Bridging the generation gap1 January 1999
How dependent are the major hydro producing countries on hydro power? Gemma Newman asked members of the industry for their thoughts
Despite the high proportion of hydro power in the generation mix, major hydro producing nations are not entirely dependent on this source of energy. Many countries that have successfully harnessed their hydro potential still have to consider measures to cope with electricity consumption if low rainfall significantly affects generation.
In Norway hydro power accounts for 99% of both capacity and generation. In 1998 the generation mix was:
•Hydro power — 99.4% (116,277GWh).
•Thermal — 0.6% (668GWh).
•Wind — 0.07% (8GWh).
‘Norway is less dependent on hydro than the generation mix suggests because the country is closely interlinked with other Nordic nations,’ says Jørn Høistad of Norplan. Sweden and Norway now form a single electricity market and Finland and Denmark also have access to this. Norway is also planning inter-connections with the Netherlands in 2002 and with Germany in 2004. The total hydro dependency in the Nordic market was 54.8% of generation in 1998. If hydro generation declines significantly in Norway there is little excess capacity domestically so other Nordic countries act as a reserve. During periods of low rainfall or exceptionally cold winters, the reduction in hydro power generation is compensated for by increased imports of electricity, notably from Denmark. Norway also imports a large amount of electricity from Sweden and a little from Finland and Russia (see table). However, there is an established system for rewarding large utilities who install small scale thermal plants. These companies receive preferential terms for keeping this capacity available. In return the system operator could call on the capacity in periods of low system reserves.
It is unlikely that Norway will increase its dependence on hydro power in the future — realistically there is little untapped hydro potential left. There have been a few applications for licences to construct new hydro power plants but most projects are now renewals of old plants, according to Høistad. The Norwegian utility Naturkraft has applied for licences for two gas-fired thermal projects on the western coast of Norway, but following a heated political debate concerning the use of North Sea gas, the projects have been delayed. ‘A 100MW wind project was reported a few days ago,’ Høistad said. ‘But I don’t think the plans are very firm yet.’
In Iceland dependency on hydro power is set to compete with the foreseeable increase in the production of geothermal power. In 1998 hydro production was about 95.8% of the total power generation in the country. Even though hydro is an important resource in Iceland only 35% of hydroelectric potential has been harnessed so far.
Unlike Norway the geographical isolation of Iceland means the country cannot import power from other countries. Extra precautions must be taken to allow electricity generation to continue if there is low rainfall. Thorsteinn Hilmarsson from Iceland’s national power company Landsvirkjun says: ‘We design our power system based on historical data on the rivers, weather and ground water. The production capacity of the system is rated according to its production capacity in the worst historically known year. We must take on extra costs of providing primary electricity to our clients resulting from a new record low in production capacity.’ As in Norway, the glaciers and snow often compensate for warm and dry years by melting more. There are also small diesel stations throughout the country that function as back-up power in case of hydro breakdown.
Landsvirkjun finds that most years are better than the historical low and the company acquires an excess production capacity in its system. ‘With this, we produce secondary electricity sold at a lower price with the option that we can stop delivery in years when the excess capacity is not available,’ says Hilmarsson.
The economical and environmentally sound power potential in Iceland is estimated at 30TWh of hydro and 20TWh of geothermal energy. Hilmarsson claims: ‘We have only harnessed about 15% of this so far, primarily with hydro projects.’
In Switzerland hydro power at present covers approximately 60% of the electricity supply, the remaining 40% being mostly nuclear. The amount of hydro power used will probably not change significantly in the near future. There are various reasons for this but, as Walter Hauenstein of the Swiss Association for Water Economy explains: ‘Climate changes may influence production. Available studies do not predict less rainfall but the glaciers are melting away more rapidly than 100 years ago. The production due to melting ice will be reduced once these glaciers have disappeared.’ Economically, Switzerland is not dependent on hydro power. Exports exceed imports in summer whereas production and consumption is more or less equal in winter. However, in a dry year Switzerland cannot store enough water to meet its own needs. On a short term basis there are certain reserves stocked in the reservoirs and a number of fossil fuel plants to compensate if hydro fails.
There is also a permanent exchange of electricity with neighbouring countries and a surplus of electricity which is mainly due to long term contracts with French nuclear power plants. As with the Nordic nations, Switzerland has interconnections with its neighbours, so reduced hydro production is generally compensated for by reduced exports or increased imports of power.