BY KAI-UWE GRAW An old dream of humanity is to make use of the almost im­measurable energy of ocean waves. Their destructive power has however up to now not permitted any economically rea­sonable design to survive for long, although there have been many promising attempts and approaches. T he reduction in carbon dioxide emissions, which […]

BY Detlef Stolten In times when nuclear power in some countries is being phased out and CO2 emissions must be reduced, the path towards renewable energy sources is clearly marked out. However, due to their strong fluctuations, renewable sources can not be very readily integrated into existing energy infra­structures. Can hydrogen serve as an energy-storage […]

The MCFC takes its name from its electrolyte of alkali car­bonates, which is used in molten form at the operating tem­perature of 650° C. The electric current is carried in the electrolyte by carbonate (CO32-) ions. Maintaining the charge transport within the electrolyte thus requires CO2 circulation between the fuel gas used and the air, […]

Beginning in 1986, a simply-constructed wave power plant was built in Norway, where it was operated for about twelve years. The plant was on the island of Toftestallen near Bergen, and it was intended as a demonstration project for interested groups. The TAPCHAN (TAPered CHANnel) di­rects the water from the incoming waves into a channel […]

With regard to energy technology, hydrogen has become rel­evant again today due to environmental problems. The ex­tensive combustion of fossil fuels such as coal, petroleum and natural gas is a large-scale intervention by mankind in­to the natural balance of the earth. The global warming pro­voked by the increasing concentration of CO2 in our at­mosphere will […]

In the SOFC, a thin ceramic layer of yttrium-oxide-doped zir­conium oxide (YSZ) serves as electrolyte, allowing the pas­sage of oxygen anions at its operating temperature of 900 to 1000° C. The power output of the systems currently being test­ed ranges from one kilowatt for household energy provision using natural gas up to a pressure-driven 200 […]

OWC is the abbreviation for Oscillating Water Column and describes a design which makes use of the wave motion in rising and falling water columns. Figure 5a shows how a typ­ical OWC functions. It consists of a chamber with two open­ings. One of these is on the side towards the incoming waves and lies beneath […]

As the lightest element, hydrogen has a high mass-specific energy storage density of 120 MJ/kg. This corresponds to about three times the storage density of diesel fuel, at 43 MJ/kg, referred to the so-called lower heating value. How­ever, this physically favorable property of hydrogen cannot readily be applied in a technological setting. While an automobile […]