The replacement of inefficient halogen lights and other bulbs in kitchens and living areas would save Britain money, cut carbon emissions and improve energy security. For an expenditure of around £60, the householder would typically save £30 a year.
At the peak at about 5.30 on a December evening lighting uses about 15GW (gigawatts / billion watts) out of total UK demand of approximately 52GW.
This is an almost unbelievable 29% of our need for electricity, met at the precise moment that future blackouts are most likely.
And there's a simple way to cut that peak electricity demand - making our lighting more efficient by a mass switch to high efficency LED lightbulbs.
If all lights across the country were switched to LEDs my calculations (carried out under a project for Greenpeace UK) suggest that the need for electricity to provide improved lighting would fall by about 8GW, a saving of about 15% of all power consumption.
The LED switch would also reduce fuel poverty by lowering electricity bills, and cut the need for expensive and polluting diesel generators and other dirty coal fired power stations that are kept going only to meet peak demand.
There are very few circumstances in which LEDs would not represent a cost-effective improvement on current lighting systems. They switch on instantly, have an almost indefinite life, contain no mercury (a dangerously toxic metal) and offer better quality light than almost all alternatives.
But although LEDs are growing in importance, the number installed is still a small fraction of the total stock of lightbulbs.
The case is backed by 100 case studies in diverse sectors
As part of my work for Greenpeace, I located 100 case histories of switches from other types of lights to LEDs in industry, commerce and public sector. On average, replacing less efficient bulbs saved two thirds of the electricity bill.
These studies were usually written up by companies with an interest in selling more LED bulbs, but show a very consistent pattern across factories, shops, schools, sports clubs and offices. In most places, lighting quality was improved substantially. In some locations electricity costs were reduced because LEDs produce less waste heat and therefore cut the need for air conditioning in places such as hotels and large office buildings.
Even a much more restricted national campaign that just focused on domestic houses would have a dramatic impact. If we switched the lights in the parts of the house that are in use in early evening - essentially the kitchen and living areas - we would reduce home demand by more than 50%.
Importantly, these rooms are the places where we now often use halogen downlighter bulbs, the most inefficient lights currently on the market. A standard halogen GU10 bulb uses 50W of power. The LED equivalent does the same job with just 5W.
We can cut the typical demand for electricity to run lights from today's evening average of 180W to 80W by replacing about 21 bulbs in the typical home.
The impact of this is to reduce electricity demand by 2.7GW. This represents 5% of UK peak demand and would be more than enough to protect the country against power cuts in the years to come. The payback period of such a scheme is about two years at current LED prices. For an expenditure of around £60, the householder would typically save £30 a year.
What does the £60 buy? The home gets six LEDs to replace conventional bulbs (now almost all compact fluorescent lamps, of course) and 15 to switch out halogens. LEDs are now as cheap as £2 each when bought in packs of five or more. From my personal experience of buying bulbs at this price, the reliability and light quality is very good.
A one-off £1.6 billion well spent
The total cost of this switch, adding up all homes in the UK, is about £1.6bn. Contrast this with current government plans to pay electricity generators to keep plants open that would otherwise close. The budget for this is about £1bn just for one year and the UK gets very little for this expenditure.
By contrast, the replacement of inefficient halogen lights and other bulbs in kitchens and living areas would save Britain money, cut carbon emissions and improve energy security.
Even if those who have already installed compact fluorescent (CFL) lightbulbs can save energy and money by switching to LEDs, which typically use about half as much electricity for the same amount of light - though obviously the payback period is much longer than for replacing halogen and incandescent bulbs.
Any rational national energy policy should include a push for a very rapid switch to LEDs. The mechanisms that could be used might include sending a voucher to every home, street-by-street visits handing out LED bulbs and grants to volunteer organisations to help the less-advantaged swap out all their old lights.
Perhaps more in line with the current government's thinking, we could temporarily abandon today's ECO scheme for improving home insulation. The utility companies that are (very reluctantly) obliged to manage and implement ECO would be mandated instead to replace light bulbs in most UK homes within two years. This would be cheaper, easier and save more energy than ECO.
Capacity margins (the difference between power generation capacity and demand) will dwindle to almost nothing over the next two years. A crash programme to switch to LEDs is necessary, and also beneficial to householders and businesses.
Chris Goodall is an expert on energy, environment and climate change, and a frequent contributor to The Ecologist. He blogs at Carbon Commentary.
This article was first published on Carbon Commentary. Ideas expressed in this article are explored in far greater detail in The Switch, a book about the global transition to solar power, published this month by Profile Books.