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Q&A: Renewable energy

The UK aims to produce 15% of its energy from renewables by 2020. Alok Jha from The Guardian explains the technology behind the target.

What is renewable energy?

Anything that can be used to make heat or electricity without unsustainable fuels and which does not make a net contribution of carbon dioxide to the atmosphere. This includes wind power, waves and the tides, solar energy, geothermal energy and biomass. Nuclear power, although it is low-carbon, cannot be counted as a renewable source of energy because its fuel, uranium, is finite.

What are the UK's commitments on renewables?

The UK is committed to producing 15% of its energy from renewable sources by 2020 — this is equivalent to around 35% of its electricity.

What are the leading technologies?

The UK has huge resources in wind and wave power and, in the first of these, has done relatively well to ramp up development and installation.

By 2007, there were 2GW of turbines installed. The British Wind Energy Association (BWEA) says 9GW of offshore wind will be in place by 2015, overtaking installed nuclear power. This month, Centrica and RWE npower came close to approving two offshore wind farms costing an estimated £3bn.

According to the Centre for Alternative Technology, wave power could supply 10% of the UK's energy needs but this technology is at a much earlier stage. Although there are scores of British designs for wave energy converters, none are anywhere near commercial scale.

The biggest tidal project on the cards is at the mouth of the Severn river. This has the second highest tidal range in the world, and the government is consulting on a range of projects that could harness the energy. The plans preferred by the government, which include a large 10-mile barrage across the river, have dismayed many environmentalists. Bristol-based group Stop the Barrage Now say that the largest barrage would add to local flooding, reduce fish stocks, damage bird life and destroy the Severn bore, the tidal wave that flows up the river. They also argue the development will ruin mudflats across an area of more than 77 square miles.

Many green groups favour tidal lagoons, which have lower impact but are unproven technologies. These artificial lagoons flood as the tides rise and then trap water as the tide falls. The water then passes through a hydropower turbine to generate electricity.

Solar technologies include photovoltaics or PV, where sunlight is used to create electricity directly and solar thermal, which can be used in small set-ups to heat water for homes. Concentrating solar power plants focus sunlight from hundreds of mirrors onto a central tower, where water is superheated into steam that can turn turbines and make electricity.

Geothermal energy involves tapping the heat stored underground - traditional methods harnesses naturally occurring pockets of steam or hot water that rise from deep underground, bringing with them the energy stored by the rocks there. Enhanced methods allow those traditional techniques to be applied almost anywhere by drilling deep into the Earth and pumping water into the hole, the underground hot rocks fracture, allowing the water to circulate and be heated.

What is the progress globally?

The UK still only gets 1.8% of its energy from renewables, according to government figures. EU figures for 2005 show that, in Sweden, the renewable share was upwards of 40% and Finland's was around 30%. Denmark got more than 20% of its electricity-generating capacity from wind power thanks to consistent support ion the technology from the government. Germany gets 5.9% of its energy from renewables, largely thanks to a feed-in tariff for solar energy, which pays consumers a premium rate for any electricity they feed into the national grid.

According to the Renewable Energy Policy Network (REPN), global power capacity from new renewable energy sources (excluding large hydro) reached 280,000 MW in 2008 – a 16% rise from the 240,000MW in 2007.

Green energy investment overtook fossil fuels in attracting investment for first time last year, according to the United Nations. Wind, solar and other clean technologies attracted $140bn (£85bn) compared with $110bn for gas and coal for electrical power generation, with more than a third of the money destined for Britain and the rest of Europe. The biggest growth was in China, India and other developing countries.

What is the UK's problem?

Some people blame the market, others argue that the government has not been bold enough in tangible, long-term support for renewables industries. Since the 1980s, the government has been keen not to pick winners in technology terms and has created non-specific incentives such as the renewable obligations certificates (ROCs) to encourage renewable technologies. The problem is that this has only encouraged low-risk renewables such as onshore wind.

What plans are there for the future?

The REPN says that, as of 2009, at least 73 countries have renewable energy policy targets and, in response to the financial crisis, many governments are spending their economic stimulus funding towards new green jobs the renewable energy sector can provide. In the US, part of the economic stimulus package will invest $150bn over 10 years in renewable energy. South Korea has ear-marked 81% of its stimulus package worth £23bn to green measures.

China is planning a big increase in its use of wind and solar power in the next decade — officials there believe it could match Europe by 2020, producing a fifth of its energy needs from renewable sources. In the current development plan, the goal for wind energy is 30GW but the government is thinking about increasing this goal to 100GW by 2020.

In the US, the Waxman-Markey bill recently proposed a tentative agreement to create a renewable power target of 15% by 2020.

The UN believes $750bn needs to be spent worldwide between 2009 and 2011 although the current year has started with a 53% slump in first quarter renewables investment to $13.3bn.

What are the commercial opportunities?

The government reckons that the low-carbon environmental goods and services sector was worth £3,046bn in 2007/8. Asia accounted for 38% of this total, Europe 27%, and the Americas 30%. In the UK, this sector was valued at £106.5bn, making it the world's sixth largest low-carbon and environmental economy, with 3.5% of global market share.

The report went on to forecast up to an additional 400,000 jobs over the next eight years, many of these in the renewable energy and new low-carbon industries. Just taking these sectors alone, the market value of low-carbon technology and services could be £127bn in 2014/15, employing 1.04 million people.

According to the Carbon Trust, the UK could benefit from 250,000 jobs and up to £70bn in revenue from offshore wind and wave technologies by 2050. But this potential will only be realised if the government gives clear signals to industry, so that investors know where to put their money, rather than leaving new technologies to face the market alone. It would need investment of up to £600m into research, the removal of regulatory barriers and incentives to increase the deployment of the turbines. In the UK this means installing around 29GW of wind by 2020 and upwards of 40GW by 2050. A large part of the economic benefit would come from exporting technology developed here.

