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

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11 Future prospects for hydro

World total electricity production in 2016 was nearly 25 000 TWh and hydro power provided 16% of this, about 4000 TWh.

The percentage contribution from hydro has been falling gently for many decades, as the building of new plants has failed to keep up with the rapid growth in total world electricity consumption. As shown in Figure 5.4 most of the increase in world hydro output since 2005 has taken place in China where in 2016 hydro provided 19% of the total electricity demand. Here, electricity consumption has been increasing at about 8% per annum, but this growth rate has been matched by hydro construction whose output has more than doubled in the last decade.

According to the estimate shown in Table 5.2, China would appear to have already developed nearly a half of its hydro technical potential. In 2016, it had 331 GW of hydro installed capacity and, according to the International Hydropower Association, the potential to develop a further 200 GW (IHA, 2017). However most of the hydro resource is located in the mountainous west of the country and will require the construction of long distance high voltage transmission lines to distribute the power to the population centres in the east.

There is also large potential for hydro development in South America, where it already supplies about a half of the electricity. This requires tapping into the flows of large rivers, which may have serious environmental consequences.

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 19 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

One form of hydro development that is generally expected to attract support in the coming years is pumped storage. World pumped storage capacity reached 150 GW at the end of 2016 with about 6.4 GW being added in that year (REN21, 2017). China has announced a target of 40 GW of pumped storage by 2020 to help balance the output from the large increase in output from PV and wind power (IHA, 2017).

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).

Finally, there is the hydro potential of the many thousands of dams in the world (possibly 30 000) that currently do not support a hydro plant.

That concludes this week. You can now attempt the end of week quiz.