Giant battery maxes out solar energy
Being able to store energy from renewable sources, such as solar and wind, is crucial for the green transition. But how is it done in practice? In a pilot project for housing on KTH's campus, a system with giant batteries that store solar electricity is being tested.
Solar and wind are unparalleled at producing cheap and environmentally friendly energy. But they only work when the sun is shining or the wind is blowing. Therefore, some technical solution is needed to store the energy – and be able to use it when it is needed most.
The batteries in the research project, the entire system weighs six tonnes, are located in a specially built technology room in KTH Live In Lab – a property with 305 student apartments that is also a test bed – and will take care of leftover electricity generated by the solar panels on the roof.
Linda Lundmark, industrial doctoral student from battery manufacturer Northvolt, is working on tuning a control system to charge and discharge the batteries in the most optimal way. The challenge is to match the supply of electricity with demand, and to keep the cost of energy supply down.
”We hope that through the project we can gain a better understanding of how energy storage and renewable energy can function as an integrated part of the buildings of the future,” she says.
Greater benefits from solar energy
It can be about using solar energy when electricity from the grid is more expensive, or charging the batteries from the grid when it is cheapest to buy electricity. By using data from the residents' behaviour and the weather, the researchers will use AI-driven algorithms to develop a control system for daily electricity consumption.
The batteries were commissioned at the end of last year. After a few months of driving, thanks to smarter control, it has been possible to take greater advantage of the self-generated solar electricity. According to the researchers' calculations, half of the electrical power generated by solar panels can be recovered with the help of batteries, which is about 20 percentage points more than before.
For the annual total energy supply in the house, solar electricity is estimated to account for 20 percent, which is twice as much as without batteries. The solar energy that is not used is sent back to the grid.
Standardized solution
The hope is that the project will result in a standardized solution and serve as a model for how to integrate batteries and solar cells in apartment buildings.
”Energy storage linked to solar cells is a promising solution to remedy the power shortage in urban environments, a problem we must solve to enable the electrification of modern society,” says Linda Lundmark.
In addition to the technical aspects, the project will also examine issues related to economics and building codes.
”This may concern what investment support is needed to increase the use of solar cells in cities and to develop rules and policies on how the houses of the future should be designed to be able to work with integrated battery systems.”
Text: Christer Gummeson
English translation by KTH Live-In Lab