Solar energy

Pima County Az tilting at climate change

In the novel “The Ingenious Nobleman Mister Quixote of La Mancha” by Miguel de Cervantes, first published in 1605, the protagonist, Don Quixote, imagines that windmills are giants to be destroyed. Don Quixote attacks the windmills with his lance, an action called “tilting,” all to no avail. From this story comes the idiom “tilting at windmills” which means confrontations where adversaries are incorrectly perceived, or courses of action are based on misinterpreted or misapplied heroic, romantic, or idealistic justifications. We can add the motivation of political correctness to the Pima County, Arizona, plan to reduce carbon dioxide emissions.

Since President Trump has withdrawn the U.S. from the Paris Climate Accord, Pima County Supervisors have approved their own version of the Paris Accord and pledge to reduce the County’s carbon dioxide emissions.

In a previous article, “Impact of Paris climate accord and why Trump was right to dump it” I show that if all countries fully comply with their promises under the Paris Accord, it would make a difference of only 0.17°C by the year 2100.

According to an article in the Arizona Daily Star, Pima County government will attempt to cut its greenhouse-gas emissions by 42 percent from current levels by 2025, mainly by using more solar energy. The county government will attempt to get 40 percent of its electricity from very unreliable solar generation. The county will also buy 20 new electric-powered sedans for its vehicle fleet a year, at $30,000 to $40,000 apiece.

These electric vehicles are much more expensive than gasolene-powered versions of the same model. According to a new paper published in the journal Issues in Science and Technology entitled Electric Vehicles: Climate Saviors, Or Not?, driving an electric vehicle rather than a conventional petroleum-powered vehicle effectively does nothing to reduce global-scale CO2 emissions. The net carbon dioxide emissions depend greatly on how the electricity for recharge is generated.

The Star story also notes that the county government’s share of regional greenhouse gas emissions is minuscule. It generated less than 0.1 percent of all emissions produced in eastern Pima County in 2014.

In my opinion, Pima County’s action with regard to reducing carbon dioxide emissions is simply a quixotic exercise in political correctness that will have absolutely no effect on global temperature nor on Tucson temperature. The action also diverts taxpayer money from projects that would actually benefit county citizens, such as repairing roads.

“In climate research and modeling, we should recognize that we are dealing with a coupled non-linear chaotic system, and therefore that the prediction of a specific future climate state is not possible.” — Final chapter, Third Assessment Report, IPCC.

See also:

A Simple Question for Climate Alarmists which asks: “What physical evidence supports the contention that carbon dioxide emissions from burning fossil fuels are the principal cause of global warming since 1970?” Expert climate scientists can’t cite any such evidence.

Evidence that CO2 emissions do not intensify the greenhouse effect

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Pima County solar project raises questions

Pima County has contracted to buy $22 million worth of solar-produced electricity over a period of 20 years from Solon Development, a company which received a no-bid contract from the County. Solon will built 11 solar arrays over parking lots.

Pima County will pay a fixed price of 12.8 cents per kilowatt over the life of the contract, versus 12.1 cents per kilowatt the County now pays to Tucson Electric Power (TEP). Doing a little math shows that while the TEP price remains at 12.1 cents, the County (taxpayers) will be spending about $60,000 more per year for electricity under this deal. Pima County, however, claims there will be a savings of $4.5 million over the life of the contract.

How did the county come up with that number? It seems that Solon Development has a crystal ball. They published a chart (see below) of anticipated TEP rate hikes (see column F). A call to TEP reveals that even TEP doesn’t know what its future charges will be. Any rate changes must be approved by the Arizona Corporation Commission. Here is the chart:

Solon rate estimate

There is something suspicious about Solon and the timing of the contract. The Arizona Daily Star characterized Solon as a local company and, indeed, they have a office in Tucson. But here is what I think needs more explanation: Solon Development, LLC was created on April 17, 2015 and the County awarded it a contract on May 5, 2015, less than three weeks later. What went on behind the scenes for such an apparently rapid decision? The graphic below shows the incorporation notice:

 Solon creation

Although Solon is touted as a local company, creating the impression of awarding jobs locally, Solon is actually part of a company based in the United Arab Emirates (UAE). Here is the chain of ownership:

While “Solon Development, LLC” may technically be local, it is actually a subsidiary of Solon Corporation, a German company. According to Solon Corporation website, their legal address is SOLON Energy GmbH, Am Studio 16, 12489 Berlin, Germany.

