Future power generation in a water constrained environment

Posted on January 18, 2016
Posted By: Harry Valentine
Topic: Hydro
 
A European climate researcher group recently advised that changing weather patterns could adversely affect future hydroelectric and thermal power generation between 2040 and 2069, both of which depend on water. In recent years, changing weather patterns have indeed affected both hydroelectric and thermal power generation. A summer drought and heat wave reduced the cooling capacity of cooling towers at air-cooled French nuclear power stations that had to operate at reduced output. A few years ago, drought conditions also reduced water volumes at Hydro Quebec's James Bay hydroelectric power installations, perhaps North America's largest hydroelectric location.

The occurrences in both France and Quebec provide opportunity to explore possible methods by which to ensure sufficient future power generation during periods of prolonged adverse weather patterns. The earth's weather history includes extended periods of the El Nino weather pattern that decimated the Mayan empire of South America, as well as periods where the Arctic was essentially free of ice cover. Changing weather patterns are part of the earth's history and have the potential to adversely affect hydroelectric and thermal power generation. A drought in Southern Australia turned a mega-size water storage dam into a dry lake bed.

Seawater Cooling:

Developers of thermal power stations in countries such as Japan and South Africa perhaps inadvertently developed seawater-cooled, ocean side nuclear power stations. Fukushima is one of several of Japan's seawater cooled thermal power stations and officials knew of the geological fault line, the location of the tectonic plate as well as the potential for tsunami and earthquake before the power station was built. It is perhaps to the credit of Japan's energy department that most of their seawater cooled thermal power stations are located at coastal locations with minimal risk of earthquakes and tsunamis.

At the present time, construction of some 35-nuclear power stations is either under way or planned for worldwide. Over the next 25 to 40-years, some 60 to 100-thermal power stations of over 1,000MW output may be built, perhaps even using radiation-free fusion technology. Several of these power stations may be built at ocean coastal location using seawater cooling combined with thermal desalination. At some locations, coastal thermal power stations offer the advantage of being able to provide the thermal energy to allow for development of technology that can produce controlled water spouts that pump water droplets to high elevation.

Mega-Size Air Cooling:

Future thermal power stations built at inland locations that require air-cooled condensers may borrow from South African mega-scale cooling tower technology that allows a 4,000MW clean-coal thermal power station to operate in sub-tropical conditions. It may be feasible to build the identical size of cooling towers to operate a future thorium fueled nuclear power station of 2,500 to 3,000MW output. While GE has developed higher-temperature, helium gas-cooled reactors that transfer heat into boilers, ultra-high temperature helium cooled reactors that energize gas turbine engines and offer the prospect of combined gas/steam cycle operation, are still under development.

Several research groups have borrowed from the precedent of chimneys that draft heated air from buildings to provide convection cooling, as a basis for power generation chimneys that are essentially super-mega-size cooling towers capable of processing massive volume flow rates of air. There may be future scope to combine inland thermal power stations with ultra-large scale cooling towers, including cooling towers that include woven fabric upper sections of chimney held aloft by helium-filled `balloons'. Another possible cooling tower concept may use the exhaust heat to generate controlled cyclones and pull a rapid flow of air through turbines.

Micro Thermal Power:

There are ongoing advances in small-scale thermal power conversion that include some air-cooled technologies. The thermo-acoustic engine is a promising technology that converts heat to standing sound waves inside a pressurized tube and the waves drive a linear alternator. It can operate at equivalent thermal efficiency of a mega-scale thermal power station while delivering 25 to 50kW, with projected future prospects going up to 200kW per unit. Units at inland locations would utilize air-cooling technology while water cooling may be applied at seaside locations, including an option where a pipe network could connect to multiple small power stations.

At the present time, solid state thermo-electric converters deliver as low as 5% thermal efficiency. Several groups are engaged in research to improve efficiency of electric power production, however, an unexpected breakthrough that greatly raises efficiency is still possible and perhaps a few years into the future. Both air cooling and liquid cooling are possible. Micro thermal power technologies may feasibly be built as remotely monitored and controlled small-site installations, making it a future decentralized or distributed power generation concept that could operate inside large buildings or in residential city blocks to provide private homes.

