If the price is the same as the non-renewable suppliers and not all electricity is from renewable sources, then by switching to a renewable supplier all you're doing is bumping someone else onto a non-renewable supplier aren't you?
Presumably if everyone switched to a theoretical renewable-only supplier with no offset certificates now, they would have to stop making the renewable energy promise?
Eon are not the only ones coming up with such tariffs, most suppliers are jumping on the bandwagon.
What I want is the big picture, moving the needle towards more renewable. I don't want all of my electrons to come from a wind turbine, just voting with my wallet such that renewable percentage goes up and up.
With all the challenges it implies in terms of peak management, storage, seasons etc.
Advertising "100% renewable energy" means that there is enough renewable energy produced to meet demand at all times.
That's part of why I am dubious of these claims. It does not seem straightforward to guarantee this to millions of customers.
gas is 40%, wind 16.9% solar 4% biomass 6.3% [1]
E-ON is about 13% [2] of the market share, just wind is enough to cover that and more (and 13% is assuming the grid generates energy just for customers, not industries, which it isn't)
Point is, there is enough renewable energy on the grid, it's a matter of how energy suppliers are going to fight to package it to clients. If the fight becomes hard on their end, they will be incentivised to generate more renewable.
[1] http://www.mygridgb.co.uk/last-12-months/
[2] https://www.ofgem.gov.uk/data-portal/electricity-supply-mark...