Also on their website, they brag: “Founded in 2007, SOLON Corporation is a subsidiary of the SOLON Group, a leading international provider of solar solutions for residential, commercial and utility-scale applications. The SOLON Group, one of oldest pure play solar companies in operation, was established in 1997 and operates subsidiaries in Germany, Italy, Australia, India and the U.S.”

Solon would seem to have a great deal of experience. So why did they go bankrupt? According to a story in Greentech Media, “Solon joined Solyndra, Evergreen Solar, and SpectraWatt in 2011’s bankruptcy pool.” But that’s not all. The story goes on to say “The next chapter in the Solon saga was announced today [March 6, 2012]. Microsol, a vertically integrated United Arab Emirates (UAE)-based cell, module and system manufacturer, acquired essential components of the insolvent Solon SE and its subsidiaries, including U.S.-based Solon Corporation.”

So, our very own local company is not so local.

Was Pima County in negotiations with the parent company before creation of Solon Development? In the chart above, does the expected performance (column A) take into account that PV solar panels typically produce only about 20% of its rated capacity? Will County taxpayers really save money?

Is a proposed Tucson Metropolitan microgrid of solar energy a good idea?

A guest opinion in the Arizona Daily Star (Jan. 23, 3015) by Terry Finefrock proposed that Tucson build a system of photovoltaic solar energy facilities and connected electrical storage units (see article here). Finefrock claims “By using rapidly developing energy storage equipment on feeder circuits we can manage fluctuations in demand or supply, essentially creating a metropolitan microgrid.” He also claims that photovoltaic generation of electricity is less expensive than fossil fuel generation.

I emailed him asking what”rapidly developing energy storage equipment on feeder circuits” was and whether such equipment is at a stage sufficient for commercial deployment. He responded the same day referring me to http://www.greentechmedia.com/. The answer seems to be a whole bunch of batteries.

At the website, I found a story on British pumped hydro storage (not likely to work in Tucson); a story saying “General Electric is significantly scaling back production of its sodium-ion Durathon batteries, a move that comes amid what the company says is a slow-to-develop market for grid-scale energy storage”; and a story on “Faulty Solar Panels Are Creating ‘Uncertain Risk’ for Chinese PV Projects.” I searched the site for the word “storage” and got several more articles about batteries connected to the grid.

I know from other sources that several schemes are in the works. For instance, a solar-thermal plant in Gila Bend proposes to store excess heat in molten salt containers that they claim will provide 12 hours of generation. Tucson Electric Power was also planning a solar-thermal system with heat storage in Tucson. But what happens if it is cloudy two or three days in a row?

The biggest problems with solar and wind electrical generation, other than cost, is their intermittency and unreliability. Solar panels can deliver significant energy only from 9am to 3pm on a clear day – a maximum of 25%of the time. A good storage system for electricity could possibly help extend that time, but much of solar’s peak generation would need to be used for recharging the storage equipment rather than providing for consumer demand.

Typically, solar systems provide less than 25% of their rated capacity whereas fossil fuels provide at least 85% of their rated generating capacity according to the Energy Information Administration (EIA). This is what EIA calls capacity value “which depends on both the existing capacity mix and load characteristics in a region. Since load must be balanced on a continuous basis, units whose output can be varied to follow demand (dispatchable technologies i.e. fossil fuels and nuclear generation) generally have more value to a system than less flexible units (non-dispatchable technologies such as solar and wind), or those whose operation is tied to the availability of an intermittent resource.”

Dr. John Morgan, Adjunct Professor in the School of Electrical and Computer Engineering at RMIT (Australia), claims “energy storage cannot solve the problem of intermittency of wind or solar power. Not for reasons of technical performance, cost, or storage capacity, but for something more intractable: there is not enough surplus energy left over after construction of the generators and the storage system to power our present civilization.” Morgan claims that the energy required to manufacture and operate solar photovoltaic systems and battery storage for electricity is about equal to the energy produced over the life of the facility, so there is little to no net energy produced. (See article here)

In the Star article, Finefrock claims that solar energy is less expensive than coal or natural gas fueled generation, but he seems to ignore manufacturing and capital costs for solar systems and batteries.

The U.S. Energy Information Administration (EIA) takes a different view when comparing energy sources. They use a metric called “Levelized cost of electricity (LCOE)” which “represents the per-kilowatt-hour cost (in real dollars) of building and operating a generating plant over an assumed financial life and duty cycle. Key inputs to calculating LCOE include capital costs, fuel costs, fixed and variable operations and maintenance costs, financing costs, and an assumed utilization rate for each plant type.”

