This is how Ukraine can be connected to the rest of Europe’s electricity grid

Illustration: Wikimedia Commons

Ukraine has long wanted to free itself from the Russian electricity system and be connected directly to the rest of Central Europe. The Russian invasion is clearly a devastating blow to that process, and the prospect of a realistic timetable has disappeared.

The process has otherwise been ongoing since 2005 and was intensified following Russia’s annexation of Crimea in 2014, after which Ukraine cut off the peninsula from its power supply. Instead, Crimea was connected directly to the Russian network via a 220 kV power transmission line across the Kerch Strait.

Ukraine’s electricity interconnections. Illustration: SWP

But connecting a large electricity system like Ukraine’s to Europe is not that simple. Even though it is technically possible to build high-voltage interconnectors and synchronise the generators, there is also a risk associated with it. Because as much as many power plants can help keep the electricity system stable, in an emergency they can contribute to taking the system down should a major fault occur.

The Khmelnytskyi nuclear power plant in western Ukraine is connected to Poland via a high-voltage interconnector that is not in operation. Illustration: Wikimedia Commons

Soviet-era system

The interconnection to the Russian system dates back to the Soviet era and goes by the name IPS/UPS. Today, it includes all former Soviet Union republics. The Baltic countries have also been through a decoupling process and expect to become synchronous with the Central European system by 2025 via a connection through Poland.

The Burshtyn TES coal-fired power plant with a capacity of 2,334 MW, which is already connected to UCTE today via connections to Slovakia, Hungary, and Romania. Illustration: Wikimedia Commons

Ukraine may have good reasons for wanting to become synchronous with Europe rather than Russia. As the current situation clearly shows, Ukraine has wanted to become independent of Russian influence—including its electricity grid. The connection to Europe also includes the prospect of the system being more stable and Ukrainian power producers being able to sell electricity on the market, something that is not possible today with Russia.

If Ukraine is to be synchronised with the Central European UCTE system, it will also, due to the geography, require Moldova and, by extension, Transnistria to be disconnected from the Russian IPS/UPS system. It was therefore planned for the whole region to be connected to UTCE in 2023 and for the two countries to become full members of ENTSO-E, the European association of transmission system operators.

Ukraine is a major power producer

In 2020, Ukraine produced 149 TWh of electricity, just over half of which came from the country’s 15 nuclear reactors. 37 percent of the production came from coal- and gas-fired power plants plus a small contribution from hydropower and other renewable energy. The total installed capacity is 55 GW, 52 percent of which consists of fossil power plants and 24 percent of nuclear power. The rest consists of renewable energy, primarily hydropower (22 percent).

But synchronising such a large country with UCTE is not without technical challenges. Not only does the frequency have to be synchronous but the neighbouring countries will also suddenly have to adapt their electricity grid to a completely different flow of energy. This also applies to the countries, Belarus and Russia, which are now being decoupled from Ukraine.

However, Ukraine already has some experience with being connected to the UCTE, as the Burshtyn TES coal-fired power plant in western Ukraine has been operating as an independent network since 2002. In addition to the Burshtyn TES (2,334 MW), a 200 MW gas power plant and 27 MW of hydropower are also connected to the system as well as to UCTE via high-voltage interconnectors through Slovakia, Hungary, and Romania.

There is also an interconnector between the Khmelnytskyi nuclear power plant and Poland, but it has not been in operation for several years. In addition, an interconnection via Moldova to Romania is being built.

There are also regulatory challenges

Once all the equipment is in place, the actual synchronisation will happen when Ukraine disconnects from IPS/UPS and goes into island mode operation. That is, the country itself will need to maintain frequency and voltage. This was tested as late as 23 February, i.e. just days before the invasion, and it was planned to go on for 72 hours before connecting to IPS/UPS again.

After that, all generators must be modulated so that they are synchronous with the generators in UCTE before the new interconnectors can be connected.

In addition to all the technicalities, there will also be regulatory challenges. The price of electricity in Ukraine is heavily regulated, and a few private companies earn large amounts of money on electricity production. On top of that, Ukraine will have to adopt some form of a CO2 regulation that can be incorporated in the relevant EU regulation.