They are paving the way for future feasibility of solar based energy.<p>The big problem is that the sun shines very strong/bright in the middle of the day. So you need to store energy for the night. But what if your batteries are fully charged already? Then who will use all the excess energy? You are pissing away profits if you do not spend/sell that energy.<p>Hooking up some old and payed-off bitcoin mining machines that are only economically making sense when energy is (near) free is a great idea: you recuperate some of your solar panel investment costs.