Heat pumps used for heating oil to keep generators at ready-temperature. There are considerable saving compared to the current practice and compared to the block heater controllers that is a current measure. Energy Trust got a presentation from hot start, the vendor making these systems. We can share more once we get some more data. There is some here. https://www.hotstart.com/solutions/energy-efficient-heaters/ This could be a very large saver in data centers.
