by Ted Crook
The average size of a power plant is probably about one gigawatt ( one billion watts).
It takes 500 2 megawatt windmills to obtain a gigawatt when they are spinning at rated RPM. To get a reliable gigawatt might take a thousand windmills, since windmill power varies as the cube of the velocity--a barely perceptible drop in wind speed can cut the power in half.
At the standard 15 watts per square foot, it takes at least a couple square miles of solar panels to produce a gigawatt--when the sun is shining.
A gigawatt of electric train storage ( the current darling) will require some 40 to 50 5 or 6 engine trains (assuming 6000 horsepower electric motors).
100 million 50 hp automobiles would use somewhere between 100 and 1000 gigawatts of power, depending on the use cycle. That’s somewhere between 50,000 and 500,000 windmills. A properly designed rail system could use a tenth of that to move more people.
No one(except in Turkey and China)wants to see any new hydroelectric plants.
Power from space: collect it where the sun really shines, beam it to earth somehow. In 2006, I wrote an almost completely unread novel about remote controlled lunar mines and huge mirrors beaming light to collectors on Earth at night. I still think the concepts are possible.
Carbon sequestering technology is probably something we really need in the long run. Suck the carbon out of the air now, pump it back later when an ice age threatens. It would be possible to regulate climate within narrow limits with proper systems ( and probably a lot of energy). I still think sequestering carbon from coal fired power plants could make them the green darlings--essentially no pollution at all.
Since Fukushima, the world has felt that nuclear power is terrible.
Though this is undoubtedly distasteful to all environmental types, I would diffidently submit the thesis that nuclear power is probably the best hope for the planet.
The problems with nuclear power are almost entirely the result of poor designs and inept political decisions. The better designs are available. The current water reactors, for example, require power and instrumentation for safety. Other designs do not.
Early reactors were dangerous, dirty, and often despicable. Manual procedures abounded: pulling control rods by hand, pouring fuel out of buckets, pushing fuel packets with sticks.
Physicists and engineers could calculate the consequences of a design, but were often overruled by ignorant workers, managers and politicians.
There have been three serious accidents in the 80 years of nuclear power reactors: Three Mile Island, Chernobyl, and Fukushima. While there have been deaths, the disasters have been mild in comparison to earthquakes, explosions, genocide, firearm accidents, drunk drivers, or suicide.
In all three cases, the water in the reactor turned to explosive hydrogen and oxygen. In Chernobyl and Fukushima, there were actual explosions.
Three Mile Island and Chernobyl were much the same type of accident: operator and instrumentation failure. No one died at Three Mile Island because the reactor was designed with good containment. The deaths at Chernobyl were the result of the (stupidly) removable lid being blown off the reactor and the desire of officials to downplay the disaster.
The world of instrumentation has changed drastically since the eighties. It is possible to do more now with a 20 dollar Arduino than could be done with the whole control room at Three Mile Island or Chernobyl. In the old days, everything relied on the skill of an often bored (or even ignorant) operator.
Current reactors use water as coolant and neutron moderator. If the reactor overheats, steam voids remove the moderator effect and the reaction slows down. If the reactor heats up too much, of course, the steam separates into hydrogen and oxygen and becomes explosive. At Three Mile Island and Chernobyl, the flow of water stopped.
Fukushima was a failure of seawall design. The Japanese plant closest to the Earthquake, the Onagawa power plant, had a much higher wall and shut down with no problem. The Fukushima wall was designed for average tsunamis--even though it was known that a medieval quake’s tsunami had exceeded that height.
The Onagawa wall had been made higher over the objections of tsunami experts by one stubborn engineering hero. It has been raised again since the accident.
The most interesting “new” reactor design is the molten salt reactor. The fuel is mixed with salt. Meltdown of the reactor is impossible because the salt is already molten. Instead of water coolant, helium can be used. Helium is never explosive and forms no radioactive isotopes from fission. A coolant leak would be harmless--just helium floating away into space.
The temperature of the reactor is largely regulated by the expansion and contraction of the mixture. Heated up, the mean free path of the neutrons increases and the reaction slows down.
The Oak Ridge molten salt reactor ran for 6 years in the sixties without incident.
All control, monitoring and safety instrumentation systems add more safety on top of this stable design. The control rods can still SCRAM (slam into the reactor to provide an emergency stop), but the reactor is easier to control and doesn’t need steam and hydrogen forming (explosive) water inside the reactor.
If--despite every precaution--the salt reactor does overheat, a metal plug in the bottom of the reactor melts, allowing the salt to flow into some storage tanks of less than critical mass. The reaction stops, and all is well.
Salt reactors can use a large variety of fuels and can even be used to “burn” spent fuel rods from other plants. Siting such a reactor beside an existing plant could permanently solve the waste problem.
China is going full tilt toward construction of salt reactors.
As everyone should know, the ultimate power source is fusion. All the power we need forever--pollution free. The reactor would take in a small amount of water (probably less than a gallon) and the end product would be inert and safe helium.
The problem is plasma containment. The one reactor we use, the sun, is a gravity containment fusion reactor. It takes a lot of gravity to make that happen.
The Chinese have gotten a plasma to stay around for 100 seconds in their superconducting (thank you again, CERN) Tokamak reactor. That’s thousands of times better than the old days, but not likely to power a city anytime soon (who wants lights for only 100 seconds, anyway?).
Other labs have announced fusion breakthroughs as well--no plant on the horizon yet (if ever), of course.
I think with good new designs, intelligent instrumentation, and good political support, nuclear power can be the solution to most of our problems. The main impediment is ignorance and misplaced fear.
It would be easier to build good nuclear plants than to build tens of thousands of bird killing windmills.