Geothermal heating plant Unterföhring
| Geothermal heating plant Unterföhring | |||
|---|---|---|---|
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| location | |||
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| Coordinates | 48 ° 11 '36 " N , 11 ° 39' 34" E | ||
| country | Germany | ||
| Data | |||
| Type | Geothermal heating plant | ||
| Primary energy | Geothermal energy | ||
| power | 64 MW, of which 22 MW geothermal | ||
| operator | GEOVOL Unterföhring GmbH | ||
| Project start | 2005 | ||
| Start of operations | 2009 | ||
| Website | www.geovol.de | ||
The geothermal heating plant Unterföhring is the only geothermal heating plant in Germany to date that has been expanded with a second geothermal double drilling (doublet). The plant has an installed geothermal output of 22 megawatts , making it one of the most powerful geothermal heating plants in Germany. It supplies over 2,700 households and around 50 commercial customers in the Upper Bavarian municipality with district heating . The operator of the system is GEOVOL Unterföhring GmbH, which is 100% owned by the municipality of Unterföhring .
Project progress
In 2005 the district of Munich formulated long-term goals for a sustainable energy supply in the region. The 29 municipalities in the district supported the concept and committed themselves to doing their part in realizing the plans. The municipality of Unterföhring placed particular emphasis on the use of geothermal energy - also because geothermal energy projects in Pullach and Unterschleißheim got off to a promising start around 2003. In 2005 the municipality therefore decided to secure the exploration rights in order to be able to use the geothermal heat. The community subsidiary GEOVOL Unterföhring GmbH was founded in 2007 to implement the project. The two wells were drilled in spring 2009. The geothermal district heating supply could already be started at the end of 2009. In 2014, the existing duplicate was supplemented by a further double drilling, increasing the geothermal output of the plant from 10 MW to 22 MW in order to be able to supply the entire community with geothermal district heating. It is the only geothermal project in Germany to date that has been expanded to include a second duplicate. The new energy center, fed by the second duplicate, was put into operation at the beginning of 2016.
Milestones of the project implementation
| 3/10/2005 | The Unterföhrings local council unanimously resolves that the 32 km² claim “feringeo” should be secured in order to drill for thermal water there |
| 2006 | A 2-D seismic is carried out to explore the subsurface |
| 3.9.2007 | Foundation of GEOVOL Unterföhring GmbH |
| 11/21/2008 | Start of drilling |
| 6.2.2009 | The first thermal well has found it |
| 3.5.2009 | The second thermal well has found it |
| Fall 2009 | Start of district heating delivery |
| August 2010 | Completion of the energy center I. |
| February 12, 2014 | Beginning of drilling for the second duplicate |
| 1.4.2014 | The third thermal well has found it |
| June 27, 2014 | The fourth thermal well has found it |
| Fall 2014 | Start of construction of the energy center II |
| February 25, 2016 | Commissioning of the energy center II |
| Summer 2016 | Start of heat supply from energy center II |
Geology in Unterföhring
The process of hydrothermal geothermal energy is used in Unterföhring: The Malmkarst , a water-bearing rock layer (aquifer), is located under Unterföhring at a depth of approx. 2,000 - 2,500 meters . Fossil groundwater has been stored in the up to 600 meter thick Malm layer since the last Ice Age. It flows very slowly there and heats up thanks to the heat in the earth's interior, which is largely caused by natural radioactive decay processes. To use this thermal water, double boreholes are drilled into the karst: One borehole is used to convey the thermal water, the other is used to return it to the rock layer (reinjection), where it is heated again and the cycle is thus closed.
