Massive solar thermal plants planned for UAE eco city to be built in Spain

Solar thermal keeps gaining traction. The latest announcement is for a joint venture between Abu Dhabi's Masdar and Spain's Sener. It will be called Torresol Energy, and the initial investment is €800 million (or $1.24 billion) into three solar thermal power plants to be built in Spain.
Masdar will supply energy for the United Arab Emirates-funded consortium behind Masdar City, a zero-carbon, zero-waste, self-contained community meant to house 50,000 people, to be completed over the next eight years.

All told, the $22 billion Foster & Partners-designed megaproject will include cutting-edge solar power and water treatment systems, nonpolluting underground light rail, and a small research university operated in conjunction with the Massachusetts Institute of Technology.

The solar thermal vision is of the sun-blessed lands of the world – the Mediterranean, the world's deserts – being carpeted with systems like this with the power cabled to the drizzlier lands of northern Europe, North America and Asia.

Solar thermal plants use mirrors and/or lenses to focus the sun’s light onto a receiver which absorbs the energy as heat. The heat is used to create steam and power turbines to produce electricity. There are a variety of designs and technologies used in these massive power plants, and companies are working on innovations to reduce the costs and increase the efficiency of the process..

One of Torresol’s plants will use an array of heliostats surrounding a central tower receiver (pictured below), which the company claims will be the technology’s first commercial deployment. This is same centralized power tower design that startups like BrightSource, SolarReserve and eSolar are planning on using.

Sandia National Laboratories has been developing this technology since the 1970s and successfully demonstrated it at their Solar Two installation using molten salt in the central receiver. The surrounding array of heliostats, or sun-tracking mirrors, reflect and concentrate sunlight onto a central receiver, generating a great amount of heat. The design is more efficient because all of the heat exchanging and steam generation take place inside the central tower, but the heliostats are also delicate and expensive.

The other two Spanish plants in the works will use parabolic trough technology, Torresol tells us. Startups like Solel are also using the trough approach, which heats liquid-filled tubes. The hot liquid must be pumped to a steam generator at an energy cost, but the troughs are supposed to be more robust than heliostats.

Torresol also has some even loftier hopes for its solar thermal technology. The company plans to “facilitate” 500 megawatts of concentrating solar power plants around the world by 2012, in places like the American Southwest, the Middle East, North Africa and Northern Australia.

From the BBC, May 2007:
There is a scene in one of the Austin Powers films where Dr Evil unleashes a giant 'tractor beam' of energy at Earth in order to extract a massive payment.

Well, the memory of it kept me chuckling as I toured the extraordinary scene of the new solar thermal power plant outside Seville in southern Spain.

From a distance, as we rounded a bend and first caught sight of it, I couldn't believe the strange structure ahead of me was actually real.

A concrete tower - 40 storeys high - stood bathed in intense white light, a totally bizarre image in the depths of the Andalusian countryside.

The tower looked like it was being hosed with giant sprays of water or was somehow being squirted with jets of pale gas. I had trouble working it out.

In fact, as we found out when we got closer, the rays of sunlight reflected by a field of 600 huge mirrors are so intense they illuminate the water vapour and dust hanging in the air.

The effect is to give the whole place a glow - even an aura - and if you're concerned about climate change that may well be deserved.

It is Europe's first commercially operating power station using the Sun's energy this way and at the moment its operator, Solucar, proudly claims that it generates 11 Megawatts (MW) of electricity without emitting a single puff of greenhouse gas. This current figure is enough to power up to 6,000 homes.

But ultimately, the entire plant should generate as much power as is used by the 600,000 people of Seville.

It works by focusing the reflected rays on one location, turning water into steam and then blasting it into turbines to generate power.

As I climbed out of the car, I could hardly open my eyes - the scene was far too bright. Gradually, though, shielded by sunglasses, I made out the rows of mirrors (each 120 sq m in size) and the focus of their reflected beams - a collection of water pipes at the top of the tower.

It was probably the heat that did it, but I found myself making the long journey up to the very top - to the heart of the solar inferno.

David had to wear sunglasses to shield his eyes from the glare
A lift took me most of the way but cameraman Duncan Stone and I had to climb the last four storeys by ladder. We could soon feel the heat, despite thick insulation around the boiler.

It was like being in a sauna and for the last stages the metal rungs of the ladders were scalding.

But our reward was the cool breeze at the top of the tower - and the staggering sight of a blaze of light heading our way from down below.

So far, only one field of mirrors is working. But to one side I could see the bulldozers at work clearing a second, larger field - thousands more mirrors will be installed.

I met one of the gurus of solar thermal power, Michael Geyer, an international director of the energy giant Abengoa, which owns the plant. He is ready with answers to all the tricky questions.

What happens when the Sun goes down? Enough heat can be stored in the form of steam to allow generation after dark - only for an hour now but maybe longer in future.

Anyway, the solar power is most needed in the heat of summer when air conditioners are working flat out.

Is it true that this power is three times more expensive than power from conventional sources? Yes, but prices will fall, as they have with wind power, as the technologies develop.

Also, a more realistic comparison is with the cost of generating power from coal or gas only at times of peak demand - then this solar system seems more attractive.