Ltd. “Salaspils Siltums” is a modern heat supply company that provides district heating in Salaspils and Saulkalne. The company’s activities are aimed at a long-term and environmentally friendly development so that customers would be provided with a reliable heat supply for the lowest possible price. Solar energy as a fraction of 90% of renewables in energy production is now not just a number, but an existing reality in district heating, provided by ‘Salaspils Siltums’. First solar collector field for centralized heating in Latvia and the largest one in Eastern Europe together with an accumulation tank and a new wood chip boiler house ensures 95% efficiency, reduced heat losses and minimal damage to the environment. The project implemented in Salaspils is a successful example of how Latvian cities, by attracting co-financing from EU funds, can modernize their heat supply systems in order to reduce the consumption of fossil fuels and provide citizens with more environmentally friendly heat energy and a cleaner environment. Within the project 1720 solar collectors with a total active area of 21762 m2 were installed, an 8000 m3 accumulation tank was built and a new wood chip boiler house with a total capacity of 3 MW, equipped with a flue gas condenser, was set up. The fraction of renewables has accelerated up to 90%, from which 20% is achieved by means of solar energy, thus considerably reducing CO2, NOx and other harmful emissions into the atmosphere.