Tuesday 2 October 2012

Liquid air 'offers energy storage hope'


Turning air into liquid may offer a solution to one of the great challenges in engineering - how to store energy.

The Institution of Mechanical Engineers says liquid air can compete with batteries and hydrogen to store excess energy generated from renewables.

IMechE says "wrong-time" electricity generated by wind farms at night can be used to chill air to a cryogenic state at a distant location.

When demand increases, the air can be warmed to drive a turbine.

Engineers say the process to produce "right-time" electricity can achieve an efficiency of up to 70%.

IMechE is holding a conference today to discuss new ideas on how using "cryo-power" can benefit the low-carbon economy.

The technology was originally developed by Peter Dearman, a garage inventor in Hertfordshire, to power vehicles.

A new firm, Highview Power Storage, was created to transfer Mr Dearman's technology to a system that can store energy to be used on the power grid.

The process, part-funded by the government, has now been trialled for two years at the back of a power station in Slough, Buckinghamshire.

IMechE says the simplicity and elegance of the Highview process is appealing, especially as it addresses not just the problem of storage but also the separate problem of waste industrial heat.

The process follows a number of stages:

"Wrong-time electricity" is used to take in air, remove the CO2 and water vapour (these would freeze otherwise)
the remaining air, mostly nitrogen, is chilled to -190C (-310F) and turns to liquid (changing the state of the air from gas to liquid is what stores the energy)
the liquid air is held in a giant vacuum flask until it is needed
when demand for power rises, the liquid is warmed to ambient temperature. As it vaporizes, it drives a turbine to produce electricity - no combustion is involved

IMechE says this process is only 25% efficient but it is massively improved by co-siting the cryo-generator next to an industrial plant or power station producing low-grade heat that is currently vented and being released into the atmosphere.

The heat can be used to boost the thermal expansion of the liquid air.

More energy is saved by taking the waste cool air when the air has finished chilling, and passing it through three tanks containing gravel.

The chilled gravel stores the coolness until it is needed to restart the air-chilling process.
Delivering durability

Highview believes that, produced at scale, their kits could be up to 70% efficient, and IMechE agrees this figure is realistic.

"Batteries can get 80% efficiency so this isn't as good in that respect," explains Dr Fox.

"But we do not have a battery industry in the UK and we do have plenty of respected engineers to produce a technology like this.

"What's more, it uses standard industrial components - which reduces commercial risk; it will last for decades and it can be fixed with a spanner."

In the future, it is expected that batteries currently used in electric cars may play a part in household energy storage.

But Richard Smith, head of energy strategy for National Grid, told BBC News that other sorts of storage would be increasingly important in coming decades and should be incentivised to commercial scale by government.

He said: "Storage is one of four tools we have to balance supply and demand, including thermal flexing (switching on and off gas-fired power stations); interconnections, and demand-side management. Ultimately it will be down to economics."

full article

Saturday 18 August 2012

Should You Fix Your Energy Bills Now?



If you’ve never switched supplier before then you could save nearly £300 off your annual bill by switching gas and electricity provider, based on figures quoted across energy comparison sites.

However, if you’ve already switched then the savings are likely to be much smaller, maybe £50 a year, and often dependent on when you switch and how you pay your bill.

You can slash money off your bill by switching to an online tariff and paying by direct debit.

If you choose a fixed tariff then the cost of your energy will be locked in for a period of time, usually a year but sometimes two, before you can leave without paying a penalty.

Some experts think that households should always be looking at fixed price deals. Mark Todd, from Energyhelpline, said: The risk of a price rise is always a great prompt for people to fix. Where the difference is small and there is no cancellation fee, or a low cost to exit the tariff, then I would suggest that people always go for a fixed tariff.’

Scott Byrom, energy expert at MoneySupermarket.com said; ‘With a lot of uncertainty over the movement of energy prices I recommend getting on to good value fixed price energy product to safeguard from any increases to the cost of gas and electricity over the term of the deal.'

But if customers want to leave during this period then they are likely to have to pay a termination fee and this may cancel out any benefit of fixing in the first place.

