Month: July 2011

Solar Energy Projects Picking up Again After Uprising

Solar Energy Projects Picking up Again After Uprising

by Bibi-Aisha Wadvalla

(This article also appeared on Al Jazeera)

CAIRO, Jun 22 (IPS) – On a blazingly hot summer’s day in Cairo, it’s 36 degrees Celsius in the shade. Air-conditioners and fans whirr across the city, burdening the national electricity grid. Last summer, the populous city experienced frequent water and power cuts, causing a furore. Consumption had grown by 2,600 megawatts, an increase of 13,5 percent from 2009.

Over 1,000 years ago ancient Egyptians worshipped the sun god Ra. Centuries later, modern Egypt is only just beginning to realise the importance of utilising the sun as an energy source. One of the most sunlight-rich countries in the world, this North African country is making slow strides with solar energy.

About 100 km south of Cairo lies Kuraymat, Egypt’s first solar plant, which is expected to produce 120 MW. A hybrid power plant, 20 MW will be from solar energy and 100 MW from natural gas. Initially expected to start up in Dec. 2010, its activation has been postponed several times. The Jan. 25 uprising further stalled the launch.

“Foreign partners on the project left and we couldn’t continue”, says Khaled Fekry, director of research and development at the New and Renewable Energy Authority (NREA), a government body. German companies Ferrostaal and Flagsol, a subsidiary of Solar Millenium, provided the technology.

Currently, Kuraymat is in the final stage of commissioning, with tests being carried out. Fekry hopes it will be ready at the end of June.

A second 100 MW plant in Kom Ombo was announced last July and should be completed in 2017. Fekry lists other projects: “We aim to develop a 200 MW plant for cement factories and a 1,000 MW plant for the private sector. ”

This is all very ambitious but ties in with Egypt’s plan of producing 20 percent of energy output from renewable sources by 2020. Solar energy will provide a third, or 7,200 MW, of that percentage. Fekry is confident it can be achieved.

While large-scale projects won’t have a direct effect on Egyptians just yet, a joint undertaking by NREA and the Italian ministry of environment has changed the lives of villagers living deep in the Western Desert. The villages of Ain Zahra and Umm al Saghir, not connected to the national energy grid, have had their homes, schools, mosques and hospitals electrified with photovoltaic (PV) solar energy since Dec. 2010.

NREA engineers have remained on site, providing training to the villagers. Six months in, Fekry reports, there have been no complaints.

But Mohab Hallouda, senior energy specialist at the World Bank’s Egypt office, explains that, although PV energy is suitable for outlying areas, “the price must decline to be a viable alternative to electricity from the grid”.

Away from the bureaucracy of government-led proposals, a simple concept, SolarCITIES, is empowering residents of local communities. Darb el Ahmar and Manshiet Nasser are two of Cairo’s poorest areas.

Crumbling buildings are built close together, lining narrow streets and jostling with animal, vehicle and pedestrian traffic. Many residents cannot afford heating appliances and “women’s duties” include having to boil water on kerosene stoves. Winter is a hazardous time with frequent burn injuries being reported.

Mustafa Hussein, a Darb el Ahmar resident, is a founding participant of SolarCITIES. He became convinced of the usefulness of the technology after meeting Thomas Culhane, SolarCITIES founder, who sketched him a prototype of a solar panel and heater. The system was built; 25,000 dollars in funding was obtained from the U.S. Agency for International Development; and 35 units installed.

Amm Hassain, 70 years old, was one of the first residents to agree to the installation of the unit on his building’s rooftop. No longer does his family have to laboriously boil water for a bath, risking potential injury.

The unit provides 200 lt of hot water per day, which can serve up to 10 family members comfortably, and 200 lt of rooftop coldwater storage to help them get through the many days when water is cut in the community.

Mustafa Hussein feels projects like these have more value: “The government plans are removed from us. Here we involve the community directly. I live here, I know this place, I know how to connect with people.”

