Heat accumulation at CHPP-2

The project is co-financed by the European Union Cohesion Fund. Total project expenditure is EUR 9 045 041.85, of which total eligible expenditure is EUR 8 544 841.85. The planned EU co-financing is 30% of eligible expenditure, not exceeding EUR 2 563 452.55.

The heat accumulation system will deliver primary energy savings (at least 2 421 MWh per year) and a CO₂ reduction (at least 9 041 t per year), and will accumulate at least 65 013 MWh of heat per year. The system will improve the security of heat supply on the right bank of Riga's district heating system (DHS). It will not only help save energy resources and improve efficiency indicators, but also increase the use of the CHPP-2 power units in cogeneration mode and create additional conditions for lower market prices for electricity and heat in Riga and across the country.

On 5 November 2018, Latvenergo AS and the Central Finance and Contracting Agency (CFCA), on the basis of Cabinet Regulation No. 495 of 22 August 2017 “Regulations on the implementation of the second project application selection round under specific support objective 4.3.1 “To promote energy efficiency and the use of local renewable energy sources in district heating” of the operational programme “Growth and Employment””, concluded agreement No. 4.3.1.0/18/A/021 on the terms and procedure for implementing the project “Establishment of a heat accumulation system at the Latvenergo AS CHPP-2 plant”. Following a procurement procedure, on 30 January 2019 a contract was concluded with the joint stock company “UPB” for the construction of the accumulation system at the Latvenergo AS CHPP-2 plant.

In 2019, it is planned to carry out a pre-feasibility study (including geological investigation and topographic surveys), development of the construction project, coordination of the construction project with the state authorities and start construction of the foundations for the heat storage tank.

The foundations were laid in autumn 2019, and construction of the roof of the heat accumulation tank began in January 2020. Wall construction is under way in February.

The tank construction technology involves lifting the tank roof, which is fabricated on site, with jacks so that the tank wall sections can be built beneath it. After each wall section is completed, the structure is raised with jacks and the next wall section is built, until the tank reaches its design height of 47.8 metres. At the same time, the foundations are being built for the utility rack (pipelines, electric cables, communication cables).

In recent years, new large-capacity heat accumulation projects with storage volumes of up to 50 000 m³ have been installed and planned in Europe. For example, in 2017 Germany had around 12 heat storage tanks with a volume of over 20 thousand m³.

Construction work on the “Establishment of a heat accumulation system at the Latvenergo AS CHPP-2 plant” project is still under way. The accumulation tank has already reached its design height of 47.8 metres. At the same time, the foundations for utilities, the utility rack and the pumps are being built. The connection to the heat network has been built and shut-off valves have been installed on the CHPP-2 power unit lines. Construction work will continue until the end of 2020. Commissioning and testing of the heat accumulation system had been planned for completion by the end of October 2020, but due to the spread of Covid-19, delivery of the equipment for the accumulation system from European manufacturers is delayed. As a result, the “Establishment of a heat accumulation system at the Latvenergo AS CHPP-2 plant” project may be delayed by several months.

The connection to the heat network has been built and shut-off valves have been installed on the CHPP-2 power unit lines. In June 2020, the utility rack and pump foundations were built and installation of the process pipelines began. At the end of summer, the main pumps of the system were installed, the accumulation tank was filled with heat carrier, and the hydrostatic test of the tank was carried out. In September, construction of the process pipelines was completed and installation of the tank's thermal insulation began. This month, the pipeline connections to the main pumps of the system are also planned to be completed.

Adjustment and testing of the heat storage system was planned for December 2020 – beginning of 2021, because deliveries of equipment from European manufacturers intended for the construction of the heat storage system have been delayed due to the spread of COVID-19. The CHPP-2 heat storage system is planned to be commissioned in February 2020.