When producing heat the energy coming from the bedrock/ground is totally CO2-free while the electricity for driving the heat pumps represents CO2 emissions. In Sweden there is 10 gram CO2 per kWh energy from the electrical grid. But since a geoenergy solution generates 3-4 times the input of electricity the CO2 is less than 3 gram per kWh geoenergy. As a comparison heat or hot water from fossil sources represents several hundred grams of CO2 per kWh and the average district heating solution in Sweden emits 80 gram CO2 per produced kWh.
When geoenergy is using wind power or electricity generated from solar panels there are no green gas emissions at all. That goes for hydro-electricity as well.
In Sweden it is possible to order a subscription of guaranteed CO2-free electricity making geoenergy totally CO2-free.
The EU Commission declared geoenergy “Renewable” less than ten years ago. This is a reason why the “old” sustainable energy sources: Wind and Solar, have had more attention than the almost CO2-free geoenergy solutions. Despite the fact that bedrock/ground has clear advantages as energy source:
1. Geoenergy is available 24/7 and not dependent of the wind blowing or the sun is up
2. Geoenergy is self-financed without subsidies from the government. It is an energy investment which gives a good economic return – normally > 10 % per year when compared with other alternatives.
3. Geoenergy installations are unseen – to compare with the very visible wind power stations and solar cells
4. Geoenergy fits ideally as the hub in combination with solar panels and CO2-free wind power.
5. Geoenergy is a truly sustainable system where 6 % of an installation has a lifespan of more than 50 years. It is only the electro-mechanical components which have to repaired or replaced within the first 20 years.
The heat pump technology behind geoenergy is continuously improving – giving a better-and-better performance and economic return to the owners. Energy-in-a-Box is an industrial step forward by making geoenergy solutions available in large scale to large buildings without the hassle of months of handicraft work.
Under dimensioned boreholes – which makes them cooler and cooler – is the biggest risk in geoenergy solutions. When this happens more energy is taken out from the bedrock/ground than what is stored and refilled during summer. The process takes several years but results in lower energy production and less favourable outcome.
Test drilling in combination with careful computer simulations is one way to avoid this risk. Using solar cells for sending down warmed air into the holes is good way to store energy to create the balance between intake and outtake of energy.
Something which ought to be mandatory in larger installations is online monitoring of the temperature in the boreholes. Another way to adjust the unbalance is adding a few more boreholes – which is better done before – than a number of years after the installation of the geoenergy system.