Published on March 12th, 2020 📆 | 6237 Views ⚑0
Nuclear Power And Other Energy Solutions For Japan Now
Certain nations of the earth, such as Japan and Indonesia, have a special combination of problems that makes obtaining energy extremely difficult. Specifically:
- They can be subject to extremely large (> 7.0) earthquakes and accompanying tsunamis that, as recent events have shown, make nuclear power plants vulnerable to crippling damage and resulting escape of radioactive products.
- The very nature of nuclear plants with its radioactivity danger to the population makes it desirable to place several together in a small zone to limit exposure of the population to radiation. This concentration of power resources in a small area, however, means that a major portion of a nation's power production capability is vulnerable to a single event that can cripple the operational capability of that nation.
- They have little or no coal or oil reserves, and would prefer not to import fossil fuels for anything other than auto and truck use to limit foreign exchange deficit and dependence on foreign resources. In addition, the carbon dioxide that results in fossil fuel use is believed by most to cause climate warming with a resultant reduction in glaciers and ice caps, an increase in sea level, and a shift in desert zones toward the poles along with a resultant loss of agricultural land, so it is desirable to eliminate its use.
Nuclear power in these countries has problems. How does such a nation provide for its energy needs, and still maintain a margin of safety for its population against radioactivity and also ensure that overall power production is not subject to a single catastrophic failure?
We need to look for an energy production source that has the following critical features:
- Is plentiful enough to cover the nation's base load needs in the long run.
- Energy production sources capable of being dispersed so the nation's power production capability is invulnerable to a single crippling event.
- Is free from carbon dioxide production and other pollutants.
- Is price competitive with existing sources, so it can start replacing the existing energy sources now and later become a major energy supplier for that nation as more new similar sources are constructed.
- Is able to use the existing energy distribution systems now.
- Able eventually to make fuels that can replace fossil fuels for portable power plants (autos, aircraft, etc.).
Several possible energy sources have been proposed, namely:
- Nuclear fission reactors of a different design.
- Land based wind turbines.
- Shore based wave generators.
- Land based solar cells and / or solar thermal generators.
- Fuels to replace fossil fuels such as alcohol and oil from food crops, waste wood, kelp and algae.
- Land based deep thermal wells.
- Ocean based wind turbines, wave generators and solar cells.
Let us investigate these options one at a time.
Nuclear fission . Nuclear fission reactors are currently being used for base load (Load Factor ~ 0.98. Note that Load Factor is the fraction of time a source can be used to provide energy) and can operate at ~ $ 0.08 / KWH or more. There is enough nuclear fuel to last more than 100 years without using breeder reactors. A breeder reactor is one that creates more fuel than it uses. If we use breeders, there is enough fission fuel for several thousand years.
Safety is the big issue. The vulnerable element in the light water reactors currently being used in Japan and elsewhere is the coolant pump. Backup pumps are always provided, but if all electricity is lost inside and outside the facility (as happened in Japan), the backup pumps are useless. The neutron absorbing control rods and emergency shut down systems will deploy without the electricity and shut down the fission reaction, but the residual radioactivity in the fuel rods will continue to heat the rods and melt them down (as apparently happened in Japan). If the coolant pump is offline long enough the rods may melt through the containment vessel and vent radioactive material to the environment.
It appears feasible to design some reactors (for example, pebble bed reactors) with low enough energy density in the fuel elements that the residual radioactivity will not melt them down. This approach appears promising, but it does not solve the problem of what to do with the radioactive spent fuel elements, nor does it help us to disperse the power generators so that one catastrophic event will not cripple a nation's electric production. It will always be desirable to concentrate radioactive fission reactors in one area to reduce population exposure.
Finally, it does not make non-fossil replacement fuels for autos, trucks and aircraft.
Land based wind turbines. Land based wind turbines are non-polluting but expensive (~ $ 0.10 / KWH or more). Also, they require carefully selected windy sites that are not common enough to provide a significant part of the base load. Further, they are not available all the time (Load Factor ~ 0.5 to 0.7 in good sites, less elsewhere). These generators are not suited for base load generation that must be cost competitive and reliable. They are useful, but appear best suited for operation in high energy cost areas on an as-available basis.
Shore based wave generators. Shore based wave generators are also non-polluting but expensive, however not as expensive as land based wind turbines (~ $ 0.09 / KWH or more). Again, they require carefully selected wave sites that are not common enough to provide a significant part of the base load (Load Factor ~ 0.4 to 0.6 in good sites, less elsewhere). Also, they are not available all the time. These generators are not suited for base load generation that must be competitive and reliable. They are useful, but appear best suited for operation in high energy cost areas on an as available basis.
Land based solar cells and / or solar thermal generators. Land based solar cells and solar thermal systems have serious problems for base load operation. They are the most expensive source (~ $ 0.17 / KWH or more). Solar thermal systems require expensive storage systems to operate when the sun is down or obscured (Load Factor ~ 0.4 to 0.6 in desert zones, less elsewhere) which increases the cost even more. Solar cells cannot operate at all without the sun. Both need huge tracts of carefully selected land for each KW of power generated. (~ 0.1 KW / sq meter). Furthermore, this land can be used for very few other purposes. In general, solar generators are not suited for nations (such as Japan) near the ocean where clouds and fog are common.
