Polywell nuclear fusion could be the most sustainable energy technology. Proton boron fusion is aneutronic, which means that no radioactivity is involved. Polywell fusion could also be the cheapest energy supply in terms of levelised cost of energy. To test that claim, a fusion reactor needs to be built that is large enough (say 3 m in diameter for the polyhedral electromagnetic coils) to produce about 100 MW. Funding and talent is required to build such a reactor.
Polywell fusion reactors could also be used for space travel, at a much faster speed than with technologies today, add mentioned by Robert Bussard in his Google Tech Talk.
ProtonBoron is one enterprise that is seeking to develop polywell fusion. It has a fundraising scheme where you can buy units of 1000 kWh for 5 USD. When ProtonBoron successfully achieves it’s mission – the development of a commercially profitable fusion reactor production facility (successful completion of stage three of our plan), we will launch a repayment program to begin honoring our obligation to the ProtonBoron community of fusion supporters. This program may involve us sending you a payment for the value in KWH’s you purchased relative to a globally averaged price per KWH of electricity. For more information, see here.