I cannot speak for the utility laws in your country, but for us here in the US we would not get cheap energy. Fact is, practically if not all states have given utility companies the authority to charge more for energy supplied by renewable 'Green' resources. It is this incentive that builds windmills that cost more than they will ever pay back.What's the worst that can happen? Someone steals your design, patents it, and gets rich. The world gets cheap energy whether you or someone else holds the patent.
We pay more for wind and solar, yet due to political pull hydro-power is not considered 'renewable'... This little known fact is in my favor as I use hydro.
For utility companies to produce power via a gravity machine patent or otherwise it will not help John Doe the consumer one bit, it will escalate his monthly bill.
Ralph