Most people still want hot water in the summer, so some of the surplus heat can be used for that. The thing to keep in mind is that solar panels are cheap, so

Most people still want hot water in the summer, so some of the surplus heat can be used for that. The thing to keep in mind is that solar panels are cheap, so it’s not that big a deal if some of the energy collected from them is lost as heat during the summer. What really matters for the viability of this system is the cost of the fuel cell and hydrogen storage medium.