Solar Thermal Power Plant

How does solar thermal compare to solar PV?

If you are asking the question, then you probably need to know the major differences between the two renewable energy systems that use the power of the sun.

Solar photovoltaic (PV) power is probably what you are most familiar with.  PV panels are the blue-shaded rectangular installations that include silicon solar cells that convert sunlight into electricity.  These are typically installed on individual properties to supply distributed generated electricity.

On the other hand solar thermal is utility-scale solar power.  Using parabolic mirrors to concentrate sunlight to super heat water in a tower to create steam and turn generators, solar thermal is more efficient than solar PV.

Just how more efficient?

PV has an efficiency rate of about 12%, costing approximately 25-35 cents per kilowatt hour (kWh).  On the other hand, solar thermal boasts an impressive 55% efficiency, at a mere 12-15 cents per kWh.

PV solar panels tend to get more attention because they are heavily subsidized by governments.  This is in part because people believe that they have the longest payback.  But others believe that the lowest-cost energy technology – solar thermal – should be promoted over photovoltaics.

What are your thoughts?  Solar thermal or solar PV?

Blue PV solar panels have some people seeing red

Anyone that has been following the news over the past few years in Southern California will see that the politics of solar power is not easily navigated.  When it comes to utility scale solar power plants, the idea of green, renewable power isn’t the end of the story.  For many environmentalists, developing what would otherwise appear to be bare, scrubby desert land with shiny, reflective PV panels or thermal solar power plants including parabolic mirrors and a ton of water for steam is just as bad as slapping up a WalMart mega-store.

Fragile habitat for various species that inhabit the Mojave Desert and other desert southwest areas where the sun shines brightly, just begging to be utilized for solar energy, has called in groups like the Sierra Club to litigate against proposals for solar energy development.  Sure, solar power can bring green jobs and reduce our carbon emissions.  But when the politics of solar power come into play, the result can be abandonment of U.S. development to countries like China, where environmental opposition is less likely to occur.

As the U.S. and the world struggle to address issues related to global climate change and finding new, reliable sources of energy, many are finding it ironic that environmentalists are the ones often opposing clean power like solar and wind.  I’ve been a land use attorney since 1994 and my view is that some of these groups and individuals simply oppose development of any kind or nature, no matter its overall purpose or goal.  Yet, the land use development systems in the United States (at the federal, state and local levels) allow for citizen input, detailed environmental review and a siting process intended to insure that proposed development is appropriate in scale and for its location.

All development will have some impact.  You simply cannot site any construction without change.  The question becomes one of balance, mitigation of impacts and a long-term vs. short-term consideration.  Let the debates continue.  The politics of solar power have an appropriate place and open discussion is the hallmark of any political process in this country.  But, hopefully, we can all agree that coal plants need to be replaced with utility scale solar (and wind, hydro and even nuclear).

Solar development plans scaled back to protect the desert tortoise

The solar debates in the Mojave Desert have pitted green vs. green.  Proponents of renewable energy look at the vast expanse of land in sunny Southern California as a great location to generate solar electricity.  But concerns over the fragile habitat of the endangered desert tortoise have had some people seeing more red than green.  The clash in California appeared to be at an impasse.

But this week, Brightsource Energy announced it would scale back its proposed solar thermal power plant in order to protect the desert tortoise.  The move comes in response… and in an effort to compromise with… the environmental groups who have voiced concerns over the impact of utility scale solar projects in the region.

Instead of a three-phase project that would have covered five square miles of the Mojave Desert and produced 400 megawatts (MW) of solar electricity, Brightsource will significantly reduce the size of the planned Ivanpah solar power plant.  Overall area of the plant will be cut down by 12%, the third phase will be reduced by 23%, and only one power tower, instead of the five towers originally planned, will be constructed.

For an idea of the scope and scale of a solar thermal power plant, consider this video of a similar Brightsource Energy plant:

With respect to Brightsource Energy’s proposed plant in the Mojave Desert, the overall amount of the reduction is not as important as the location of the cut backs.  Specifically, the announced changes will carve out specific sections of land that would have required a significant amount of grading.  Now, the desert tortoise will not lose important desert flora and fauna, rocks and natural water features on which it relies for its habitat.

Defenders of Wildlife estimate that the population of the desert tortoise has decreased 90% in the last 50 years.  Many believe that there are less than 100,000 of the creatures alive today:

The reduction in size and scope of the Ivanpah solar thermal plant is probably not the last.  Developers of concentrated solar power projects have been considering and proposing projects that can be sited closer to the urban areas that demand electricity in order to minimize environmental impacts… and delays in permitting.

As environmental pressures mount from a number of different directions, the balancing act of all concerns may become more challenging.  Utility scale solar requires a great amount of land, but can efficiently power thousands of customers.  Greater numbers of smaller plants would be required, but perhaps at a savings with respect to the environmental cost.

Your perspective?

Solar mirrors in Spain

Solar mirrors, the reflective surfaces that are used for concentrated solar power, are manufactured right here in the USA.  Utility-scale solar power, generated by CSP – also known as thermal solar power – is used in California, Nevada, Spain and will soon be constructed in the Sahara Desert.

Many of these facilities use FLABEG solar mirrors.

Also known as parabolic panels or solar thermal collectors, solar mirrors are installed on the ground to reflect solar energy towards hot water tanks.  The water is then superheated to produce steam, which turns turbines and generates clean, green electricity.

In Pittsburgh, PA, a new solar mirror manufacturing plant was opened last week by German company, FLABEG.  The corporation now owns and operates 11 factories worldwide, focused on supplying fine glass products.  As announced on its website:

FLABEG doubles its capacities for solar mirrors. Starting in late 2009, the full range of high performance mirrors for concentrating solar power (CSP) will be manufactured on a production area of 22,465 sq.m. FLABEG’s product range then covers all solar technologies, including parabolic trough power plants, power tower, linear Fresnel and parabolic dish applications. FLABEG Solar chose Allegheny County because of its skilled work force, and 200 jobs will be created in the Clinton Commerce Park. FLABEG’s strength is the application of new technologies using innovative methods to provide renewable solar energy for our future.

The new FLABEG solar mirror plant has created 300 new green jobs in the region.  Located in the Clinton Commerce Park, near the Pittsburgh International Airport, the 209,000 square foot facility is already up and running.  First solar mirror production orders will be shipped this month.

The new solar mirror plant has a greater product range than some of the company’s other operational plants.  I was surprised to read the following from the FLABEG website:

These days, concentrating solar power (CSP) is the only solar technology that could achieve the level of output required to replace fossil-fueled and nuclear power plants. The first nine privately funded plants of this nature (SEGS I-IX), which are still in commercial service, were built between 1984 and 1991 in California’s Mojave Desert – and fitted with FLABEG mirrors. Though this was quite a success story, it was a good fifteen years before the next CSP project came to fruition.

If you live in the United States and want more information about the FLABEG solar mirrors plant, be sure to contact:

FLABEG Technical Glass
U.S. Corporation
Church & Bridge Street
Po Box 71
Naugatuck, CT 06770
Connecticut
USA
Tel. +1 203 – 729 5227
joe.bonessi@flabeg.com