Monday, April 6, 2009

Gulf Stream Underwater Turbine Power

This post is short. As long as I'm on the alternative power concept, check out the potential for extracting power from the Gulf Stream. Remember, this is different from wave power, and offshore wind farms, which anyone can research online. Here's a good link to the Gulf Stream power research. And here's a neat article on Benjamin Franklin and the Gulf Stream.

Borehole Nuclear Reactor

After some research on geothermal heat pumps, I realized that if you extract heat faster than the heat-conducting rate of the soil or rock allows the heat to move into the volume you have exhausted, the system will be tapped out. Heat can't radiate back towards your collectors fast enough. Now, this doesn't mean geothermal is unviable, it means each system has a maximum and if that is exceeded, it will not work as well. Also, in areas where summer air-conditioning needs equal winter heating needs, all is well. And in areas where air conditioning needs exceed heating needs, there is a similar problem: you are pumping heat into the ground faster than it can dissipate.

But in the American North, heat is the more precious commodity. This led me to ponder "recharging" heat in the earth with nuclear power. And my familiarity with deep holes in the petroleum industry led to my next idea:

After you run a nuclear power plant for a while, radiation will erode the reactor liners and concrete containment vessels. Eventual disposal or abandonment of all this material is expensive.

I propose lowering working fuel and control rods into the boreholes of either abandoned oil and gas wells, or drilling deep holes specifically for this proposed technology. Steam heat exchangers would be at the surface for electrical power generation. Or, for facilities such as government installations, colleges and universities, etc., the heat alone could be used to warm the buildings.

Eventually each reactor hole will be abandoned, using standard well-abandonment techniques. This involves heavy rubber and iron plugs topped with cement and should guarantee no contamination of groundwater. The heaviest-irradiated zones will be deep in the earth, in effect being "pre-disposed of." No further transportation of these deep abandoned materials will be required.
One advantage to this is it keeps operating core and waste nuclear materials far away from any terrorists. 10,000 feet of rock is a good deterrent to this sort of mischief.

UPDATE 5/1/09
A nuclear technician has pointed out to me that there's too much radioactive water in that l-o-n-g heat exchanger. I need a secondary heat exchanger. Or a liquid sodium design.

Thursday, April 2, 2009

Mobile CO2-Sequestering Coal Electrical Plant

My latest idea is the mobile coal-burning electrical generator. It's used in older oilfields, where CO2 is either desired to assist in oil production, or where it's merely acceptable to dispose of the CO2 exhaust in played-out oil or gas sands far below the surface. The requirements are only that a rail line be nearby and transmission towers for the power generated be nearby. Short temporary pipelines and power lines are acceptable. When each subsurface formation is optimally full of CO2, the mobile plant is moved to its next location.

This is for areas where CO2 pipelines are not available. See "green pipelines."

Coal cars are delivered to the generator during its period of sequestration / generation at each location. Some sulfur gases may also be sequestered underground.

The plants are not as efficient as other coal burning power plants because some power is used to deposit the CO2 into the deep formations.

The ridiculous illustration I cobbled together merely shows the equipment needed: a power plant, a generator, a transformer, and a pump for the burned exhaust gases. Ash will also need disposal. There will be empty rail cars after they deliver coal. It is possible ash could also be pumped into the same formations and could possibly neutralize the low pH of the sulfur, if any. As always, groundwater must be protected; these techniques already exists.

Cooling water for the turbine is the biggest problem. To generate electricity with a turbine efficiently, cooling is mandatory. Brine water present in many oil-bearing formations could possibly be used. Engines need a heat difference.

My back-of-the-envelope calculations (done mentally- can you scribble mentally on the back of an imaginary envelope?) tell me this would never amount to over a few hundred megawatts nationally. I can't say with certainty however that this a completely worthless idea. It might contain the germ of something worthwhile.

UPDATE 4-14-09 Scientific American has several articles on one page dealing with carbon sequestration.