Professor Dan Zaslavsky and Dr. Rami Guetta from Technion-Israel Institute of Technology are trying to develop an idea first patented by Phillip R. Carlson in 1975. In what is known as a downdraft energy tower, water is sprayed onto solar heated air at the top of a hollow tower. Now cooled and denser, this air falls rapidly to the bottom of the tower where it drives turbines and generates electricity. Annapolis Maryland – based Clean Wind Energy Tower, Inc (CWET) has plans to build two such towers near the US – Mexican border in San Luis, Arizona. At 3000 feet, the tower’s height will surpass Burj Khalifa, but unlike most skyscrapers, this one is designed to give more than it takes, in the form of clean electricity.

[youtube]http://www.youtube.com/watch?v=Iftbh_Nj9Tk[/youtube]

Downdraft energy towers…an idea so bold, so fantastic, so crazy…

At first glance, this idea seems incredibly simple when compared with mile deep oil rigs and nuclear reactors.

There are significant technical challenges to building any 3000 foot high structure, much more so when the tower contains an artificial thundercloud and generates electricity.  Evaporative-cooled downdraft towers such as this require a very dry climate.

The deserts of the US southwest, the Mideast and North Africa seem ideal for this, but that cooling water has to come from somewhere.  So designers have proposed that saltwater should be used to cool the air.

The side benefit is that this could become part of a desalination system, the downside is corrosion of turbines and structural components.

Another problem is that it takes energy to pump water 3000 feet into the air, about a kilowatt-hour for every 1000 liters pumped.  To compensate for this loss, Zaslavsky and Guetta proposed to install vertical wind turbines into the walls of the tower.  Their models show that it should be possible to generate electricity for between one and four cents per kilowatt-hour.

Energy Towers might just work

Of course there must be careful planning of water usage, environmental impact, distance from energy consumers, cradle-to cradle carbon footprint.

But if this project succeeds, it will pave the way for all of us.  Solar energy, reusable grocery bags and buying local will no longer seem like such far-out lunatic ideas.

As Green Prophet’s Tafline Laylin pointed out, Israel is a world leader in producing green technology which is used everywhere except Israel.  So if this bold Mideastern idea comes to fruition, San Luis, Arizona USA will have bragging rights.

Clean Wind Energy Towers, Inc already received approval to lease land for this project and began seeking zoning approval a few days ago.  But in the strange world of business economics, their progress was taken as bad news and CWET shares plummeted.

Clearly this project is not for the faint of heart but hey– the US is a country which sent men to the moon.  This is a country which boldly flings hundred billion dollar bailouts in the same way circus clowns toss candy.

Just a stone’s throw from the tower’s proposed site in San Luis is a three layer 18-foot high stretch of wall fence which extends for 87 miles to the west and 379 miles to the east.

This is a nearly completed portion of a $6 billion wall which is designed to protect this bold country from stone-throwing Mexican teenagers.  Nevermind the fact that teenagers can climb it in 20 seconds, assuming an average height of 3 meters over its length gives an area of approximately 2 million square meters for the San Luis section of wall.

So if Mexican teenagers glued solar panels onto their side, the wall would generate about 600 Megawatts of electricity.  The panels would cost $500 million at Chinese “dumped” photovoltaic prices, a fraction of what the US paid for that ungreen concrete and steel wall and probably less than the stock market dips every time Ben Bernanke blows his nose.

Even if it never generates as much electricity as Mexico’s photovoltaic border wall would, this 3000 foot high energy tower is already a success.  It helps us think outside of the wall box.

::Clean Wind Energy

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Cogenra was founded by Dr. Gilad Almogy, with a BSC in Physics and Mathematics from the Hebrew University in Jerusalem, Israel, and the inventor of over 30 registered US patents. Before founding Cogenra, which Vinod Khosla also had a hand in creating, Almogy was a senior VP of the Display and Thin Film Solar Products at Applied Materials (AMAT).

His innovative solar cogeneration (making heat and electricity from solar power) succeeds in bringing solar power costs down to the level of fossil fuels – but without those catastrophic health and climatic side effects!

Because it simultaneously eliminates both traditional electricity from a utility, and the gas used to heat water, it eliminates greenhouse gas emissions at nearly three times the rate of traditional PV and at twice the rate of solar hot water alone.

By producing both electricity and hot water, Cogenra’s unique hybrid solar system extracts five times the net energy, and at 80% efficiency; actually outdoes ZenithSolar, another solar cogeneration company born in Israel, and now making inroads overseas (72% Efficient ZenithSolar Gets Demo Down Under)

This week his company Cogenra will announce a contract to supply the Southern Arizona retirement community La Posada with a solar cogeneration system, making it sustainable to host a retirement community in the arid desert. Formerly La Posada had high energy costs resulting from its position in the desert – and future energy uncertainty.

Arizona depends on nuclear power, but nuclear cannot take the heat that represents the climate future of Arizona. Dry spells and climate change have shut down nuclear plants around the world: rivers are running at record heat in the US, and nuclear is constrained to stop operating when the rivers they discharge to reach temperatures over 86 degrees. So nuclear power is unsustainable in a hotter future.

Because solar eliminates the ongoing expenses for increasingly unpredictable and unknown energy costs in Arizona, any solar displacement of electricity bills is ideal for its retirees, who need to live a long life on a fixed income. Buying solar upfront takes energy out of the cost equation, bringing real security to seniors.

Cogenra also offers a contract-for-energy-produced option, where a company would just pay for power by the hour. That is through Cogenra’s Heat & Power Purchase Agreement (HPPA) which provides predictable long-term energy costs without upfront expense, debt or ongoing maintenance exposure. The company is confident enough that their technology delivers at the cost advertised that they are willing to back it themselves by selling the power it produces at a fixed rate.

How it works:

A long narrow array of solar photovoltaic cells face downwards towards the reflected and highly focused sunshine bounced up by the mirrors. Above the solar array is the tube that carries the liquid being heated by the same intense focused sunlight. It removes the heat for use in solar hot water.

As with PVT’s Echo, the hybrid solar co-generation technology also solves a problem with solar PV: that it is somewhat less efficient when it is too hot. Solar electricity can be more efficient in Minnesota on a snowy day than in Arizona during a heat wave, because solar panels produce more power when they are not overheated.

The liquid is constantly removing the heat built up behind the solar panels, siphoning off heat so that the panels produce at their optimum. Nevertheless, the heat production versus the solar electricity production is about four to one: making these ideal for businesses like large industrial food processors, hotels, laundromats and restaurants: that need to make four times more hot water or heat than electricity.

::Cogenra

Read more on solar energy from Israel:

One Solar Cell. 2KW Power. 5KW Heat. ‘Nuff Said?
Forbes Names Israel’s Shari Arison As One of the World’s Greenest
Gonen Fink’s Pythagorean Theorem: a Skylight that Makes Electricity

The post Cogenra Solar Brings Heat&Power to Arizona’s La Posada appeared first on Green Prophet.