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A major complication is an emerging consensus that burning fossil fuels may be a culprit behind global warming. While intermittent renewable energy supplies (e.g. wind, solar, etc.) and conservation can help, the undeniable truth is that the vast quantities of power we continuously consume overwhelm the practical capabilities of the “green” sources.
A developing new hybrid technology is aimed directly at using abundant coal supplies to produce reasonably priced and exceptionally safe electrical power, transportation fuels and energy independence with a timely benefit of dramatically reduced emissions, particularly CO2. These seemingly impossible objectives are met by a unique marriage of nuclear, gas turbine and coal gasification technologies to produce an unexpected result -- the hybrid-nuclear power plant. Several facets of energy production and economics provide keys to understanding the amazing potential of this new family of hybrid energy production plants.
- Natural Gas. A modern combustion turbine power plant relies on igniting fuel with compressed air that then spins a turbine attached to an electrical generator. About half the turbine’s energy is actually used to compress the air and a steam turbine driven generator is also used to recover energy from the gas turbine’s hot exhaust. The “combined-cycle” power plant uses about 50% of the fuel’s energy but the high demand for a dwindling domestic supply of natural gas has caused the price of this fuel to nearly triple, with little prospect for reduction. The plants, however, are not particularly expensive and can be rapidly constructed.
- Coal. About half of the electrical energy used in the US is produced from coal for which hundreds of years of reserves apparently exist. The power generation process is straightforward (heat from burning coal creates steam that spins a turbine/generator) but generally not particularly efficient. Coal is inexpensive (being a fraction of cost of natural gas) but this comes at the price of emissions, particularly CO2. While most of these emissions can be sharply reduced, major CO2 reduction efforts dramatically increase the cost to build and operate the facilities and cause the plant’s efficiency to plummet.
- Coal Gasification. Major efforts and expenditures are occurring to re-introduce a rather old technology involving turning coal into a gas. Coal gasification involves heating but not actually burning coal, with the synthetic gas produced then used in a combined-cycle power plant. The cost to build such a plant is somewhat higher than a coal plant and emissions are somewhat lower. As with the coal plant, technology can reduce CO2 emissions but at much increased costs, although not to the level that would occur with a coal plant.
Large-scale CO2 reductions introduce large-scale complications for all fossil fuel based facilities, including troubling issues as to “sequestered” CO2 removed from the plants. Increasingly strident political opposition is casting doubt on the practical ability to construct new coal and gasification plants that burn an abundant but environmentally challenged fuel.
- Nuclear Power. Conventional nuclear plants are expensive, being perhaps two to three times the cost of comparable coal or gasification plants, with much of this expenditure required to insure the safety of the public. The production process is relatively simple and involves using nuclear heat to create steam that subsequently drives a turbine generator. However, the high cost of the plants (billions of dollars) can introduce potentially high financial risks to owners and investors alike, as history has demonstrated. While the plants are relatively inefficient (~33%), the price of nuclear fuel, as with coal, is a fraction of the cost of natural gas. Nuclear plants operate at full power for technical reasons and avoid the daily routine large load swings of the electrical grid. Fossil plants are normally used for such purposes.
For the most part, efforts to construct new nuclear facilities face competitive challenges in most markets.
In an effort to reduce the perceived risks associated with nuclear energy, a promising but not new technology relies on using a nuclear reactor to heat helium gas that subsequently drives a turbine generator, with the helium then recycled back through the reactor. The process uses relatively inexpensive nuclear fuel and is efficient - approaching 50%. A key feature (unlike a conventional nuclear plant): one could simply walk away from the facility, the core will not melt and the public remains quite safe. However, this high level of safety comes at a price as the gas reactor can only be about 1/7 the size of the conventional nuclear cousin. The initial investment risk is, however, more manageable as the plant is less costly. Japan and China are operating prototype high temperature gas reactors and South Africa is building a prototype power plant. The U.S. is conducting research and has spent several hundred million dollars on gas reactor technology over the last 25 years.
Hybrid-nuclear
This unique, patent pending, technology takes advantage of the observation that about half the power produced by a combustion turbine is used to compress air. By using a helium nuclear turbine to drive an air compressor, instead of a generator, electrical power output is doubled. Stated somewhat differently, two combustion turbines would be required to produce the same electrical output as a single hybrid-nuclear unit. The higher capital cost of the hybrid-nuclear reactor is off-set by lower-cost nuclear fuel and a lower-cost power generation block. The net effects are much reduced production costs relative to an equivalent combined-cycle plant burning natural gas. A serendipitous environmental benefit: emissions are nearly halved.
Applying the hybrid-nuclear design to coal gasification allows for the emissions-free compression of the air used extensively by both the combustion turbine and gasification plant while simultaneously increasing the overall efficiency of the baseline plant. Also, the size of the gasification and power blocks are about ½ of that otherwise required. These effects yield more competitive and environmental friendly power plants.
Major Safety Features
- Passive cooling; reactor core cannot melt.
- Reactor located underground.
- Reactor block isolated from grid and environment; readily handles upsets and accidents.
- Existing proven, approved materials used.
Benefits
- Exceptionally low emissions.
- Compact, modular, cost effective design.
- Efficient, large load following capability; well suited for wind/solar co-operations.
- Reasonable fuel costs.
