Can renewable energy sources power the world?
Can renewable energy sources power the world?

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Can renewable energy sources power the world?

8 Hydro as a component of a power system

Few large power stations operate in isolation, and the extent to which a proposed plant can form a useful part of a supply system is important with the ideal power station characteristics being:

  1. constant availability
  2. a reserve energy store to buffer variations in input
  3. no correlation in input variations between power stations
  4. rapid response to changing demand
  5. an input which matches annual variation in demand
  6. no sudden or unpredictable changes in input
  7. a location which does not require long transmission lines.

Few, if any, sources meet all these criteria, but each compromise with the ideal adds to the effective cost

Almost all hydroelectric plants score well on item 4, and in regions with cold, dark, wet winters, on item 5 as well – unless the water is locked up as ice. Furthermore, sudden unplanned fluctuations in input (item 6) are rare, at least in large plants.

How well hydro performs on items 1, 2 and 3 depends in part on the type of plant. A high-head installation with a large reservoir will normally have little difficulty in maintaining its output over a dry period, whereas the water held behind the low dam of a run-of-river plant may not be sufficient to compensate for periods of reduced flow. A serious drought can of course affect all hydro plant over a wide region, so it cannot be said fully to satisfy the third requirement.

Overall, hydroelectricity ranks reasonably well in terms of the above criteria. And it may also offer a bonus. A hydro plant with a large reservoir not only maintains its own reserve of energy – it might, as we have seen earlier, provide a store for the surplus output of other power stations.

But does hydroelectricity impact the environment? And if so, in what ways? You will look at that next.

RENBOC_1

Take your learning further371

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses372.

If you are new to university level study, we offer two introductory routes to our qualifications. Find out Where to take your learning next?373 You could either choose to start with an Access courses374or an open box module, which allows you to count your previous learning towards an Open University qualification.

Not ready for University study then browse over 1000 free courses on OpenLearn375 and sign up to our newsletter376 to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371