Why force solar through batteries a second time to heat our buildings? It’s a good question, because there are costs and energy losses involved. These are due to what engineers call ‘round trip inefficiencies”. In other words, batteries cannot deliver all the energy they store on account of ‘load losses’.
Heating our buildings with oil and gas is falling out of fashion. This is because these carbon-based fuels are contributing to global warming. Using renewable electrical energy from the sun is becoming more popular. However, this usually involves passing the energy through batteries twice, and accepting more load losses.
- When we store the solar energy in batteries, some of this energy is absorbed by the system.
- When we release the stored solar energy from batteries, they consume more of this energy.
Must We Store Solar Energy in Batteries?
Richard Dickson, writing in Linked, In challenges the assumption we have to force solar through batteries twice, in order to heat our homes. Mind you, he comes from Finland where community micro grids pump hot water through citizens’ homes to heat them.
These systems use energy-efficient solutions like various geothermal media. So this is not something we could introduce overnight in Canada, although the idea is nonetheless interesting.
Sand, Not Batteries for Storing Solar Energy
Sand is a great medium for storing heat. Who of us does not remember cat-footing across beaches on hot summer days? Here’s how Richard Dickson dreams of warming homes in Finland:
- Use surplus renewable electricity to heat air and circulate it through sand.
- Keep the sand hot in an insulated container until you need the stored energy.
- Circulate water through the hot sand. Deliver it to a community heating system.
We described how a sand battery works in principle. This is not a pipe dream. There are working examples in Finland and elsewhere. Asking why force solar through batteries is a good question, and we found it well-worth answering.
More Information
Sand Batteries Throughout the World
Energy in Sand Beneath Our Feet
