Sounds far-fetched, but it will soon be a reality near Las Vegas.  A new solar power plant being planned in Tonopah, Nevada will use heliostat mirrors to focus sunlight on a water tower, superheating water and creating steam that turns a turbine, generating electricity.  The solar thermal power plant will not require photovoltaic (PV) solar panels to generate solar power.  So-called Concentrated Solar Power (CSP) plants like this one hold great promise for the future of renewable energy.

Concentrated solar power using molten salt can extend solar electricity generation overnight

The Crescent Dunes Solar Energy Project will also use the focused sunlight to heat millions of gallons of molten salt to temperatures as high as 1,050 degrees Fahrenheit.  While the salt heats the water to produce steam (which turns the turbines to generate power), it also retains heat overnight.  This allows the plant to continue generating solar power throughout the night.

Using solar thermal technology with inexpensive molten salt will allow SolarReserve to provide power at a cost lower than traditional coal or natural gas.  With the ability to generate solar power 24 hours a day, the power plant will be able to continually feed clean  electricity into the grid at any time, unlike other solar power plants.

SolarReserve estimates the solar power plant design could extend electricity generation operations by as much as 12 hours.  The Department of Energy recently announced it would guarantee $737 million in loans for the plant. The Crescent Dunes Solar Energy Project is planned to begin operations in 2013.

Concentrated Solar Power becomes Building Integrated

Concentrated solar power is a technology for generating utility scale solar power.  But Syracuse’s Center of Excellence in Environmental and Energy Systems (SyracuseCoE) is showing that it can also be building integrated and used on a smaller, direct generation scale.

At SyracuseCo, the building itself is a LEED-platinum-certified, 55,000 square-foot building that serves as a testing ground for renewable energy and efficiency technologies.  But head to the south wall of the building and there, you will find a concentrated solar facade (pictured above), that serves multiple functions.

This is building integrated photovoltaics in a whole new light!  The 8×8 foot facade includes clear pyramid heliotropic lenses that concentrate sunlight on high-efficiency PV solar cells.  Solar energy is generated at an efficient rate, and any additional power not needed for electricity is used to heat the building and water.  Not only that, but the clear panels add natural light for the interior, which reduces lighting requirements.

The facade was designed by the Center for Architecture Science and Ecology and HeliOptix has marketing rights.

Solar Farm in the UAE

Solar power holds a lot of promise.  Particularly when it comes to sun-drenched regions in the world, like Abu Dhabi.  The world’s largest solar plant will soon be built in the United Arab Emirates (UAE), about 75 miles south of Abu Dhabi.

Like many other utility scale solar plants worldwide, the power plant will use concentrated solar power, also known as CSP.  Giant parabolic mirrors reflect sunlight, which is used to super heat water to create steam and move turbines, which in turn generates clean electricity.  The Desertec project will be a 100 megawatt (MW) power plant, potentially replacing the equivalent of 10 coal fired plants.

While there may be big plans for the project, that installation may still be years away from construction and operation.  Still, the hope is that the plant will hep UAE meet its renewable energy goal of 7% by the year 2020.

Financing the largest power plant in the UAE will be a joint effort, including Abengoa Solar (a Spanish company), oil giant Total (based in France) and Masdar, the planned eco-city in the UAE.  Approximately 768 parabolic trough solar collectors will be provided by Agengoa Solar.  A natural gas boiler will be used to turn the turbines overnight.

** The claim that the UAE solar plant will be the world’s largest has been the subject of some debate.  The SEGS solar power plant in California’s Mojave Desert, generates as much as 354 MW of solar electricity.  However, the facility is comprised of nine solar power plants operating together.

Sundrop Fuels announces its hybrid solar biomass refinery

Talk about biofuels has waxed and waned over the past decade.  On one hand, people are excited about an alternative fuel to gasoline or diesel.  On the flip side are concerns about the amount of energy it takes to produce a barrel of biofuels.  Add into the mix the idea that taking corn off our plates and into our fuel tanks may not make the most sense!

Sundrop Fuels has come up with a way to address these issues, with its hybrid solar biomass refinery.  The New-Mexico based company plans to produce bio-ethanol using concentrated solar power (CSP) technology.  Instead of the end-product being solar electricity, biofuel is the product created by superheating plant scraps and woodchips with parabolic reflective mirrors.

