Place de l'hydroélectricité dans le bilan énergétique mondial

Share of hydro-electric power in the world energy balance

Secrétaire Général Commission Internationale des Grands Barrages Contrôleur Général adjt. Direction de l'Equipement - Electricité de France

Abstract

Hydro power and other renewable energy sources arise from features that cannot be dissociated from the place they occur, unlike solid, liquid or gazeous fossil fuels of non-renewable energy sources that are readily transportable. Hydro power is only able to come into its own in combination with electricity, but river harnessing has always been seen as man's triumph over the forces of nature and has become something of a religious cruisade. Total developable hydro potential is estimated at 10000 -12000 TWh, repressenting 27 % to 33 % of the total theoretical potential put at 36 000 TWh. But authors calculate in energy or capacity using different units of measurement, and there are many errors in the literature. Hydro power is more evenly distributed throughout the world than coal, oil, gaz or uranium reserves although within large regions like the African continent, there is considerable imbalance with most of the potential being concentrated in a few countries or even at a few sites like Inga. In 1978 developed potential (expressed as actual electricity output in that year) represented 17 % only of developable potential (98 000 TWh) and 21.7 % of total electricity production. But two-thirds of the developed potential was confined to the 24 OECD countries, which have harnessed 50 % of their potential on average ; France, by the end of 1981, had reached a figure of 90 %. By the year 2000, 35 % might be developed, with the OECD countries accounting for 15 %, USSR, India, Mexico, Brazil and Yugoslavie 12 %, and the rest of the world 8 %. Long transmission distances will not be a brake on development. The new thyristor rectifier technology for large-capacity d.c. lines is promising. Mini-hydro is not a universal cure and can only contribute a few percent of output. Pumped storage, expanding fast in Japan, USA and Western Europe is just its attractive to engineers and the construction industry as conventional hydro but is does not produce energy ; it merely stores it for later use. The plants are sometimes very large indeed (1 800 MW at Dinorwic in Wales). Conventional hydro schemes are also growing in size, being increasingly sited on large rivers in the plains (10000 m3/s average river flow at Itaipu in Brazil). Where alternative capacity exists on the grid, hydra is being used for peaking duty (10 000 MW at Grand Coulee on the Columbia and at Guri on the Caroni in Venezuela). The share of hydro in total electricity will have dropped from 40 % in 1925 to 13 % by the year 2000. But its share in total energy, which rise from 1.7 % in 1925 to 5.3 % in 1974, is expected to reach 6-7 % by the end of the century since predicted annual growth rates are : total energy 2.5 %, hydro 3.5 %, total electricity 5 %, for a world economic growth of 3 %. By 1978, hydro power occupied the same place in electricity output as nuclear power is expected to do by 1990.