On the Pvoutput website you can see the generated energy, and next to it the website also shows the total amount of CO2 emissions prevented. Expressed as ton CO2, cars, houses, trees and a couple of other measures.
But how is this calculated? For my installation, it shows 1,4 MWh as total production, which would be equivalent to 1.4 tons of CO2, or 37 trees, or 1 house. So it seems the system assumes 1000 g CO2 per kWh? That makes about sense for coal-fired plants - but not for an average west-european production mix. 37 trees (grown for 10 years according to the tooltip)? Assuming that same 1,4 tons of CO2, that would mean an average of 37 kilo per tree - 3,7 per year? That seems a pretty low number. I understand that the figures for ‘one tree’ can quite different depending on your assumptions of what kind of tree, and how old - but in comparison, Solaredge shows the same amount of electricity as the equivalent of just 2 trees.
I have a similar question. Is there somewhere where the CO2/KWh value can be set, as this is different from country to country. I have brought this up with SolarEdge themselves as their estimate of CO2 saving for my power produced is way to high for New Zealand. They are looking at being able to adjust the modifier for different regions/countries in a future release. Is it possible to modify that value on PVoutput?
It is based on Coal burning emissions at 1070g CO2 per kWh.
Conversions were based on the US EPA site below which have since been revised -
Thanks. That at least explains clearly where the calculations come from - even if they might not be applicable everywhere in the world, or maybe outdated. I’m especially glad that that US EPA site uses the marginal emissions factor (currently 707 g CO2/kWh) - which is in my opinion indeed a much better figure than the average production mix.