PNM ‘Prosperity’ Project Case Study (New Mexico, United States)

Background

PNM, the leading electric utility company in New Mexico, United States, has integrated an Ecoult UBer™ (UltraBattery® Energy Resource) with a solar energy-generating farm to demonstrate smoothing and shifting of volatile solar power and the ability to use the combination as a dispatchable renewable energy resource. The PNM Prosperity project is the first solar energy storage facility in the United States that is fully integrated into a utility’s power grid. It features one of the largest combinations of photovoltaic (PV) energy and solar panel battery storage in the United States.

Sponsors

Sponsors

Sponsors

Client Challenge

Increasing levels of renewable energy penetration poses integration challenges for grids. The use of solar power storage helps to transcend these challenges. In the case of the PNM Prosperity solar energy technology project, there were two particular objectives:

• To better manage the misalignment between PV output and utility distribution grid and system peaks
• To better manage intermittency and the volatile ramp rates of renewable energy sources that cause voltage fluctuations

Ecoult worked closely with PNM, Sandia National Laboratories, the University of New Mexico and a number of other contractors to demonstrate:

• Peak shaving, targeting elimination of 15% of the feeder peak – benefit defined by avoided industry standard costs of substation and feeder expansion
• Smoothing of PV ramp rates and minimizing of voltage fluctuations – benefit defined by avoided cost of system upgrades that would be installed with high-penetration PV
• Demonstration of dispatchable renewable resource – benefit defined by contrasting the cost of an equivalently dispatched combustion turbine, allocating fuel, operation and maintenance, and capital to a levelized cost of energy (LCOE) comparison and noting an allowance for CO2 emission avoidance

Solution Provided

In the PNM Prosperity project, the UBer™ solar energy storage system provides 500KW of power smoothing capability (utilizing UltraBattery®) and 250kW/1MWh of energy shifting capability (utilizing Deka Synergy®). The UBer™ is successfully smoothing and shifting PV output and demonstrating the ability to combine PV with a storage system. Using these batteries for solar integration into the grid provides multiple benefits to making renewable resources reliable and dispatchable. Initial results indicate that the targeted objectives of the solar power storage project are easily being met.

More information about the PNM solar energy storage facility as well as the power smoothing and energy shifting capabilities of UltraBattery® when used as a solar power battery solution, is available in the following case study, published by EPRI (Electric Power Research Institute, October 2012): ‘A Case Study on the Demonstration of Storage for Simultaneous Voltage Smoothing and Peak Shifting’. To download the case study visit www.epri.com and insert the product code 1026445 into the search box.