First hybrid solar-wind renewable energy tower
The small Arizona border town of San Luis will be the site of the first Solar Wind Energy Tower installation in the world. The US$1.5 billion project would generate electricity through the use of ambient desert heat that passes through a concrete structure its proponents say would be the tallest in North America. When completed it will generate 425 megawatts of electricity each year. A typical home in Arizona consumes approximately 12 megawatt hours of electricity annually. Read More
Arizona town to get solar wind energy tower
Alan M. Petrillo, Special to Inside Tucson Business (11 August 2014):
The small Arizona border town of San Luis will be the site of the first Solar Wind Energy Tower installation in the world.
The $1.5 billion project would generate electricity through the use of ambient desert heat that passes through a concrete structure its proponents say would be the tallest in North America.
At 2,250 feet high, the Solar Wind Energy Tower looks similar to the cooling towers seen at nuclear power generating plants.
Ronald W. Pickett, president and chief executive officer of Solar Wind Energy Tower Inc., said he expects the plant, when completed, to generate 425 megawatts of electricity each year. The company has all local agreements in place, Pickett said, and is working to obtain a federal Environmental Protection Agency emissions permit, although the plant will have no carbon emissions, as well as a Federal Aviation Administration permit to get on the air charts because the structure is so high.
The San Luis city council approved participation in the project in April with the signing of a Development and Protected Development Rights Agreement that allows the energy company to purchase 640 acres from the city to site the plant. The agreement also calls for the city to provide untreated city water to the tower at the rate of 8,000 acre-feet of water per year for 50 years. The water would initially be provided at the rate of $1.15 per thousand gallons with a built-in cost of living escalator. An acre-foot is equivalent to 325,851 gallons of water.
San Luis is a 26-1/2-square mile city in Yuma County with a population of 25,505 on the United States border with Mexico, opposite San Luis Rio Colorado, Sonora. Retail trade, manufacturing and agriculture make up the bulk of the San Luis economy, along with light industry on both sides of the international border.
Tadeo De La Hoya, the city’s director of operations, said the agreement calls for Solar Wind Energy Tower to sell the city electricity at the lowest fixed rate, which is to be determined, for 20 years after it begins generating.
Advantages of the agreement for the city, De La Hoya said, “are that our tax base will be increased, meaning more tax revenue for the city, as well as for the three school districts in the area.” He continued, “No subsidies, tax credits or development incentives have been given in the agreement.”
Pickett pointed out that while Solar Wind Energy Tower is buying 640 acres, the tower and its associated facilities will only cover a fraction of that space.
“Besides the tower, there would be a guard house, personnel and administration building, a water retention pond, a maintenance facility and relay stations for the power,” Pickett said. “We expect to be generating on an annualized basis more power than the Hoover Dam currently generates — more than 4 million megawatt hours.”
A typical home in Arizona consumes approximately 12 megawatt hours of electricity annually, according to the U.S. Energy Information Administration.
Pickett said the Solar Wind Downdraft Tower is the first hybrid solar-wind renewable energy technology in the market. The patented structure is made up of a tall hollow cylinder with a water injection system near the top and wind tunnels containing wind turbines near the bottom.
A series of pumps deliver water to the tower’s injection system at the top where a fine mist is cast across the entire opening. The water introduced by the injection system, Pickett said, then evaporates and is absorbed by hot dry air which has been heated by the sun’s solar rays.
The result is the air becomes cooler, denser and heavier than the outside warmer air, and falls through the cylinder at speeds up to and in excess of 50 miles per hour. This air then is diverted into wind tunnels surrounding the base of the tower where turbines inside the tunnel power generators to produce electricity.
Pickett said he expects the project to have 60 tunnels with 120 turbines and 30 generating rooms. Eleven generators in each generating room each will produce from 500 kilowatts to 10 megawatts of electricity, depending on their design. The tunnels, Pickett noted, “are a couple of hundred feet long and have about a 35-foot radius from the turbines.”
The city of San Luis was chosen after an exhaustive study of sites around the world, Pickett maintained.
“We considered areas of the world where the tower would be most efficient,” he said. “We require very hot and arid areas, such as parts of the Mideast, northern Africa and the U.S. Southwestern desert, which is one of the driest areas in North America.”
Pickett said his company was able to access a decade of weather data gathered by the U.S. Department of Defense for strategic reasons — a database that had hourly data at different elevations — and take that information to build a picture of what happened month to month over a ten year period.
“We then knew how to predict almost exactly what the tower would do in that area, so San Luis became the prime place in North America for the tower,” he said.
The property that Solar Wind Energy Tower is purchasing previously was a farm, Pickett pointed out.
“If the farm were still operating and growing a thousand acres of hay, it would use more water than we will need for our operations,” Pickett said. “We will be taking water out of the ground and putting it back through evaporation, so we will not be a net user of water.”
Pickett believes the Solar Wind Energy Tower will be an economical way to make green power.
“It will compete with fossil fuels,” he said. “We plan to be part of the energy solution. Our system can make both AC (alternating current) and DC (direct current) at the same site without swapping out generators in the different generating rooms. We are able to pipe DC current up to a distance of 2,500 miles.”