Background Exposure to noise is a considerable environmental problem in many parts of Europe. Noise is also one of the greatest environmental problems in Lerum, since the municipality is divided by major transport thoroughfares for both road and rail traffic. Although noise is not regarded as life-threatening in the same way as many other environmental problems, noise management is of increasing importance to human health and quality of life. More than two million people in Sweden are exposed where they live to traffic noise exceeding 55 dB Laeq24h. At the same time, targets have been set in Europe for energy saving and investment in renewable energy in an attempt to tackle global warming. The municipality of Lerum will reduce emissions of greenhouse gases by 2050 to minimise its contribution to global warming. Objectives The main objective of the NOISUN project is to demonstrate innovative noise barriers that produce solar energy for distribution to local district heating systems. This will be achieved by installing and evaluating specially adapted solar collectors at major road and rail thoroughfares in Lerum. Sub-objectives of the project include: Demonstrating an optimal design for noise barriers with solar heat production adapted to both road and rail environments; Demonstrating an optimal technical solution for connections to the district heating system and compatibility between solar energy provision and other energy sources in the energy system; Testing and demonstrating the technical solutions in a pilot-scale facility along a stretch of the main western railway line and the E20 motorway through Lerum that are known to be exposed to noise; Measuring and optimising the contribution of solar energy production to the district heating system; and Evaluating the socio-economic effects of the facility based on noise reduction and solar energy contributions to the energy system. Expected results: The project will lead to a number of primary quantitative environmental improvements. Based on one possible placement with 400 m noise barrier and some 250 properties, the results will be as follows: Noise: A 5-10 dB reduction of noise levels, from 65 dBA to 60-55dBA (an 8-10 dB reduction is perceived as a halving of the noise level); and A 60-90% reduction in the number of citizens and properties experiencing sound levels above 55 dBA. Energy: Production of 400.000 kWh/yr of renewable energy; A saving of 440 m3/yr of woodchips (heat value 3 Mwh/tonne); A saving of 20.000 kWh of electricity (required to produce woodchips); A saving of 200 tonnes of CO2 emissions - some 130 tonnes of biomass (trees) can remain in the forest and thus bind CO2; and A saving of additional CO2 by reducing the need for forestry and transportation of biomass. Socio-economic: A reduction in the costs associated with noise of SEK 630 000-945 000 per year; and As a result of reduced noise levels, an overall increase in the value of properties in the project area of SEK 19.5 million-29 million, which represents a rise of some 5%.