In EIA’s latest report, they estimate LCOE for solar photovoltaic to be 230 $/MWh, and solar thermal at 243 $/MWh versus 96 $/MWh for conventional coal and 66 $/MWh for conventional natural gas.

As to the question in the article title, a microgrid connected storage system is technologically possible, but given the facts that solar energy is unreliable and expensive; that storage equipment is expensive and could provide a backup for only a limited time; and that a very large number of batteries to make it beyond a few days would take most of the PV output to charge them, it makes little sense to retire fossil-fuel fired plants in favor solar energy as Finefrock suggests.

UPDATE:

From Carmine Tilghman is senior director of wholesale, fuels and renewable energy for Tucson Electric Power in response to editorial by Terry Finefrock:

“We must also abide by economic realities and proven facts, including the higher cost and lower reliability of solar power. Such concerns do not burden everyone who takes an interest in energy issues. Last week, a Terry Finefrock (“Economic development: Start with a Tucson microgrid,” Jan. 23) offered a series of misleading assertions about energy costs and issues. Energy-storage systems are not yet capable or cost-effective enough to provide an alternative to the constant support and backup capabilities of a utility’s local electric grid.” Read full article at http://tucson.com/news/opinion/column/guest/response-to-assertions-made-about-energy-s-costs-systems/article_c6bda9a8-6bd7-52f9-a08d-99f823e608db.html

See also at the Arizona Daily Independent:

Impact of Solar and Wind Electricity Generation – the European experience is that “green” energy is turning out to be 10 to 100 times more expensive that originally thought.

Top Google Engineers Say Renewable Energy ‘Simply won’t work’

Avian mortality from solar farms

See more on Wryheat::

Solar energy cannot economically compete in electricity generation

The economic impact of Arizona’s renewable energy mandate

Does alternative energy actually replace fossil fuel consumption? In a study from 130 countries, it was found that each unit of electricity generated by non-fossil-fuel sources displaced less than one-tenth of a unit of fossil-fuel-generated electricity.

Top Google Engineers Say Renewable Energy “Simply won’t work”

Google Corporation has been in the forefront of developing renewable energy projects. One of their goals was to run Google completely by renewable energy.

Google is part owner of the infamous Ivanpah solar station, west of Las Vegas, the plant that fries birds and needs to use natural gas to produce electricity, but even with use of natural gas the plant produces only one quarter of the advertised electricity. See these stories:

Avian mortality from solar farms

Ivanpah solar plant wants to burn more natural gas

Ivanpah solar seeks government grant to pay off government loan

A few years ago, Google started a project called RE<C, which aimed to develop renewable energy sources that would generate electricity more cheaply than coal-fired power plants do.

“At the start of RE<C, we had shared the attitude of many stalwart environmentalists: We felt that with steady improvements to today’s renewable energy technologies, our society could stave off catastrophic climate change. We now know that to be a false hope… As we reflected on the project, we came to the conclusion that even if Google and others had led the way toward a wholesale adoption of renewable energy, that switch would not have resulted in significant reductions of carbon dioxide emissions.” (Source)

Now, after 4 years of effort, Google engineers who led the program conclude the research effort by Google corporation has been a complete failure, renewable energy “simply won’t work.”

“The key problem appears to be that the cost of manufacturing the components of the renewable power facilities is far too close to the total recoverable energy – the facilities never, or just barely, produce enough energy to balance the budget of what was consumed in their construction. This leads to a runaway cycle of constructing more and more renewable plants simply to produce the energy required to manufacture and maintain renewable energy plants – an obvious practical absurdity.” (Source)

The State of Arizona has not yet realized that renewable energy “simply won’t work.” They persist in imposing the State’s Renewable Energy Mandate and Tariff which has raised our electricity rates. December is a good time to write to your state legislators asking them to repeal the mandate. In December the members are composing new legislation for the upcoming legislative session.

For some background and ammunition to repeal the mandate, see my ADI article:

Five reasons Arizona should repeal its renewable energy standards mandate

Ivanpah solar plant wants to burn more natural gas

In a previous article, Avian mortality from solar farms, I featured the Ivanpah generating station, in the Mohave Desert southwest of Las Vegas, which uses 173,500 heliostats each with two mirrors to focus sunlight on three towers where water is converted to steam to generate electricity. This method is called “solar-flux” and it generates very high temperatures. Birds experience traumatic impact with the mirrors, but the larger danger is getting singed by the heat flux which is up to 800 degrees F.

