The humble house brick has been turned into a battery that can store electricity, raising the possibility that buildings could one day become literal powerhouses. The new technology exploits the porous nature of fired red bricks by filling the pores with tiny nanofibres of a conducting plastic that can store charge. The first bricks store enough electricity to power small lights. But if their capacity can be increased, they may become a low-cost alternative to the lithium-ion batteries currently used. Strictly speaking, the power bricks are supercapacitors rather than batteries. The advantage of supercapacitors is that they charge and discharge far faster than batteries, but to date they can only hold a small fraction of the energy. “What we have done is provide a new ‘food-for-thought’ option, but we’re not there yet,” said Julio D’Arcy, at Washington University in St Louis, US, who was part of the research team.