Anyone who claims to understand energy policy is either mad or subsidised. Last week I wrote that politics is seldom rational. It is more often based on intuition and tribal prejudice. This week we have a thundering example: the government's new policy on nuclear energy.

Do not read on if you want a conclusion on this subject. For years I have read papers, books, surveys and news stories, and am little wiser. I trust to science and am ready to believe there is some great mathematician, some Fermat's last theorem, who can write an equation showing where energy policy should turn. I have never met him.

The equation would start with the current market price of coal, gas, oil, nuclear and so-called "renewables". That would give simple primacy to coal and gas. The equation would then factor in such variables as security of supply, which – being imponderable – can be argued from commercial interest and prejudice. Then it would have to take account of global warming and the virtue of lower carbon emissions. At this point the demons enter.

We must consider CO 2 reduction through substituting gas for coal, carbon capture, nuclear investment, biomass, wind, wave, solar and tidal generation. We must consider the application of fiscal policy to gas and petrol use, to energy efficiency and house insulation. Each has a quantity attached to it and each a fanatical lobby drooling for subsidies. As for achieving a remotely significant degree of global cooling, that requires world diplomacy – which has, as yet, proved wholly elusive.

Britain's contribution to cooling can only be so infinitesimal as to be little more than gesture politics, yet it is a gesture that is massively expensive. Meeting the current EU renewables directive, largely from wind, would cost some £15bn a year, or £670 a household, and involve the spoliation of swaths of upland, countryside and coast. It is calculated to save a mere 0.2% of global emissions, with negligible impact on the Earth's sea level.

Yet the government wants to commit a staggering £100bn to wind farm subsidies over the next decade, almost all to rich landowners. Northamptonshire, with England's most planned wind farms per acre (and least wind), will probably have turbines visible from horizon to horizon. Will this really so impress China and India as to persuade them to change their emissions policies? It is like a primitive tribe burning its wives and treasure to awe an enemy into submission.

So complex is the mathematics of these calculations that it rapidly dissolves into naked prejudice: irrational fear of nuclear, urban hatred of landscape, leftwing loathing for oil companies. Yesterday the government was forced to pretend that it is not subsidising nuclear power at all, a fuel I can support but which is ruinously expensive on present, probably exaggerated, estimates of risk. Investing in it would require massive government intervention – with consumers paying some £200 a year above the market price of electricity – almost as much as does "free" wind power.

The energy minister, Ed Davey, squirmed on the BBC yesterday morning, a politician who could not persuade people he was doing the right thing – and was therefore probably doing the wrong one.

Energy policy is a dark underworld populated by fanatics and necromancers. Read through the literature and you will learn that nuclear means tsunamis, terrorists and Frankenstein monsters, or is as harmless as a local radiology clinic. Biomass is the new dawn, or threatens half the world's forests. Wind turbines are free energy, or they tear up peat and exhaust Mongolian minerals.

We face a "peak oil" crisis, or we do not. We face a nuclear winter, or not. We can live for ever on shale gas, or it causes earthquakes. The world is doomed anyway (James Lovelock) or not doomed at all (Nigel Lawson). All Europe could be wired to the Saharan desert, or perhaps only in theory.

We feel our way through this miasma by relying on gut instinct or on those we blindly trust. The public sums allotted in grants and price enhancements to green energy – with 8 million people facing fuel poverty – are so enormous they have bred an army of lobbyists clamouring to protect every programme for every resource under, and including, the sun. They pounce hysterically on any opponent of their favoured watt or therm.

For my part, I must patiently await my mathematician. Until then I will never be persuaded that the beauty of the British landscape should be sacrificed for an insignificant reduction in global warming, one that is obliterated by a Chinese power station in minutes. My view is reinforced by the Welsh scientist, Sir Roger Williams, in his 2009 British Academy lecture. He remarked his "greatest hope among renewables is of tidal power … both predictable and potentially substantial". He supported the Severn barrage, a sacrifice of landscape preferable to putting the Cambrian mountains under wind turbines.

Another trusty is Dieter Helm, Oxford professor of energy policy, who makes the seemingly obvious point that since gas is cheap and prevalent and has lower emissions than coal, the biggest carbon gain is won by a straight switch from coal to gas. As for preferring direct resources to the two most expensive energy sources, nuclear and offshore wind, that could appeal only to an institution now as befuddled and beset by lobbyists as the British Treasury.