Scholarship on the energy transition has given a good deal of attention to battery storage, because it can help make variable renewables more dispatchable over longer periods of time, and because it’s a core part of electric vehicles. Numerous models have projected that we’ll need a very large amount of battery storage starting several decades from now, when renewables approach 80% of grid power supply, meaning long-duration and seasonal storage will become more necessary. But what if that isn’t true? Many of those models assume that heating, ventilation and air conditioning (HVAC) loads, which account for about half of total power demand, will need to be met by electricity stored in batteries. But what if we could provide heat directly, by saving or recovering waste heat, and then using it as heat, without going through the conversions (and energy losses) of converting heat to electricity and then back to heat? What if using waste heat and other low-temperature sources were actu...