If I could snap my fingers I would just copy the strategy by the anti-nuclear movement. As an strategy, theirs were both a great success, market friendly, easy for politicians to support and economical.
First step is to forbid creating new fossil fueled power plants for increased capacity. This has zero impact right now on the grid, but sets the road for the industry. Projects created before this date is not impacted.
Second step is to set a deadline where existing plants need to be demolished. The date get set around the time of existing plans for investments to be recovered. This makes current investors happy, while we also get a definitive date where the plants will be gone.
At this point we are done. New investors will look at the market and see an opportunity for increase demand for energy down the road, and at the same time see old capacity that will need to be replaced. There is no tax nor tax politics involved. No decisions regarding pipelines, trains or ships. Just two political decisions that has zero impact on anyone right now.