Helsinki has an environmentally and economically viable system of district heating and cooling that reduces emissions in the city by 40% a year - an average 2.7 Mt CO2 annually. Primary energy saved amounts to 9700 GWh in the Helsinki Energy system. A world-leading heat pump plant is playing an important role by recycling sewage to generate heating for the city - its one of a number of innovative strategies that are cutting fossil fuel use in Helsinki and helping to meet the City’s targets to reduce greenhouse gas emissions by more than a third of the current levels by 2030.
What is it?
Combined Heat and Power (CHP) and District Heating (DH) have long been the basis of Helsinki’s energy supply – without this system, emissions would be much higher in the city. Energy consumption in heating is a critical part of the Helsinki’s struggle with CO2 emissions. Of Helsinki’s consumption-based greenhouse gas emissions, 44% comes from heating, 30% from the use of electricity and 20% from traffic. In 1998, trials with District Cooling (DC) systems began and by 2001 they were permanently introduced to the city. The production of DC is based on renewable and other energy sources otherwise wasted.
How does it work?
Helsinki Energy produces over 90% of the heat demand of the city in CHP plants with over 93% of buildings connected to the DH network. Power is generated in the same process, exceeding the consumption in Helsinki. So excess electricity is sold to the Nordic market, generating revenues for the City. DH and DC are local products available to households - they compete with other heating and cooling methods and customers choose what to buy on a free market.
While the main sources of CHP production in Helsinki are gas and coal. A growing part of DH and DC energy is based on resources that otherwise would be wasted. This means the efficiency of the CHP system exceeds 90%, generating an annual saving of 40% CO2 emissions. Future plans will shift generation further away from fossil fuels to renewable sources.
District Cooling (DC) is outsourced production and distribution of cooling energy for air-conditioning and cooling of offices and residential buildings. DC is delivered to customers via chilled water in a separate distribution network. During winter, cooling energy is obtained from cold seawater through heat exchangers. In summer, condensing heat from power generation is diverted to absorption chillers for DC, which increases the efficiency of thermal power plants.
Additionally, a heat pump plant utilizes waste heat energy from purified sewage. This facility opened in 2006 and is the world’s largest production plant, combining DH, DC and heat capture from sewage water and sea water. This plant has a 90MW capacity for DH and 60MW capacity for DC, and is projected to cut CO2 emissions by 80% compared to alternative forms of production.
The Helsinki Metropolitan Area, comprising four cities and 1 million people, has high per capita energy consumption compared to other large Nordic cities - over 6 t CO2eq per person. This, however, is relatively low in Finland, as there is little heavy industry in the region. The Helsinki Met Area has reduced its GHG emissions from 1990-2000 by 5.7%, a cut largely due to a 12.8% fall in Helsinki city. This fall is largely attributed to improved energy efficiency in energy production and reduced use of coal for generation.
Local air quality has improved through DH, as it has practically replaced house-specific heating equipment and chimneys. Moreover, CHP and DH lead to decreased energy bills and much lower emissions. DC has the same effect, using natural resources and technical measures for services that could be inefficiently produced using building-specific equipment.
DC frees up space in buildings by reducing the need for compressors, fans and condensers. It also reduces urban noise and vibrations from cooling equipment. This means property owners can increase their space, reduce installation and maintenance costs of equipment, plus improve the indoor environment, as well as reduce emissions. The overall lifetime of DH or DC systems is much longer than that of a building-specific unit.
In the European Union, the “Primary Resource Factor” (PRF) is used to measure and compare the efficiency and emissions of different heating and cooling systems. Low PRF value means an efficient, low emission system has been developed, and in recent years, there has been a rise in market share for these systems.
CO2 emissions reductions
* In 2006, fuel energy used in CHP production amounted 17 070 GWh in Helsinki. This represents less than 64 % of fuel which would have to be used in separate production of electricity in condensing power plants and heating in separate boilers in buildings. The estimated saved energy use was 9 319 GWh corresponding to 826 000 tons of heavy fuel oil. Based on the mean fuel price of EUR 419 /ton in 2006, the annual financial saving for Helsinki was EUR 346 million. Similarly, CO2 emitted was about 3 million tons less.
The city-owned Helsinki Energy company is responsible for infrastructure investments and operations. Investments have focused on improving the eco-efficiency of DH and DC plants (from 2005-2007, total investment USD 77 million) and were mainly self-financed, with some additional state subsidies in the heat pump plant project. The company operates in free competition, and is very profitable to the city.
**) Improving the eco-efficiency of District Heating (DH) and District Cooling (DC) in Helsinki is a combination of separate ongoing projects, eg.
- Salmisaari absorption plant (35 MW, 5 units) in 2005, USD 15 M
- Katri Vala purified sewage water heat pump (60 + 90 MW), in 2006, USD 38 M
- Tunnel for DH, DC, water (-50 m in the bedrock, 4 km) in 2007, USD 24 M
Energy remains the leading source of GHG emissions in Helsinki and consumption of energy is projected to rise. Thus, extending DH in new suburbs, DC in the city center, maintaining the efficiency of the system and improving the efficiency on the consumer side, are key issues now and further on. The substitution of fossil fuels with biomass and other carbon-neutral sources will take place in the future. Other measures will focus on low-energy city planning and buildings, efficiency and energy saving training for proprietors and consumers, improved procurement, etc.