I'm sorry, but I just can't beleive this at all.
The energy arriving from the sun is vast. It is called the "Solar Constant" and falls on the entire surface of the earth.
On the other hand, the amount of energy released by mankind from fossil fuels and nuclear energy is negligable by comparison. Most is released into space apart from that which is retained by an increase in greenhouse gases. These greenhouse gases retain heat wherever it comes from.
The end conclusion is however the same in that the energy sources you state as preferable are not CO2 releasers.
It's the CO2 duvet that makes the difference, not the tiny amount of extra energy in producing this duvet.