Технические науки/5. Энергетика

Krasnyuk A., Tabaeva S.

KSTU, Karaganda, Kazakhstan

Technological features and application of renewable energy sources

After the energy crisis in 1973, national governments and private companies have taken extraordinary measures to find new types of energy resources for power generation. Such a source in the first place was the solar energy. There were developed parabolic-cylindrical concentrators. These devices concentrate solar energy on the tubular receivers that are disposed at the focus concentrators. Moreover, shortly after the start of the oil embargo in 1973, a planar concentrator was designed. It was success of science and engineering.

This led to the creation of the first solar power plants (SPP) tower. Widespread use of efficient materials, electronic devices and parabolic-cylindrical concentrators allowed solar power stations to build a reduced cost modular system. This system was first implemented by Luz Company (Israel) in California. Contracts were signed with the firm Edison for solar power stations plants construction in southern California. Water was used as the coolant and generated steam to the turbines.

The first solar power stations, built in 1984, had a 14.5% efficiency, and the cost of electricity produced was 29 cents / (kWh). In 1994, the company reorganized into Luz Solel, based in Israel, and continues to work towards a successful solar power stations is building capacity of 200 MVt/18 / as well as developing new energy storage systems. In the period between 1984 and 1990 by Luz was built nine solar power stations total capacity of 354 MW. Recent solar power stations, built by Luz, produce electricity at 13 cents / (kWh) with the prospect of a decline to 10 cents / (kWh). Milo D. from the University of Sydney has improved the design of solar concentrator, using the tracking of the sun on two axes and using an evacuated heat sink got efficiency 25 - 30%. The cost of electricity produced by 6 cents / (kWh). Construction of the first of the experimental setup with the hub started in 1994 and the Australian National University, the plant capacity of 2 MW. It is believed that such a system will be set up in the U.S. after 2000, and it will reduce the cost of electricity produced up to 5.4 cents / (kWh). With the construction of such indicators of solar power stations will be cost effective and competitive with thermal power plants.

Another type of solar power stations and their current development, installation began with a Stirling engine, placed at the focus of a parabolic mirror concentrator. Efficiency of such installations may reach 29%. The intended use of solar power stations such small autonomous power supply for consumers in remote areas.

In the future, it can be used to generate electricity temperature difference of layers of water in the ocean, which can reach 20°C. Stations on this basis (OTPP) are under development. The first version of such a plant with a capacity of 5 MW projected in Israel. Smaller power plants operate in Australia, California and several other countries.

Since the 70's, governments of industrialized countries have spent a billion dollars for the development of photovoltaic cells. Over the past 10 years, the cost of photovoltaic cells decreased and reached 3,5-4,75 dollars / watt, and the cost of the energy produced 25-40 cents / (kW / h). World output from 6.5 MW in 1980 increased to 29 MW in 1987 and in 1993 amounted to more than 60 MW.

In Japan annually produce 100 million calculators with a total capacity of 4 MW, accounting for 7% of world trade photovoltaic cells. More than 20 million homes in Mexico, Indonesia, South Africa, Sri Lanka and other developing countries use a photovoltaic system mounted on rooftops to generate electricity for domestic purposes.

The best example of the use of such systems is the Dominican Republic, where two thousand houses power stations have PV systems designed in the past 9 years. The cost of such installation is 2 thousand dollars.

In the future, the cost of small systems installations will be reduced, for example installing fluorescent lights. In Kenya, for the past 20 years, thousands of homes were electrified by the photosystems, compared with 17 thousand houses, where for the same time introduced the centralized power. World Bank will provide a loan of 55 million dollars for electrification of 100 thousand homes in India photosystems. In the U.S., the cost of 1 km of electricity distribution is 13-33 thousand dollars. The contract for the installation of 500 MW, including electricity at home, lighting, radio, television and the computer, is not less than 15 thousand dollars. (Including battery). Already has 50 thousand of such facilities in towns and built annually about 8 million units.

Even if the world each year 4 million homes (1% of those that electrified each year) will be supplied by photosystems, the total installed capacity of photosystem will be only 200 MW, which is in 4 times less than their global production in 1993 if production reaches photosystem 1 year % of the total sales of energy in the world, their production compared to the current level should be increased tenfold, and the increase to 10% of this sale will hundredfold increase in the production of the photosystems. For the successful implementation of the photosystems their unit cost should be reduced to 3-5 times before there will be large power system.

Half of sales accounted for the single crystals of silicon, polycrystalline modification also has a great future. Big future system will have the thin film, in particular amorphous silicon. Some samples of photo-converters based on amorphous silicon have an efficiency of 10%, the unit cost of $ 1 / W, the cost of electricity produced 10-12 cents / (kW / h) - is lower than it was worth in 1993, has the prospect of reducing the cost of to 4 cents / (kW / h) in 2020.

So, the photo energy may be the energy source of the world's leading large-scale industry. This is confirmed in 1994 made development, experts say.

Literature:

1. Beschinsky A. Common problems of the fuel and energy situation in the world. / / Thermal Engineering. 2004. Number 5, p. 26-30.