Daylight Saving Bill

Debate between Alan Reid and Caroline Lucas

Friday 3rd December 2010 Commons Chamber

[Caroline Lucas]

If it were to be proved that such a change would make carbon emissions worse, I would reconsider my position, but I think that is highly unlikely to happen. The hon. Gentleman keeps talking about empirical evidence, but the only way for us to get relevant empirical evidence is to pass this Bill now and have the cost-benefit trials that we are talking about.

[Mr Reid]

Surely, if we passed the Bill, we would be more active at the coldest hour of the day—the hour before dawn—and would therefore use more fuel for heating at that time. The Building Research Establishment investigated this and found that there would be an increase in domestic heating if the Bill were passed.

[Caroline Lucas]

That was an early intervention in my speech, and if the hon. Gentleman listens to the next bit, some of these questions will be answered, because I do not agree with his point.

On reducing demand for artificial lighting, about 13% of domestic electricity consumption and about 30% of electricity consumed by commercial and public buildings currently goes on lighting. An extra hour of evening daylight would reduce the need for domestic lighting as people arrived home from school or work. Recent research by the Policy Studies Institute shows that the effect of the proposed clock change would be to lower demand for domestic lighting by as much as 9%. In other words, the Bill would lead to household savings of nearly £180 million per year on electricity bills alone. A common argument—I expect this will be made, so I will pre-empt it—against daylight saving time is that any drop in demand for evening lighting will be cancelled by the need for extra lighting on darker mornings. That may be true during the winter months, when the days are shorter, but the Bill proposes an adjustment of clock time throughout the year, which means less need for artificial lighting in the evenings all year round.

Regarding commercial demand for evening lighting, it is more difficult to quantify the potential savings for offices, workplaces and public buildings, as patterns of lighting often vary widely from sector to sector, but again, the studies indicate that overall demand from commercial customers is also likely to be lower. That aspect must be subject to detailed research during the initial trial period proposed in the Bill, as it offers the greatest potential for a nationwide reduction in domestic carbon emissions.

My second point is closely related to the first. Daylight saving will cut carbon emissions from power generation because it will even out the daily peaks in demand for electricity. For power companies, the late afternoon peak period determines the maximum number of power stations that are required to be on stream to match consumer demand. Currently, the extra capacity required for that short period of peak demand comes from inefficient and carbon-intensive sources such as oil-fired stations and pump storage facilities or, as has been said, by imports from France, which can be an expensive alternative.

The introduction of daylight saving would reduce peak demand for electricity on winter evenings. During that famous 1968-71 experiment with retaining British summer time throughout the year, the evening peak was reduced by 3%. Research carried out by the university of Cambridge calculates that lighter evenings now would reduce peak demand by up to 4.3%. The electricity industry also acknowledges that a reduction in evening peak demand would reduce carbon emissions by avoiding the need to keep inefficient and polluting spare generating capacity on stream.

The university of Cambridge study calculated that a move to daylight saving would mean a drop in CO₂ emissions from power stations, across the UK as a whole, of about 450,000 tonnes a year. That is the equivalent of taking off the roads about 200,000 cars. There would also be a significant reduction in power companies’ generating costs, both for resources and for the transmission and distribution infrastructure.

In addition to reducing demand for lighting, daylight saving also offers potential for reducing fuel costs and carbon emissions from heating. Domestic demand for heating is highest from November to February. The PSI study found that whereas there is little variation in average temperatures between 6 am and 8 am, when most people leave the house, temperatures tend to fall much more quickly in the late afternoon, around sunset, when people are arriving home from work or school.

Since the introduction of daylight saving will mean that it gets colder later, it is possible that households will be able to save money on their heating bills, while shrinking their carbon footprint. A small increase in fuel use for heating in offices and commercial and public buildings may be likely because of the earlier start to the day, but the resulting carbon emissions will be offset by reductions in domestic fuel use, so overall there is a clear reduction in carbon emissions.