at present we already pay gas, and previously coal, generators to be there to run idle, it's called the Capacity mechanism.
And if we followed Ecotricity's suggestion those generators would still get their bid price, just everyone would get their bid price, not what the gas generators, as the most expensive bidder gets.
In my view what each type of generator should get should be determined by their long term cost of supply, which surely is set through their Contract for Difference price, not the cost of the marginal supplier on the day.