Solar water heating pays for itself five times over

The total global capacity of Solar Water Heating could exceed about 1.5 billion sqm by year 2020. This would give the world a solar thermal capacity of 1,100 thermal gigawatts, the equivalent of 690 coal-fired power plants

AN ANALYSIS of the engineering and economics for a solar water-heating system shows it to have a payback period of just two years, according to researchers. The current focus in the developed world is on advanced technological approaches to alternative energy sources, such as photovoltaic cells for solar power and harnessing wind and wave with elaborate systems to generate electricity. However, the cost of such systems may be prohibitive for some applications in the developing world. They also often ignore the fact that a mundane process such as heating water might best be carried out using direct heat from the sun rather than including a waster energy conservation step.

The harnessing of solar energy is expanding on every front as concerns about climate change and energy security escalate. Government is offering incentives for harnessing solar energy and the costs decline while those of fossil fuels rise. One solar technology that is really beginning to take off is the use of solar thermal collectors to convert sunlight into heat that can be used to warm both water and space.

China, for example, is now home to 27 million rooftop solar water heaters. This technology is sweeping in China like wildfire, which is already approaching market saturation in some communities. Beijing plans to boost the current 114 million square meters of rooftop solar collectors for heating water to 300 million by 2020. The energy harnessed by these installations in China is equal to the electricity generated by 49 coal-fired power plants. Other developing countries such as India and Brazil may also soon see millions of households turning to this inexpensive water heating technology.

European Solar Thermal Industry Federation (ESTIF) has established an ambitious goal of 500 million square meters, or 1 square meter of rooftop collector for every European by 2020—a goal slightly greater than the 0.93 square meters per person found today in Cyprus. Most installations are projected to be Solar-Combi systems that are engineered to heat both water and space.

China is setting a goal of 300 million square meters of solar water heating capacity by 2020, and ESTIF’s sets goal of 500 million square meters for Europe by 2020, U.S. is setting up installation of 300 million square meters by 2020. Japan has 7 million square meters of rooftop solar collectors heating due to which the import of LPG will be reduced.

If China and the European Union achieve their goals and Japan and the United States reach the projected adoptions, they will have a combined capacity of 1,180 million square meters of water and space heating capacity by 2020. With appropriate assumptions for developing countries other than China, the total global capacity could exceed about 1.5 billion square meters by year 2020. This would give the world a solar thermal capacity of 1,100 thermal gigawatts, the equivalent of 690 coal-fired power plants. The huge projected expansion in solar water and space heating in industrial countries could close some existing coal-fired power plants and reduce natural gas use, as solar water heaters replace electric and gas water heaters. In countries such as China and India, the solar water heaters will simply reduce the need for new coal-fired power plants.

The gas consumption in Pakistan is growing steadily, while the gas reserves are getting short day by day. The total domestic, commercial and industrial gas consumption in Pakistan is about 554,691 Million cubic feet per year. If we adopt the solar thermal heating, we can save this natural gas usage as Pakistan is also located in the sun-belt region which has plenty of solar radiation daily available throughout the year. If it is assumed that 22% of natural gas is being consumed in domestic, commercial and industrial sectors for heating water, by use of solar thermal we can save not only about 123,256 MMBTU gas (amounting Rs. 56.10 Million per year) but can also save 10.11 Million Ton of Carbon di oxide per year to a take part in the reduction of environmental population.

According to the experts, residential solar water heater systems for 6 person cost between Rs.25,000 and Rs.45,000, compared to Rs.14,000 to Rs.28,000 for gas heaters. With savings in electricity or natural gas, solar water heaters pay for themselves within two to three years max. And solar water heaters last between 15 and 20 years – the more as conventional systems. After that initial payback period is up, zero energy cost essentially means having free hot water for years to come. By adoption of solar water heating we can extensively save firewood, kerosene oil, liquid petroleum gas, charcoal, diesel and electricity. Hence solar thermal is the best substitute for water heating.
http://www.technologytimes.pk/mag/2011/feb11/issue03/solar_water_heater.php