Solar power is the key component to Sundrop Fuels’ reduction of energy consumption at the refinery.  Using a SurroundSun reactor, the technology borrows heavily from the CSP process that is used to generate solar thermal electricity.  However, there is an important difference.  Whereas concentrated solar power generally focuses solar heat on water and/or molten salts, the hybrid solar biomass refinery will “blast organic materials with super high temperatures…tearing apart the materials at the molecular level…which creates a synthetic gas that can be formed into gasoline or diesel,” said Sundrop CEO Wayne Simmons.

A typical concentrated solar power plant

Using the new technology, Sundrop Fuels claims that it can save up to 1/3 of its energy costs in producing bio-ethanol at the solar biomass refinery.  Another downside of biofuel production – competition with food supply – is also addressed through the use of plant scraps and wood chips that would otherwise be burned or discarded.

A call for investors has been made so that Sundrop can build a demonstration project in the next 2 years, by 2012.  That one plant alone could create 8 million gallons of alternative fuel each year!  The balance of the decade would be devoted to expanding into foreign markets that have demonstrated to be ideal solar power markets (North Africa, China and the Middle East).

Can we use solar power overnight?

As more and more people turn to solar energy for reliable, clean renewable power, there is still one major stumbling block.  You can only tap into solar power when the sun is shining.  But what if you could use solar power overnight?  How could that work?

Scientists at SolarReserve have come up with the antidote to night skies and overcast days.  A solar energy farm can store solar energy in heated molten salt.  Up to 7 hours of stored solar energy  is held by the heated salt, which creates steam to generate an electrical turbine.

The technology is similar to concentrated solar power (aka solar thermal power).  Giant mirrors, called heliostats, follow the path of the sun and reflect sunlight toward a 500-foot tower holding millions of gallons of liquid molten salt.  The heliostat field is approximately 2 square miles in size.

As described on SolarReserve’s website:

A tower resides in the center of the heliostat field. The heliostats focus concentrated sunlight on a receiver which sits on top of the tower.

Within the receiver, the concentrated sunlight heats molten salt to over 1000 degrees Fahrenheit. The heated molten salt then flows into a thermal storage tank where it is stored, maintaining 98% thermal efficiency, and eventually pumped to a steam generator. The steam drives a standard turbine to generate electricity. This process, also known as the “Rankine cycle” is similar to a standard coal-fired power plant, except it is fueled by clean and free solar energy.

Heliostat field

Researchers believe that the energy generated by the solar power towers will be cheaper than coal or natural gas.  The clean electricity is fed back into the grid and purchased by utilities for sale to their end customers.  Lest you question the “green-ness” of storing solar power overnight in molten salt, the technology is both safe and inexpensive – not to mention reliable:

The molten salt storage loop enables the plant to generate electricity whenever it is needed – 24 hours per day or during “peak demand” periods. Molten salt is an efficient and inexpensive medium to store energy. The salt used in the process is an environmentally friendly mixture of sodium and potassium nitrate, the same ingredients used in garden fertilizer.

Solar Reserve’s plant will generate between 100-600 megawatts of electricity, depending on the configuration of power load that the utility requires.  A single megawatt is enough power to supply approximately 1,000 households.  That’s some serious juice!

Talk about solar technology that’s worth its salt!

Rooftops in Spain go solar

Our European counterparts have done a better job converting to solar energy than those of us in the United States.  Many rooftops in Spain boast solar panels. In fact, one of the biggest stories in solar energy last year was the solar panels installed at a Spanish graveyard.

Spain also now includes a large concentrated solar power plant near Seville, and there are a number of photovoltaic solar power facilities throughout the country.

As noted in a Wikipedia Article on “Solar Power in Spain“:

“Spain is one of the most attractive countries for the development of solar energy, as it has more available sunshine than any other European country. The Spanish government is committed to achieving a target of 12 percent of primary energy from renewable energy by 2010 with an installed solar generating capacity of 3000 megawatts (MW). Spain is the fourth largest manufacturer in the world of solar power technology and exports 80 percent of this output to Germany.”

Solar power in Spain

Future solar growth in Spain will be in neighborhoods, business sectors and agricultural operations.  According to Bjorn Persson, executive vice president of European operations for Premier Power:

“We continue to see substantial growth opportunity in Spain for rooftop and building integrated solar energy systems.”

Recently, three new solar panel projects in Spain were announced.  They are planned to be completed by the end of 2009 and will generate an additional 400 kilowatts (kW) of clean solar energy.  General Electric is providing the crystalline (photovoltaic or PV) modules for the projects.

