The project was carried out by Greenfield Consulting in cooperation with Vantaa Energy Ltd, which is one of Finland’s largest municipal energy companies. The company is owned by the City of Vantaa (60%) and the City of Helsinki (40%). Vantaa Energy produces and sells electricity and district heating. In addition, it offers natural gas for the needs of industry. The company is responsible for the construction, operation and maintenance of district heating networks in Vantaa. A significant part of the electricity is generated efficiently at the Martinlaakso combined heat and power plant, which uses natural gas and coal as main fuels.

Heat and electricity demands as well as potential energy supply schemes for the new residential and workplace area of Marja-Vantaa were evaluated by Vantaa Energy Ltd.

District cooling has not been assessed before in the area of Vantaa. Currently only two large scale district cooling networks exist in Finland, located in Helsinki and Turku. The target of the project was to evaluate the cooling potential of Marja-Vantaa area, and to find out the most cost-effective district cooling system taking into account the environmental aspects. The study also included comparing centralized district cooling with decentralized cooling production.

To start with, the study reviewed the general global development trends in air conditioning. After establishing the cooling demand at Marja-Vantaa, a concept design was carried out for different cooling alternatives including network design and extent, routing and specific sites. Different cooling production technologies based on absorption process and electrical compressors were assessed as well as all the other components associated with district cooling systems from the cooling production down to customer side were evaluated.

Three district cooling system configurations were formed by comprising absorption chillers, compressor chillers, heat pumps and other components related to a district cooling system. The work included assessing the operational efficiencies, investment and O&M costs for each alternative. Financial analysis included net present value and internal rate of return taking into account all investment and operating costs for each system configurations during the operation of 25 years. Carbon dioxide emissions were calculated and climate effects of refrigerants of the chillers were evaluated.

As a conclusion, the compressor cooling system proved to be more cost-effective compared to either absorption cooling or heat pump system, although margins were not significant. From CO2 emission point of view, the heat pump system would be the most advantageous, saving a total of 1,700 tonnes of CO2 annually. Compressor cooling system would cause annual emissions of 210 tCO2 and absorption cooling system 160 tCO2 respectively.

Client: Vantaa Energy Ltd

Vantaa Energy Ltd is one of Finland’s largest urban energy companies. Vantaa Energy produces and sells electricity and district heating. In addition, it offers natural gas for the requirements of industry.