The Lithuanian heat sector is in the midst of a rapid and radical transformation process, introducing a 70 % share of renewable energy sources, mainly biomass, in district heating within just a few years. Now, networks are upgraded and new possibilities with solar and heat pumps are being examined, assisted by the countries participation in the EU-projects Upgrade DH and RES-DHC.

The upcoming challenges of the transition are mostly based in the condition of the district heating grid and the current heavy reliance on biomass, the later making Lithuania a high potential replicator in the RES-DHC project, as its targets most probably cannot be reached simply by scaling up biomass DH generation. Aiming to introduce renewable energy sources into district heating and cooling, participation in the project and the international cooperation and know how coming with it, will assist the country in the development of new solutions.

Like most Eastern European countries, Lithuania has a highly developed district heating grid with more than 50 % of households connected. However even until 2013, most of the heat was generated with natural gas and heavy oil imported from Russia. In an effort to leave this dependency behind, the country has been transforming its energy supply at an unprecedented speed. To support the transition, the country takes advantage of the EU Structural Funds. Using excess biomass from the lumber industry, the share of renewable energy had grown to almost 70 % by 2017, making it one of the highest in Europe. “We call it a European record” says the director of Lithuanian Energy Institute, Dr. Sigitas Rimkevičius.

Utilising local biomass and supported by technological progress, an important challenge of any energy transition is being met: heat prices in Lithuania have actually been decreasing since 2011, as the price of local biomass correspondents to only roughly a third of natural gas. “Lithuanian forests are not only big,” says Dr. Valdas Lukoševičius, President of the Lithuanian District Heating Association. “They are also among the most fit for wood production in the world.” Excess biomass is not only cheaper than natural gas, it is also more climate friendly and creates independence in the energy supply. Yet pressure created by international competition and rising demand results in an increasing scarcity of wood-based biomass. Even though the high heat demand in the cold Lithuanian winters will be impossible to cover with other renewable sources, solar solutions for hot water supply during summer are a first option considered to complement biomass. This, however, is not an easy switch. According to Lukoševičius “An important precondition for phasing in solar, is to reduce the operating temperature in the grid to 60°C. That in turn will require reducing heat losses both in the building stock and in the grid.”

Heat consumption of Lithuanian buildings is twice as high as western European countries, which can be attributed to high heat losses. This is exemplified by the more than 30 year old district heating network in the city of Šalčininkai where both a poorly insulated building stock as well as over-dimensioned heat generation and transmission installations contribute to high losses. Because of this, Šalčininkai has been a pilot for the “Upgrade DH” project funded by the European Union’s Horizon 2020 Research and Innovation Program. “Upgrade DH” is aiming to improve the performance of existing district heating networks in terms of efficiency and CO2-emissions. In Šalčininkai among other upgrading measures, old steel piping is being replaced by pre-insulated pipes to achieve lower heat losses. Despite the temperature limitations, sometimes even flexible plastic pipes are used because of their improved flow characteristics. A network optimization plan is implemented as well. The results of the project will not only bring Lithuania closer to a future of renewable and smart district heating that includes solar thermal and heat pumps, but are expected to be replicated all over Europe.

In the coming months, more efficient combined heat and power plants are coming online to replace biomass boilers. For the near future, all state support to biomass is canceled, but new subsidies for smart solutions in combination with solar and heat pumps are in the pipeline.