The Department of Energy and the nation’s utilities are exploring ways to make cities more resilient in the face of mounting and costly blackouts from severe storms and heat waves that are increasing with climate change.
They will use of a variety of relatively new features appearing in urban grids, including large storage batteries, a rising number of rooftop solar installations, and new computer-controlled programs and switches. They will also ask for help from homeowners.
Some utilities are already promoting devices such as two-way controls on air conditioners, thermostats and even electric water heaters to reduce consumer power demand on super-warm days.
The most ambitious effort would give control to a local utility to make a rapid grid reconfiguration at the onset of a blackout. It will attempt to collect and distribute enough renewable energy to support an “island,” or smaller area of the grid that can quickly repower hospitals, police and fire stations, and other emergency centers.
The stage for this experiment is called the Mueller neighborhood in the east-central part of Austin, Texas, a large modern housing development started in 1999 on the runways of what was the city’s former municipal airport. Mueller has many pieces of the puzzle that might be needed, including a proliferation of new homes with rooftop solar arrays and a recently installed large battery storage system that Austin’s municipal utility, Austin Energy, helped acquire with a federal grant.
Austin’s first goal was to use the neighborhood and the big battery to help expand its reliance on renewable energy to 65% by 2027. Austin Energy has already started using the battery, installed on the edge of the Mueller neighborhood, to collect enough solar power to help it meet increased electricity demand during spates of 100 degree days.
“We’re also using it to do energy arbitrage,” said Cameron Freberg, a strategist for the utility. The battery collects and delivers solar power for use during the day, when electricity rates are high. The system recharges at night with cheap wind power from the grid, so it’s ready for the next day’s struggle to keep up with air conditioning demands.
In June, DOE offered Austin Energy part of a $5 million grant for a more complex challenge. It is to create “flexible energy pathways” from the solar arrays on the homes in Mueller, so that they might be tapped for electricity during a blackout. To do that, the local utility is joining a larger team sharing the DOE grant to explore prompt ways to minimize a storm-caused blackout.
It’s called the Solar Critical Infrastructure Energization system, or SOLACE for short. It’s not aptly named, because it’s unlikely that there will be any immediate solace for those involved in the experiment.
The physics of storms and renewable electricity present a tough nut to crack. The electricity generated by solar arrays or stored in batteries is in the form of direct current, and the electricity used on the grid is alternating current. It is a mismatch that can normally be solved by a common device called an inverter on the solar array that translates DC into AC.
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