Now the real thing is what can be the minimum setup to start at the first stage of mining and how much watts of electricity will cost it?
If you want to mine Bitcoin you have to spend several thousand $ worth of ASIC equipment, and it will probably not be worth the price even with free solar electricity.
You can mine using your home computer(s) instead. You might want to mine Monero, another cryptocurrency that can be mined on any computer, then converting it to Bitcoin using services such as fixedfloat, or to your local currency using localmonero (which might be dangerous if crypto is banned in your country).
You can search on your search engine of choice about how to mine Monero with p2pool, a decentralized mining pool, and then start mining.