More and more individuals and property owners are investing in solar panels, and the market is growing rapidly. Patrik Ollas, researcher at RISE and former industrial PhD student at Chalmers, published his thesis on battery storage and solar energy in the spring, looking at new opportunities for the technology.
– Battery storage has an interesting future and there is a market for it, not least in terms of controlling energy use and interacting with self-generated solar energy. This is also what I focused on in my thesis, he says.
One part of the thesis is to investigate the benefits of DC power for a building with batteries for energy efficiency. Typically, both DC and AC are used in houses, where most of the appliances are powered by DC and all the distribution in the house is AC.
– One of the things I looked at was what conditions would be required to make DC favorable for small houses and office buildings. This included how solar radiation and climate affect the technical potential of DC. It turned out that energy can be saved, but there is a catch: few products exist for a market that is still in its infancy.
What role can solar and battery storage play in an increasingly electrified airport?
Electrification of aviation
Patrik Ollas has also analysed a future scenario in which society uses a lot of electric flights and electric car charging.
– What role can solar power and battery storage play for an airport with increased electrification? A third part of the thesis is about battery modeling; how can you modulate the battery to estimate energy losses and more, he says.
Part of Patrick's research is based on the so-called Research Villa at the RISE facility in Borås. Access to this testbed allows the models to be validated and evaluated in real operation.
One way to make investments in battery storage more economically viable is to allow the battery to provide services to the external grid, for example through frequency regulation. The grid in Sweden is supposed to have a frequency of 50 Hz, but this varies during the day depending on production and use.
– Frequency regulation is very topical at the moment. I am a firm believer in battery storage for the future. Its use to reduce peak demand will become even more important as electrification continues. This is also something we are looking at in a follow-up project for application at an airport, funded by the Swedish Transport Administration. "How do you have to design and control a battery in order to be able to charge electric aircraft with high power for short periods of time, and how does the rest of the airport's energy infrastructure interact with this", is one example of a research question being investigated in the project. Today's power supply to airports may not always be able to cope with future scenarios. We know that flights are usually on time and we know when they are due to depart. In that way we also know when the batteries are most needed.
Patrik Ollas also sees other opportunities for battery storage:
– Major events are an example of an application. You know when the peak is coming and how much is needed. The battery is like the Swiss army knife of the power grid. There are so many different tools and purposes that a battery can serve. Everything from storing excess power (from solar energy), to reducing power peaks, to price arbitrage management, where you buy electricity at night when it is cheap and use the battery when electricity is expensive, he says.
Batteries as energy contingency
Another interesting application is in the development of resiliency and emergency preparedness, where battery storage can act as a backup power source.
– There are examples of commercial buildings that have installed battery storage systems for emergency operation of mobile phones and other essential components in the event of a power grid failure during a crisis or other event, explains Patrik Ollas.
RISE has been commissioned by the Swedish Energy Agency's test lab to test solar power and battery systems. This means that we will carry out a test sequence of the combination of solar power and battery storage for small house applications.
– We will start with two systems that we will study and show what is possible and what is good to consider, mainly for private individuals. In the long term, we hope to test more systems to further demonstrate the possibilities and how to size the battery storage according to the building conditions. RISE has the expertise to develop the market and support our Swedish companies, he concludes.