Safety
The safety of the Hybrid-nuclear nuclear plant is a significant improvement over conventional nuclear facilities because of the inherent fail-safe heat removal features of the hybrid’s small reactor. In addition, substantial safety margins as well as operational flexibility are present because the reactor is not normally connected to a constant speed generator. (One should note that conventional nuclear plants are exceptionally safe but high levels of vigilance and associated costs are required to achieve and maintain such a state).
The reactor’s silicon carbide fuel is remarkably rugged. Also, extracting weapons grade material is exceptionally difficult and requires expensive and sophisticated equipment.
Environmental
Relative to emissions, the hybrid-nuclear philosophy is straightforward: minimize the production of greenhouse gases by partial use of nuclear power, thereby reducing pollution by a factor of almost two. Such an approach is effective and practical, particularly given the relative absence of proven underground formations to permanently store massive quantities of CO2. However, the CO2 removal methods currently envisioned for gasification and coal plants could also be employed by a hybrid-nuclear plant, but at a much lower cost as only about half as much equipment is required.
Because the hybrid-nuclear reactor is quite small by conventional standards, nuclear waste is minimal. Unlike a coal plant, ash from a coal gasification hybrid-nuclear plant is an environmentally benign, non-leeching glass-like slag. Further, such solid wastes are significantly less than those generated by comparable coal or gasification plants.
Water use is less than half that of coal or conventional nuclear plants.
Economics
In a market driven economy, the cost to produce power is only half the picture. The investment must also be profitable. Today’s de-regulated electrical market is highly volatile, with large seasonal power price swings - for that matter, large fluctuations exist between early morning and afternoon. Include highly volatile fuel prices, such as natural gas, and power plant economics become exceptionally challenging for consumer and investor alike. The hybrid-nuclear financial approach combines stable low-cost coal and nuclear fuels with a reasonably priced power plant to minimize the potentially large risks of the uncertain power market.
Approximate financial predictions (return on investment before taxes) for new coal, combined-cycle, gasification, nuclear and hybrid-nuclear plants, constructed in the Eastern US and using 2006 electrical grid as well as fuel prices and similar financing assumptions follow.
- The hybrid-nuclear plants as well as the coal plant achieve comparable positive returns (sub-teens), while that of the gasification plant is somewhat less.
- The combined-cycle plant posts small losses, absent higher market prices for power.
- The nuclear plant profitability is problematic absent relief or higher market prices.
The economic analysis provides a rough indication of investment potential in a market driven economy. While a fully regulated market is somewhat different, the trends would be similar.
Energy Storage
Ordinarily, electrical power is difficult to economically store. However, the flexibility of the hybrid-nuclear technology readily supports energy storage, thereby taking advantage of the large market price differentials between day and night power usages.
During off-peak periods, the reactor block driven compressor can divert pressurized air to an underground storage cavern, with the compressed air released for use with a combustion turbine or a combined cycle block during periods of high electrical energy demand. On a comparative basis, the 2x1 hybrid-nuclear facility exhibits approximately double the output of an equivalent conventional 2x1 combined-cycle plant. The hybrid configuration, when coupled with the higher daytime market price for power, should lead to a highly profitable investment.
Co-operations with Renewable Sources
The configuration of a hybrid-nuclear plant allows for a unique integration with renewable solar energy. For those regions where sufficient quantities of solar energy are available, the hybrid-nuclear plant can use solar energy to pre-heat the compressed air fired with the combustion turbine. Fossil fuel use (already significantly reduced) can be further lowered roughly 15%, which when coupled with the much higher market price for power during the day, likely yields a more profitable investment than conventional applications using concentrated solar energy.
With respect to wind energy, the ability of hybrid-nuclear plants to readily alter output can smooth the power fluctuations normally associated with wind energy farms. This joint configuration allows for accruing higher market prices than wind energy can normally command.
Summary
A summary comparison of large-scale energy options yields interesting observations.
The hybrid-nuclear plants leverage the advantages of underlying technologies and minimize the disadvantages, thus offering a more effective solution than any of the single fuel options.
The Future
Longer range, the hybrid-nuclear technology readily supports a hydrogen economy, but in an unconventional fashion. A steam electrolysis block can be integrated with the facility to produce Hydrogen (byproduct) and Oxygen, with the latter used in the coal gasification block. The reactor block provides compressed air, heat and steam; the combined-cycle block provides steam and generates power; and the gasification block provides synthetic fuel. Such an integrated process could supply hydrogen for several hundred thousand fuel cell vehicles and enough power for a city. Further, the gasification block could also supply diesel and jet fuel, with emissions significantly less than any existing processes that convert coal into such liquid fuels.
An economically sustainable and environmentally realistic future would involve:
- Extensive conservation of energy and widespread use of renewable sources.
- Prudent use of fossil fuels.
- Conventional nuclear providing base load electrical generation.
- Hybrid-nuclear providing electrical generation and transportation fuels.
Such a strategy would allow us to shape our own energy and economic destinies while providing future generations with an environment significantly better than today’s.
Conclusion
The family of hybrid-nuclear technologies offers a safe, practical, simple, clean and cost effective means to provide energy not only for today but for future generations while simultaneously and significantly lessening dependency on volatile foreign energy sources. Because of the unique integration with proven energy production methods, hybrid-nuclear power plants can be fully developed and deployed relatively rapidly.
In the final analysis, we can agonize over our dilemma or move forward with solving the problem. Hybrid-nuclear energy can be a practical and realistic part of the solution.
