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Location: Fevik, Norway
Challenge: Reduce the electricity consumption of a family home by optimising use of self-generated solar power with the help of energy storage.
Solution: Installation of an Eaton xStorage Compact energy system with a capacity of 50 kWh.
Results: Storing energy from on-site PV panels and/or the grid when prices are low to use when demand and/or prices are higher. Consumption of electricity from the grid reduced by 45% (20,000 kWh), saving the family approximately €4,000 per year.
I love technical gadgets, and it is undoubtedly a pet project of mine to reduce our power consumption as much as possible
Background
Bjarne Tveit is a father of four from Fevik in southern Norway who has set himself the goal of drastically reducing the electricity consumption of his home. As the owner of Byggmester Bjarne Tveit AS, a building company that installs hundreds of solar panels per year, he also has a sound knowledge of photovoltaics.
Given Tveit’s passion for sustainability, the family’s 400-square-metre home is packed with technology inside and out, including solar cells, solar panels on both the roof and the façade – and in the garden, Norway’s first “sunflower”, which Tveit’s company imports and distributes: a flower-shaped arrangement of solar cells that rotates to maximise energy production.
In addition, the family has also replaced windows, improved insulation and installed a geothermal water-to-water heat pump that cools the house during summer and provides heat in the winter. To further optimise energy consumption, Tveit was already using a smart home system from Eaton to control heating and lighting.
However, despite all this sophisticated technology, much of the self-generated energy was sold back to the grid cheaply because it was produced when consumption was low and could not be stored. Consequently, Tveit and his family had little control over when they needed to purchase electricity from the grid. In Norway, this consideration is now especially important as a “rush-hour charge” will soon be introduced, penalising consumers who use a lot of electricity at the same time.
Challenge
“When we moved in, the power consumption was about 44,000 kWh per year. The goal is to bring this down by two-thirds, saving about 30,000 kWh,” says Tveit. However, it was clear that this target could not be met with additional efficiency measures alone.
As it turned out, the missing link in Tveit’s comprehensive sustainability efforts was the ability to store the self-generated solar power for use during periods of peak demand. On the one hand, this would enable the family to reduce its reliance on the grid, and on the other to avoid costly peak charges, which are only set to grow further.
Solution
To reach his ambitious goals, Tveit thus decided to put in place such an energy storage system. And given his previous experience with Eaton technology, he opted for the company’s intelligent xStorage Compact system.
“The battery has a capacity of 50 kWh and an output of 20 kW. This not only enables us to use more of our self-generated solar power, but also to buy electricity from the grid when prices are low, typically at night,” he says.
“We are a big family and we have an electric car. If we charge the car, cook and run the washing machine at the same time, this would have led to very high electricity bills. The new electricity pricing model makes our self-generated solar power even more profitable, especially in combination with energy storage.”
xStorage Compact consists of batteries from the car manufacturer Nissan and advanced control technology from Eaton. After a certain period, the batteries are no longer suitable for use in electric vehicles but still have plenty of power in them. Nissan then sends these electric vehicle batteries to Eaton, which gives them a new life.
“This is the circular economy in practice. Even though the capacity of these batteries is too low to function optimally in an electric car, in combination with our control technology, they can still be of great benefit in homes and commercial buildings,” notes Helsingeng. Moreover, energy storage also contributes to grid stability and provides back-up power in case of a blackout.
Result
Tveit’s solar cells have an installed capacity of 26 kW and produce an estimated 20,000 kWh of electricity per year. Thanks to the xStorage Compact system, the family can now make the most of this capacity. While the Tveits are among the first in Norway to have installed energy storage in a private home, Helsingeng expects residential demand to increase: “As the interest in solar panels has exploded, more and more people will want to store solar power in batteries in the future.”
Tveit estimates that the family has already managed to cut its use of electricity from the grid by half – or about 20,000 kWh – per year. At a price of 2 kroner per kWh, this amounts to annual savings of around 40,000 Norwegian kroner (c. €4,000).
“We have implemented many electricity saving measures, and we hope to achieve our goal of reducing our consumption by two-thirds. The xStorage system is an important tool in this regard because we get to use more of our own solar power – plus, it’s also great fun to test new solutions and then watch as your electricity bill shrinks,” says Tveit.