Technical specifications
| Duplicate I. | Duplicate II | |||
|---|---|---|---|---|
| drilling | "Thermal 1" borehole (reinjection borehole) | "Thermal 2" borehole (production borehole) | "Thermal 3" borehole (reinjection borehole) | "Thermal 4" borehole (production borehole) |
| Drilling time | November 21, 2008 - February 6, 2009 | 03/13/2009 - 05/03/2009 | May 19, 2014 - June 27, 2014 | 02/12/2014 - 04/01/2014 |
| Drilling time | 71 days | 51 days | 39 days | 48 days |
| Drilling section | 3,042 m | 2,578 m | 3,050 m | 3,897 m |
| Drilling depth | 2,512 m | 2,124 m | 2,053 m | 2,341 m |
| Thermal water temperature | 86 ° C | 87 ° C | 84 ° C | 93 ° C |
| Bulk | 85 l / s | 85 l / s | 100 l / s | 90 l / s |
Energy centers
Energy center I
- 2 titanium plate heat exchangers
- 4 mains pumps
- 2 redundancy and peak load boilers (20 MW)
- Photovoltaic system on the roof (49.71 kWp)
- emergency generator
Energy center II
- 2 titanium plate heat exchangers
- 4 mains pumps
- 2 block-type thermal power stations
- Adsorption refrigeration system
- Photovoltaic system on the facade
- Redundancy and peak load boiler (> 20 MW)
District heating
In the final stage, the district heating network in Unterföhring should be 40 kilometers long and reach all parts of the community. In the spring of 2019, it will be around 34 kilometers long and supply around 600 buildings in the community - from single-family homes and large residential complexes to large companies such as Allianz and ProSiebenSat1. Heat sales are steadily increasing due to the expansion of the district heating network: in 2018, almost 55,000 megawatt hours of geothermal heat were sold, around seven percent more than in 2017. A special feature of the heat supply in Unterföhring is that the district heating network consists of two networks, each with its own energy center: That "Nordnetz" is fed by the energy center I, the network for the south of the community is supplied by the energy center II, which was built in 2016. Both networks are, however, connected by a heat exchanger so that heat can be "shifted" between the two networks. Due to the different customer structures, this network architecture has advantages: While one network has more private customers, the other supplies more business. This results in power peaks at different times of the day, which can be effectively buffered with the other network. This not only increases the security of supply, but also means that the operating times of the fossil-fueled peak load boilers can be greatly reduced.
In Unterföhring there is no compulsory connection. Nevertheless, the connection rates that GEOVOL achieved are very high: in existing buildings they are on average 70 to 80 percent, in new buildings they have so far been 100 percent.
Geothermal cold
In order to use the excess heat in summer, GEOVOL has expanded its business area to include the supply of cooling. For this purpose, ad or absorption chillers are installed directly at the customer's premises , which can convert geothermal district heating into cold for air conditioning. A large ProSiebenSat1 office complex has been supplied with room cooling via a geothermally operated refrigeration system since 2015 (see picture). In the spring of 2019, the refrigeration supply for the local adult education center is to be put into operation.
economics
By mid-2018, the community had invested around 64 million euros in geothermal heat supply through the community-owned company. The drilling of the second doublet alone cost around twelve million euros, and the construction of Energiezentrale II cost around eight million euros. For further network expansion, GEOVOL has to spend an average of around three million euros per year. GEOVOL will probably be able to report an annual surplus for the first time in 2022. Until all annual losses from previous years have been balanced out, i.e. the investment for the municipality has amortized, it will be 2033 according to current planning.
swell
- ^ Project list of the Federal Geothermal Association. Retrieved May 3, 2019 .
- ↑ GEOVOL Newsletter No. 33. Retrieved on May 12, 2019 .
- ↑ Company website. Retrieved May 3, 2019 .
- ↑ GEOVOL Newsletter No. 34. Retrieved on May 12, 2019 .
- ↑ Lohr: "In new buildings the question does not arise: district heating or not". Retrieved May 12, 2019 .
- ↑ GEOVOL press release from February 22nd, 2019. Retrieved May 12, 2019 .
- ↑ Lohr: "In new buildings the question does not arise: district heating or not". Retrieved May 12, 2019 .
- ↑ GEOVOL-News from March 24th, 2019. Retrieved May 12, 2019 .
- ↑ Press release from GEOVOL from July 9th, 2015. Retrieved May 10, 2019 .
- ↑ GEOVOL Newsletter No. 31. Accessed on May 10, 2019 .