Geothermal energy: heat pumps and CO2, energy savings and CO2 emissions
To our taste, geothermal energy is all too often presented as a renewable and “green” energy.
This article concerns the surface geothermal energy, called heat pumps, not deep geothermal or deep heating networks catchments themselves are completely renewable.
So while geothermal energy is less energetically worse than electric heating, the heat pump heating method remains of electrical origin. In this sense there remains an ecological and technological aberration since, in France, an average of 2,58 units of primary energy heat is required to make 1 electrical unit. When we produce an electric kWh, we therefore reject 1,58 in nature, in "dead" loss!
In all honesty it must therefore be divided by the famous 2,58 COP that are the pride of Representatives and installer of geothermal systems.
The coefficient 2,58 is also applied for any DPE, as shown in this example of Energy performance diagnosis.
So much for the energy aspect, now let's look at the CO2 aspect.
Heat pump and CO2: comparison with other energy sources
Here is a comparison from a Swiss site for geothermal development.
What can we deduce?
a) That the interest, on the CO2 criterion, of a heat pump powered by “European” electricity is quite small, not to say zero (see negative) see b) and c).
b) A heat pump emits, on the European average, only 25% less CO2 (did you say clean?) than a gas boiler.
c) The additional financial cost (therefore CO2: any professional activity emits CO2) of a heat pump compared to a gas boiler must be taken into account in the overall CO2 balance over the life of the installation. For us it is clear that a heat pump, sold 3 to 4 times the price of a gas installation and often exceeding 20 €, has very little chance of being profitable on CO000.
d) In France nuclear enables broadly lower emissions of CAP but in Germany a COPA 2 heat pump will emit more CO2 than an oil boiler!
e) Finally, only a heat pump powered by green energy can be considered as renewable energy. But few people currently have green contracts.
f) Can we use these data to determine the average of European emissions? And therefore the average COPA retained for the installation?
- 5500 kg of CO2 emitted by fuel oil correspond to fuel oil consumption of 2150 L, ie with 90% efficiency a useful energy of 19 000 kWh.
- We assume a COPA (and not COP see definition here: COPA geothermal and COP ) Of 3
- We therefore need 19/000 = 3 electric kWh per year to supply the heat pump.
- Or emissions of 3050/6333 = 480 g / kWh.
This seems consistent (see Emissions of CO2 in Europe), the COPA retained is therefore of the order of 3.
Edf you we will soon have more than light!
Currently in France there is a real race to install heat pumps under pressure from Edf and its ally ADEME. Advanced ecological and economic agruments are deceptive (we have just developed at least one ...) ...
We dare to assert that it is an outright econological scam and portends an econological disaster to come for those who have decided to equip themselves with this energy ...
A CAP is currently economically "interesting" simply because the price of electricity in France is undervalued. As this will not last and the ROI duration of a CAP is quite long, there is a good chance that: choosing a cap means losing money in the end!
We had already spoken about it extensively and it was the subject of a previous news that we invite you to read: heat pump = renewable energy?
Conclusion: yes but then choose?
If you have to choose an equipment soon, think twice before signing up for geothermal energy!
And turn you rather a truly green energy, renewable, locally produced independent of political will: the wood pellets.
THEcombination of wood and solar remains for us the best solution econologically speaking at present. This is the solution we have at home: a wood boiler to supplement the solar!