For wave, the outlook is more modest. Around a quarter of the world's wave technologies are being developed in the UK and the Carbon Trust said Britain should be the "natural owner" of the global market in this area. It could generate revenues worth £2bn a year by 2050 and up to 16,000 direct jobs.


OFTEC reveals oil is low cost option

Oil heating is still the cheapest choice for off gas main households, according to the latest independent figures.

The Sutherland Tables show that the cost of heating an average three bedroom home with an oil condensing boiler works out at £996 per annum. That’s 31% cheaper than an LPG condensing boiler which costs £1454 per annum to run.

Once again, the figures demonstrate the advantages of using a condensing appliance, which can knock up to 18% off the average household heating bill.

The figures also show that the price of oil has remained relatively stable over the last five years. Commenting on the figures, OFTEC Director General, Jeremy Hawksley, said “this is good news for those households in rural areas that do not have access to mains gas. Oil is a safe and economical choice, and the introduction of liquid biofuel later this year means those households can easily convert to a low carbon fuel if they wish to.”

The figures for LPG include the cost of tank rental, whereas oil users generally own their storage tank.

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Air Source heat pumps 101

Heat your home with energy absorbed from the air around you

Air source heat pumps absorb heat from the outside air This is usually used to heat radiators, underfloor heating systems, or warm air convectors and hot water in your home.

•How do air source heat pumps work?
•The benefits of air source heat pumps
•Is an air source heat pump suitable for my home?
•Costs and savings
•Ground source heat pumps
•Find out more
How do air source heat pumps work?
An air source heat pump extracts heat from the outside air in the same way that a fridge extracts heat from its inside. It can extract heat from the air even when the outside temperature is as low as minus 15° C.

Heat pumps have some impact on the environment as they need electricity to run, but the heat they extract from the ground, air, or water is constantly being renewed naturally.

Unlike gas or oil boilers, heat pumps deliver heat at lower temperatures over much longer periods. This means that during the winter they may need to be left on 24/7 to heat your home efficiently. It also means that radiators should never feel as hot to the touch as they would do when using a gas or oil boiler.

There are two main types of air source heat pump system:

•An air-to-water system distributes heat via your wet central heating system. Heat pumps work much more efficiently at a lower temperature than a standard boiler system would. So they are more suitable for underfloor heating systems or larger radiators, which give out heat at lower temperatures over longer periods of time.
•An air-to-air system produces warm air which is circulated by fans to heat your home. They are unlikely to provide you with hot water as well.
Heat from the air is absorbed into a fluid which is pumped through a heat exchanger in the heat pump. Low grade heat is then extracted by the refrigeration system and, after passing through the heat pump compressor, is concentrated into a higher temperature useful heat capable of heating water for the heating and hot water circuits of the house.

The benefits of air source heat pumps
•Can lower fuel bills, especially if you are using conventional electric heating.
•Can reduce your carbon footprint: heat pumps can lower your home’s carbon emissions, depending on which fuel you are replacing.
•No fuel deliveries required.
•Can provide space heating and hot water
•It’s often classed as a ‘fit and forget’ technology because it needs little maintenance.
•Can be easier to install than a ground source heat pump, but efficiencies can be lower.
Is an air source heat pump suitable for my home?
To tell if an air source heat pump is right for you, there are a few key questions to consider:

•Do you have somewhere to put it? You'll need a place outside your house where a unit can be fitted to a wall or placed on the ground. It will need plenty of space around it to get a good flow of air. A sunny wall is ideal.
•Is your home well insulated? Since air source heat pumps work best when producing heat at a lower temperature than traditional boilers, it's essential that your home is insulated and draught proofed well for the heating system to be effective.
•What fuel will you be replacing? The system will pay for itself much more quickly if it's replacing an electricity or coal heating system. Heat pumps are not recommended for homes on the gas network.
•What type of heating system will you use? Air source heat pumps can perform better with underfloor heating systems or warm air heating than radiator-based systems because of the lower water temperatures required.
•Is the system intended for a new development? Combining the installation with other building work can reduce the cost of installing the system.
Read more about planning permission for renewable energy technologies

To find out more about whether an air source heat pump is suitable for your home, try the Energy Saving Trust Home Energy Generation Selector tool.

Costs and savings
Costs for installing a typical system suitable for a detached home range from about £5,000 to £9,000 including installation. Running costs will vary depending on a number of factors - including the size of your home and how well insulated it is.

Savings - will vary depending on many factors, some are outlined below. It is important that the system is controlled appropriately for your needs. Actual savings figures will depend on your exact fuel prices

•The heat distribution system: If you have the opportunity, underfloor heating often provides greater efficiencies than radiators because the water doesn’t need to be heated to such a high temperature. If underfloor heating isn’t possible, then use the largest radiators you can.
•Fuel costs: you will still have to pay fuel bills with a heat pump because they are powered by electricity. The saving you achieve can be affected by the price of the fuel you are replacing and the price of the electricity for the heat pump.
•Efficiency of old and new system: the efficiency of the old heating system will affect how much you spent on heating bills previously. If the old heating system was inefficient heating bills could have been high and the difference between the new running costs and the old running costs will be greater, therefore providing a greater saving.
•If the system is providing hot water as well as space heating: the provision of hot water can lower system efficiencies, therefore making running costs higher.
•Temperature setting: if you heat your home to much higher temperatures with a new heat pump system than you did with an old heating system then your home will be warmer,, but heating bills will be higher than if you continued with the same heating pattern. It’s a good idea to set thermostats to around 18 to 21 degrees centigrade.
•Using the controls: learn how to control the system so you can get the most out of it. Your installer should explain to you how to control the system so you can use it most effectively.

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