Well why not try to build up your small farm of mining rig by using solar panel if you are getting expensive bill to your electricity bill then you need to invest also for solar power. But I'm pretty sure you are going to get the return of your investment for few months and you are going to have no problem with your electricity consumption.
The mining rigs alone will cost you a lot, the land and the materials that will be used in building the room for the farm will cost you a lot, the solar panels will cost you a lot = This is some serious large amount of money.
Be realistic and live in the current situation but always consider your dream in the future.