The way we use energy is shockingly wasteful. Every year, we throw away more than eight times the amount of energy supplied by all of the UK's nuclear power stations combined.
Through our inefficient use of energy (gas guzzling vehicles, badly insulated buildings, poorly designed appliances etc) we needlessly throw away almost a third of the energy we use (source).
Yet implementing energy efficiency saves more money than it costs. The government's own research put the economic potential for saving energy across all sectors, including heat, transport and electricity, at 30 per cent.
The same research found that introducing these measures would save consumers £12 billion a year in reduced bills.
Meanwhile, researchers in the US have found that for each pound invested, efficiency measures are 10 times more effective than nuclear power (pdf) at reducing CO2 emissions and closing the energy gap.
Heat - domestic and industrial - accounts for half of our national energy use. In terms of energy security, this makes it the single biggest challenge that we need to meet. Heat also accounts for more of our carbon emissions than any other sector - around 40 per cent (pdf). If we're to meet our global responsibility in reducing CO2 emissions, it's clear that we have to tackle the heat challenge as well as deal with electricity.
Because nuclear power supplies only electricity, not heat, it makes almost no contribution towards meeting our heat needs. So nuclear plays no effective role in reducing emissions or improving energy security in the biggest single area of energy use.
By contrast, efficiency can make an enormous difference.
Most heating (and most natural gas) used in the UK provides warm homes, offices and hot water. If we're worried about the future of our gas supplies, it's here that we can make the biggest savings, by being more efficient.
According to the government's Energy Saving Trust, the vast majority of homes in the UK are inadequately insulated. When you consider that a massive 83 per cent of domestic energy is used for heat (pdf), this is obviously the top priority.
Source: The Rise of the Machines, The Energy Saving Trust
For example, more than 9 million homes have cavity walls, but no cavity wall insulation (pdf). Cavity wall insulation is one of the cheapest, simplest and most effective measures to save heat - as much as a third of heat lost from homes is lost through the walls. Another quarter is wasted through the lack of loft insulation, which is also cheap and simple to install.
It may seem obvious (and even dull), but actually insulating buildings properly can have an enormous impact. And yet, as a country, we still haven't done it.
For new buildings, insulation standards are improving, but they still fall well behind best practice. Every new building that's not of the highest standard (so called Zero Emission Development standards and beyond) is a liability, both in terms of the climate and fuel security. Pioneering new developments, such as Gallions Park in London, are aiming to deliver new Zero Emission communities at close to the cost of a standard, and highly inefficient development. This should be the benchmark for all new buildings.
While making the heat sector more efficient is crucial, the electricity sector is still important; having a large component from coal fired power stations, our power sector is a major polluter.
We're also often told that the closure of old coal plants and old nuclear power stations threatens to leave us short of power, that the lights could go out. But, just by being more efficient, we can save far more than the so called ‘electricity gap'.
For example, appliances on standby account for eight per cent of electricity used in the home. It's possible to design appliances without standby, or to engineer them to consume the minimum amount of power while in standby. Government action could achieve this.
Meanwhile, old-fashioned incandescent light bulbs waste as much as 95 per cent of the energy they use. If all retailers in the UK only stocked energy efficient light bulbs, we could save over five million tonnes of CO2 emissions a year. That's the equivalent of the output of two nuclear power stations, or more than the CO2 emissions of the 26 lowest emitting countries combined.
Imagine the impact of having similar tough standards for all appliances. In Japan it's against the law to bring out new products that are less efficient than the older models. We already have efficiency ratings from A to F. Why would we allow anything less than A ratings onto the market?
We can all do our bit by using more efficient products and by being more careful with our energy consumption - but government regulation could totally transform the picture almost overnight. It's like the difference between changing people's light bulbs one house at a time and changing the whole lot at once.
The savings of maximizing efficiency in all our appliances by introducing minimum efficiency standards would be enormous - far more than the electricity provided by a whole new nuclear fleet. They would also save us money, rather than costing us billions.
Better efficiency (to control demand) would do far more to ensure energy security than nuclear power ever could, because efficiency can reduce fuel used to provide heat - as well as electricity - which nuclear power just can't do.
Pound for pound, reducing demand is the most effective way to reduce CO2 and has the most immediate impact. If a penny saved is a penny earned, then the same is true for Watts and Kilowatts.