I have made some statements in my previous paper that solicited questions. I will try to answer most of them by posting here a few pertinent excerpts from my book.

I assume that a future, thoroughly electrified grid will require 10,365 TWh annually. This assumes 13% transmission loss.

In broad brushstrokes, the envisioned, proposed power grid would function in this manner: The photovoltaic installations provide the bulk of the needed energy from the morning to afternoon hours and the solar towers provide for the rest of the hours of the day and night via molten salt which is utilized as needed. Wind blows when it’s in the mood. And when it does, it would either be used directly and immediately or alternatively it would in effect be converted to hydrogen, to be stored underground—along with the excess generated by solar technologies. When the combined yields of solar tower, PV, nuclear, and wind do not suffice in a given period, the hydrogen gas is brought back up and converted to electricity that is pushed into the grid. In the very rare moments in which this still does not suffice, extremely potent, short bursts of energy can be brought online from the many millions of car batteries that are plugged into the grid at any given moment. The final version of the plan to provide North America with all of its energy needs would require 224,284 square kilometers worth of installation.

You can see a graph of anticipated demand and energy generation of my model for every hour of the year by going to http://getreal.info/7.10-color-energy-chart.jpg Under this proposal, concentrated solar tower installations would be established in five areas across the Southwest and South regions. They would be in the general vicinity of Oklahoma City (OK), Lubbock (TX), Bakersfield (CA), Limon (CO), and Dallas (TX). Each of these five regions would have 3,234 installations with a footprint of about 34,000 sq km per region. This comes to 16,170 installations throughout North America with a combined footprint of around 173,600 sq km—or a combined area the size of the state of Florida. (See figure 7.11.) Each of the 16,170 installations would have around 18,500 heliostats. In total, there would be 44 billion square meters worth of mirrors in all installations. The installations would use air-dry. The combined total water consumption for all installations would be 550,000 acre feet of water annually. In the center of each installation would be three massive salt storage tanks, a steam turbine generator area, and an air-cooled condenser area. At the very center would be a 327-meter high (≈ 1,070 ft.) solar receiver tower. The tower would be a steel-lattice tower. Its width, foundation depth, and composition are modeled after the specs of a 274-meter tall (≈ 900 ft.) Self Supporting Tower built by Rohn Products International Holdings and installed in Jakarta, Indonesia. In terms of raw materials, the solar power tower array call for 1.4 billion tons of steel, 1.4 billion tons of concrete, 35,000 tons of silver—among other raw materials. This is largely based on the work by Sargent & Lundy Consulting Group. The modeling was done on SAM courtesy of NREL.

The pleasure has been mine.

Daniel Rirdan

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