What is the solar potential of your region? Here 2 cards France the average sunshine reflecting the solar energy potential.
Keywords: solar energies, photovoltaic, thermal, water heater, potential, France, region, kwh / year m2, m².
Here is a more detailed map: DNI solar map of France and some panels and solar photovoltaic products here
1) Average sunshine duration in hours per year.
Example: if you live in the Bas-Rhin (Northern Alsace) you will have less 1750 hours of sunshine per year.
2) average energy potential in thermal kwh per year per m2.
Example: if you live in the Bas-Rhin (Northern Alsace) you will have less energy 1220 recoverable kwh per year.
3) Example with a concrete case: a thermal solar panel mounted in Alsace in the Lower Rhine.
As read on the cards, we have a year:
- Less sunshine 1750h, take 1500h arbitrarily.
- Less than 1220 kwh / m2 energy, take 1100kwh arbitrarily.
b) Power demand by m2.
So we have an average power of sunshine (when the sun shines) of 1100 / 1500 = 733W. This is very correct (the world average is given for 1000W by m2).
For information, the average power over the year calculated on half a day (on 12h of "day") would be 2 * 1100 / 8766 = 251W.
At these values to obtain the recoverable thermal energy, multiply by the performance of the solar panel (assuming there are no losses which is usually false) or 70% for heat and to 10% photovoltaics.
c) Recoverable Energy annually.
Each would bring m2 * 1100 0.7 770 = kWh.
We recall that a liter of fuel oil has a calorific value of about 10 kWh. Assuming a boiler efficiency of 0.8, a panel m2 give the equivalent of 770 / (10 0.8 *) = 96,25L of oil is roughly, given the various estimates: 100L by panel m2.
Depending on your current fuel consumption, so you can estimate the number of m2 required to fully compensate your oil consumption.
d) Financial "Analysis"
Thus, an Alsatian house that consumed 2500 L of fuel oil will be needed, ideallyOf 2500 / 100 = 25m2 panels (it's much the m2 installed costs on average, with tank and installation, approximately € 1000 now, prices excluding grants and subsidies) and save each year the equivalent of 2500 0.65 * = € 1625 of oil (it is quite small in comparison the price of installing 25m2 which must be located in 2010 and out subsidies between 15 and 20 000 €) ...
We ideally noted because the reality is not that just perfect. Indeed; in winter, solar thermal (share of the heating temperatures low enough damage) only allows heating of domestic hot water or make extra (before the boiler) of conventional heating circuit. To switch to solar 100%, we must have a floor (or wall) heating low temperature.
This is why very few people use solar heating as the vast majority of installations are intended to only heat the domestic hot water (which is on average and about 10 15% to the annual energy consumption ).
Conclusion: a difficult profitability, mentalities to change ...
This brief calculation shows that the profitability of solar thermal is difficult to achieve for people (the vast majority of us) who argue that the financial calculation. Grants and other assistance, as explained in a page of this website, are not changing much ... (quite the contrary)
It will be so long as the non-renewability of fossil fuels and their induced pollution will not be reflected in their costs or the ecological aspects will pass after the financial aspects when buying ...
The moral aspect (abuses of some multinationnales) should ideally also play in favor of the choice of non-fossil energy ...
Is this not the basis of a econological society and not only petrolo-financial ...