Ivanpah1

But since the sun doesn’t shine all the time, the plant uses natural gas to keep the water hot. And, apparently, there hasn’t been enough sun to do that.

Bright Source Energy, the company operating the plant, is petitioning the California government, requesting permission to burn more natural gas and to emit 94,749 more tons of carbon dioxide per year. That’s the equivalent of emissions from about 16,500 automobiles. (See full story at the Hockey Schtick)

If the permit is approved, then this “solar” plant will produce about 35 percent of its electricity from fossil fuels.

The Hockey Schtick blog notes:

“The plant cost $2.2 billion and has a ‘gross capacity’ of 392 MW [but may actually perform at a much lower average capacity], thus a minimum cost of $5.64 million per MW capacity.

By comparison, a 650MW gas turbine power plant can be built for around $630 million and run 24/7/365 without requiring fossil-fuel back-up, a cost of $0.97 million per MW or about 6 times less. Since ~35% of the proposed plant output would be from fossil fuels, the solar maximum capacity would be ~255 MW, increasing the cost for the actual solar-derived energy to ~8.6 times higher than a conventional gas turbine power plant [which has much lower greenhouse & particulate emissions than firing boilers in the Ivanpah plant].”

Another problem with the facility is that airline pilots are complaining that they are being blinded by the glare from the mirrors (see, for example this Breitbart story).

As Kermit said, it isn’t easy being green.

(This story originally appeared in the Arizona Daily Independent.)

Book Review – Let It Shine, The 6000-year Story of Solar Energy by John Perlin

Let it shine coverPerlin’s history of solar energy use is very interesting.  The book is rich in historical incidents and illustrated with old photos and drawings.

Perlin divides the book into six sections.  He begins Part 1 of his tale by discussing how the ancient Chinese, Greeks, and Romans designed their buildings to take advantage of solar heating in winter and to minimize over-heating in summer.  He discusses “burning mirrors” used to concentrate the sun’s rays to start fires, heat objects, and even as weapons of war.  Some of that evolved to using lenses to concentrate the sun.  The Romans used glass to trap heat, but after the fall of the empire, this was abandoned because hard times required defensible homes and besides the Church frowned on growing exotic plants outside their natural habitat.  However, by the sixteenth Century, the influence of the Church was broken and greenhouses started to be used.  A good thing too, because during the period 1550 to 1850, called the Little Ice Age, growing seasons were very short.  Another technique was to grow plants near a heat-absorbing brick or stone wall.   Perlin discusses various methods of glass-making and greenhouse design.

Part 2 deals with the history of  solar syphons and engines used mainly to pump water. Of course, the problem with most of these contraptions is they didn’t work at night or on cloudy days.  There were, however, a few installations that stored heat during the day to run, or partially run, the motors at night.  However, such installations were much more expensive to build than conventionally fueled plants.  World War I interrupted some grand schemes and cheap oil available after the war caused investors to lose interest.  Perlin also mentions use of solar evaporation to produce salt.

Solar water heating is the subject of Part 3.  “The story of solar water heating begins in the nineteenth century when Europeans and Americans began to bathe on a regular basis.” Perlin first describes conventional, in home systems, then moves on to solar water heaters. He provides many drawings of the devices he describes. Within this section, Perlin has a chapter on the solar still, a device used by downed-airmen to desalinate sea water.

I note here that solar energy provides about 85% of the hot water needs in my home (the rest is from natural gas).

Part 4 deals with the history of using solar energy to heat homes.  In Europe, knowledge of proper house citing to take advantage of the sun was seemingly lost after the fall of the Roman Empire, and cities were built without regard to structural position relative to the sun. But ancient knowledge was revived and improved upon during the “Enlightenment” beginning ca. 1800.  The basic principle is to have large windows facing south-southwest (in the northern hemisphere), to take advantage of the low winter sun angle to heat the house.  During the summer, the high angle of the sun does not penetrate much into the structure.

In America, solar architecture was practiced early on by the Pueblo Indian tribes of the Southwest.  The Spanish colonials also practiced proper solar orientation of structures as did settlers in New England with the “saltbox” style of housing.  There was much experimentation and refinement ( and controversy) with solar architectural techniques.  In this section Perlin discusses various types of solar collectors.

Part 5 deals with the discovery of the photovoltaic effect and the development of photovoltaic solar collectors.

Part 6 deals with what Perlin calls the post-oil embargo era.  For 30 years after World War II, oil and gas were abundant and inexpensive. The U.S. government was providing encouragement for nuclear power, “atoms for peace” but provided little or nothing for solar energy research.