But, unless more funding is received, SolarCITIES may not grow. With the average annual income in these areas being 610 dollars, the 678 dollar unit is unaffordable for most.

Hussein feels people will realise the importance of turning to solar energy within a few years. “We’ll experience more power cuts. Last summer there was a scarcity of gas tanks and people died fighting for them.”

Fekry wants Egypt to follow the Tunisian model: “The government subsidised solar water heaters, and provided them on credit with low interest rates,” he explains.

But, with an unequal playing field, a paradigm shift toward renewable energy seems unlikely. Even with gas subsidies in Egypt being phased out, fossil energy remains cheap, while a lack of competition won’t reduce the cost of solar energy.

Kuraymat cost 360 million dollars and the Kom Ombo plant’s cost is estimated at 270 million dollars. The Egyptian government plans to spend 100-120 billion dollars to triple capacity by 2027.

Fekry points to taxes on imported solar components as the culprit contributing to the high cost of solar energy. He also believes that, “we can only expand if we have finance. Foreign investors should direct funds to Egypt now, and not wait until the country is stable. ” (FIN/2011)












Reducing Drag Through Vapour

Reducing drag through vapour


Bibi-Aisha Wadvalla

A vapour-encased sphere can move at much higher speeds through a liquid due to reduced resistance.Ivan Vakarelski

If water is poured on a hot metal plate above 100°C, it will skate across the surface rather than begin to evaporate. According to the 225-year-old Leidenfrost effect, a liquid produces an insulating vapour layer when it comes in contact with a solid surface that is hotter than its boiling point: known as the Leidenfrost point. Two researchers decided to take on this phenomenon and published their results in Physical Review Letterslast month.

Ivan Vakarelski, a chemical engineer at King Abdullah University of Science and Technology (KAUST), Saudi Arabia, and Derek Chan, a professor of mathematics at the University of Melbourne, Australia, decided to see what happens in reverse: they dropped hot metallic spheres into a fluorinated liquid with a boiling point of 56°C.

“This makes it easier to initiate the ‘inverted’ Leidenfrost effect — a thin film of vapour covering the metal,” explains Vakarelski. Just as the vapour layer moves liquid across the surface of a hot plate, it allows for faster movement of the spheres through the liquid. “We thought that this could be the perfect system to model the drag reduction by [the] vapour layer,” he adds.

Research had demonstrated the reduced hydrodynamic drag that vapour layers can have on objects moving through liquids. Vakarelski says their study is the first measurement of the limit of drag reduction a vapour layers can produce. “We showed that the Leidenfrost vapor layer can reduce the drag on a sphere by up to 85%.”

Possible uses

Any object moving through a fluid experiences drag, or resistance. The drag coefficient, the measure of an object’s drag, of the vapour-encased sphere reduced from 0.4 to 0.07, a change of 571%.

These findings could help engineers optimize liquid flow through pipes and make microfluidic devices more efficient, says Vakarelski. It can also be applied on a larger scale, such as in shipping or submarines.

A reduced drag could save energy and reduce carbon emissions. “For ships or high-speed underwater vehicle achieving even 10% or 20% percent would be a substantial result,” says Vakarelski.

The research is fundamental and it will take a few more years before findings can be commercially applied though. Vakarelski hopes that devices exploiting the Leidenfrost effect could be ready for testing in a couple of years. “Our focus is on the formation and sustainability of bubble layers in water which will bring us closer to practical applications. We hope that this next stage will be completed before the end of this year.”

Alaa Ibrahim, an astrophysicist at the University in Cairo (AUC) says the research is original and of great value to the industry. Ibrahim also envisages application of the technology in shipping. “However, you will have to spend energy to heat up the surface of the moving body and this in itself opens up another interesting research investigation to minimize the energy consumption and safely insulate the cargo.”

  • References

    1.  Vakarelski, I. , Chan, D. et al. Drag Reduction by Leidenfrost Vapor Layers.Phys. Rev. Lett. 106, 214501 (2011) | Article | PubMed | ADS | ChemPort |
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