applicability of this technology, as well as the feasibility of deploying in disadvantaged communities has been initiated in parallel.
This project is now waiting on regulatory approval and permits to operate the system from both the Federal Energy Regulatory Commission (FERC) and Kern County. Work has temporarily been paused until these permits are obtained, and as a result, the 1-year operational period and field tests have also been delayed.
The Issue
The increased emphasis on resiliency in the state is driving the need for longer duration energy storage backup capabilities. Longer duration energy storage and energy discharge is needed to respond to an unplanned grid outage, curtailment risk, Public Safety Power Shutoffs (PSPS) and to increase renewables penetration. Disadvantaged Communities (DAC) and low-income communities are especially vulnerable to preemptive shutoffs. Many of them cannot afford emergency generators. As wildfires become more common, new energy storage/discharge technology is needed that can provide economical, standalone power when the grid is down.
The California grid is facing three issues that could benefit from longer duration energy storage:
1. Evening Ramp Up: There is not enough power for the grid during the 5-hour evening ramp up (from 4:00 to 9:00 p.m.) as solar goes offline but consumers turn on appliances. The 2-4 hour discharge of lithium batteries has trouble covering the 5-6 hour ramp up period.
2. Public Safety Power Shutoffs (PSPS): Increased wildfire risks have forced Investor Owned Utilities (IOU) to shut down transmission lines during high wind events. For example, in October of 2019, power to 800,000 customers (2.5-3.0 M people) was shutoff due to wildfire risks. These preemptive shutoffs created major disruptions and may have contributed to at least one death.
3. Overgeneration: In non-summer months, especially in the springtime, there is a glut of solar energy in the afternoons and a dearth of generation in the early evening hours. This creates risks of overgeneration and curtailment of renewables.
Over 90% of the energy storage systems built to date in California use lithium ion batteries. Excessive reliance on lithium batteries can create materials and minerals shortages, and safety issues from thermal runaway. Also, lithium batteries have a limited lifetime due to the number of cycles that can be performed, typically 500 to 1,500. With daily use, a lithium battery is worn out in about 3 years. Old lithium batteries create a disposal problem. They are also limited to a 2-4 hour discharge, which is not enough to cover the evening ramp up.
Project Innovation
This Agreement is to demonstrate and define the necessary technical, financial, and operational resources to assess the potential of energy storage/discharge with APH to provide continuous energy discharge during grid outages, during peak periods, and during PSPS events; which provide end-user benefits that may drive wide-scale adoption of the technology in California.
The goals specifically are:
• Demonstrate how APH offers the end user customer the opportunity to receive increased reliability, resiliency, cost saving and other services during times of power interruptions;
• Identify how continuous energy discharge with APH can be applied to avoid disruption of power supply to critical facilities like hospitals, nursing homes, and emergency charging centers during PSPS events;
• Demonstrate how energy storage with APH can provide extra energy discharge during the summer evening ramp up; and provide seasonal storage to address absorption of surplus renewables in the winter and spring on the weekends during off-peak or super off-peak hours, thereby mitigating renewable curtailment;
• Demonstrate how the behind-the-meter APH technology can incentivize participation by IOU customers; and
• Demonstrate the commercial potential of the APH technology in California due to the distributed nature of wells, benefits for transmission congestion, distribution reliability, end-user energy shifting and scalability.
A groundwater storage facility in eastern Kern County, Willow Spring Water Bank (WSWB), will be used for demonstration. Groundwater will be used to fill and drain a small surface reservoir. Five existing wells at WSWB with nameplate capacities ranging from 112 kW (150 HP) to 225 kW (300 HP) will be retrofitted to also act as generators. At 30 percent generation efficiency, each individual WSWB well will produce 34kW to 67 kW of power. The technology is behind-the-meter and will require a Net Energy Metering (NEM) interconnection agreement with Southern California Edison (SCE). For the demonstration, the stored energy will be discharged to provide on-peak power to SCE during the evening ramp up and recharged off-peak. The end-user customer, WSWB, will benefit from the differential between on and off-peak SCE rates.
Please also see EPC-19-058 project information to better understand the scaling of this technology.
Project Benefits
This Agreement will result in California ratepayer benefits including: (1) reduced peak power cost, (2) power during PSPS event, (3) longer life cycle than lithium battery, energy storage dispersal through the utility distribution system, (4) rapid implementation especially within DACs. APH can also be used to inject water into contaminated aquifers where clay layers prevent conventional recharge with percolation, diluting contamination and improving water quality. The benefits will be measured and verified during the demonstration test.