HEATING OF BUILDINGS USING GEOTHERMAL ENERGY [STAGE 2]

Cel

To demonstrate the economic viability of using geothermal heat (76 deg. C) from the Southampton 1 well with a flow-rate of 20 l/s ( drilled with EEC support - see GE/69/81), to heat buildings at a cost more favourable than the alternative low fuel.
A civic centre and swimming pool will be the first buildings to benefit from the project. Additional building will be supplied by an extension of the network. A boiler plant will be constructed to ensure peak load (12 MW). The geothermal exploitation system will be comprised of a heat station with geothermal exchanger (3.
8 MW) and a gas heat pump to increase resource heat recovery (1,500 MW). The well will be pumped at 310,000 m3/y with a cumulative resource life of 15 - 20 years. Estimated energy savings are 3,145 TOE/y with a payback of 169 years.
After one year of operation, the installation has run successfully : no stoppage of the downhole pump, good performance and running of the pumping system and the monitoring equipment.
The geothermal kWh is produced at UKL 18,4 per MWh to be compared with the cost of conventional energy at UKL 19,7 per MWh.
The economic success of the scheme is dependent on the ability to cover a high proportion of the annual energy requirement from geothermal heat, supplemented in the future with waste heat recovered from electricity generation.
The energy production capacity of the geothermal well is determined by the rate of brine production and also by the return temperature of the heating water. Prior to the installation of a heat pump, geothermal heat will provide 1400 kW capacity and an annual energy contribution of 26 000 GJ/year. If a heat pump is used, this performance will increase to 2 700 kW and 50 000 GJ/year.
The competitive cost of geothermal energy gives a satifactory payback of 8years, better than expected and which can be improved using a heat pump.
During the long term trials carried out in 1983, geothermal water was obtained from the aquifer at a temperature of 74 deg. C, a flow rate of 72 m3/h and a corresponding drawdown of 300 m. In 1987, the well was reactivated and the expected temperature and capacity of the well was easily obtained.
The well was lined with a 340 mm diameter steel casing to a depth of 1000 m and then to 1700 m, just above the aquifer, with a 215 mm diameter.
Scientists specified the conservative operation capacity of 12 l/s in order to envisage a 20 year life for the well. Recent pressure variations were recorded at another well at Marchwoodat a distance of a few miles. That was positively interpreted by the geologists as evidence that the geothermal reservoir is much larger than expected with no permeability barrier. The result can be an increase in the life of the well or an increase in the pumping capacity.
The principal brine properties are as follows :
Ph 6. 0
Suspended solids1. 0 mg/l
Chlorides as Cl 75. 9 g/l
Amonia as NH+ 36 mg/l
Density at 25 C 1. 088 g/cm3
For the pumping of the brine, the technical solution of a turbo -pump has been selected. The heat station is designed to enable future plant extension and contains :
- a 2000 kW geothermal heat exchanger;
- a 250 kVA (electrical)/400 kW (heat) diesel generator with engine and exhaust gas heat recovery;
- a 2000 kW gas/gasoil fired high efficiency (92%) watertube boiler;
- a water treatment plant for the district heating system;
- the generator control and switchgear panels;
- the central control and monitoring system for the heat station, well head, external boilerhouses and consumer plantrooms.
Space provision is made within the heat station for a gas engine generator of 2000 kW (el)/4000 kW (heat) capacity, and a heat pump to enable greater heat extraction from the geothermal brine. The heat station can be expanded in the future to provide space for a further 2000 kW (el)/4000 kW (heat) capacity generator and a 4000 kW boiler.

Program(-y)

ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985

Temat(-y)

4.1 - HEATING

Zaproszenie do składania wniosków

Data not available

System finansowania

DEM - Demonstration contracts

Koordynator

SOUTHAMPTON CITY COUNCIL

Wkład UE

Brak danych

Adres

Civic Centre
SOUTHAMPTON
Zjednoczone Królestwo

Koszt całkowity