The Hindu Business Line : More people turn to the sun for energy needs

Washington, Aug. 26 For a world grappling with concerns over climate change and rising carbon footprint, the sun is increasingly providing some solace and clean energy.

Expansion in solar thermal heating is clearly trending up according to latest available data. There obviously is some message for India. Solar thermal heating harnesses the sun’s energy for domestic water heating, space heating, swimming pool heating, drying and other industrial processes.

Solar thermal heating expanded by about 19 gigawatts of thermal equivalent (GWth) to reach 147 GWth of capacity in 2007, according to a recent report of Worldwatch Institute, a Washington DC-based independent research organisation, on solar thermal trends. This level of global production was enough to meet the equivalent heating needs of 15 per cent of US households.

China leads

Much of the increase has been in China which has the largest solar thermal heating market and has two-thirds of global capacity. Despite a market downturn in 2007, the country accounted for 80 per cent of newly installed systems that year.

In China’s coastal city of Rizhao, about 99 per cent of all households use solar water heating. The initial capital costs for solar water heaters are said to be on par with conventional electric system. The lifecycle costs demonstrate annual savings of 3-6 per cent of the average of 2006 household income, the report pointed out.

Heating accounts for more than two thirds of total energy use in buildings, which emit 30-40 per cent of global greenhouse gases.

Renewable heating resources such as solar thermal energy displace conventional heating fuels, primarily natural gas and electricity.

Apart from China, countries as diverse as Turkey, the US, Europe (led by Germany) and Cyprus are rapidly adopting the renewable energy for heating purposes.

“Integration of solar thermal heating systems into architectural designs is becoming more prevalent and provides additional benefits including shading and thermal insulation,” the report pointed out adding the best commercially available solar thermal heating systems demonstrate efficiencies of nearly 70 per cent.

For India which is seen gradually slipping into energy insecurity, there is much to learn and emulate. There are not many countries in this world that enjoy 270 days of sunshine a year; India does. The huge potential provided by solar energy – clean and renewable – needs to be tapped to meet the growing energy needs, especially in rural areas.

One of the critical applications could be setting up of solar driers for rapid drying of freshly harvested produce.

The thermal route uses the solar energy for water heating, cooking, drying, water purification, power generation and other applications, while the photovoltaic route converts the light in solar energy into electricity which can then be used for a number of purposes such as lighting, pumping, communications and power supply in un-electrified areas.

Another area of interest to developing countries such as India that burn large quantities of fossil fuel is waste-energy recycling which captures smokestack waste and other waste energy and puts it to work.

Waste-energy recycling currently contributes to 10,000 MW of electric power to the US national total each year.

But a recent study estimates that if energy content of all US smokestack waste were recycled, it could replace roughly 30 per cent of the electricity produced by burning fossil fuels, the Worldwatch Institute reported.

But such recycling is not confined to the US alone. Russia gets over 30 per cent of its electricity from waste-energy recovery, while Denmark gets more than 50 per cent.

In ‘Bridge to a Renewable Energy Future,’ co-authors Robert Ayres and Ed Ayres explore this underutilised technology and its ability to bridge the transition from fossil fuels to renewable energy sources, noting that expanding these technologies is often a boon for the investor’s bottom line as well as the environment.

“As atmospheric levels of carbon dioxide also rise – and as public concerns about the global energy dilemma also rise – private investment in the energy transition bridge may shift from tentative to robust,” they write.

“The key…is that in many cases, such investments can bring the double dividends of both corporate and social benefits, often with a rapid return on investment.”

Despite their potential, these proven technologies have been seriously underused to date. And energy recycling is just one of several high-potential strategies that can reduce both fossil-fuel use and carbon emissions during the long transitional period ahead. Admittedly, waste-energy streams are not a substitute for renewable energy; but are surely a useful source of energy.

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