 Call it the second dash for gas. George Osborne's conference speech hinted strongly at a trade-off between keeping prices down and hitting emissions targets, and now the Government, in supporting Centrica's gutsy ?13 billion supply deal with Norway, has made its choice.  after all the talk about a diverse energy mix, with renewables and nuclear playing a bigger role, the UK's main source of energy until 2025 will be the one to have dominated since the original 1990s dash for gas.  The decision is bold and pragmatic. It recognises that, with new nuclear power stations set to be delayed and with the cost of renewables pushing up household bills, gas is the best way to ensure affordable security of supply.  Competition for gas in Europe is rising: the retirement of Germany's nuclear plants has been accelerated, post-Fukushima, European Union rules are disincentivising the use of coal and carbon capture looks a dead duck.  Centrica had already lined up big reserves of LNG. But pumping natural gas straight from the North Sea is preferable to LNG shipments from the Middle East that can be diverted to Japan or anywhere else at short notice.