Machines gen­er­ate waste heat when they do work for us. And this year, sev­en bil­lion of us will use twenty-five tril­lion kilo­watt hours of elec­tric­i­ty. An awful lot of that will end up as waste heat. So, we treat waste heat as a prob­lem. We see it as a chal­lenge to design how we can man­age it. We don’t think of it as a resource. If we thought of it as a resource, that would be results we are just throw­ing away.