Simply put, Spain continues to lead with solar power.   Here’s hoping the rest of the world catches up, and catches onto the wonderful clean, renewable resource we have in the sun!

Google's Mirror Technology

Google, the well-known Internet search corporation, is getting into the solar energy business.  It is working on mirror technology to be used in solar powered turbine plants.  These plants use solar thermal power: sun shines on specially designed mirrors which focus the energy to superheat water which is then used to turn turbines, generating electricity.  This type of power generation is also known as concentrated solar power.

You might be wondering… what does Google have to do with solar power?  Well, its headquarters are in sunny California and, perhaps more than anything else, however, it has resources to invest!  Google has partnered with two solar thermal companies, eSolar and BrightSolar to develop cheaper mirrors and turbines.

The company has a “green energy czar,” Bil Weihl, who has this to say about Google’s mirror technology:

“We’ve been looking at very unusual materials for the mirrors both for the reflective surface as well as the substrate that the mirror is mounted on.”

They are also working to develop turbines that run on solar power, rather than natural gas, which will increase electricity savings even more for utility customers.

In order to understand the basics of concentrated solar power, consider this primer:

Solar thermal technology improving with Google's R&D

At a recent conference in San Francisco, Google announced that the new technology could cut the cost of manufacturing heliostats, which are the fields of mirrors that track the sun’s path across the sky and concentrate its energy.  And not by a small amount, either.  Google’s mirror technology could result in savings by a “factor of three or four.”

When might we expect the results of Google’s R&D?  Internal review should begin within a few months, which means that we could see on-the-ground installations within a year or two.  Perhaps sooner?

Google is predicting that the mirror technology will allow the creation of renewable solar energy at a price less than coal.  And, its putting $50 million where its mouth is, through investing with eSolar and BrightSolar.

We hope to see more companies follow Google’s lead and invest sums towards energy R&D that will help our country get off of fossil fuels, and towards a brighter future.

Solar Thermal Power (image from afromusing on Flickr)

Solar thermal power, also known as concentrated solar power, is used to make solar energy more efficient – in other words, you get more electricity from the same amount of sunlight. Unlike photovoltaic solar panels which you might have seen on rooftops or powering traffic signals, solar thermal power is generated by huge satellite dishes that are fitted with special mirrors.  The curvature of the mirrors focuses sunlight into a small, 7-inch area.  As you might imagine, this focus area is blisteringly hot.  Actually, unimaginably hot: the equivalent of 13,000 suns!

At the Solar Thermal Test Facility, owned by the U.S. Department of Energy, at Sandia National Laboratories in New Mexico, six solar thermal power dishes stand in the desert near Albuquerque.  The official site notes:

The primary goal of the NSTTF is to provide experimental engineering data for the design, construction, and operation of unique components and systems in proposed solar thermal electrical plants planned for large-scale power generation. In addition the facility can provide: high heat flux and temperatures for materials testing or aerodynamic heating simulation; large fields of optics for astronomical observations or satellite calibrations; a solar furnace; a rotating platform for parabolic trough evaluation.

How does solar thermal power work?  As the focus area in the center of each dish is superheated, the energy runs a “Stirling engine,” the operation of which is described in a San Francisco Gate article:

“The heat . . . creates mechanical energy from an external heat source, as opposed to the internal fuel combustion that powers most auto­mobile engines. Hydrogen gas in a Stirling engine’s four 95 cc cylinders expands and contracts as it is heated and cooled, driving pistons to turn a small electric generator. The configuration of the dish and engine represent the fruit of more than a decade of steady improvements, developed in collaboration with Arizona-based Stirling Energy Systems.”

Concentrated Solar Power

In general, concentrated solar power is said to be 25% efficient, more than double the average 12% efficiency rate of ordinary photovoltaic solar panels.  However, the dishes at the Solar Thermal Test Facility exhibited a 31.25% conversion efficiency – the highest ever recorded in a commercial solar device.

What’s equally exciting is that the energy comes from the heat of the sun, not the sunlight itself.  Heat can be better stored so that solar energy continues after the sun goes down.  The Solar Thermal Test Facility in New Mexico is just the beginning.  More solar thermal power is coming in the future in Arizona, and additional concentrated solar power plants exist in the Mojave Desert in California.

The Department of Energy predicts that solar electricity will be less expensive than than grid prices by 2015.  That’s just six years from now.  We’re starting to see what the future of solar power looks like!