It is strange to remember now that only a few years ago energy was scarcely mentioned in UK politics, and in business was a subject strictly for the nerds. Energy was seen as rather dull, as fears over our ability to "keep the lights on" had long ago receded. Gas and oil from the North Sea were still streaming in, and fuel prices were on an upward trend but not uncomfortably so. Greenhouse gas emissions fell rapidly through the 1990s and early 2000s.

How much has changed. In the past year alone, we have seen soaring domestic bills; energy bosses warning of blackouts; businesses claiming high prices would force them to close factories; increasing numbers of people choosing between heating and eating; a fight over how to divide dwindling resources if Scotland breaks away; and headline-grabbing protests over shale gas. Meanwhile, after years of declining, greenhouse gas emissions are suddenly on the increase yet again.

Britain is not alone in facing these problems. The "energy trilemma" – a term coined by the World Energy Council – sums up our difficulty in finding secure energy supplies and catering to rising demand without prices becoming unaffordable, all while reducing greenhouse gas emissions.

How did it come to this? There were some early warnings: the fuel price hikes of the early 2000s gave rise to protests. Refining capacity was a concern. The turning point at which the UK became a net importer of fuel, as the North Sea's riches dwindled, came far sooner than most had expected.

One major factor, however, is the mere fact that energy had been neglected for so long. Energy companies willingly admitted to "sweating their assets" to keep costs lower for consumers. Almost the only new generating capacity came in the form of onshore wind turbines, but construction was nowhere near enough to replace the assets that were slowly falling off the grid – ageing coal-fired plants and nuclear reactors coming out of service.

The grid itself was also ageing but new energy infrastructure projects were scarcely to be seen. Energy policy consisted merely of changing and often ineffective subsidies for renewables.

Little wonder that energy – how we make it, where we get it and how much we pay for it – is now one of the country's hottest political and social issues. Though the concerns are obvious, the solutions are still bitterly fought over. When Ed Miliband announced that Labour, if elected, would freeze energy price for two years, he was pilloried by the energy industry who said it would throttle investment. George Osborne's response was to raise the tax breaks and public money available to gas.

What technical solutions are there to the trilemma? Energy efficiency is the most obvious, and the cheapest. While we all know energy efficiency makes sense, uptake is heavily reliant on policy and the government's Green Deal has so far failed to deliver promised savings by retrofitting homes with energy-saving measures.

Renewable energy would give off an indigenous energy supply but still requires subsidy. Shale gas – even its strongest proponents admit – will not bring down fuel prices, and the signs are that it will not lead to real carbon cuts either.

The prospect of building more than one or two new nuclear reactors seems remote, given the high price and difficulties over construction. Carbon capture and storage? It's the new nuclear fusion: always just a few years over the horizon. Some experts talk hopefully of new technology such as demand management tools, but the rollout of a vital component – smart meters – has been delayed as companies fight over who should pay.

So far, there is no consensus on any way out of the energy muddle. Meanwhile, vulnerable people sicken in freezing homes and businesses despair over rising costs.

The problem we are facing is unprecedented. Energy used to be one of the UK's success stories. Concerns over security of supply are new, as we used to enjoy abundant supplies of coal (when we were untroubled by climate change concerns) and latterly North Sea gas; in days of abundance, these kept prices low.

We have been complacent too long and have never solved such a trilemma before. Whatever solutions we choose, we need them fast. We cannot afford to let energy slip down the country's agenda again; we may not find a way back.

This feature is part of the Guardian's big energy debate series. Click here to find out more about this project and our partners.