Coal is not really renwable, the closest we have is some of the peat bogs. Coal comes from a very warm and productive period of earths history to coincides with the advent of plant lignin, which took microbial life a very long time to figure out. Thus a unique period of plant matter buildup on earths history. It will likely not bounce back to pre-industrial level particularly in the sorth of time frame man cares about. v
For renewable to work as reliably as the grid now, you need massive investement in the grid for redistribution, load balancing, and connection to the remote places with the most wind/solar in the first place. In some places that are sunny and have high electric prices solar can be cheaper than the grid if you can roll it into a mortgage or have thousands of dollars of cash laying around.
"Methane power stations making use of sewerage and rubbish disposal, in conjunction with solar and wind could provide sufficient power for general usage"
-- No, just No. Have you even tried to look at the math for this? Sewage or landfill methane is just and afterthought. At best sewage methane captrues a minute franction of the energy cost to produce and transport food in the first place.
"So how much will greed and 100% consumption taxes on luxury items cut back on energy demands."
Problems:
1. Who decides what a luxury is?
2. Why is the tax the same if different luxuries to different damages
3. The tax can easily fuel something more destructive like war or building more roads (rather than shared transit systems).
4. This may drive higher turnover, people buying the best "non-luxury" car every year rather than a "luxury car" every 3-4 years.