The modern solar movement may have been born on “Sun Day” in 1978 according to Perlin.  Reports of the time said the solar movement “has some of the attributes of a political movement.”  Solar pool heating made inroads in the 70’s and 80’s.  The counterculture embraced solar energy and solar architecture was rediscovered.

The oil embargo of October, 1973, brought great disruption.  The Arab’s cut back on oil exports as a reaction to U.S. support of Israel in the Yom Kippur War. This was also the time that “peak oil” predictions began, i.e., concern that we were using oil faster than new reserves were being discovered. (Shale oil and gas and vast new resource discoveries on the continental shelf have put the “peak oilers” out of business.) Nevertheless, at the time, there was more interest in alternative energy sources and solar energy was one of them.  There was much interest and many  schemes for equipping homes and businesses with photovoltaic arrays and solar collectors to produce electricity and heat.  Perlin describes the various programs, public and private, and the development of solar cell technology.

Overall, this is a very interesting book on the development and use of solar energy through the ages.  I was somewhat put off by the Forward to the book, written by Amory Lovins, chief scientist at the Rocky Mountain Institute, which struck me as  mainly propaganda that made some questionable claims. For instance, he claimed that renewable energy projects, mainly wind and solar, receive subsidies smaller than nonrenewable energy projects get. That may have been in the early days but CBO data shows that is not true, at least since 2008, see: http://www.cbo.gov/publication/43032

Perlin takes a dim view of utility scale solar electricity generation because of its high cost.  He prefers dispersed arrays on individual buildings.  Indeed, the cost of electricity produced by utility-scale arrays is much higher than from conventional generation (see my post “Solar energy cannot economically compete in electricity generation“).   There is also the inconvenient fact that the footprint of solar and wind farms is very large. (See my post “The Scale Problem.)

This book is a recommended read.  It can be found at Amazon, and at Barnes & Noble.

Solar energy cannot economically compete in electricity generation

The Arizona Corporation Commission has imposed a renewable energy mandate that requires electric utilities to produce 15% of electricity from renewable resources by 2025.  In Arizona the utilities are turning mainly to solar power to meet the requirement.  That policy means that the cost of generating electricity and our electric bills will soar.  Who benefits?

The graph below shows the relative costs of producing electricity by various means.  The data are from the U.S. Energy Information Administration’s Annual Energy Outlook for 2011. (Link).  The data were graphed by Willis Eschenbach.  The costs are in cents per kilowatt hour. The blue part represents capital and transmission costs; the red part represents fuel, operation, and maintenance costs.

estimated-levelized-cost-new-gen-resources-20161

As you can plainly see, solar energy is much more expensive and would not be considered for utility-scale electricity generation were it not for government mandates and subsidies.  Another problem with solar generation is that it requires backup power because even in Arizona, the sun doesn’t shine all the time.  Solar plants typically produce just a fraction of their rated capacity.  For instance, TEP operates one of the largest solar PV arrays in the United States, a 5-MW system. But over two years of operation, the capacity factor for that generator has averaged 19%, meaning it produced only 19% of its rated capacity most of the time.

One of the rationales for using solar (and wind) energy is that it is supposed to reduce our carbon dioxide emissions, but that isn’t necessarily so if the backup generation comes from fossil-fuel powered plants.  A study in the Netherlands shows that the intermittent generation by wind actually increases carbon dioxide emissions because the fossil fuel-run backup generators have to cycle up and down constantly rather than being run efficiently at a constant output.  That cycling uses more fuel. (Note, the study was specific to wind power, but it could be applied to intermittent solar power also due to variable generation on cloudy days.)

Some may argue that the cost of solar cells is rapidly falling.  But, the cost of the cells themselves is a small part of what goes into a utility scale power plant.

Our modern society depends upon having a reliable source of electricity.  Wind and solar generation are not reliable.  As we increase our dependence of these unreliable sources we increase the risk of electrical brownouts or blackouts which disrupt vital services and commerce.

Perhaps our corporation commissioners think they are doing the right thing for the planet, but their benighted mandate may actually be doing the opposite because it ties up money and resources that could perhaps be put to better use to help solve real problems.  Again, who benefits?

Our state legislators should repeal the renewable energy standards mandate and let the utility companies produce electricity by less expensive and more reliable means.

Then we will see whether or not the utilities employ solar energy voluntarily.

See also:

APS wants electric energy efficiency to cost more

Arizona Corporation Commission May Ration Electricity

Smart Grid may ration electricity

Will you let the power company control your air conditioner?

