Estonian renewable-energy company Sunly has entered Latvia’s electricity market after its subsidiary SIA Sunly Hz was prequalified to provide up to 100 MW of frequency reserve.
The prequalification by Latvia’s transmission system operator Augstsprieguma Tīkls AS, known as AST, allows Sunly to aggregate the capacity of multiple generation and storage units into a single reserve unit. The company can provide manual frequency restoration reserve, or mFRR, for both upward and downward regulation, according to the press-release.
Sunly will combine generation and storage capacity
Frequency reserves help keep the electricity grid balanced when production and consumption fluctuate. Reserve providers must be able to activate additional production capacity when the system faces a shortfall or reduce the output of operating units when there is an oversupply.
The need for these services increased after the Baltic states left the Russian-controlled BRELL electricity grid in February 2025 and joined the Continental European electricity system. The Baltic countries have since managed their frequency independently, requiring greater flexibility and faster responses from the regional power system.
AST board member Gatis Junghāns said the summer had shown how local renewable generation and frequency reserve services could help protect Latvian consumers from price shocks. “Today, solar and wind power plants already account for 40% of Latvia’s total installed generation capacity, which is increasing the need for balancing capacity. We are pleased to see that a growing number of renewable energy producers recognise the economic potential not only in generating electricity, but also in participating in the provision of balancing services,”says Junghāns.
Renewable parks will support the Latvia expansion
Toms Nāburgs, Sunly’s head in Latvia, said a recent storm in the country had highlighted how much homes, businesses, hospitals, schools and public services depend on a reliable electricity system. Frequency reserves cannot prevent physical damage to the grid, but they can help the system remain balanced as conditions change.
Sunly has developed energy parks in Latvia that combine renewable-energy generation and storage. Some of the parks are already operating, while others are in the launch phase. That portfolio will allow the company to use the parks for more than electricity production alone, Nāburgs said.
Sunly’s Latvian reserve portfolio will include up to 100 MW of technically qualified capacity. The company said it has already built experience in the Estonian frequency reserve market, where it has provided services since 2024 using both renewable generation and storage.
Estonian frequency reserve experience moves south
In Estonia, Sunly works with national electricity and gas system operator Elering and participates in all frequency restoration reserve markets with more than 20 MW of qualified capacity. The company has also previously secured financing to expand its presence on the market.
“Our experience in Estonia shows that a solar park combined with storage can serve a much wider role than simply producing electricity,” said Janno Jõulu, Sunly’s head of energy trading. “We are now bringing the same experience to the Latvian market.”
Jõulu said demand for energy services across the region would grow as the Baltic renewable-energy market expands.
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