Have a look at slide 53 of the summary pdf. It's specifically about Virginia, and it says the same thing I wrote above (minus my personal opinion about 100% renewables being a good thing). Just to be clear, it doesn't say that VCEA is the only contributing factor to price increases: they attribute ~70% to VCEA, with higher natural gas prices accounting for the rest. There's a chart in the upper-right of the slide showing how these two factors have contributed over time.

I'm not an expert, but my understanding is that solar has a much larger up-front cost than, say, a natural gas plant -- but because there are no ongoing fuel costs, it is expected to be cheaper per kWh over the lifetime of the plant. So this is a great investment in the long term, but there are significant costs that must be absorbed in the short term -- and that's what is impacting prices right now.