Selection and Location of Power Plants: 14 Considerations

The selection of the site for a power plant depends upon many factors such as cost of transmission of energy, cost of fuel, cost of land and taxes, requirement of space, availability of site for water power, storage space for fuel, transport facilities, availability of cooling water, nature of load, degree of reliability, pollution and noise, interest and depreciation etc.

The following discussion provides various points in detail. All these points should be considered together in taking final decision about the selection and location of power plant:

Consideration # 1. Cost of Transmission of Energy:

A power plant should be located as near to the load centre as possible. This reduces the transmission costs and losses in transmission.

Hydroelectric, steam (coal based) and nuclear power plants cannot be located near the load centres and need transmission lines of larger, shorter and moderate length. Diesel and gas turbine power plants can be located anywhere and so no transmission line is required. However, the modern power plants are of large capacities and feed a grid which supplies power to large areas. As such other considerations become more significant than the consideration of location of plant near the load centre.

Consideration # 2. Cost of Fuel:

The cost of fuel is an important consideration in deciding the type of power plant for a particular location. With hydroelectric power plants there is no cost of fuel as the source of power is water but water should be available in huge quantity and at sufficient head.

For steam plants, the cost of coal for the boilers and the availability of coal are important considerations. If cheap oil is available, the boilers may be oil fired and steam plants may complete other types of power plants. Steam power plants are most economical near coal mines and by the side of river or canal.

Fuel used in nuclear power plant is expensive and is difficult to recover. Diesel engines need oil as fuel and cost of this depends on the location of the power plant. For instance, if the plant is to be located near oil fields where oil is available in plenty and at cheaper rates and the transportation cost is extremely small, it may be economical to install a diesel power plant from the point of view of fuel cost.

Consideration # 3. Cost of Land and Taxes:

The costs of land as well as taxes on the land are dependent on the situation of the proposed power plant. The cost of land near a load centre (in a big city) may be very high as compared to that at remote place. The taxes also would be higher for land in the centre of a commercial city. This is therefore, an important point to be considered in the economic selection of site.

Consideration # 4. Requirement of Space:

The space and building requirements of the power plant is another point to be considered. If the building and space required are both large, the cost of land as well as building will be large. Thus, large power plants in the hearts of big cities and near the centre of gravity of load are not economical.

A hydroelectric power plant requires a lot of space for civil engineering construction works like dams etc., the building has to be much larger than required by other types of power plants, and a number of arrangements have to be provided in the building as special features which are quite different from those in other types of power plants. The location, however, is suitable at site where water is available at enough head and the cost of land is not excessive.

Steam power plants do not need so much space, but they require space more than that required by other power plants (diesel, gas turbine, nuclear). Diesel power plant needs minimum space. The space required for gas turbine power plant is more than that for diesel power plant but less than that for hydro, steam and nuclear power plants.

In case of nuclear power plants, the substrata must be strong enough to support the heavy reactors which may weigh as high as 1,000,000 tonnes and impose bearing pressures around 50 tonnes/m². Area remote from coal fields and hydro site are preferable so as to improve the reliability of supply over the area. The site selected for nuclear power plants should have adequate space and arrangement for the disposal of radioactive waste.

Consideration # 5. Availability of Site for Water Power:

In deciding the type of power plant for a given location, it is desirable to investigate whether any suitable source of water and sites are available for the development of hydroelectric power plant. Some of the considerations are topography of land, rainfall during the year, catchment area, suitable site for storing water behind the dam, huge quantity of water at sufficient head and cost of civil engineering works.

Consideration # 6. Storage Space for Fuel:

A steam (coal-based) power plant needs space for storage of coal in amounts depending on the size of plant. A supply of coal for the next 2/3 weeks at least should always be available on site. The amount of reserve stock required depends on the location of power plant. If the plant is near a coal mine it may not be necessary to store a large quantity, while if the coal has to be transported from a long distance over lake or rail etc., a large stock may be required.

For oil fuel the space required is comparatively small. The quantity required as space depends to a great extent on the degree of security of oil supplies.

Consideration # 7. Transportation Facilities:

The location of a power plant is dependent to some extent on the availability of transportation facilities. It is necessary to have a railway, line available and extended to the yard for bringing in heavy machinery for installation in the beginning and for bringing in fuel-coal or oil as well as material required for maintenance. Alternatively, the plant may be located on the bank of a river where facilities are available for transport by barges or ships.

The machinery to be transported for a steam plant is rather heavy, as the plant will in general be much larger than a diesel plant. For a diesel power plant the problem of transport is not so acute, the plant is generally small, the machines and equipment to be brought in are not very heavy, and large quantities of fuels are not required.

