Mention renewable energy and many in industry think you’re talking about a worthy project that the nanny state wants us to carry out but that doesn’t really make commercial sense. Will Jones finds out if there’s any truth in that

Forget the menace of global terrorism. According to Sir David King, the government’s chief scientific officer, the greatest threat facing civilisation is global warming. The consumption of fossil fuels is forecast to raise the temperature of the earth between 1.5°C and 5.5°C by the end of the current century.

The Kyoto treaty was an attempt to co-ordinate an international response to global warming. The British government has been a leading advocate of Kyoto, and is using the regulatory system to reduce greenhouse gas emission. High visibility proposals include plans to force owners of 4×4s and other petrol slurping cars to carry red warning stickers. Less visibly, but more importantly, it has introduced Planning Policy Statement 22: Renewable Energy, which came into force in August 2004. This sets down national policies that are affecting the way developers design and work. The local planner is now encouraged to, and may insist upon, incorporating some form of renewable energy into the scheme, whether it be a single dwelling or a 500-unit development above a retail and leisure complex.

Jillian Hastings of Arup was project manager on the production of a companion guide to PPS22. “Current renewable energy generation stands at about 3% of total energy production in the UK,” she says. “PPS22 is intended to support the government’s commitment to generate 10% of our electricity from renewable sources by 2010. This means each region of the country is encouraged to identify areas of potential to generate energy from a range of renewable resources.”

So, as you read this, councillors, environmental officers and planners across the country are looking at ways of including renewable energy sources into buildings. Richard Hodkinson, director of environment consultant Hodkinson Consultancy, says they are doing more than just looking. “The requirement to have 10% renewable energy on site as opposed to a wind turbine on the Wash is being pushed quite heavily in housing, even though PPS22 says councils may require it, provided that it is not burdensome. There is a need to look at the wider agenda of national versus local energy. But instead there is a push for locally generated power, and as a result, there is a danger that we’ll be left with a legacy of inappropriate solutions.”

Alasdair Nicholls, chief executive of Native Land, the company managing the develpment of the 5.3 million ft2 Silvertown Quays scheme in London Docklands, says PPS22’s requirements could prove onerous for developers. “It could become as big an issue as affordable housing,” he says.

As well as having to physically find the space on site or on buildings for renewable energy technologies, developers also face the cost of installing the technology. The approximate figures given here, which are for a single home, show that there can be significant financial burdens attached.

“There won’t be a very positive reaction to PPS22 from many quarters,” says Allan Jones, head of the GLA’s climate change agency. Jones has the unenviable task of complying with PPS22 and also of implementing mayor Ken Livingstone’s energy strategy. This includes installing 7000 domestic and 250 commercial photovoltaic installations; six large and 500 small wind generators; 25,000 small and 2000 large solar water heating schemes; and more anaerobic rubbish digestion plants with biomass-fuelled combined heat and power plants.

So how can housebuilders and developers go about satisfying PPS22? There are six main options, each with its own quirks and suitabilities (see boxes).

However, some interested parties are arguing against the implementation of PPS22. Jones says: “The lobby groups that are opposed to renewable energy are very vociferous but they are also small in number. We will overcome them with sustained effort; PPS22 is a good and necessary step in maintaining the consistently good energy supply that people in England expect.”

It should be remembered that PPS22 is not a set of statutory rules like the Building Regulations and local authorities’ translation and uptake of it will vary depending on where you are. However, it is there and you will come across it, so design with PPS22 and the future of the planet in mind.

  • Planning for Renewable Energy: A Companion Guide to PPS22 can be downloaded free from www.odpm.gov.uk.

Although it is aimed at planners and regional and local decision-makers, the guide offers a wealth of information for the housebuilder and developer.

Solar power

Solar power is the most widely recognised of these renewable energy resources but there are differing methods of using it. The simplest is passive solar energy: this has to be considered at design stage as the orientation of the property, room layout, window size and position, and insulation all have a bearing on the result. However, well-designed properties can save up to 25% of their heating and energy requirements using this method, and at little extra cost.

Next is thermal or solar hot water heating. Suitable for new-build or retrofitting, roof-mounted panels collect solar energy and use it to heat water as it passes through them. There is a common misconception that solar energy is not effective in Britain’s climate. This is not true: a well-designed solar system should provide 50-60% of the annual hot water requirements of the average household. Finally, there is active solar energy in the form of photovoltaic (PV) panels. These can be fitted to new or existing properties and roof tile companies, including Lafarge (see case study), are now producing PV tiles that are laid flush with normal tiles.

Kirk Archibold, of the Energy Saving Trust and programme manager of the DTI’s Major PV Demonstration Programme, says: “PV is cost effective to install on new-build projects, and it is almost as cost effective to consider PV roof tiles when replacing your existing roof. If developers market PV homes as energy self-sufficient, surely they would be able to market them at a premium.

“PPS22 is something that I know some developers are becoming concerned about. They prefer the simplicity of legislation like the Building Regulations because they know where they stand. But, however ambiguous and open to interpretation PPS22 is, developers that embrace it are likely to steal the march on their competitors while also maximising the potential for planning gain.”

