Some of the factors to be considered while installing a power plant are as follows: 1. Selection of Power System 2. Location of Plant 3. Building Layout 4. Selection of Prime Mover 5. Selection of Operating Conditions 6. Cost 7. Selection of Units.

Factor # 1. Selection of Power System:

The type of power plant to be installed depends upon the source of energy. A hydropower plant should be installed where sufficient head of water is available whereas a steam power station is suitable near coal mines. A nuclear plant should be installed near a source of water for example, lake, river etc. Diesel plant is preferred for smaller loads.

Further choice about the number of generating units should be made. For example if a steam power plant of 200 MW capacity is to be installed then it is to be decided whether a single boiler will be supplying steam to a single steam turbine or there will be two units each of 100 MW capacity Unit system in which a single boiler supplies steam to single turbine is preferable.

The points to be considered while choosing the type of generation are as follows:


(i) Type of fuel available,

(ii) Type of load to be supplied,

(iii) Reliability of operation,

(iv) Cost of land,


(v) Cost of fuel transportation,

(vi) Availability of cooling water, and 

(vii) Cost of power transmission.

Factor # 2. Location of Power Plant:

It should be installed near the load centre so that the cost for transmitted power is reduced. It should be nearer to source of fuel and sufficient amount of water should be available near the power station. The soil should be such that special and costly foundation is not required. The plant site should be accessible by road or railway line so that the transportation of equipment is easy.

Factor # 3. Building for a Power Plant:


The power plant building should be simple, rugged and should have pleasing appearance. The size, arrangement and shape of power plant depends upon the type of power plant, the roofs are made usually flat. The roof deck can be carried on reinforced concrete slabs and beams.

The floors may be made up of concrete or tiles. Concrete floors are preferred. The structure should be fire proof. While laying out the various equipment allowances should be left for future expansion. The rooms of the building should be spacious, un-crowded, well lighted and clean.

Factor # 4. Selection of Prime Mover:

Depending on the load and type of power stations, the selection of steam turbine, hydraulic turbines, boilers, diesel engines, gas turbines should be made. The units installed should have capacity more than the peak load and some provisions should be made for future expected load. For example, the peak load of one city is 360 MW. Then two units each of 200 MW could be used keeping in view the future load.

Heat transfer is the primary function of the boiler. It should be capable of utilising the heat of the combustion of fuel to a great extent; in central power stations water tube boilers are preferred. Coal fired boilers have higher efficiency, than boilers using oil or gas as fuel because hydrogen loss is more in gaseous fuels. Pulverised fuel is preferred in case of low ranking fuels such as lignite etc.


The cost of boiler depends upon operating pressure, operating temperature, type of firing and efficiency desired. Higher pressure requires forced circulation. For higher temperature superheats are needed and. therefore, cost becomes high. The system used for coal firing in the boiler also influences the cost of boiler. Stoker firing is cheaper than pulverised fuel firing.

The efficiency of boiler is increased by adding heat recovery equipment such as economisers and air adding heat recovery equipment such as economisers and air preheater. Economiser improves the efficiency of boiler by about 4 to 10% whereas preheater further improves the efficiency by about is 6 to 8%.

The temperature of exhaust flue gases should be below 150°C because otherwise the condensation of moisture may take place and in combustion with sulphur dioxide it (moisture) will produce sulphuric acid dilute solution which is harmful for equipment.

In selecting a boiler its fixed cost and operating cost should be considered. The working pressure and capacity of modern boilers are quite high. In modern boilers working pressure has reached up to about 360 kg/cm2 and evaporative capacity of about 2000 tonnes per hour.

Factor # 5. Selection of Operating Conditions:


The power plant should supply the varying power demand. To supply varying power the supply of fuel, air, water, etc., should be varied accord­ingly. In order to keep the power plant efficient, the older and inefficient units should be re­placed by new and efficient units.

Factor # 6. Cost:

The cost of power plant consists of fixed cost, operating cost, depreciation charges etc. Cost of the power station should be kept as low as possible.

Some of the factors, which affect the cost, are as follows:

(a) The cost can be kept low by installing the power station near the load centre.


(b) The cost can be reduced by selecting prime movers of proper capacity. The cost of the power station is increased if the prime movers installed are of too high capacity as compared to the maximum expected power demand.

(c) As considerable area is required for a power station so the cost of land should be reasonable. As far as possible site sub-soil condition should be such that piling or blasting is not required and a good foundation can be made at reasonable depth.

(d) Water should be available in large quantity in case of steam power station, nuclear power station and diesel power station.

Factor # 7. Selection of Power Generating Units:

The generating units should fulfill the follow­ing retirements:


(i) The number of units selected should not be too many but they should not be less than two. In case two units are selected each should be capable of supplying the maximum load.

(ii) The units selected should be capable to supply the maximum load. The future de­mand extension should be kept in view while deciding the capacity of the units.

(iii) A reserve unit should be installed to supply the load if there is a break-down of highest capacity.

(iv) The units should operate at high load factors and should have high efficiency and their cost should be low.