Could Gila Bend, Arizona, Become the Solar Capital of the World?

The headline of this post is the headline of a Department of Energy press release.  Gila Bend, Arizona is a town with a population of about 2,000 and given to growing cotton and alfalfa.

Gila-bend-300x243Currently First Solar (Paloma project) and Cotton Center have solar plants under construction that will provide Arizona Public Service with enough electricity to power 9,000 homes so they claim.  Several other companies have permit applications pending.

According to the article, “the town government [is expediting] the speed at which solar companies’ construction plans could get approved. Processes that usually take at least a year, and often several years, can now go through public hearings, citizen review sessions, planning and zoning commissions hearings, publication in a newspaper, and council approval in as little as four weeks.” See complete press release here.

First Solar, a Tempe manufacturer of solar panels,  is one of the companies that received loan guarantees just one day before the federal program expired.  Cotton Center is getting its solar panels from Solon Corp. in Tucson.

These two photovoltaic plants join the Solana plant which is a concentrating thermal solar facility that broke ground near Gila Bend in December, 2010, aided by a $1.45 billion federal loan guarantee.

This boomlet of solar installation is funded by taxpayer subsidies and is a result of the state’s renewable energy standards mandate that require electric utilities to produce at least 15% of their electricity from renewable resources by 2025.

In general, electricity production from solar power is much more expensive than from coal or natural-gas fired plants . (see National Renewable Energy Standard Will Mean Higher Electricity Bills).  Already I can see extra fee charges on my electric bill from Tucson Electric Power.

Two 2500-foot solar towers to be built in Arizona

I first wrote about solar towers in August, 2009. Now, Southern California Public Power Authority (SCPPA) says they have agreed to buy power from two 2,500-foot towers to be built between the towns of Parker and Quartzsite in La Paz County, Arizona, with construction to start in 2012.

lapaz_img1

 h tower will be surrounded by a mile-wide greenhouse designed to heat air, which will then rise through the tower after passing through turbines. The rated peak capacity will be 200 megawatts for each tower.

According to SCPPA, “The Solar Tower facility is anticipated to generate more than 1,000,000 MWhs of renewable energy per year.” The towers were developed and will be built by an Australian company, EnviroMission. I could not find figures on the exact cost, but an October, 2010, estimate by Phoenix Business Journal puts the figure at somewhere between $700 million and $1 Billion. In December, 2010, the Arizona Republic put the cost at $750 million for one tower. That capital cost works out to about $3,750 per Kwh capacity. To put that in perspective, coal plants cost abut $3,167 per Kwh, natural gas plants cost about $1,003 per Kwh, and solar voltaic plants cost about $4,755 per Kwh according to the Energy Information Administration. So far there are no data on how much of the peak capacity will actually be available. Availability is generally near 90% for fossil fuel plants and less than 25% for solar voltaic plants.

If built, the towers will be the tallest structures in the U.S. and second only to the Burj Khalifa skyscraper in Dubai.

Solar Updraft Towers, an alternate, alternative energy source

solar-towerA solar updraft tower collects warm air that forms near the ground, funneled by a canopy, and sends it up a chimney. Turbines in the airflow produce electricity.

I was first made aware of this device from the blog of Dr. Roy Spencer, Principal Research Scientist at the University of Alabama in Huntsville and former Senior Scientist for Climate Studies at NASA’s Marshall Space Flight Center.

Spencer says, “It’s a little like wind tower technology, but rather than just extracting energy from whatever horizontally-flowing wind happens to be passing by, the Solar Tower concentrates all of that warm air heated by the ground into the central tower, or chimney, where the air naturally rises. Even on a day with no wind, the solar tower will be generating electricity while conventional wind towers are sitting there motionless.” And it works at night.

“The total amount of energy that can be generated by a Solar Tower depends upon two main factors: (1) how much land area is covered by the clear canopy, and (2) the total height of the tower.” It also depends on the temperature difference between the power plant’s surroundings and the air underneath the canopy.

A prototype was built in Spain a few years ago.

See here for a You Tube demonstration of this project.

A private company, EnviroMission, is constructing a 200 Megawatt solar tower in the Australian outback.

This technology may be economically competitive with coal fired power plants, unlike current wind or solar generation schemes.

In the Spanish test, they expected that the ground under the canopy would be barren due to the very high temperatures. However, they found that the greenhouse effect (a physical barrier to cooling, unlike greenhouse gases) caused condensation at night and produced lush vegetation under the canopy. Perhaps special crops could be grown at these stations.