Road transport should, however, be available. For hydroelectric power plants, remote from the normal available rail and other transport facilities, roads are to be built leading to the site and arrangements made so that the equipment can be taken to site. Heavy equipment may have to be transported in parts and assembled on site. As nuclear power plant needs very little fuel, hence it does not require direct rail facilities for fuel transport. However, transportation facilities are required during the construction stage.

Consideration # 8. Availability of Cooling Water:

A steam power plant needs larger quantities of cooling water than diesel and gas turbine power plants. Water is circulated through condenser tubes to condense the steam and to maintain a high vacuum in the turbine condenser for high efficiency. Thus, site adjacent to larger bodies of water are preferable. Alternatively, tube-wells and cooling towers have to be installed and their cost must be taken into account.

Availability of reasonable pure water as make up water is another requirement. A diesel power plant requires water for cooling the cylinders of engines, and for this, water is required to be circulated through the cylinder jackets. The quantity of water required is, however, very small compared to the requirement of the steam power plant, and the diesel power plant is much smaller.

The diesel power plant, therefore, can be located at a place that is suitable from other points of view. Gas turbine power plants, also need little cooling water and can be located anywhere if other requirements are met. Nuclear power plants need more than twice the water required for the steam plant of the same size for cooling etc. Hence, the site selected for nuclear power plant should be near a river or lake or by sea side.

Consideration # 9. Disposal of Ash:

A steam power plant produces huge quantity of ash. A site where ash can be disposed off easily will naturally be beneficial. In case of nuclear power plants, the disposal of products (radioactive in nature) is a big problem. They have either to be disposed off in a deep trench or in a sea away from the seashore.

Consideration # 10. Pollution and Noise:

A site for a power plant near a load centre may be objectionable from the point of view of noise and pollution. Diesel engines are noisy and people in the vicinity are likely to raise complaints. Similarly gas turbine power plants also produce noise. A steam power plant in the centre of city may also cause noise, though not so much as a diesel power plant. Smoke from the chimney of a steam power plant is undesirable in cities.

There is a danger of presence of radioactivity in the atmosphere near a nuclear power plant. However, as a precautionary measure, a dome is used in the plant which does not allow the radioactivity to spread by wind or underground water ways. Noise of exhaust from diesel engines is objectionable, but may be reduced to some extent by means of silencers.

Consideration # 11. Nature of Load:

The nature of load to be supplied affects the choice of the power plant to a certain extent. If the load varies suddenly to a great extent; so that the load factor is poor, and if the load is not very large, a diesel or a gas turbine plant will be chosen as they are more adaptable than a steam/nuclear power plants as they can be started quickly and can be put to share full load within few minutes.

With a steam plant the boilers have to keep banked and ready to pick up load any time. The steam power plant also requires a longer time for starting and for taking load, as the necessary vacuum has to be created and maintained before the load can be shared. Nuclear power plants are not well suited for varying load since the reactor does not respond to the fluctuations of load efficiently.

Nuclear power plants also needs a longer time (2-3 hours) for starting and taking load. If hydroelectric power plant of small or suitable capacity is available, it can be started quickly and take up load, and thus can be employed for the varying loads.

Consideration # 12. Reliability of Supply:

In case all the big power plants are located on one side of a state, the reliability of supply in remote areas would be poor. As such power plants should be located in different areas of the state so that reliability of supply is good everywhere.

Consideration # 13. Equitable Growth of Different Areas:

It has been seen that availability of power from a nearby source in an area encourages setting up of heavy industries in that area and consequently, the ancillary industries are also to come up. This can improve the economy of a backward area significantly. In a welfare state committed to growth of all regions, some power plants should, therefore, be installed in backward areas. In such areas land and labour will also be available at cheaper rates.

Consideration # 14. Interest and Depreciation:

The capital required initially depends on the total investment on the power plant, power system layout and installation. The rate of interest on capital depends only on the availability of money in the market, and not on the type of power plant. The depreciation cost, however, varies with the type of power plant. The depreciation in case of hydroelectric, steam, nuclear, diesel and turbine power plants may be taken as 1 -2%, 3 1/2 -4 %, 3-4%, 5-6% and 6 1/2% respectively.

In case of plant proposed for an industrial complex, the problems of selection of the type of the plant and its location are quite simple. If the site is near a lake, river or sea the condensing steam power plant may prove economical. If there is a scarcity of water supply, then the possibility of setting up of either a steam plant or a diesel plant using spray ponds or cooling towers may be investigated. If the site is near a river with a favourable hydro site, then the hydro plant can be set up. Anyhow before deciding the type of plant, the total annual cost for each option must be worked out.

There can be no generalization in respect to the choice of the type of plant. Each case will have to be studied individually and decided on its merits by working out the economics involved. Whatever the choice, the power supply must be reliable and available at cheaper rates.