Speaking as a Canadian, so take it with a grain of salt. I get where Biden is coming from with regards to transitioning away from fossil fuels towards a heavier reliance long term on renewables. The plan in and of itself isn't a bad one, but you need something to bridge that gap and it's pretty much only going to be gas and oil, unless there is a major rise in the rollout of nuclear (which looks promising as the next gen reactors are being developed, which have uses for the spent material, etc. but that's another topic).
But, the way he put it in the debate was not a good look for him in the least. Trump definitely capitalized on it by mentioning Texas etc. right away. That can't be great for the democrats when races in some of these states were tightening up in the polls. I feel like the nuance required to explain a long term paradigm shift in the energy industry is just going to produce negative soundbytes and not be effective in the debate setting. It's easier for a person facing loss of their current job in the oil/gas inudstry to get riled up about this than it would be for someone thinking about a prospective employment opportunity in renewables down the road to get excited.