Grid problems plague the return of solar energy in the Czech Republic



The lack of a transparent network capacity system in the Czech Republic undermines the business model of self-consumption of solar energy, and in some parts of the country network bottlenecks delay network connections.

“ČEPS decided to activate the containment plan after exhausting the normally available power system control measures,” said spokeswoman Hana Klímová.

Normally, the grid operator would send surplus energy to neighboring countries, but this was not possible on April 10, as all possible importers were surplus. The Czech Republic is now planning to expand its solar fleet thanks to high energy prices and strong subsidies.

“The market itself is moving from residential buildings to commercial projects. We expect C&I to account for 80% of new projects, which is a significant change, as in the last three years we had a 50/50 share,” said Radek Orsag, CEO of local distributor SolSol. “We expect 150 MWp to 200 MWp in residential and 600 MWp to 800 MWp in the commercial segment.”

The momentum is built on the fourfold growth seen in 2022, when a total of 289 MW was installed.

“We expect between 800 and 1,100 MW of new solar capacity this year,” said Jan Krcmar, president of the Czech Solar Association (CSA), adding that the first solar projects to be installed in the country are starting after more than a decade of no activity in this market segment.

However, he warns that the Czech grid is not ready to accept a growing share of renewable energy sources.

“The problem with network capacity is not a technical (issue), but rather a mathematical one,” he said.

In the Czech Republic, there is no transparent system where investors can check whether network capacity is available in a certain location. As a result, they sometimes look to consolidate large capacity across the country to see where they should buy land. However, this can clog the system.

“These reservations for large solar projects are the reason why some transmission system operators may refuse to connect more small rooftops, even though large ground-mounted plants may not be built at all,” Krcmar said. “Therefore, large self-consumption is impossible in some areas, and transmission system operators can force customers to install much smaller systems or prohibit them from feeding surplus into the network under threat of punishment.”

In some parts of the country, network bottlenecks become network connection delays. Especially in E.ON’s owned EG.D network, customers wait eight to nine months for solar electricity to be connected. Since the payment of the roof electricity discount is tied to joining, many wait almost a year to receive their money. This affects installers, who are usually paid only after the discount.

Asymmetric space

Another grid-related handicap for Czech solar power is the Europe-wide unique phase measurement in its low-voltage grid. This requires most inverter manufacturers to make firmware changes to ensure that all solar consumption goes through a single phase, allowing for higher self-consumption. Not all manufacturers are ready to implement such changes, so a few Chinese manufacturers claim the largest market share.

“The largest market share in the Czech Republic in 2022-2023 is held by GoodWe, Growatt and Solax. However, due to the limited supply of asymmetric inverters and their compatible batteries, we have had a shortage in the market,” said Orsag of SolSol, which reportedly owns more than 30% of the Czech solar market.

It has been estimated that using inverters in this asymmetric mode shortens the life of the products by 7-8 years, which ultimately leads to higher costs for producer consumers.

“The official reasons for this kind of electricity market design is the stability of the network and the fact that it motivates people not to overload the phases, but the unofficial reason is that the grid companies collect network connection costs and fees from it at the annual level of several million euros and of course there are electricity traders who make money from this, Krcmar said .

Phase measurement can also cause a huge imbalance in energy communities founded on the principle of energy sharing. For example, in apartment buildings, this would mean that one household would get cheap energy from the sun at one stage and another expensive energy from the grid.

In response to lobbying by the solar energy industry, the Czech Senate called on the Ministry of Industry and Trade to study grid design and possible changes that could be implemented to overcome such restrictions.

David is a passionate writer and researcher who specializes in solar energy. He has a strong background in engineering and environmental science, which gives him a deep understanding of the science behind solar power and its benefits. David writes about the latest developments in solar technology and provides practical advice for homeowners and businesses who are interested in switching to solar.

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