Dieter Helm just wrote in the Financial Times:
But a moment’s reflection yields the unfortunate conclusion that not only are current renewables making little difference to global warming but that they never could. Wind in particular is a low-density, intermittent energy source. Future renewables might well close the gap, but not the current forms of renewable energy.
So he should know that the Roadmap assumes 55% percent of energy coming from renewable energy in 2050 at the very least. I would call that making a big difference.
The fact that wind is intermittent and low-density is actually not relevant. You just build more capacity. No need to wait for any new wondrous technology to get developed.