Case study: Solar in use

At the Braunstone Six Streets project in Leicester, Environ, the city’s environment charity, is managing the installation of Lafarge’s PV800 photovoltaic panels in the roofs of 50 homes. Construction company Newlife is completing the project, which is the second largest in the country, as part of refurbishment works to the estate. The panels are similar in size to concrete roof tiles and clip together to form a large PV module that covers much of the south-facing roof slope. The DC current generated by the PV module is converted into AC by an inverter the size of a microwave oven, allowing the electricity to be used in the home or exported to the National Grid.

Residents have been schooled on the benefits of their homes’ solar power capacity and dial meters are installed to show them how much electricity the PV modules are producing. These dials also indicate when the optimum amount of electricity is being produced and tenants have been advised to use appliances such as washing machines at these times, because the electricity will be free of charge. Surplus power is sold to the National Grid and the money earned will be ploughed back into energy saving measures on the Braunstone estate. The PV scheme cost £450,000, and was funded by government grants.

Plus points

  • The renewable aspect of this project was funded by government grants
  • Non-specialist can install the tiles
  • Electricity is free of charge
  • Surplus power creates revenue for the owner, single occupant, housing association or similar
  • Photovoltaic electricity does not generate waste products

Wind power

In the recent past there has been opposition to siting wind turbines on remote hillsides because they supposedly spoil the view. This opposition is what Allan Jones is referring to when he says we take our energy for granted. No longer can we object to wind farms for aesthetic reasons, unless we also want to revert to living by candlelight.

Turbines will, however, take up valuable development space on site. For this reason alone, they are likely to remain unpopular with developers.

Turbines are now available at competitive rates for single homes and multiple schemes of up to 1200 dwellings but both operate in the same way: the blades are attached to a shaft that drives a generator, producing electricity to use or export to the National Grid.

Biomass

This type of technology uses biomass and energy crops as a fuel to burn and produce energy. Typical fuel products include: forestry by-products such as small diameter timber, twigs and branches; waste products such as sawdust, pallets and furniture offcuts; crops such as straw and fast growing timber such as willow; poultry litter; and biodegradable municipal waste.

This type of renewable energy production is common in Scandinavia, and the UK opened its first straw-fired power station near Ely in 2002. This generates more than 270 GWh of electricity a year – enough to power 60,000 homes. Elsewhere, especially in rural areas, wood biomass is used in smaller plants to provide heating for schools and public buildings. Specialist companies will advise, supply and install the equipment required.

Hydroelectric power

Hydro power is well developed in the UK, with most large sites already fitted with a turbine. However, many smaller sites could still be developed and could generate enough power for individual homes. Rural developments could well benefit from this power source which operates in a similar fashion to wind power – water drives a turbine which, in turn drives a generator. An important consideration when developing a hydro power plant is other uses that the water course may have.

Biological and thermal

This energy type involves the collection and use of waste gases for energy production. Gas emitted from landfill sites, sewage gas and bio-emissions from agricultural, domestic and industrial waste, all are ripe for production via anaerobic digestion. This may not sound appetising as an option to the housing developer, or potential residents for that matter, but the process of anaerobic digestion traps the gas within a chamber and compresses it. It can then be used to power generators to supply heating systems. Landfill sites are already a significant contributor to national renewable energy supplies, according to landfill gas generation company Ener•g.

Combined heat and power

CHP is a dual-action system that produces energy and heat at the same time, hence the name. Powered by a variety of sources including biomass and natural gas, the fuel drives a generator that provides electricity. However, these fuels also give off heat, which is transferred to a thermal store and used to deliver central heating and hot water. CHP had been used intermittently on large schemes for more than a decade now. And, in his previous job with Woking council, Allan Jones used them to drastically reduce the council’s energy expenditure. Forteen years later, Woking saves an estimated £974,000 a year in energy bills (see Building, 14 March 2003).

Plus points

  • Micro CHP units are not much more expensive than conventional condensing boilers
  • They can be installed in single dwellings
  • Dwellings look no different to conventional properties
  • They are low maintenance

Case study two: CHP units in use

CHP units are now available in a wide range of sizes, and can supply heat and power to entire housing estates or to single homes.

At The Way in east Manchester, a 550 home new-build development, housebuilder Lovell has teamed up with Powergen and CHP maker Gledhill to install the individual or ”micro” units.

The houses themselves are being factory-built using the Kingspan Tek system of highly insulated panels. The micro CHP units take the place of a traditional gas-powered boiler. This CHP burns gas to heat the dwelling and also to generate electricity.

This makes the unit much more efficient than a boiler. To put it in monetary terms, the most effective condensing boiler on the market is about 90% efficient – for every £1 spent on fuel, the boiler will provide 90p worth of heat. However, with the micro CHP unit, for every £1 spent, the unit will generate £1.55 of benefits – 75p in the form of heat and 80p as electricity.

Residents of these super-insulated, micro CHP equipped homes stand to save between £100 and £200 a year on their electricity bills; the estimated saving in carbon dioxide emissions is 500-700 kg per dwelling per year.

Mike Fallon, project manager for Lovell, says: “The micro CHP units are part of Lovell’s environmentally conscious strategy at The Way. They seem to work very effectively, with no more maintenance required than that of a conventional boiler.”

Note: All costs are very approximate installed costs for an installation to supply a typical home

Source

RegenerateLive