Interdependent Power Generation:

A system of interdependent power generation would link different technologies, expanding beyond combined-cycle and compound-cycle systems. A coastal thermal power station located between sea and a coastal mountain can supply its downstream exhaust heat to a cyclone engine that propels droplets of seawater skyward as a water spout. Wind would push the evaporation from the evaporation of the waterspout toward the coastal mountain and through wind turbines placed upwind of the watershed area of a storage dam. The turbines would cool the humid air as it enters the watershed shed area, perhaps producing fog.

Fog fences strategically placed around the watershed area could extract water from the air and transfer it into a (hydroelectric) storage dam. The combination of a coastal, seawater cooled thermal power station that produces an offshore water spout and strategically placed wind turbines upwind of a watershed area that a hydroelectric power dam offers a method by which to offset the negative effects of changing weather patterns. The inevitability of the construction of additional thermal power stations in the future provides planners with the option of combining several indirectly interdependent power technologies that complement each other.

Conclusions:

While future drought could adversely impact future thermal and hydroelectric power generation, several alternative strategies are possible and offer methods by which to ensure continued power generation during such future periods of climatic adversity.

 
 
Authored By:
Harry Valentine holds a degree in engineering and has a backround in free-market economics. He has undertaken extensive research into the field of transportation energy over a period of 20-years and has published numerous technical articles on the subject. His economics commentaries have included several articles on issues that pertain to electric power generation. He lives in Canada and can be reached by e-mail at harryc@ontarioeast.net .
 

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Comments

January, 19 2016

Malcolm Rawlingson says

Some good points here Harry but I would not give the Japanese Engineers too much credit for their foresight in putting power plants on the coast and cooled by the sea. Japan is a very mountainous country and the simple fact is there is nowhere else to piut power plant except on the coastal areas. The UK, with which I am very familiar, has few inland power plants. Most of them both nuclear and coal are on the coastal areas. For nuclear plants the siting policy was to put them in remote areas of the country on the coast where there were few people. Almost all nuclear plants are on the coast (with the exception of Hartlepool I think).

Your point about dry conditions affecting hydroelectric plants is well taken. When building massive projects like James Bay in Quebec I do not think enough consideration has been given to the assumption that there will always be water to power them. If you place all your power eggs in one basket and rainfall deteriorates then your power system is - to coin a phrase - dead in the water...or should I say dead without water.

Climate changes all the time courtesy of Mother Nature and we may have affected it detrimentally as well by burining billions of tons of coal.

Your article underscores a point I have made here many times that relying on natural energy solutions such as wind and solar and hydroelectric makes the presumption that the places where you locate them will always be sunny, always be windy or always have rainfall. If that changes - and according to climate scientists it will - then the power plants installed to capture the energy are useless.

THAT is the fundamental reason why nuclear power must be the basis of the power system in all countries. Power output is controlled by humans and is not dependent on nature....although cooling for some plants could be an issue nevertheless.

A slight correction to the statement "At the present time, construction of some 35-nuclear power stations is either under way or planned for worldwide". That is not correct. There are currently 68 power plants being constructed as we speak with 135 planned (that is financing secured) and another 350 proposed. For up to date information and excellent resources is the World Nuclear Association. Reactors under construction can be found here

http://world-nuclear.org/NuclearDatabase/rdresults.aspx?id=27569&ExampleId=62

China alone has about 25 under construction and last year announced 8 more to be built with a further 8 per year to be announced from 2016 to 2020.

Of course all of these use steam on the Rankine Cycle so most of the energy is discharged into bodies of water which is something that engineers need to take into account. With possible sea level changes water intake structures must be flexible enough to accommodate water level differences. Most I think will adapt quite well since they already cope with tidal changes of the order of several feet and most intakes on coastal areas are drawn from the sea bed rather than the surface although that doesn't apply to all plants.

But very good points Harry and well taken. Soething engineers need to take into account in their design of future and present power systems. Malcolm

January, 26 2016

Vince W. Marshall, CEM, MBA says

Harry;

We have developed technology that reduces a thermal power plants dependency on outside cooling water. Our Neptune system captures low grade waste heat and recycles part of it back into the plant it came out of. This also increase efficiency slightly. (2%-5%)

I have a one page summary if you would like to know more.

Very Respectfully,

Vince Marshall Cherokee Energy vince@cherokee-energy.com 757-615-0387

January, 29 2016

Malcolm Rawlingson says

That is really interesting Vince. It has always concerned me that we throw away so much heat to water bodies from all our power plants. It would be great there was a practical and economic way to harness it. Malcolm

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