Without this care, it could quickly diminish. The potential benefits of Advanced Rail Energy Storage are being investigated in the US . The idea involves creating a power plant on wheels , with the motor of a railway car being powered by renewable energy as it goes up hill and then giving that electricity back as the car goes downhill with the motor in reverse . The technique claims to have 86 % conversion efficiency and reliability and could deliver anything between 20MW and MW of power . Rail energy is likely to appeal to investors due to its low - tech re - purposing of existing materials , and the fact that it does n't degrade like batteries .
The potential benefits of Advanced Rail Energy Storage are being investigated in the US . The idea involves creating a power plant on wheels , with the motor of a railway car being powered by renewable energy as it goes up hill and then giving that electricity back as the car goes downhill with the motor in reverse . The technique claims to have 86 % conversion efficiency and reliability and could deliver anything between 20MW and MW of power . Rail energy is likely to appeal to investors due to its low - tech re - purposing of existing materials , and the fact that it does n't degrade like batteries .