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Renewable Energy of the World

"All over the hill... there were wind turbines of gigantic dimensions... the wheels of wind turbines rotated noisily in the gusty wind..."

Herbert D. Wells, When the Sleeper Wakes, 1899

"Wind power promises a clean and free source of electricity... The U.S. Department of Energy (DOE) aims to see 5% of our electricity produced by wind turbines in 2010...A little research, however, reveals that wind power does not, in fact, live up to the claims made by its advocates..., that its impact on the environment and people's lives is far from benign, and that with such a poor record and prospect, the money spent on it could be much more effectively directed."

A Problem with Wind Power

by Eric Rosenbloom

http://www.aweo.org/ProblemWithWind.html

Renewable energy sources known to modern mankind are associated with solar radiation reaching the Earth, and with the mutual asymmetry of the arrangement of the orbits of the planets, primarily of the Moon relative to the Earth and the Earth relative to the Sun. Solar radiation can be directly converted into thermal or electrical energy, but, in addition, it forms all biological energy sources, as well as atmospheric and oceanic thermal flows and the cycle of river and ground waters. The asymmetry of the planetary orbits provides a harmonic change in gravitational forces, causing deformations in the earth's crust, long waves in the atmosphere, seas and oceans, manifested in the regular rise and fall of the water level, especially noticeable in bays and straits. These changes in the water level are naturally accompanied by flows filling the respective bay in one phase of the tide, and emptying it in the other phase.

Wind energy and water energy directly related to solar radiation and the presence of the earth's atmosphere are the most ancient energy sources mastered by human society. If Noah's Ark really existed, then it probably moved under sails and oars. The mill driven by the force of the wind or the flow of water has been grinding grain in Persia as early as 200 years before the Common Era. Even earlier, wind turbines and water wheels were used in China. In Europe, wind turbines appeared in the 8th century. The practical development of wind energy as a source of electrical energy began only at the end of the 19th century. The first 12-kW wind turbine (Fig. 1.1) was built by Charles Brush in 1888 in the Cleveland area (Ohio, USA). It worked without any problems for almost 20 years.

This unit echoed the ideas of using active wind pressure, incorporated into the design of old windmills. They worked almost independently on the shape of the blades (wings) moving slower than the wind, and the efficiency of using wind energy was very low.

Fig. 1.1 Charles Brush's Wind Turbine. Cleveland City, USA, 1888.

The rapid development of aerodynamics at the beginning of the 20th century, associated primarily with aircraft construction, affected the theory and practice of using the energy of free water and air flows. The simple, but very important results of German scientist A. Betz and Russian professor N. E. Zhukovsky determined the efficiency limits of wind turbines and indicated the ways of their optimization-the blades should have well-streamlined profiles and move faster than the flow. A 100-kW first large wind turbine having a special aerodynamic design was built in Crimea near Balaclava City in 1931 (Fig. 1.2).

By 1936, a new project, a 5000-kW wind turbine, was designed in Russia, which, however, was not implemented, and the wind energy line in Russia itself was assigned to the section of agricultural production, where it stalled. The situation was not much better in the United States after the failure with the Putnam-Smith project; the said project led to the construction of a 1250 kW wind turbine in 1941, which collapsed on 23 March, 1945, because of having produced wind lower than what was estimated. Consequently, the interest in wind energy was lost for almost 40 years.

Fig. 1.2 High-speed wind power unit. 100 kW. Balaclava City, Crimea, USSR, 1931.

The energy of tides compares favorably with the energy of wind and that of oceanic or sea flows of other origin, by its high predictability. Although the height of the tides and the shape of the smoothed seagram at each fixed point do not remain constant, these changes are well predicted by modern methods. Attempts to harness the energy of tides in a variety of forms have been made since ancient times. Engineering initiatives in the last 100 years have been aimed at creating and using the static pressure occurring on the barrier blocking the mouth of the sea bay with high tides. Relevant projects based on the experience of river hydropower were put forward in Canada, the USA, England, France, and Russia. Finally, in 1936, the construction of a tidal power plant (TPP) of Kwodi (USA) began with a traditional dam, a hydroelectric power station, spillways and all the rest of the set of structures and equipment typical for a river hydroelectric power station. This attempt, dubbed "economic madness," was soon abandoned. In the next 50 years, four more TPPs with a traditional set of hydraulic structures were nevertheless built. These were TPPs Rance (France, 1967), Kislogubskaya (USSR, 1968), Annapolis (Canada, 1984), Jiangxian (China, 1985), which, despite various new technological methods of construction, turned out to be not as effective as estimated and very expensive. As a result, practical interest in this field remained stifled for a long time.

A noticeable revival in the field of tidal energy has been observed in recent years, when the Russian technology for the use of floating power units almost completely equipped in the factory and transported to the installation site has been generally accepted; experience has been accumulated in the study of orthogonal turbines, the operation of which does not depend on the direction of flow and, most importantly, there were ideas to move away from the traditions of pressure river hydropower and directly use the energy of tidal flows.

It is important that, with the new technology of using tides, a system of several TPPs can provide a guaranteed basic power even without external storage devices, although storage elements are needed to fully utilize the energy of the tides.

According to this principle, with free-flow collinear turbines resembling traditional wind turbines, the first TPPs of a new generation have already been built in Devon Coast (England, 2003, Fig. 1.3) and in Hammerfest strom (Norway, 2004) with 300 kW turbines each.

Fig. 1.3 Hydraulic unit MCT in repair and maintenance position. Devon Coast, 2003. 300 kW.

The costs of these pioneering facilities turned out to be so high (in Norway, for example, about 11 million US dollars per vehicle) that plans to expand work in this area and create a large TPP (Fig. 1.4) have not yet been set into motion.

We hope that the situation will change with new, orthogonal turbines in combination with a new technology of using tidal energy and floating block technology for the construction of TPPs.

The large-scale use of any renewable sources was constrained by a number of general technical and economic reasons:

• - high degree of dependence on natural factors;
• - lack of confidence in the perfection of available technologies;
• - large initial capital investments;
• - low level of world prices for fossil fuels;
• - relatively low share of these sources in the balance of energy resources consumption.

The development of alternative energy sources was understood by many people as a kind of additional source for a niche market, such as for the agriculture industry. In addition to that, progress in this sector was also hampered by the insufficient purchasing power of the population and the lack of funds of local authorities for investing in facilities, which was most typical, for example, for Russia during almost the entire 20th century.

Fig. 1.4 Tidal power plant project based on the unit at Hammerfest strom.

However, the undeniable advantages such as lack of fuel costs, and environmental safety which the inexhaustible resources have, are a favorable basis for the recognition of alternative energy and assure investors a quick return on promising projects.

The search for an environmentally friendly alternative to the traditional energy industry prevailing today in the context of special public attention to the problem of environmental protection is of great importance also because energy facilities operating on natural fuel negatively affect the environment by polluting the air and water basins, causing acid rains, etc.; this leads to their making a significant adverse contribution to worsening the greenhouse effect.

The use of renewable energy from water currents on a large scale has taken place since the mid-19th century in the form of the construction of dams and diversion hydroelectric power plants, and since the mid-20th century in the form of the construction of tidal power plants with a traditional pressure front cutting off the bay from the sea. In the USA, Italy, South Korea, Russia, and Canada, a number of projects have been implemented to use tidal flows, without creating a pressure front. The authors also have proposals for Bangladesh. We usually considered layouts with collinear...