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Wednesday, 7 September 2011

Nuclear energy phase-out is possible

ETH Zurich
Sept 2, 2011

Restructuring the energy system without nuclear power by 2050 is in principle technologically possible and economically manageable. However, it will demand a concerted effort by the whole of society. This is the conclusion reached by ETH Zurich researchers in a study they presented at the Energy Talks 2011.

Over the past few months, a group of researchers at the Energy Science Center (ESC) of ETH Zurich have carried out an intensive examination of whether the available options will enable Switzerland to scope out a medium-term energy future without nuclear power, as decided by the Swiss Federal Council in May. Their answer was «yes».

However, a step-by step restructuring of Switzerland’s energy systems during the coming years and decades will require great efforts by all areas of society. Nevertheless, a phase-out is not only technologically possible but would also enable positive long-term growth in all sectors of the economy. The study examined the period up to 2050. The researchers presented the most important results of the study (see box) at the Energy Talks at ETH Zurich on 2 September 2011.

No relaxations in climate targets
The unalterable boundary conditions applying to the ETH Zurich researchers’ modelling calculations are that the global climate targets – a maximum warming of two degrees centigrade – must be complied with. For Switzerland this means reducing annual per capita CO2 emissions from the present 5.2 to less than 2 tons by 2050 and to 1 ton towards the end of the century.

These targets require that, by 2050, this country must achieve, among other things, CO2-free building heating systems, efficient, partly electrified mobility, and minimal CO2 emission in electricity generation, all developments that are expected to be necessary and possible.

Hydroelectric power and new renewable energy sources

One of the biggest challenges facing the studies was to make plausible forecasts of the future electricity supply, which turn out differently depending on economic growth, population development and efficiency increases. For this purpose, the researchers calculated three demand scenarios and predict that, in 2050, Switzerland will have a gross electricity production of between 67 and 92 terawatt-hours (TWh). The most likely «medium» scenario assumes an annual electricity demand of around 80 TWh.

According to Konstantinos Boulouchos, coordinating author of the ETH Zurich study and Professor of Aerothermochemistry and Combustion Systems, it is clear that hydroelectric power, which amounts to just under 50 percent of total electricity generation and has limited potential for expansion, will continue to make an important base-load contribution. If the remaining 40 TWh is to be provided without nuclear energy, this will need a major expansion in new renewable energy sources, mainly photovoltaic, followed by the localised utilisation of biomass and finally geothermal energy. According to the ETH Zurich researchers, flexible gas-fired power stations or electricity imports will be indispensable to cover demand peaks, at least in the short term. However, foreseeable technological development should enable, from 2020 to 2025 onwards, the construction of combined gas-fired power stations in which the CO2 produced can be captured and stored.
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