Drawn up by Estonian transmission system operator (TSO) Elering, the Estonian gas transmission network development plan for 2025-2034 highlights that in the past 15 years, natural gas consumption has decreased by 65 percent, reaching 3.5 terawatt-hours (TWh) by 2023.

Even so, the importance of the gas network in ensuring the country's security of supply is increasing. Estonia's climate policy is based on the goal of achieving carbon neutrality by 2050, with the target of renewable electricity production equaling consumption by 2030.

This means the country needs dispatchable electricity production capacities for periods with limited wind or sun.

Currently, these needs are covered by oil shale-fired power plants, the likely future alternatives for which are gas plants and electricity storage systems. According to the development plan, this will increase the gas network's role in ensuring energy security as well as electricity supply.

The country has greater ambitions for CO2-neutral electricity and heat production by 2040. However, as alternative hydrogen infrastructure as well as biogas and synthetic gas value chains will still be under development by then, the development plan recommends that in order to mitigate energy security risks, Estonia should aim to maintain its gas network until 2050.

"In the context of ensuring society's long-term energy security and security of supply, about €200 million needs to be invested in the transmission network over the next 25 years, up to 2050," Elering states.

"Considering the extent of the work needed to extend the life of the network, this work must begin in the coming years already," it adds.

New gas plants are expected to be added and Estonian gas consumption is projected to grow in the coming decades, with consumption primarily concentrated on cold or windless days. The gas transmission network is slated to evolve beyond merely its gas transmission role to become more of a provider of peak demand capacity.

Forecasts indicate that beyond 2035, network gas consumption will decline, but the fall in peak consumption will be slower. Since the gas transmission network must ensure supply during peak demand, Elering believes that the network tariffs structure will need to shift to a capacity-based model.

Security of supply ensured by Finland, Latvia links

For this winter, Elering has assessed Estonia's regional supply channels as sufficient to ensure security of supply throughout the heating season. This security of supply is ensured via connections to Latvia and Finland.

As of early November, the Incukalns underground gas storage (UGS) facility, a critical component of the Baltic countries' gas supply, was nearly 80 percent full, equaling nearly 20 TWh in supply.

Gas can also be delivered to the Baltics via the Klaipeda LNG terminal as well as the Gas Interconnection Poland-Lithuania (GIPL) pipeline.

Elering believes that the market has adapted to the situation where gas deliveries from Russia have ceased. The TSO deems security of supply to be ensured for the next decade as well.

According to the development plan, both the undersea Balticconnector gas pipeline, which was damaged by the Hong Kong-flagged container ship Newnew Polar Bear last October and remained under repair through this April, as well as Estonia's connection to Latvia play a vital role in ensuring the country's security of supply.

If only one foreign connection were to exist, a major system failure could require restricting supply to non-protected consumers, such as those who are not residential consumers or businesses producing heat for residential heating purposes.

Estonia's gas transmission network consists of 973 kilometers of pipelines, including 39 kilometers of the Balticconnector pipeline.

All gas transported through the transmission network comes from Latvia's Incukalns UGS facility, the Klaipeda LNG terminal in Lithuania, the Inkoo LNG terminal in Finland via Balticconnector or, potentially, from a floating terminal in Paldiski.

"Due to the robust integration of these transmission networks, there is a risk that a failure could impact the entire regional gas system," Elering states.

Since acquiring Estonia's gas transmission system, the TSO has invested approximately €280 million into it.

Many pipeline segments in need of repair

Elering estimates that €156.6 million will need to be invested over the next 26 years to ensure the reliability and safety of the gas transmission network's pipelines.

Urgently in need of repair, for example, is the 203-kilometer Vireši-Tallinn transit pipeline. Built in 1993, this pipeline is critical to ensuring regional gas supply, and previous assessments have revealed significant corrosion damage along practically the entire pipeline.

This damage is expected to reach critical condition within the next five to ten years, threatening to compromise sufficient operating pressure within the pipeline.

A 31-kilometer stretch of the Tallinn-Jõhvi pipeline, or Northern Pipeline, is already in critical state, and given that the pipeline is already 61 years old, it will need to be replaced outright in the long term. Estonia's entire domestic gas network depends on this particular stretch of gas pipeline.

Also in need of attention are a 4.5-kilometer stretch of the Jõhvi-Narva pipeline, which is in critical shape and must be replaced altogether, and the Tartu-Rakvere pipeline, which needs to be reinsulated to ensure safety assurance.

On top of ensuring pipeline reliability, Elering notes that it's also necessary to handle the renewal of valve nodes, the reconstruction of gas plant equipment and buildings as well as the improvement of cathodic protection facilities.

The TSO expects that gas supply will continue to remain closed at the Russian border, and therefore, according to the company's strategy, Estonia's domestic transmission network will remain a dead-end pipeline system with a single entry point at the gas pressure regulation station in Kiili.

Elering notes that significant changes in the need for gas network investments could arise from the knowledge of where and with what capacities gas-fired power plants supporting Estonia's electricity system will be built.

For the 2025-2029 period, however, it is not yet possible to reflect the locations of these gas-fired power plants in relation to the gas network.

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