Renewable power

Geography of Pakistan · Power. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.

Test this topic free All Geography of Pakistan topics

The idea

Renewable sources are not used up: flowing water (hydel), wind, waves and sunshine. They need no fuel and give off no smoke, but each depends on nature, so output is not steady.

Hydel is Pakistan's main renewable. Large dams such as Tarbela and Mangla are multi-purpose: they make electricity, store water for irrigation and help to control floods. They cost a great deal, drown land and villages, and slowly fill with silt.

Small schemes suit places far from the national grid: micro-hydel on fast mountain streams, solar panels in sunny, dry areas. Supply is still short and unreliable because demand grows faster than supply and much power is lost on the way.

Rules to remember

Hydel: cheap to run and clean, but high building cost, people must be resettled, reservoirs silt up, and output falls in winter when rivers are low.
Good dam site: narrow, deep valley; strong, solid rock; large, reliable river flow from rain or snowmelt.
Wind: best in the Gharo–Jhimpir area of southern Sindh, where strong sea winds blow; output changes with wind speed.
Solar: plenty of sunshine and no grid needed; no power at night without batteries, and panels cost money to buy.
Wave power: equipment is costly and storms damage it, so it is hardly used.
Shortages (load-shedding): demand rising faster than supply, old lines losing power, theft, and costly imported fuel.
Remote, scattered villages are often off the grid because lines to them cost too much.

Common mistake

Students write that renewable power is free. The source is free, but dams, turbines and panels are expensive to build, and the output is not constant.

Worked example

Engineers find that the Tarbela reservoir holds less water now than when the dam was new. Why, and how does this affect the scheme?

The Indus carries a heavy load of silt from the northern mountains.
The reservoir slows the water, so the silt settles on the reservoir floor.
Year by year the silt takes up space that water used to fill.
Less stored water means less for irrigation and less to turn the turbines in the dry season.

Answer: Silting has reduced the storage, so the dam gives less irrigation water and less electricity when river flow is low.

Ask about this

Type what you are stuck on. The helper finds the explanation, worked examples and the notes to read, free and instant.

Read the full notes

Geography Key-Terms List

Keep going

← Non-renewable power Agricultural systems →Take a Geography of Pakistan test