Oil crises spurred innovation
District heating traces back to the hot water-heated baths and greenhouses of ancient Rome, but the modern version came to Europe from the USA at the end of the 19th century, when Frederiksberg, a part of Copenhagen, needed somewhere to dump the waste from its 75,000 inhabitants. To solve the problem, in 1902 Frederiksberg built Europe’s first district heating plant, which produced not only heat but also electricity based on waste.
However, district heating remained a minor heat source until the oil price quadrupled in 1973-74. Denmark was among the many Western countries whose energy production depended almost exclusively on imported oil, so people shivered in their homes, factories were forced to shutdown temporarily and driving was banned on Sundays.
After the crisis Denmark therefore vowed to wean itself off oil imports, determined to improve its energy security.
Fast-forward to 2015 and district heating networks are now supplying heat to a massive 64% of Danish households. And the plants also produce electricity, making them much more efficient than standard power stations.
Other Northern European countries have the same heat production potential as Denmark: A report commissioned by the Greater London Authorities has found that enough heat is wasted in London to meet 70% of the city’s heating needs. Capturing this heat and delivering it to the heat network would dramatically improve fuel bills, fuel poverty, fuel security and carbon emissions.
Crispin Matson, Country Manager of Ramboll Energy UK, agrees. He points out that using heat pumps in the Islington project for secondary heat source utilisation is more carbon efficient than gas-fired combined heat and power (CHP), the usual heat source in the UK’s district energy schemes.
“We believe that the use of large-scale heat connected in this way to urban district heating systems will play a major part in decarbonising the UK’s heating energy,” says Crispin Matson. Energy Services Manager Lucy Padfield from Islington Borough Council praises the project’s innovative nature. “It combines the use of large-scale heat pumps from low-grade heat sources with a district heating scheme that serves both new and existing homes and council facilities,” Lucy Padfield points out.
Even bigger potential in the U.S.
Germany is another country with a big district heating potential. And Danish companies are also beginning to win their first major contracts in the U.S.
The U.S. relies primarily on steam heating, which can be costly to operate and maintain, as well as being a potential safety hazard. Looking for an alternative, Bridgeport, located 100 km northeast of New York City, is now implementing a low-temperature heating and cooling system that uses waste heat from various CHP plants. The project, for which Ramboll is the lead designer, will not only provide cost-effective heat to Bridgeport but also reduce 70% of the city’s greenhouse gas emissions, amounting to 13,000 tonnes a year.
Another U.S. first-mover on district heating is the Ivy League university Dartmouth. Ramboll has conducted a renewable energy study for the school, highlighting the benefits of switching the existing steam system to modern hot water.
Professor Sven Werner sees the North American potential for district heating as even bigger than the European.
“But how to exploit the great potential in Europe and the USA is also a political issue,” he says.