| Abstract |
Lunds Energi AB is a municipality owned company, situated in the province SkÂne, in south of Sweden. The owners are four municipalities, Lund 82,4 %, Eslˆv 12 %, Hˆrby 3,5 % and Lomma 2,1 %. The services supplied by the company are district heating, district cooling, distribution and selling of electricity and natural gas. Lunds Energi produces 930 GWh of district heating annually, based on geothermal heat pumps, sewage heat pumps, combined heat and electricity generation with gasturbine and heat recovery boiler and bio, oil and natural gas fired heat only boilers. The geothermal system was taken into operation 1984 and 1986 in two steps. The system consists of 4 production and 5 injections wells. From the production wells 550 to 700 meters deep, a saline water (5%) at a temperature of 20 ?C is pumped by means of electrical submersible pumps, installed at 80 meters depth. The geothermal water with a maximum flow 1 600 m3/h is taken to our production plant in GAP (Glasfibre reinforced plastic) pipelines. In the production plant we have two heat pumps capable of producing 19 MW and 21 MW heat. The compressors are running on electricity. The geothermal water is cooled down to four degrees C after the evaporator of the heat pump. The heat pumps raise the temperature of the district heating water from 45 to 80 ? C, which is sufficient for our district heating system during 8 months. During wintertime we have to peak the temperature up to 118 with gas boilers if necessary. After the heat pumps the geothermal water is transported to the five injection wells also between 550 and 700 meters deep. The distance between the production wells and the injections wells is approx. 3 km with the production plant in between. The energy to the district heating network from the geothermal heat pumps is around 35 % of the total energy needed, which means a substantial saving in oil- and gas consumption, not to mention the decrease in emissions from carbon dioxide. The geothermal system has saved approximately 500,000 tonnes of oil since the commissioning in 1984. |