I read some old stuff from 2001. Finland leads the world in combined heat and power production (CHP). A total of 77% of the country's district heat was sourced from CHP facilities in 1999; and the remaining 23% from separate district heat units.
CHP or cogeneration plants make the maximum use of fuel energy by generating both electricity and heat. Plants typically have total efficiencies of 80% to 90%. This compares very favourably with conventional condensing power units, which normally turn in efficiencies of only some 40% to 45%.
The article in High Technology Finland 2001 says, "District heating accounts for 48% of Finland's total space heating requirement. In the country's largest urban areas, district heating accounts for between 80% and 90% of heating, and in Helsinki, over 90%. Some 2,3 million people, or 45% of the population, live in homes heated by district heating, and the majority of the country's public buildings are connected to a district heating system."
What has changed during the past ten years?
CHP technology is considered as one the best means of improving energy efficiency and reducing energy generating-related emissions. Cogeneration uses roughly one third less primary energy than separate generation. Lower fuel use per kilowatt of electricity generated translates into proportionally lower levels of carbon dioxide emissions when firing on fossil fuels, and similarly lower levels of sulfur and nitrogen oxide emissions.