Power Generation/Comparison

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 & stand-by 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:

• Steam/Thermal Power station
• Hydro Power station
• Diesel Power station

• Nuclear Power station
• Gas turbine Power station

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:

• Geo-thermal
• Wind

• Solar
• Tidal

Note that the Pumped-storage scheme and Gas-turbine 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 & stand-by 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 stand-by losses Diesel Power station 3 This is plant is ≈ 35% efficient. 2 This Plant has lesser stand-by losses Nuclear Power station 2 This is plant is ≈ 55% efficient 3 This Plant has less stand-by losses

Power Station Rank Maintenance costs Justification Steam Power station 3 High. Skilled staff required. Hydro Power station 1 Lowest. Diesel Power station 2 Low. Nuclear Power station 4 Highest. Highly skilled and specialized staff required.

Power Station Rank Limit of source of power Steam Power station 4 Has most Limited fuel Reserves. Hydro Power station 2 Has undependable water source due to weather variations. Diesel Power station 3 Has Limited fuel Reserves. Nuclear Power station 1 Has sufficient fuel Reserves.

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.

Power Station Rank Starting Justification Steam Power station 4 Longest starting time. Hydro Power station 1 Shortest starting time. Diesel Power station 2 Short starting time. Nuclear Power station 3 Long starting time.

Power Station Rank Transmission & Distribution costs Justification Steam Power station 2 Low. Plant is close to load center. Hydro Power station 4 Highest. Plant is furthest from load center. Diesel Power station 1 Lowest. Plant is at load center. Nuclear Power station 3 High. Plant is far from load center.

References

• This resource is prepared from Lecture notes by Thuvack.
• V.K Mehta & Rohit Mehta :- Principles of Power systems (1st ed.). S.CHAND .ISBN 81-219-2496-0