Growing energy demand adds stress to water supply

AFP

Wednesday, 24 August 2011

A Google search for "world water shortage" will produce more than four million results in 0.17 seconds. It will also use a tenth of a teaspoon of water, experts say.


Given water's role in power generation, the impact of about 300 million Google searches a day is around 150,000 litres (40,000 gallons) daily - in a world where water supplies are increasingly a major concern.

"These two things - water and energy - come together and that's a big thing for the world to understand," says Len Rodman, a US-based water and energy expert.

"If you squander water, if you indiscriminately use power, then in the long run that will have implications for the world," the chief executive of Black & Veatch, a major global water and energy company told AFP in an interview.

Water is used not only to generate power through dams and steam but also as a coolant for nuclear, coal and gas-fired power plants, which are competing with agriculture, industry and urban consumption for water supplies.

The Asian Development Bank has forecast the region's energy demand to double by 2030 to 6,325 million tonnes of oil equivalent, or about 74 billion kilowatt-hours of electricity.

Water will play an increasing role as a power source for Asia but supplies are already under threat, said the ADB.

China and India, the world's most populous nations, are expected to have a combined shortfall of one trillion cubic metres (35 trillion cubic feet) of water within 20 years.

Bangladesh, Cambodia, Nepal, Pakistan, the Philippines and Vietnam are already under "water stress" conditions, meaning they are experiencing periodic or limited water shortages.

During an international water conference in Singapore in July attended by Rodman, industry players and government officials called for better integration of water and energy policies to help find solutions to looming shortages.

"There is a growing realisation that we can no longer think about energy and water separately," Peter Gleick, president of the Pacific Institute in California, said at the conference.

A recent survey of more than 700 US utilities firms by Black & Veatch showed that for the first time, water supply was the top environmental concern among the respondents.

Asia is likely to face the same problems, Rodman said.

"It will truly be exacerbated in this region because of the urban densities that are there. You've got tremendous numbers of highly concentrated urban areas," he said.

The needs of the region's agricultural sector can also affect power supplies.

In 2008, 2.2 billion cubic metres of water were diverted from three major hydroelectric plants in Vietnam for agriculture, leading to a shortfall of 430 million kilowatt-hours of electricity, Black & Veatch said.

Research is continually being carried out on water treatment technologies that require less energy as well as power-generation facilities that would need less water, experts said.

Advanced technologies to treat polluted water as well as recycle water from toilets, kitchen sinks and sewers for use in homes and industries will help address Asia's future needs, they said.

Companies like Siemens Water Technologies are doing research aimed at integrating desalination - an energy-intensive process to purify seawater - with solar power.

Rodman said encouraging people to change their consumption patterns of water and energy by helping them understand the link between the two is equally important.

"Gone are the days when water is independent from energy," he said.

Spray-on solar may be future for green energy

Relaxnews

Thursday, 25 August 2011

As Japan seeks to optimize its use of environment-friendly energy sources in the wake of the nuclear crisis triggered by the March 11 earthquake and tsunami, a company here may just have come up with a major breakthrough: spray-on solar cells.


Mitsubishi Chemical Corp. has developed technology that enables solar cells to be applied to buildings, vehicles and even clothing in the same way that paint is applied. The breakthrough means that the places where energy from the sun can be harvested are almost limitless.

The new solar cells utilize carbon compounds which, when dried and solidified, act as semiconductors and generate electricity in reaction to being exposed to light. Most existing solar cell technology requires crystalline silicon to be sandwiched between glass sheets and positioned on the roofs of homes and office buildings, or in space-consuming "solar parks."

Scientists have been attempting to increase both the energy-gathering efficiency of solar panels and make them easier to install and use.

Mitsubishi Chemical is the first company to create prototype spray-on solar cells, which at present have a practical conversion level of 10.1 percent of light energy into electricity.

That figure is still some way behind the 20 percent that is standard in traditional crystalline silicon solar cells, but the firm expects to be able to improve the efficiency ratio to 15 percent by 2015 and is aiming to eventually reach 20 percent.

The company said the new painted-on solar cells would be particularly effective when applied to round or curved structures, such as chimneys or the noise-reduction barriers that line many highways in built-up areas of Japan.
It could also be applied to the exteriors of cars and theoretically used to help power the vehicle and even to such flexible surfaces as clothing.

The sprayed-on solar cells are less than 1 millimeter thick - far thinner than existing solar cell technology - and weigh less than one-tenth of crystalline solar panels of the same size, the company said.

Mitsubishi Chemical said it plans to work with domestic carmakers to build a car coated with the new solar cells with the aim of giving the vehicle sufficient power to travel 10 km after being exposed to sunlight for two hours.

The spray-on solar cells are a breakthrough concept, but other organizations are working on similar research to get the most out of energy from the sun. Scientists from The Australian Commonwealth Scientific and Research Organization, the University of Melbourne and the University of Padua in Italy are collaborating on 'printable laser' technology which could impose nano-particles onto wafer-thin panels which could then eventually be developed into into paper-thin solar panels.