What if we turn photovoltaic or wind energy into heat, store that heat, then convert it back to electricity when needed? What would be considered an absurd idea for many can, in fact, be profitable. At least, that's what researchers from the Solar Energy Institute at IES-UPM (Polytechnic University of Madrid) say.
The published study says that storing electricity in the form of heat to convert it back into energy can be a profitable solution for solar self-consumption in homes.
According to scientists, a residential photovoltaic self-consumption system that uses this thermal battery can generate savings of around 70 to 80% in electricity and 15 to 20% in heating, in addition to avoiding around one ton of CO2 emissions.
“If electricity is cheap enough, converting that energy into heat and then converting it back into electricity could be more cost-effective than doing so using electrochemical batteries, even though they are much more efficient. The reason is that storing energy in the form of heat is extremely cheaper than storing it in electrochemical batteries. Up to 100 times less.
Furthermore, the heat that cannot be converted into electricity can be used to produce hot water or even power an absorption system for cooling in the summer”, explains Alejandro Datas, member of IES-UPM and main author of the study.
The research also estimates that profitability could be even higher in large commercial and industrial applications, where economies of scale allow system costs to be further reduced and take advantage of much lower photovoltaic generation costs.
“Storing photovoltaic or wind energy in the form of heat will not only allow substantial savings in the cost of accumulation, but will also satisfy part of this large demand for heat from renewable sources. For this reason, the development of this system could be fundamental to reducing our dependence on fossil fuels, not only in the electrical sector, but also in the thermal sector”, concluded Datas.
Researchers have already started taking the first steps towards creating this battery. Starting in September this year, they will try to identify the market needs that will determine the design of the first functional prototypes. In the meantime, they are looking for industry partners interested in collaborating to create early prototypes.
