Another excellent idea I read about was storing solar heat in massive batteries underground. The battery being made of brick or stone, or earth. You catch hea

Another excellent idea I read about was storing solar heat in massive batteries underground. The battery being made of brick or stone, or earth. You catch heat in the summer and pipe it below ground, and warm up this underground store/battery (away from the water table). Because earth is also a good insulator the heat is localised. And in winter you reverse the process, drawing out the stored heat. Roads get very hot in the summer (in some places), and if you could store that heat for residential units in the winter that may be better than turning into electrical energy.