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

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Can renewable energy power the world?

5.11 Future prospects for hydro

World total electricity production in 2009 was 20 000 TWh from an installed generating capacity of about 4500 GW. The corresponding figures for hydroelectricity are 3270 TWh from a capacity in the region of 900 GW – roughly 16% of world output from about 20% of world generating capacity.

In terms of the general future for hydroelectricity, these two quotations offer broadly similar views, but with slightly different emphases:

In developed markets such as the European Union, United States, Canada, and Japan, where many hydropower plants were built 30–40 years ago, the industry is focused on relicensing and repowering as well as adding hydro generation to existing dams. In developing nations such as China, Brazil, Ethiopia, India, Malaysia, Turkey, and Vietnam, utilities and developers are focused on new hydro construction.

(REN21, 2010)

The least-cost way to increase hydro generating capacity is almost always to modernise and expand existing plants, where this is an option. Most of the hydro plant presently in operation will require modernisation by 2030. While capacity expansions are generally made at existing hydro stations, there are sometimes opportunities for installing generators at non-hydro dams. There are 45 000 large dams in the world and the majority do not possess a hydro component.

(WEC, 2010b)

There are of course many who would reject the implied acceptance of the construction of new large hydro plants in the less developed regions of the world, whilst not everyone agrees that countries such as the USA, Switzerland and other parts of Europe (including the UK) have no room at all for further hydro development.

Figure 18 The Itaipú hydropower plant on the Parana river between Brazil and Paraguay has a capacity of 14,000 Megawatts, an effective head of 200 metres and a reservoir area of 1350 square kilometres

Any account of the world future for hydropower must consider China:

China’s hydroelectric resources are enormous. The country has 378 GW of technically exploitable hydropower reserves capable of producing 1,920 TWh per year and 676 GW of theoretical hydroelectric capacity, which would yield 5,900 TWh per year. Both are the largest such estimated resources in the world.

(Ni, 2009)

The discrepancy between the hydro technical potential of 1920 TWh per year here and the 2500 TWh per year shown in Table 2 might be regarded as relatively small, given the doubtful nature of such data. The more significant fact is that both projections suggest a possible future Chinese output that is well over half the world’s total current output.

One form of hydro development that is generally expected to attract support in the coming years is pumped storage. World pumped storage capacity reached 127 GW in 2009 (HydroWorld, 2009), but at least 15 projects were under construction, increasing the total by about 9 GW. With rising demand for peak load balancing and the need to accommodate the growing output from intermittent sources such as wind and solar power, the demand for pumped storage is expected to increase by 60% over the next four years (WEC 2010a).

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