The PV installation was pioneer in the modality of PV self-consumption in Extremadura, and the geothermal installation was one of the first. Both monitored.
Since its construction in 1998, it has not had any important refurbishments done. So, the purpose of the project was not so much to solve a problem, but to increase the energy efficiency by changing the AC and heating system as well as to introduce self-consumption through renewable energy sources, in this case, a solar photovoltaic installation and a geothermal installation.
The PV installation only covers a small percentage of the building’s electricity needs:
- Total amount of energy consumed: 135.721,4 kWh/year
- Total amount of energy produced: 5.717,7 kWh/year
26 panels were placed along two branches, the peak power of each panel is 245 Wp.
The geothermal installation exchanges heat with the ground below the building through 6 soundings of 100 metres deep. The exchanger serves a water-water type geothermal heat pump: CARRIER AQUA SNAP 61WG / 30WG 020-090 with two compressors and reversible cycle manual from the outside using 4-way valves.
The pump has a nominal:
- cold capacity of 24-95 kW
- heat capacity of 30-116 kW
And it is expected to cover
- 100% of a cold demand of 23.4 MWh/year
- a heat demand of 60.4 MWh/year, with an accumulator of 3000 litres capacity.
The building and its installations are completely monitored remotely.
The main beneficiaries of the practice are students from different levels of education: high school, vocational training and university.

Resources needed

The investment for the PV installation was 11.687,25€ + VAT. The payback period is 10,8 years. The geothermal installation was 80.650€ and the payback period for this technology 9,9 years.
75% of the investment was financed by EU funds and the other 25% by AGENEX.

Evidence of success

The first evidence of success of the geothermal installation is that the building controls inside temperature using renewable sources, in this case the temperature of the ground below. The monitoring of the first few months reveals that the average energy savings reach 55,91%.
- Energy savings: 50.899 kWh/year
- CO2 emissions savings: 16.797 kg/year
- Economic savings: 8.144 €/year

Difficulties encountered

PV installation is simple but regulation to legalize it is not, it is a very slow and complex procedure that faces many challenges.
The main geothermal difficulty encountered, besides the usual ones of a construction site, was finding a company specialized in geothermal work and maintenance.

Potential for learning or transfer

The project is easily replicable from two complementary approaches:
- Taking advantage of the extensive public-owned buildings as a demonstration space for efficient and clean technologies, to drive new models of energy management.
- Making the environmental and socio-economic benefits of these facilities public to the citizens.
We have also learned that the ground and soil conditions we have in our region are very good for this geothermal technology, but the lack of demand raises the price and complicates the ability to find specialized companies.
The building’s facilities are open to the students for learning and academic uses.

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Main institution
Regional Government of Extremadura
Extremadura, Spain (España)
Start Date
March 2015
End Date
September 2015


RACHEL CLAIRE TULLY Please login to contact the author.

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