It's still a developing energy source. Nobody is saying Germany can be powered 100% by renewable energies right now. But, it is a fact that Germany is able to utilize more and more renewable energy each year. Germany's green power has grown by a third in just the last three years. 9.5 times more than just last year, which is a record. They produced enough renewable energy (104 billion kWh to be exact) in the first 6 months of this year to power Germany's homes for a whole year.
https://www.independent.co.uk/envir...ths-year-solar-power-wind-farms-a8427356.html
California is also blowing right through renewable energy records.
http://www.energy.ca.gov/almanac/electricity_data/total_system_power.html
Nuclear power is mostly stagnant. Not much of any progress at all is being made in the technology or application.
I might also add that solar energy is an easily decentralized energy source so many people could get solar panels just for personal use and save on their energy bill. It doesn't have to be a whole big country-wide thing like other energy sources. Because country-wide application is where we are coming up short currently.
At the current rate of progress, they are predicting the ability to use 65% renewable energies by 2030. I'm inclined to believe that because they are currently on track to meet their 2020 target. Like I said, it's a developing technology. But if it's blowing through records annually and they are meeting their targets, there's no legitimate reason to believe we couldn't power Germany almost entirely on renewable energies in the near future.