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SOLZINC: successfully storing solar energy by producing metallic zinc

The EU funded SOLZINC project has become the first to successfully use solar energy in a pilot-plant to create storable energy from a metal ore. Solar energy can be converted into chemical fuels that can be stored for long periods of time and transported over long distances. ...

The EU funded SOLZINC project has become the first to successfully use solar energy in a pilot-plant to create storable energy from a metal ore. Solar energy can be converted into chemical fuels that can be stored for long periods of time and transported over long distances. SOLZINC is a pan-European research project partially funded by the European Union within its Fifth Framework Programme under the Key Action 'Economic and Efficient Energy for a Competitive Europe'. It aims to develop solar chemical reactor technology for the solar production of zinc (Zn) by carbothermic reduction of ZnO. The project partners include PROMES-CNRS (France), ScanArc Plasma Systems AB (Sweden), ZOXY Energy Systems AG (Germany), the Paul Scherrer Institute (PSI) at the Institute of Energy Technology-ETH (Switzerland) and the Weizmann Institute of Science in Israel. Based on earlier laboratory scale work, the SOLZINC project primarily aims at scaling-up a technology for carbothermic solar zinc production to a pilot scale. A detailed study on the technology costs and economics of solar mitigation of CO2 emissions and electricity generation via the ZnO-Zn cycle was conducted at an earlier stage, and its experimental, numerical, and eco-efficiency results were used to develop a conceptual design for the reactor and the other components of the ZnO-Zn cycle. Extensive trials with reactor-prototypes at the solar-furnace of the Paul Scherrer Institute in Zürich prepared the way for the current stage of technology testing in a demonstration plant on a commercial scale at the Weizmann Institute of Science in Rehovot, Israel, where a pilot plant for 300 kW concentrated solar energy was erected. The first outcomes of the major solar test campaign, scheduled for spring-summer 2005, constitute an important milestone. Solar-made zinc offers the possibility of storing and transporting solar energy. It is a compact solid fuel that finds applications in Zn/air fuel cells and batteries. Zinc can also reacted with water and form high purity hydrogen. In either case, the chemical product from these power generation processes is ZnO, which in turn is solar-reduced to Zn. The first trials of the solar power plant have used 30 per cent of available solar energy and produced 45 kilos of zinc an hour, exceeding projected goals. A higher efficiency is expected during further tests this summer. Industrial sized plants, to be developed from this prototype, are expected to reach efficiency levels of 50 to 60 per cent. The success of this solar chemistry pilot project opens the way for an efficient thermo-chemical process whereby the sun's energy can be stored and transported in the form of a chemical fuel. The expected long-term benefits of this technology include a reduction of CO2 emissions, the conservation of fossil fuel resources, an opportunity for an almost emission-free urban transport system and an increase in employment opportunities in the field of renewable energy.