A new white paper from Enchanted Rock compares four microgrid solutions to see which of these alternatives to diesel backup power can provide the same level of resilience while also helping utilities, regulators, communities, and large energy users meet their clean energy goals.
“Improved resilience has emerged as a top priority for the U.S. power grid,” according to the paper. Threats from wildfires are growing in the west, strong storms are pounding the eastern and southern portions of the country, and a variety of other factors in other sections of the country have shown the grid’s vulnerabilities. Currently, diesel generators have been the “primary source of power supply for systems designed to provide backup power and thereby improve grid resilience,” but the demand for cleaner energy generation is driving change in the industry.
In the paper, the authors compare microgrid solutions that are viable, cleaner alternatives to diesel generators. They considered feasibility, economics, and greenhouse gas emissions. The goal was to determine which of the microgrid solutions could provide resilience, which they defined as providing “100% reliability to all load served by a representative distribution substation in Northern California for two to four consecutive days.”
“Local resilience can be provided economically by microgrids that use renewable or pipeline natural gas, alone and in combination with solar and storage. Relative to diesel, these alternatives can virtually eliminate the emission of pollutants such as NOx, particulate matter, and volatile organic compounds, which contribute to local air quality problems.” – Enchanted Rock, “Decarbonized Resilience“
The first microgrid solution in the paper includes a natural gas generator connected directly to the gas distribution system. The next system employs a renewable natural gas (RNG) generator not directly connected to the gas distribution system. The paper also looks at a community-scale solar-plus-storage microgrid with a “ground-mounted solar PV facility with an AC-tied lithium ion battery located on-site.” The final microgrid solution evaluated was a community-scale hybrid system that includes a RNG engine, solar, and battery storage.
The paper explains the methodology used in the comparison and concludes that “three of the four evaluated technology options are economically and technically feasible for resilience purposes: Natural gas generator microgrids, RNG generator microgrids, and “hybrid” systems that include solar, storage, and an RNG generator.”