One of the most challenging issues for power grids is energy storage. The ability to store energy would enable the supply of uninterrupted electricity to customers, but battery technology has been too expensive or not good enough – until now, with all the electric cars on the roads. Claude Olsen, of Gemini.no, explains
Batteries have become so cheap that they can be used for more than just smartphones and electric cars. Now, national electricity network companies will use them to stabilize the power grid.
In the Norwegian city of Skien, the Odds football stadium Skagerak Arena will, next year, be almost self-sufficient with electricity from 5,000 square meters of solar cells on the roof.
However, since the big peak in power consumption is on the day of the match, the energy produced on the other weekdays must be stored in large batteries.
Skagerak Arena is part of the Skagerak Energilab project, such as Skagerak Energi, the football club Odd and several partners behind. Here, both batteries and balancing of local production will be tested as a user case in the CINELDI research center.
Batteries have become the standard theme in all talk about the development of power systems and renewable energy, but very few distinguish between the applications and how realistic it is to use batteries.
There is a difference in how batteries should be used in Norway, which has a lot of hydro power, compared with countries with a lot of solar and wind power, says Professor Magnus Korpås at the Department of Electrical Engineering, Norwegian University of Science and Technology.
Korpås conducts research on the use of lithium-ion batteries in the Center for Intelligent Electricity Distribution (CINELDI).
In the project, researchers at Sintef Energy and NTNU have analyzed how batteries will affect the energy systems in Norway and Europe. They see that the usefulness varies greatly from country to country.
Great importance for the Norwegian power grid
Sintef researcher and center manager at CINELDI, Gerd Kjølle, says the center is concerned with the social gain of batteries in the mains.
Kjølle says: “It’s important to find out how batteries can help smooth out power peaks, stabilize the power grid, and increase utilization of existing networks to avoid net investment that would otherwise be necessary to cover power downs.”
A small electric car used only for driving, requires a large energy storage station for long periods of time. In Europe, there are more and more solar panels on the roof. There are also many in Norway who enjoy electricity prices so low that they hardly pay for it. Where a power company like Statkraft calculates back and forth on profitability before investing in a new power plant, private individuals will invest in solar cells and batteries as a lifestyle investment.
Korpås says: “Therefore, there may be a large number of solar systems locally because people will cover their own power consumption. Solar power and energy storage by consumers become a joker in the energy system. It will potentially have a lot to say about the operation and development of the local area network.”
Power from the electric cars
The researchers in Trondheim have done studies that show that parked electric cars may cover much of the need for local energy storage in Norway, whether in the garage or in a public car park.
Some of the battery capacity can be utilized without me as a car owner marking something from time to time.
For example, one can get free charge against letting the car be available as an energy storage in the network.
With hundreds of thousands of cars that are largely parked, we may not need so many additional batteries in the network. How we will put it into practice is an important research topic, including in CINELDI, says Korpås.
Balances between wind and sun
Today, fossil fuels are often used as a reserve when production from sun and wind is small. By inserting batteries instead, they can both secure power supply and cut greenhouse gas emissions.
The batteries contribute to the balance between consumption and production in the main grid. The advantage of batteries is that they can deliver power very quickly, he says.
Norwegian companies in the front
Equinor tests a large battery pack in Scotland where the cables from the wind turbines in the HyWind park enter. The battery should smooth out short-term variations in power generation so that they can deliver power as they have previously announced. The battery is too small to cover power generation when there is little wind.
In countries such as the UK and Denmark, batteries are useful as energy storage to ensure enough power, but this use is less relevant in Norway since the country has so much hydropower. It is easy to adjust up or down as needed.
The big use in Norway will be to use batteries as an alternative to building and strengthening local and regional power grids. With more solar power and wind power, often the grid to other regions will be a bottleneck and require reinforcement.
With batteries, the power from wind and sun can instead be stored locally and consumed at night or in a windscreen. The network company will not have to invest in the network.
The biggest strain on the power grids comes when everyone in the neighborhood switches on the induction ovens to make dinner and puts the electric car at the same time.
Then we get a so-called power peak.
It does not last for so long, but still requires the power companies to amplify the mains to take the peaks. This can be avoided by inserting batteries that deliver energy every time the power stops come.
Network batteries
Korpås. says: “It’s not vital to have batteries around the Norwegian mains, but it can be a good measure to improve the utilization of the existing network.”
But here is also a challenge. The online companies, who are the ones who most benefit from the batteries in the network, are not allowed to own and operate them. Every time the battery charges and charges, they are part of the power market, and the network companies do not have the opportunity. It is currently unclear how this should be solved.
Korpås. says: “We are looking for an independent operator to own and operate a battery and have an appointment with a network company about when and how the battery will charge or deliver energy.”
This could be a similar model as in the hydropower system where Statnett demands power to keep the power steady (constant frequency of 50 Hertz), and power producers report how much they can produce.
This article is republished from the website of Sintef, a technology research organization.