It appears that land-based solar cells and solar thermal systems are not suited for base load generation in nations such as Japan where they must be economically competitive and reliable. Solar cells appear best suited for specialty use where cost and area is less important, such as on top of electric cars to extend their battery range, or on top of houses to cover the day-time peak load, or near desert communities for day time peak load.
Solar thermal appears best suited for use in special isolated desert areas where the climate conditions and load characteristics work together to make these generators more competitive.
Sustainable fuels to replace fossil fuels. Alcohol from corn is currently being produced and used with gasoline to power autos. This option cannot be thought of as a long term solution, however. As population increases, the corn must be used for food. The same is true of oil from soybeans. This is not true of alcohol and oil from waste wood and sea plants such as kelp and algae. These sources provide no pressure on food production capability, so long term production is possible and also desirable. It could help replace fossil fuels for portable applications (autos, trucks and aircraft) in the long run. It should be noted, however, that it cannot replace fossil fuels for base load operations. Energy from plant growth is less efficient than that from solar cells, and it has already been noted that solar cells for base load is not economical and requires far too much land, especially in crowded nations such as Japan. Energy from plants is best suited to supply a portion of the fuel for portable power plants such as cars, trucks and aircraft.
Land based deep thermal wells. Deep thermal wells are non-polluting and may be competitive in cost. The expense is dependent on the cost of drilling a well down to the hot rocks deep within the earth's crust. New chemical drilling techniques show promise, but cost estimate details are not yet available. A pilot hole is now under way. If the pilot hole is inexpensive enough, these thermal wells can be used to provide base load. The fuel (earth heat) is available near enough to the surface in many areas on the earth, and will last for the foreseeable future. It is non-polluting. It can use existing electrical distribution systems. The hole can even be used to sequester carbon dioxide. The only disadvantages of this generator are that it is vulnerable to earthquake damage, and it is unable to provide fuel for portable power plants, although this last problem may become less important if electric cars take over the automobile market. The vulnerability to earthquake damage may make it undesirable for nations like Japan, however, although it would fail safe, unlike nuclear fission plants.
Ocean based wind turbines, wave generators and solar cells. Ocean based wind turbines, wave generators and solar cells are non-polluting and inexpensive. They can be operated on one platform or vessel to save capital expense. The cost per KWH is estimated at ~ $ 0.03 / KWH or more. The solar cells are expensive and consume so much area that they can provide only a tenth of the total generated power, so ships have only a backup roll for calm weather. The vessel can be moved to find optimum operating conditions (Load Factor ~ 0.85 to 0.95). The energy can be converted into fertilizer concentrate immediately with easy transport to land, and a ready market. This frees up natural gas (currently used to make fertilizer) for use to generate base load now. It is also possible, with development, to convert the energy harvested on the ocean along with food plant residues into hydrogen, natural gas or oil, so base load and portable applications can be directly covered in the future. Gas turbine generators can be dispersed and thus avoid vulnerability to a single crippling event. The owner can also be the operator, so overhead is saved. Part of the owner's pay is the living quarters on the vessel, thus a job and shelter is provided as well. All of the critical and desirable characteristics are satisfied. A prototype is almost complete, so implementation is near term. Clearly this is a candidate to replace fossil fuels, and, in special circumstances, nuclear fission.
Conclusions Clearly, Japan and other similarly situated nations will have to reconsider reliance on nuclear fission reactors as their main base load energy providers. In the near term, they will repair the damaged reactors that can be safely and economically repaired. Some reactors, however, are totally destroyed, and must be replaced with something, and quickly, because there is not enough capacity to cover load. The quickest and cheapest replacements are gas turbines and diesel generators and they will probably be used near term. This means Japan will have to increase their fossil fuel imports in the near term, a highly undesirable situation. So Japan will start to look for alternative options, and here is what the Japanese (and other similarly situated nations) will find.
Fossil fuel liquid and gas production is expensive and peaking out in production-oil first and gas soon after. Besides, it is undesirable because of the greenhouse gasses it generates. Sustainable fuels to replace fossil fuels such as alcohol and oil from waste wood and sea plants are not economical and require far too much land to cover base load. Land based wind turbines and wave generators are expensive, not always available and there are not nearly enough good sites to cover a significant fraction of the base load. Solar cells and solar thermal generators are extremely expensive, not always available and require far too much area that is not common in seacoast nations to cover base load.
Clearly, only three long term base load energy options are open for Japan and similar nations, namely:
- Alternative nuclear fission reactor designs such as pebble bed reactors, fast reactors and highly modified light water reactor designs that are free from escaped radiation problems, although they will always be vulnerable to catastrophic earthquake damage and the spent fuel elimination problem.
- Deep thermal well generators that are free from escaped radiation and spent fuel problems, although they will always be vulnerable to catastrophic earthquake damage.
- Ocean based wind turbines, wave generators and solar cells that are free from escaped radiation and spent fuel problems. In addition, both the ocean based fuel generators and the land based gas turbine powered electric generators necessary are widely enough distributed to be free from large scale damage by single catastrophic events. Furthermore, as ocean based fuel generators come online, they can cover all (even portable power plant) energy needs with sustainable, low-cost energy that does not require foreign exchange.
It would be wise for Japan to start now to investigate all three options now.
by Leonard Wald