"[Wind and solar are] even close to being competitive with the marginal costs of running the coal and nuclear plants we already have." Is that still true without incentives, green grants, rebates, and tax credits? Because without all of that and with mountains of red tape nuclear still produces energy at the lowest cost, and without emitting any CO2.
Almost all recent cost studies put the cost of wind and solar far below the cost of new nuclear power. See f.e: "The cost of generating solar power ranges from $36 to $44 per megawatt hour (MWh), the WNISR said, while onshore wind power comes in at $29–$56 per MWh. Nuclear energy costs between $112 and $189." https://www.reuters.com/article/us-energy-nuclearpower/nucle... "Onshore generation costs, at the upper bound…
Worth adding that after this year's round of UK offshore auctions, wind power comes in cheaper than new gas and under a quarter of heavily subsidised nuclear. Despite subsidy and six proposed plants, the only certain remaining nuclear is Hinkley C. Five of the others have had participants withdraw, go bankrupt in one case (Moorside under Westinghouse-Toshiba), and the final remaining UK proposed nuclear - Sizewell C looks increasingly unlikely. Depends on the package and strike prices I suspect as it's an exact copy of Hinkley. EDF (behind Bradwell B, Hinkley and Sizewell using a Chinese reactor design) are busy accumulating a Shenzen style reputation for worker conditions and suicides at Hinkley. Even the majority right wing UK media has noticed enough to report conditions.
The next auction round of offshore wind licences should see it easily come in under existing gas.