Ann Robinson, director of consumer policy at uSwitch.com, says: ‘It’s important that consumers ensure that they sign up to the best deal for them and that they make sure they know about any exit fees before they sign on the dotted line.’

Deciding whether a fixed tariff is suitable for you is dependent on prices – if bills start to fall then you could end up paying more.

What is happening to prices?

In the past month, two of the big six energy suppliers, British Gas and E.ON have reported that their profits had risen by nearly a quarter in the first six months of the year.

The news does nothing to help their financially squeezed customers who have seen energy bills more than double in the last ten years.

Meanwhile wholesale prices have been falling and this has put pressure on energy firms to follow with price cuts.

full article

Saturday 28 July 2012

Centrica defends 23pc leap in British Gas energy profits


Centrica defended a 23pc surge in profits at its British Gas household division, insisting the jump was due to the comparison with a “weak” 2011.

Chief executive Sam Laidlaw refused to bow to demands to cut energy prices - amid analyst predictions that Centrica was likely to increase its consumer tariffs.

Operating profits in the British Gas division rose to £345m in the six months to the end of June. The rise contributed to a 15pc increase in group profits, to £1.45bn for the period.

Ann Robinson, at uSwitch.com, said: “These soaring profits show that British Gas could and should cut its prices ahead of winter.”

Mr Laidlaw insisted the criticism was “purely because people have landed on a comparison with a prior year that was particularly weak”.
Profits had been low in the first half of 2011 due to an unusually warm winter, and gas consumption had increased again this year, Centrica said.

But gas consumption increased just 3.5pc, with the vast majority of a 21pc leap in gas supply revenues in fact due to increased prices.

Centrica said the bill rises has been needed to cover rising costs of commodities, increased social and environmental levies that it collects for the Government, and higher energy transmission costs, set by the regulator.

Mr Laidlaw said “nobody” he had spoken to felt its British Gas operating margins of 7.2pc - up from 6.9pc in 2011 - were unreasonable.

He added: “Because British Gas residential has got 16m customer accounts, the residential figure is a lot of money. But our profits equate to £3.50 a month per account before tax.”

Profits in British Gas’s business supply division slumped 27pc to £93m, as customer numbers fell. Centrica said this was due to some of the business customers going bust, and some switching supplier.

full article

Wednesday 18 July 2012

Great diesel myth


Diesel cars’ reputation for saving drivers money has been shattered by research showing they are often more expensive than petrol models.

It concludes that ‘diesels are no longer the default option for frugal motoring’.

While diesel engines may deliver more miles per gallon, it can take up to 14 years before they save the average driver any money.

This is because of the higher cost of diesel cars and of the fuel, which can be almost 6p a litre more expensive than unleaded petrol.

A report today by the consumer watchdog Which? says: ‘With drivers having to pay a premium for a diesel car – typically £1,000 to £2,000 more on a new car – our tests reveal it could take up to 14 years to recoup the up-front costs in fuel savings.

‘Lower pump prices for petrol and advances in petrol-engine efficiency mean petrol cars now often provide better value for money.’

Ironically, the findings come as diesels make up more than half of the new car market for the first time.

Which? compared similar-spec petrol and diesel versions of six popular cars – the Ford Fiesta, Vauxhall Astra, Volkswagen Tiguan, VW Sharan, BMW 5 Series and Peugeot 308 SW.

It calculated the annual fuel bill for each based on an average mileage of 10,672, and concluded: ‘In four out of our six examples, the petrol engine was the best choice for a driver covering 10,000 miles a year.

The report says diesels have become more refined than in the past, but ‘with petrol now around 5.5p a litre cheaper, and some makers offering super-economical petrol engines, it’s getting harder to justify the price premium’.

It adds: ‘Not only have we moved on from the bad old days of clattery diesels, but we’ve also moved on from diesels being the default option for frugal motoring.’

In the year to May 2012 diesel cars accounted for 51 per cent of new car sales, with petrol models at 47.5 per cent. Alternative fuel cars accounted for 1.5 per cent.

full article