Some see Qatar's bid to host the 2022 World Cup as madness. The country's hopes hinge on developing technology to harness the sun's heat to power nine stadiums with huge cooling systems. But can it be done, asks Chris Stanton The idea is so counter-intuitive it borders on the absurd: use the searing heat of the summer sun to directly power huge air conditioners for nine stadiums full of football fans.
Disclosed two weeks ago as part of Qatar's bid to host the 2022 FIFA World Cup, the plan stretches the limits of solar cooling technology, experts concede. But it shines a spotlight on the rapid advance of a concept that was once prohibitively costly, but is now being installed at hundreds of sites across the world, including Abu Dhabi. The Abu Dhabi Water and Electricity Authority (ADWEA) intends to complete one of the region's first large-scale solar cooling systems at one of its grid control centres by December. A series of solar thermal panels on the roof of the five-storey building in the capital will cover between a third and half of its cooling needs on the hottest summer days, says Peter Le Lievre, the chief executive of Chromasun, the solar cooling start-up company based in southern California that built the system.
"We see solar cooling as a good technology to offset that real spike [in power use] that occurs on the hottest, stickiest days," he says. "That's why ADWEA are funding this showcase." The technology could have big implications for the surrounding region as it confronts a continuing shortage of electricity generating capacity to meet the spike in power consumption that occurs every summer afternoon as residents switch on their air conditioners.
The turn to solar cooling is also on display in Ras al Khaimah, where the Government is contemplating the construction of several floating islands of panels that would concentrate the heat of the sun and transport it underwater by pipeline to the mainland, where it could be used to power solar cooling systems for blocks of buildings. The concept of evaporative cooling that forms the kernel of most solar air conditioners is intimately familiar to all of us. When the body sweats, the evaporation of water off the skin takes heat with it, cooling down our core temperatures.
Instead of sweat, however, solar cooling systems evaporate water mixed with a chemical medium in a closed loop. Sunlight concentrated by lenses and mirrors heats the liquid, which then passes on its own energy through a thermodynamic process that rapidly removes the heat and leaves behind a chilled liquid that can be used to cool the surrounding air. Today, about 500 of the systems are in operation worldwide, mostly in Europe, says Uli Jakob, the general manager of Solem Consulting, which has helped design and engineer solar cooling systems across the world, including the system for ADWEA.
Prices have fallen by more than half in just three years, he says, but the technology is still viable only for large office buildings in countries where electricity prices are high and corporate owners are willing to wait for years for cumulative savings on their power bills to exceed the steep upfront cost. "If you're talking about residential buildings, for example, it's not viable at present. We're talking a return on investment of 15 to 20 years," he says.
"If you're talking about commercial applications like office buildings, it's really different. Then we can get a return on investment of seven, 10 or 12 years." A typical residential system - with 10 kilowatts of cooling capacity, the same as up to eight standard window air conditioners - would today cost about €50,000 (Dh247,840), Mr Jakob says, with the sector hoping to reduce that by 40 per cent in five to 10 years.
Larger systems for corporate clients cost more in total, but economies of scale allow them to produce each kilowatt of cooling, a standard measure for the industry, at much lower cost. Today the installation cost for each kilowatt on large systems is between €2,000 and €3,000, Mr Jakob says, compared with between €4,000 and €5,000 for small systems. Any comparison with conventional systems must account for the fact that a solar cooling system by default also serves as a hot water heater and heating system for the cooler months.
Costs remain high because the systems are still custom-designed for each client, and the industry has not yet developed large, efficient assembly lines, Mr Jakob says. "At present we're talking about 100 to 200 systems (installed) per year, we're not talking about a million or something like that," he says. "It's really just a question of scale." Experts expect much larger markets for the technology to be created by new government policies in Europe, Australia, parts of the US and even India.
Abu Dhabi and other parts of the region will not become big markets unless they either increase prices for electricity to give investors a faster payback through savings on their power bill, or if governments create specific subsidy programmes that support the higher cost of the technology. A recent study found that the most efficient forms of solar cooling technology become viable on their own when electricity is priced at a minimum of 20 US cents per kilowatt hour, says Peter Armstrong, an associate professor and solar cooling expert at the Masdar Institute of Science and Technology in Abu Dhabi. Electricity in Abu Dhabi is currently priced at 4 cents per kwh for expatriates and just over 1 cent for Emiratis.
The institute and its parent company Masdar have been experimenting with solar cooling systems at the company's carbon-neutral city at the edge of the capital. Yesterday, the company said it had activated an experimental solar cooling plant on site that could potentially be used to cool the entire development. If governments worldwide create penalties for emissions from fossil fuels, the technology could become cost-competitive in 10 years, Mr Armstrong says.
"If policymakers will focus immediately and consistently on carbon taxes instead of feed-in tariffs and carbon trading schemes, we can expect to see cost-effective solar cooling systems using a variety of technology combinations, including residential scale (solar panel) powered cooling, within 10 years," he says. firstname.lastname@example.org