Israeli energy company
AORA wants to prove it doesn’t have to be sunny all the time for a
solar power plant to make electricity. To generate round-the-clock
electricity, they are combining traditional fuel – such as biomass or
diesel – with low-carbon solar power during daylight.
Haim Fried (right), CEO of Israeli
energy
company AORA, and Pinchas Doron, AORA Chief Technology Officer, stand
in front of a solar panel at their hybrid solar power station. Key to
the technology is a solar tower (in orange) that powers a turbine using
sunlight during the day, and then seamlessly switching to a biofuel
when sunlight is scarce
AORA is constructing its first hybrid solar power station
on a half-acre (0.2 hectare) plot in Israel’s Negev desert, in an
attempt to tap into the multi-billion-dollar clean energy market.
The Negev plant, unveiled to the public this week at an energy
conference in Israel’s Red Sea resort of Eilat, uses diesel for now.
“It will be online next month, producing 100 kilowatts – enough energy
to power about 40 houses,” said Pinchas Doron, AORA’s chief technology
officer.
The module comprises 30 large mirrors reflecting sunlight onto a
generator on top of a 90-foot-high tower.
“What is unique in AORA’s design is that it boasts of a gas turbine
that can handle super-high temperatures, and then work off external
fuel when sunlight is unable to produce the necessary heat,” Doron said.
“It can shift seamlessly between using the sun as fuel and a
conventional or another renewable fuel,” he added.
How it works…
One of the main hurdles in completing the hybrid power plant, however,
was creating a generator that could handle concentrated sunlight that
reaches nearly 1,000 degrees Celsius, said AORA’s operations manager,
Yuval Susskind.
“Most materials melt in that heat,” he explained.
Aora, therefore, built a special receiver on a tower that’s capable of
handling high temperatures.
Using concentrated sunlight, air is heated in this receiver and then
shot into a combustion chamber, where it expands and powers a turbine,
producing electricity.
A separate route can bypass the solar receiver and use a secondary fuel
to power the turbine when necessary, allowing the power plant to
produce non-stop electricity.
“The process also creates a by-product of some 170kw of heat, which can
be used to heat water for homes or factories,” Susskind said.
“Because each of these units sits on just a half-acre, it can provide
electricity in the most remote areas,” he said. “You can build one
outside a village, or have many together in a desert.”
A 100kw plant using traditional photovoltaic panels, which can have up
to 15 per cent efficiency, would need twice the land, AORA said. Its
hybrid-solar plant runs at 28 per cent solar efficiency.
Logical Step
Clean energy experts welcomed the new design.
“This is a logical step. In certain contexts, like remote places, this
could be the way to go,” said Ken Zweibel of the Institute for the
Analyses of Solar Energy in the US.
“It’s dispatchable. You can’t have that from photovoltaic alone,” he
said, referring to traditional solar panels.
Susskind said no other plant has hybrid technology at the same scale
and efficiency.
AORA said the cost of their electricity is competitive with other solar
technologies, and that total production costs depend on the price of
the external fuel.
A prototype constructed in China in 2006 proved the technology worked,
the company said, and it expects to begin commercial production later
this year.
http://www.mumbaimirror.com/article/7/20090220200902210218004244251bfe8/Hybrid-solar-plant
-offers-24x7-power?pageno=1
Copyright 2009© Bennett Coleman
& Co. Ltd.
