Taking the leap towards a low- to zero-carbon economy

roof
Sunlight is a proven source of renewable, clean energy that has already been adopted by many householders in the UK.
RICHARD SCOTT explains why sustainable energy is no longer an option but a necessity — and looks at heating and hot-water innovations for the 21st century.The world’s wake-up call has begun as climate change kicks in and the demand for energy begins to outstrip supply. The global community is only now reacting, albeit slowly, to address the vital and related issues of rising energy prices, energy efficiency and climate change. Fossil fuels are not only finite, but their burning has a detrimental impact on our environment through global warming and, therefore, on long-term economic sustainability. As gas and oil prices rise inexorably and the nuclear debate nears a decisive moment, sustainability is high on the political agenda. Technology Solutions are at hand — but consumers, industry and politicians have been slow to adopt them. In fact, the technology already exists to build houses in such a way that not only are they energy efficient but they are almost self sufficient. The lifetime cost savings to the house-holder are obvious. The impact on climate change, if replicated across the industrialised world, would be nothing short of revolutionary. Traditionally, electricity has been generated by burning fossil fuels. Coal, oil and natural gas are finite resources, and burning these fuels generates carbon dioxide, sulphur dioxide and oxides of nitrogen. Across the world, the demand for energy is growing and placing greater pressure on the availability of scarce fossil fuels and, therefore, the sustainability of the industrialised economies and the natural environments they are built upon.
Wake-up call — Richard Scott.
Renewable sources of energy are inexhaustible, clean and carbon free. Solar, wind, wave, biomass, geothermal and nuclear are all renewable sources of energy. The technology and the readily available products now exist for average households to harness these carbon-free sources of energy, which often have no associated operating cost. Security of supply is another important dimension, with the lurking threat of terrorism. The recent explosions at a fuel depot near Hemel Hempstead in Hertfordshire, although not thought to be an act of terrorism, was a stark reminder of the disastrous effect an accident like this can have on our communities and environment. The distribution of energy also remains hugely wasteful, which is perhaps the key environmental advantage of energy efficiency in the home. Internal energy policy is another dimension, in particular the decision to recommence a programme of civil nuclear-power generation programme, which could boost carbon-free domestic energy supplies but has the intractable problem of nuclear waste and the risk of humanitarian and environmental disaster. Many environmental campaigners have now publicly switched camps to support civil nuclear power, swayed by the climate-change benefits, great advances in safety technology and the fact that new ‘passive safe nuclear reactors’ generate only 10% of the radioactive waste of current reactors. Opportunities Technological advances are affording us more opportunities much closer to home. When fossil fuels do run out, heating and hot water appliances, often the single largest energy user in a home, will no longer be able to be powered by coal, oil or natural gas. With wholesale gas prices rising 42% since 2004 and spot-market prices doubling, clearly the ‘dash to gas’ is over. An innovative solution is required in the long-term, but the effects may well be felt long before the final breath of natural gas is guzzled by the last gas-fired power station. In April 2006, those aspects of the Buildings Regulations in England and Wales dealing with the conservation of fuel and power and ventilation were completely revised. One striking aspect of the new Building Regulations is the method of demonstrating compliance. Each building will be set a target carbon-emission rate which it must not exceed if it is to be granted building-control approval. This applies equally to a single house or a large block of flats. In the case of the latter, so called ‘block assessment’ will promote the inclusion of new technologies like solar thermal collectors on the roof, or ground source heat-pumps With electricity from renewable sources and the rapidly growing availability of domestic low- and zero-carbon products, the long-term future for heating our homes and providing us with safe hot water must rest with appliances that can utilise renewable energy in the form of electricity. In the short term, electricity has a significant role to play in the UK. Surprisingly, at least 10% of the UK population does not have easy access to a gas supply. The more rapidly the generation of electricity moves to renewable sources the better. Of course, the long-term demise of gas will dictate that all heating and hot water is either produced utilising appliances powered by electricity from renewable sources or directly from low- and zero-carbon technologies in the home. Heat recovery New Building Regulations will progressively make homes more air-tight and require ever-less energy input to achieve the same comfort levels. You may well begin to resent losing any heat at all. Whole-house heat-recovery systems are the answer. Correctly specified ducting throughout the house leading to a heat-exchanger with incoming fresh-air will solve the problem of ventilation and possible condensation in the air-tight house. Crucially, it also ensures that the energy used to create the otherwise wasted out-going heat is hygienically exchanged to the in-coming air. Time to go solar Solar is proven source of renewable, clean, energy that has already been adopted by many householders in the UK. Solar thermal collectors, either as a flat-plate design or vacuum tube, generate free hot water from sunlight. Contrary to popular opinion, they do not require direct sunlight to operate but work across the light spectrum, ensuring that hot water is produced even on cloudy days. An intelligently controlled circulation unit pumps water around the collector, heating it up in the process and then storing it in a highly insulated tank for future use. Modern solar collectors from reputable companies are extremely efficient and can provide most of a family’s hot water needs across the year. Mother Earth will provide Geothermal energy is perhaps the most bountiful after that from the Sun. At depths greater than 2 m the temperature of the earth is higher than the surface temperature and remarkably stable throughout the seasons. Ground-source heat-pumps can efficiently use that free energy. The process is quite simple; pump refrigerant through an underground pipe network to transfer heat underground into the liquid, which in turn is transferred to the water in a heating system. This hot water can be stored in much the same way as a solar thermal collector or used for space heating. But as you already have stored hot water from your newly fitted solar collector, the installation of an underfloor heating system will now afford you an almost carbon- and bill-free central-heating system. Heat-pumps do not have to rely entirely on the ground for a source of free geothermal energy. Water, brine and air-source heat pumps are all commercially available, working to slightly different principles and degrees of efficiency. It is also worth remembering that heat pumps currently qualify for just 5% VAT on installation. The range of innovative products and solutions to meet these needs grows daily and is readily available from reputable manufacturers. In terms of availability, there is no excuse not to play a positive part in the drive towards a low- to zero-carbon economy. Richard Scott is business manager at Applied Energy Products Ltd.
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