Technology

Keeping warm in winter

 By Nicholas Newman

In many countries, cold winters are a fact of life only made bearable by the availability of good heating. Even with electricity prices rising in winter, households, businesses and civic institutions still require affordable heat. An increasingly popular solution to this dilemma is locally produced heating for whole communities, business districts and town suburbs. This feature looks at how district heating solutions save energy and cut emissions…

What is District Heating?

In essence, district heating systems are industrial-sized central heating systems capable of heating a complex of buildings, suburbs or even towns through a network of insulated pipes. These pipes distribute heat in the form of hot water and steam to multiple homes, offices, shops and even factories. The pipe networks can vary in size and length — from carrying heat just a few hundred meters to several kilometers, supplying heat, hot water, and even electricity to entire communities and industrial areas.

Power sources also vary. Typically, conventional fossil fuels such as coal, oil or gas and biomass fuel a network of dedicated boilers. Alternatively, the systems utilize the surplus heat from a combined heat power plants (CHP) or steam from commercial and industrial processes. In addition, energy generated from municipal waste incineration and natural heat sources such as solar, geothermal or wind are becoming more widely adopted.

The pipe networks can vary in size and length

Some examples

District heating schemes are commonplace in northern and central Europe. As Anton Koller, Divisional President, District Energy, an industrial engineering company states, “the high level of efficiency and the great flexibility of district heating systems are the main reasons why many European countries, especially in Scandinavia, have chosen this energy pathway.” For example, “in Denmark, one of the key drivers for district heating was the new energy policy developed in the late ’70s in reaction to the oil crisis.”

Consequently, district heating systems connect over 63 percent of Danish households, such as the system supplying the country’s second city, Aarhus. Here, the local incinerator facility generates 16 percent of the heat consumed by the district heating system, with the rest supplied by the combined heat power plant (CHP) that serves a city of 319,680 people.

Biomass Fired Combined Heat and Power Plant, PLC, the municipality of Aarhus

Lagging well behind its European peers is the UK, where heating networks connect only around 210,000 homes, (about 2 percent of households) and 1,700 businesses. But, things are beginning to change with development of a new flagship scheme in the West country and government plans to increase this method of heating to 20 percent by 2030.

The UK’s first district heating network powered by a land-based 2,000 square meter solar thermal array and a high temperature heat pump will serve the new 3,500-home suburb currently being built at Cranbrook to the east of Exeter, Devon. The system will also heat a nearby 1.4 million square foot industrial space at Skypark.

Jeremy Bungey, Head of Community Energy at E.ON states, “district heating schemes such as Cranbrook are lower carbon by their very design and we often see carbon savings of around a quarter compared to traditional home heating such as gas boilers.” In Oxford, there are plans to create a citywide district heating system by linking together the CHP plants of its colleges, research centers, shopping centers and factories including the BMW Mini plant.

The advantages of district heating

Using excess heat and steam generated from power generation or industrial processes that would otherwise have been wasted is economical. Recipients of district heating gain the benefits of economies of scale arising from large heat production as well as reduced need to buy additional electricity. Commercial customers, such as factories, shopping centers or ports, enjoy significantly lower operating and maintenance costs since there are no individual boilers to maintain.

A case in point is the 2011 University of Liverpool’s £2.8 million district heating system, installed and operated by Vital Energi, it has lowered both operating and energy costs as well as reduced carbon emissions by 30 percent. According to Koller, if the current share of district heating in the EU were to double, it would save 4.5 EJ of energy imports — the equivalent of Poland’s entire energy supply as well as energy efficiency savings of at least 2.1 EJ — or as much energy as Sweden uses in a year.

SEE MORE: The sense of Inuit for climate change by Michelle Leslie

Obstacles to installing district heating systems

Despite evidence of lower costs, energy efficiency and lower emissions, existing local communities, especially in the UK, are resistant to change. There is opposition to linking Oxford’s main hospitals in Headington, which is designed to save around £500,000 a year and the equivalent of 3,000 cars a year in C02 emissions, notes Mr. Pyket, product manager at Vital Energi. Obtaining planning permission has proved difficult. Also delaying the project is public opposition to digging up already congested roads.

In the poorer parts of Europe availability of finance to upgrade and modernize a mature network is an obstacle. For example, 33 Polish cities are among the 50 most polluted cities in the EU. Its showcase city, Krakow, has serious air pollution caused by around 30,000 active coal boilers. However, this is soon to change with joint funding of £100 million provided by Brussels and Warsaw to encourage residents to connect to an improved district heating system or switch to electric or gas heating systems.

As for the future

Koller suggests that district heating could be the solution of the future since “it is not only compatible with the renewable energy sources of today but future energy sources can also be connected to consumers through existing district heating pipes.” Owing to its efficiency and ability to use waste heat from electricity production, district heating systems could form the cornerstone of our future energy supply.

about the author
Nicholas Newman
Freelance energy journalist and copywriter who regularly writes for AFRELEC, Economist, Energy World, EER, Petroleum Review, PGJ, E&P, Oil Review Africa, Oil Review Middle East. Shale Gas Guide. https://nicholasnewman.contently.com/