The Government believe that household waste should, where possible, be minimised and then reused, recycled or composted. Waste remaining after these processes is termed residual waste; the Government are committed to maximising energy recovered from residual waste.
Recovering energy from residual waste avoids the methane emissions arising from sending it to landfill. It also generates energy, which can offset power sourced from fossil fuel.
DEFRA has not generally expressed a preference for one technology over another, with the exception of anaerobic digestion, for treating food waste. Any given technology is more beneficial if both heat and electricity can be recovered. The technology choice needs to reflect local circumstances, which will vary, but we expect greenhouse gas emissions to be a key consideration for those developing waste to energy plants.