Iseteenindus

Energy expert recommends: a storage solution gets the most out of solar panels

10.05.2023

Estonians' interest in producing electricity from the sun is growing. This is confirmed both by the number of electricity producers joining the grid and connection applications from micro-producers, which are setting new records this year. In order to better manage monthly expenses and income from produced electricity, we recommend considering a storage solution.

In summer, the average solar plant of a private house can produce up to 50 kWh of energy per day. This covers five times the daily consumption need of an average private house. As a result, the panels produce a large amount of energy, which is simply lost. According to Mikk Tootsi, Service Manager of Solar Energy and Storage Solutions at Eesti Energia, a storage device would solve this problem.


‘A storage device, or accumulator, allows you to store the produced energy and use it whenever you need to,’ Tootsi explained. ‘This way, you do not have to direct your consumption to a time when production is active or worry that you will have to purchase electricity from the grid when you get home in the evening. With a battery, it is possible to make the most of an expensive investment and consume more of the electricity you produce. The more energy that is produced by solar panels gets used on site, the faster the project will pay for itself.’

Consuming more of your own production alongside a home storage solution also leads to significant savings in electricity costs. The financial gain comes from the electricity you do not have to buy from the grid and the resale of unused electricity.

‘The average household uses 30–40% of the electricity it produces, but an accumulator makes it possible to increase the share of consumption by 20%,’ Tootsi said. ‘This allows you to cover the energy needs of your building in part or in full, and you will need to buy even less, if any, electricity from the grid. If the income from the electricity sold to the grid exceeds the cost, your monthly electricity bills will be below zero. The advance payment accumulated in summer thanks to the below-zero invoices can be used, for example, to offset bills in the winter period.’

As a useful solution, the storage device offers the opportunity to participate in the energy market and make the latter work for you. ‘In addition to storing the energy produced by the panels, an accumulator is a good solution for timing the purchase and sale of electricity,’ Tootsi said. ‘For instance, it is not profitable to sell the produced electricity when the exchange price has dropped to zero, and the output of solar farms may be so high in fine summer weather that you would have to pay to supply surplus electricity to the grid. Instead, you can store the energy and sell it when market prices have increased.’

Examples of a producer paying a consumer for electricity are not uncommon. Negative prices have been reported in Estonia, Poland and the Netherlands. While electricity in the Netherlands cost an extreme –73.9 c/kWh the week before last, electricity prices in Estonia were last negative on Sunday 30 April, dropping to –0.92 c/kWh on the Nord Pool Spot exchange for 2 hours.

Storage devices are also useful once the summer is over and the output of the panels decreases. ‘The arrival of colder weather does not mean that a storage device has to sit on the wall of the utility room and wait for next year,’ Tootsi added. ‘Those using a storage solution and willing to keep an eye on exchange prices can benefit from the market even in winter by storing electricity from the grid at affordable times and either using it or selling it to the grid when the price is higher. This way you consume cheaper electricity and keep your electricity costs low all year round.’

You can find out more about all the solar panels and storage solutions offered by Eesti Energia on the company's website. If you need help making a choice, please contact our customer service at 777 4040 or write to us at [email protected]. Together we will find the most suitable solution.