Researchers at the University of California have come up with a new way of storing electricity: use battery-electric locomotives on the US railroad system. These researchers were exploring ways of adding resiliency to the grid system, which has been stretched by extreme weather events and intermittent power generation.
The researchers at UC Berkeley and Lawrence Berkeley National Laboratory examined the potential to use the US rail system as a nationwide backup transmission grid over which containerized batteries, or Rail-Based Mobile Energy Storage (RMES), are shared among regions to meet demand peaks, relieve transmission congestion and increase resilience. They found that RMES is a feasible reliability solution for low-frequency, high-impact events and could be cost-effective compared to other storage solutions.
The rail locomotives could serve “as a nationwide backup transmission grid” through which saved power could be shared among regions, meet demand peaks and relieve transmission congestion, according to the researchers. “Compared to new transmission lines and stationary battery capacity, deploying RMES for such events could save the power sector upwards of US$300 per kW-year instead of adding new transmission lines and US$85 per kW-year for stationary battery capacity”, the researchers said in an article for Nature Energy.
The US rail infrastructure could serve as a viable backup system partly because of its size: The network spans 137,000 miles and consists of rights of way and property in some of the most population-dense and transmission-congested regions. Meanwhile, a single train has a capacity of 1 gigawatt-hour of battery storage, which is equivalent to the carrying capacity of 1,000 semi-trucks, according to their research.
This seems a wild idea, but it also has the advantage of using an existing system to greater capacity, rather than deploying some new and untried technology, but clearly will need more research to determine whether it is practical.