Climate change: Soot's role underestimated

Black carbon, or soot, is making a much larger contribution to global warming than previously recognised, according to research.

Scientists say that particles from diesel engines and wood burning could be having twice as much warming effect as assessed in past estimates.

They say it ranks second only to carbon dioxide as the most important climate-warming agent.

The research is in the Journal of Geophysical Research-Atmospheres.

Black carbon aerosols have been known to warm the atmosphere for many years by absorbing sunlight. They also speed the melting of ice and snow.
Half a degree

This new study concludes the dark particles are having a warming effect approximately two thirds that of carbon dioxide, and greater than methane.

The researchers say black carbon emissions in Europe and North America have been declining due to restrictions on emissions from diesel engines. But they have been growing steadily in the developing world. However as these type of particles don't last very long in the atmosphere, cutting their number would have an immediate impact on temperatures.
Black carbon is said to be a significant source of rapid warming in the northern United States, Canada, northern Europe and northern Asia. The particles are also said to have an impact on rainfall patterns in the Asian monsoon.

By Matt McGrath

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How much does it cost to charge an electric car ?

I am a commuter who drives into London on a daily basis. After reading the story that electric cars may soon be the only vehicles to be exempt from the £10-a-day London congestion charge and being increasingly concerned about my carbon footprint, I have been toying with the idea of buying one.

I currently travel ten miles back and forth from the office, Monday to Friday, and roughly drive a maximum of 30 miles over the weekend.

My question is how much would it add to my electricity bills and how easy is it to find charging points around London? I have been looking at snapping up either the Nissan Leaf or the Renault Twizy.

The main stumbling block for many drivers is the amount of miles these cars can actually do before they need to be re-charged. The Renault Twizy, for instance, can manage 62 miles officially, or just over 50 miles in some review tests, on one charge while the Nissan Leaf can do 109 officially, or just over 100 miles in some review tests.

These make them ideal for short commutes – like the ones mentioned in your question – but not for longer trips, which is unappealing for most drivers.

here are some advantages to electric cars. The fact there is no road tax for one, due to zero emissions and the fact you can charge at home, rather than have to fill up a forecourt.

Also, the Government is offering those who buy an electric car 25 per cent off the price, up to the value of £5,000.

According to a spokesman for Renault, using the Twizy to drive 130 miles a week would equate to roughly £3 per week - or £156 a year - based on three charges a week and domestic electricity at 14p/kwh unit.

It takes three-and-a-half hours to fully charge the battery and can go up to 62 miles on one charge.
It doesn't however qualify for the £5,000 government electric car grant scheme as it's not classified as a car - it's labeled a 'heavy quadricycle.'

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Can you afford to turn up the thermostat?

Freezing temperatures could put up energy bills by £7 a experts have warned, adding to the pressure on households as they cope with price hikes to gas and electricity.

It costs £3 a day, on average, to heat a home, but during cold weather this can easily rise by £1 a day as people push up thermostats or leave the heating on for longer, according to figures from price comparison website, uSwitch.com.

Weather forecasts have said that some parts of the UK could get up to 10cm of snow today with freezing temperatures set to continue for up to three weeks.
All of the ‘big six’ energy suppliers have announced price hikes this winter, with the last of these, from E.ON, coming into effect next Friday.

The price increases have pushed up the average annual household gas and electricity bill by 7.4 per cent, or £94 to a record £1,352 a year.



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UK tidal power has huge potential, say scientists

The UK is underestimating the amount of electricity that could be generated from tidal sources, new research says.

The analysis says that estuary barrages and tidal streams could provide more than 20% of the nation's demand for electricity.

Despite high costs, experts say tidal power is more reliable than wind.

The predictable nature of tides makes them an ideal renewable energy source, the journal Philosophical Transactions of the Royal Society A reports.

Essentially, engineers try to tap tides in two ways: one involves building barrages across tidal estuaries that use the ebb and flow of the waters to turn turbines - a major project of this type had been proposed for the River Severn.

The other method involves planting turbines underwater in fast flowing tidal streams in areas such as in coastal waters around Cornwall and Scotland.
Smaller better

In the Royal Society report, researchers say they are "extremely optimistic" that both types of technology can be realised and relatively soon.
La Rance tidal station (Getty Images) La Rance in Brittany, France, is the site of the world's first tidal power station

"From tidal barrages you can reasonably expect you can get 15% of UK electricity needs, that's a very solid number," co-author Dr Nicholas Yates from the National Oceanography Centre told BBC News.

The massive Severn estuary tidal barrage scheme had been rejected by the coalition government because of its environmental impact, but ministers have indicated they are open to review the idea.


Developing power from offshore tidal streams is fraught with difficulty, as the BBC discovered when reporting on the emerging industry in Scotland last year.
Better than wind

But according to the authors of the latest research, 2013 could see a big breakthrough in tidal stream power. A company called MeyGen is planning to deploy tidal stream technology in the Pentland Firth that will initially generate up to 40MW of electricity, enough to power about 38,000 homes.

"This is a crucial milestone for us, it will be the first array of tidal stream turbines," observed report co-author Professor AbuBakr Bahaj from the University of Southampton.

"It will be a viable proposition for us in energetic areas of the sea - it will be give us another element in the energy mix that's more reliable than wind."

While the report paints a positive future for tidal power, a critical element is money.

In the past month ,the EU has announced funding in the region of £30m for two UK tidal projects.

Investors in tidal technology are currently rewarded with a payment of £40 per megawatt hour for energy generated from renewables, but this scheme will end in 2017.

By Matt McGrath Environment correspondent, BBC News

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