The previous Lesson was about variable loads on power stations. You are expected to remember the following from Lesson 7.
 Definitions
 Load Curves
 Types of loads on a power station
 Selecting generation units for a power station
 Base & Peak loads
 Methods of meeting load
Preview: Lesson 8
This lesson is about comparing of power stations. At the end of the lesson, you should understand how each power station discussed in this course measures up against others with respect to the following:
 Location & space required
 Initial & running cost
 Overal efficiency & standby losses
 Maintenance costs
 Limit of source of power
 Cost of fuel & clean emissions
 Starting
 Transmission & distribution costs
Five types of electric generating power stations have been discussed in this course thus far. These being:
There are other types of power stations used around the world besides the big five covered here. The following are not covered here due to the fact that they are strictly dependent on the geography of the area where they can be erected and hence do not find wide use around the world:
Note that the Pumpedstorage scheme and Gasturbine power stations are not included in this lesson as they are rarely used for base loads.
This lesson will compare the four widely used power stations (steam, hydro, diesel and nuclear) with regard to the following aspects:
 Location & space required
 Initial & running cost
 Overal efficiency & standby losses
 Maintenance costs
 Limit of power source
 Cost of Fuel & Clean emissions
 Starting
 Transmission & distribution costs
For the above comparison, sortable lists will be used with the following key of merit:
1  Highest merit (Highly desirable)
3  Second lowest merit (Tolerable)
2  Second highest merit (Acceptable)
4  Lowest merit (Not desirable)
You can click on the sorting icon to sort lists by the item you are interested in. This information is vital in deciding the type of power station that would be suitable in different situations.
Power Station

Rank

Location

Rank

Space required


Steam Power station 
2 
Where there is Enough supply of water and coal. 
3 
Needs sufficient space for all equipment.
 Hydro Power station 
4 
Where large reservoirs can be obtained by dam construction. 
4 
Needs very large space for constructing a dam
 Diesel Power station 
1 
Where there is required space & water, thus can be located anywhere. 
2 
Needs very little space for all equipment
 Nuclear Power station 
3 
Where there is enough supply of water, but must not be too far away from populated areas. 
1 
Needs the least space, compared any other power station of equal capacity


Power Station

Rank

Initial Cost

Rank

Running cost


Steam Power station 
2 
Are lower than those of Hydro & Nuclear. 
3 
Higher than hydro & nuclear.
 Hydro Power station 
3 
Are very high because of dam construction. 
1 
Practically NIL; no fuel needed
 Diesel Power station 
1 
Lowest compared to all other power stations. 
4 
Highest due to Diesel prices
 Nuclear Power station 
4 
Highest due to complex nuclear reactors. 
2 
Second lowest


Power Station

Rank

Efficiency

Rank

Losses


Steam Power station 
4 
This is plant is ≈ 25% efficient. 
4 
This is due to Boiler remaining in operation even if turbine is switched off.
 Hydro Power station 
1 
This is plant is ≈ 85% efficient. 
1 
This Plant has no standby losses
 Diesel Power station 
3 
This is plant is ≈ 35% efficient. 
2 
This Plant has lesser standby losses
 Nuclear Power station 
2 
This is plant is ≈ 55% efficient 
3 
This Plant has less standby losses


Power Station

Rank

Cost of Fuel Justification

Rank

Clean emissions Justification


Steam Power station 
4 
Maximum, due to constant demand of coal & transportation. 
4 
Has highest polluting emissions.
 Hydro Power station 
1 
Practically nil. 
1 
Biodiversity loss & greenhouse gas emissions from flooded land
 Diesel Power station 
3 
Higher than Hydro and Nuclear power stations. 
2 
Has cleaner emissions compared to steam & nuclear power stations.
 Nuclear Power station 
2 
Minimum, due to small quantities of fuel required. 
3 
Has cleaner emissions compared to steam power stations but produces nuclear waste, which is currently an unsolved problem.

