Grupo Hunosa, undergoing a transformation away from coal, its basic activity, used geothermal energy from its former mine to build a 6 MW heating and power system. The project in the north of Spain won the Global District Heating Award.
The cooperation between Hulleras del Norte SA and the University of Oviedo in Asturias helped a local district heating network become the biggest one in Spain. The utility better known as Grupo Hunosa has been transforming its failing coal business, with an accent on renewables, particularly geothermal energy and its applications in heating and power.
Two pumps use the warmth from flooded shafts at the Barredo mine 85 and 95 meters below ground and hot water is supplied to the campus in Mieres, the regional hospital and a housing project. The new facility has the capacity of 2 MW and an annual output of as much as 2.88 GWh, adding to the existing 4 MW.
Hunosa covered a third of the EUR 1.5 million project from the European regional development fund
The new project is estimated to save 440 tons of carbon dioxide emissions compared to conventional technology and bring in EUR 120,000 in turnover per year. It includes air conditioning.
Hunosa’s payroll shrank to seven hundred people from the 25,000 at its peak half a century ago, prompting the search for alternatives. The firm run by the Spanish government’s SEPI holding has ventured into projects like biomass and energy crops.
The said pumps require 90 kW for pulling 330 cubic meters of water per hour apiece to the heat exchanger, consisting of three units. If the mine was active, water would need to be pumped out at all times.
The number of the company’s employees dwindled down to just seven hundred from the 25,000 peak, reached in the 1970s
The temperature in the shaft is at a constant 23 degrees Celsius. Normally it gets one to three degrees hotter per one hundred meters of depth.
One third of the EUR 1.5 million investment was covered from the European regional development fund.
The pipes are from polypropylene, insulated with elastomeric material. The system accounts for 86.5% of the energy demand, of which it covers nearly the entire heating needs.
Asturias province, located in the country’s north, has seen a sharp drop in population numbers parallel to the disappearance of obsolete industries, as people move elsewhere for jobs. Projects like the one in Mieres are aimed at transforming the local society and improving the quality of life. It earned the Global District Heating Award in the emerging market category, as the sector is largely undeveloped in Spain.
One of the advantages of the geothermal facility is that, for instance, the water for the university and the high school can be delivered at a much higher temperature than the water for the residential buildings. It diversifies the opportunities in the market.