Interesting tidbit from Bill Gates whom also invests in clean energy:

He suggested that intermittent energy sources such as wind and solar power shouldn’t be eligible for government subsidies unless they’re matched with energy storage technology. Spending government money on wind power by itself, without also investing public money in energy storage and expanded transmission capacity to make the power more widely available, is “foolish”.

This confirms my impression of solar and wind power that it is not an alternative energy source.

To use the car analogy, solar and wind power are like a hybrid car. You can run the car on battery power for some time but when the battery runs down you need to switch to the petrol engine again.