I already have the idea and I am doing some preliminary work on it in my master thesis. I don't really intend to stay in academia after the PhD. Best case scenario - even if this is not the most realistic - I manage to develop my idea where I actually have a patentable prototype, during the PhD. Worst case I have nothing and wasted years of my life.

Does anyone of you know how the onwership rights for IP you developed during your PhD?

I looked up a couple of funding sources concerning the university I posted, but quite a bit of the made requirements I can't fulfill being a white male from Europe. I think TreeofLife already mentioned a number of funding sources, but they seem to be exclusively for the UK. Do you know any more?

Thanks for the informative answer!
I came across a PhD program which my idea fits into. (http://cee.umich.edu/research/systems energy harvesting)
I might not be looking correctly but I can't see any specific projects being advertised for PhD students. Is it a realistic option to research universities, which have a somewhat similar interest and then just submit my idea/proposal or would I usually first contact the university staff and ask for specific topics?

Hey guys,

I will probably be finishing my Master degrees in Business Engineering and Energy Science and Engineering at the beginning of next year. I have an idea for a technology in a field which is a hybrid between civil engineering and mechanical engineering I would like to pursue via a PhD. In Germany it usually isn't possible to approach a professor with an idea of your own. What is the situation in the anglosphere?
If it is possible to submit an own idea what should I be looking for with universities to apply for a PhD?

Thank you in advance for your help.