I think looking at natural gas can be a bit tricky. You may ask how much of the gas is used for heating, and get a certain figure. But if you look at it from another angle you may ask how much of the heating is relying on natural gas.This
EU estimate says 45% of the EU-27 residential heating is based on gas. I know that for countries of the former Soviet block this percentage is even higher as we had cheap and easy access to Russian gas. A Wikipedia page on Hungary's energy consumption (I could link it, but I doubt you guys read Hungarian :tongue
says 60% of our heating is from natural gas, while we also have a really high number, 17%, for District Heating (central heating for many blocks of buildings), which no doubt relies heavily on gas too. (Some of it is from burning waste). There are 3100 settlments in the country (from city to village), and 2600 of them are connected to the natural gas pipeline network. The peak gas consumption in the winter is 60-70 million m3 per day, which no doubt makes out the majority of the 13 billion m3 of gas usage per year. (We normally heat from late October to mid March.)
So that's what you would have to replace with solar. I found some data on the total number of sunshine duration per month in Hungary. In the Summer it gets as high as 270-300 hours/month, in the winter it is 40-60. (I know some of you are reasearching solar energy as well, so if you are interested
here is some official data on solar radiation for my country in English by the National Meterological Institute)
While i have all the confidence in Tesla's energy storage buinsess in the long run, I do not see how one could store elecricity generated by solar panels in June-August for heating in February. Especially not on this magnitude.
Of course, one could say the EU should build those solar farms in Northern Africa, hell, make them 5x bigger, and have all the solar energy from there during the winter. But that would be just as risky for energy independence as Russian gas, subject to local or internation power plays.