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Low Carbon Power Generation
in Copenhagen
Part of our Low Carbon Copenhagen project ... project index >
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Geothermal power in Copenhagen
There are two geothermal power plants in Denmark. The first-opened
is at Thisted on the north west side of the Jutland peninsula. The second is in Copenhagen, on the harbour within sight of the city centre. Energy experts predict that Copenhagen could power half its district heating from geothermal sources for centuries to come.
Both plants are are run by consortia that include DONG Energy as the majority stakeholder. Thisted was built 1981-84 (enlarged in 2000). The Amager plant in Copenhagen was begun in 2001 and its first geothermal energy was produced in November 2004. A third plant is planned for Sønderborg in 2012, with another in Copenhagen around 2015 and more anticipated on the Jutland peninsula.
The principle at work is to use the Earth's naturally percolated and heated water resources to either power turbines or run heating (or cooling) systems directly. Below a surprisingly shallow depth (a few metres), the temperature of the Earth is stable. But drilling deeply gets you into rising temperatures, since the Earth gets hotter as you get nearer to its core. Generally, it rises 20-30° C per km — more if you happen to be near a volcano.
Water trapped underground in aquifers heats up naturally and the hot fluid is extracted by drilling into porous rock. This fluid is used to heat the supply pipes in district heating schemes, or it is flash-heated into steam and used to power electricity generators such as those at the Amager plant (see box at right).
Geothermal energy is clean and sustainable, though some external power — usually about 10% — is used to transfer the heat from the boreholes to district heating supply pipes. Spent (cool) liquid from the process can be returned to the aquifer for reheating through a second borehole, maintaining the pressure underground.
Copenhagen's Amager plant is in the same locality as the city's largest district heating network and combined heat and power (CHP) plant, and produces 14MW from its two wells. It's adjacent to a major geological fault line (through which water percolates to the aquifers). The water from its wells is more saline and has a higher concentration of CO2 than the water from Thisted.
The planned new plant in Copenhagen will have up to six times the capacity of Amager and could cost around one billion Kroner. The major investment of any geothermal scheme is in the drilling of its very deep wells. Seismic surveys are used to identify suitable sites.
Geothermal energy is one element of Heat Plan Denmark, an integrated study of heating methods that includes information about reductions in CO2 emissions since 1980. It also outlines ideas for achieving the aim of cost effective and (almost) carbon neutral heating in Denmark by 2030 ..... next >
Top links
Aarhus University, Faculty of Science   http://science.au.dk
Information about Amager and Thisted (in news story)
Danish Energy Agency   www.ens.dk
Energy statistics and info on different kinds of power generation, incl geothermal
DONG Energy   www.dongenergy.com
Predominantly state-owned power generation company, part-owner Amager
DONG Energy   www.dongenergy.com/geotermi/
Geothermal info for Amager and Thisted (in Danish but translation button available)
Energy Map   www.ens.dk
Details of energy- and climate-related technologies to reduce CO2 emissions, incl geothermal
Geothermal Energy Association   www.geo-energy.org
American trade association for geothermal energy in the USA and worldwide
Heat Plan Denmark   www.energymap.dk
Research and development study of the entire Danish heating sector
Hot|Cool Journal   www.e-pages.dk
Article : Geothermal Energy - the Future Heating Source?
Renewable Energy World   www.renewableenergyworld
Information about all kinds of renewable energy, incl geothermal
Find out how a geothermal plant works ...
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Amager geothermal plant
number of geothermal wells  2
No.1 Well (Margarethe) operational  summer 2002
No.2 Well operational  summer 2003
geothermal fluid  19% saline water
fluid temperature  73 deg C
fluid pressure  1,000-1,500kN per sq m
fluid volume  235 cu m per hour
annual power/heat output  14MW/380TJ
serving  5,000 households
Copenhagen's Amager geothermal plant is located on the city's outer harbour, in the north east corner of the island of Amager — within sight of the city centre, facing the Middelgrunden Wind Farm across the Øresund.
In 1999, the Capital Area Geothermal Cooperation (Hovedstadsområdets Geotermiske Samarbejde or HGS) was formed to encourage the production of geothermal heat in the Copenhagen metropolitan area. It's a consortium of four companies — DONG Energy with a 46% stake and Københavns Energi A/S, Central Local Transmission Company I/S and Vestegnens Cogeneration Company I/S, each with an 18% stake.
Amager plant produced geothermal power from November 2004 but opened officially on 5th May 2006.
DONG VE operates the geothermal loop — the two wells and their pumps — and Energi E2, owner of the Amager Combined Heat & Power installation, operates the heat pump plant. Pumping is done by thermally driven absorption heat pumps, which saves electricity.
The loop is consists of carbon steel pipework with 5mm corrosion allowances, with corrosion protection rods in the filter housing that removes particles over 3 microns in size. A 650kW submersible pump brings the geothermal fluid to the surface. A titanium plate heat exchanger cools the fluid to 17 deg C. Spent geothermal fluid is pumped back into the aquifer by a 450kW injection pump at a wellhead pressure of 5,000kN per sq m.
No.1 Well  2.7km vertically into Bunter sandstone
No.2 Well  starts only 10m from No.1 but inclines to 1.3km distant at its base
Other geothermal cities
In 2005, some 29,000MW of power was generated worldwide from geothermal energy — 24 countries are generating electricity from geothermal sources and 72 countries are using it for direct heating.
Beijing China ... used geothermal pumps to power the 2008 Olympic Games
Boise Idaho, USA ... largest direct-use geothermal system in America, first geothermal heating in 1892
Klamath Falls Oregon, USA ... using geothermal heating since 1964, has more than 550 geothermal wells
Larderello Italy ... its first geothermal power plant opened in 1904, with commercial production from 1913
Madrid Spain
Masdar City Abu Dhabi, UAE ... planned to be the world's first zero-emissions city, with half its power from geothermal resources
Perth Australia ... using geothermal energy for cooling rather than heating
Reno Nevada, USA
Reykjavik Iceland ... only metropolitan area in a country of hot springs, 87% of buildings heated geothermally, 17% of electricity comes from geothermal sources
Xianyang China ... pop. 4.8 million, China's official geothermal city