What Sewie may be concerned about is that both nuclear and...

What Sewie may be concerned about is that both nuclear and renewables are clean sources of energy and as such BOTH should qualify for "renewable Energy Certificate" (REC). As such to be equitable nuclear should have the same priority on the grid as renewables. RECs mean that a generator still get paid even though the power generated is curtailed due to supply exceeding demand (i.e and the balance cannot be stored in batteries/pumped hydro). In other words Sewie objects to a competitor on the uneven playing field of grid priority access and the curtailment payments currently being received exclusively by renewable generators through RECs - this would result in competitive pressures on renewable suppliers.

See (HERE) about the how UK wind farms are exploiting this rort (Sewie doesn't want to clean it up or allow competition)