This paper discusses ultrahigh-voltage (UHV) DC as an efficient solution for bulk power transmission especially of renewable energy. The European policy and legal framework is used to illustrate how this new technology, international electricity market integration, and the distribution of wind and solar natural resources lead to the need for continent-wide internationally coordinated network planning with a view on long-term greenhouse gas reduction. First, the technical and economic aspects of UHV transmission are described, including, e.g., converter configurations and internal and external insulation. Then, UHV transmission is put into the context of other broad current questions of power system development: AC and DC, microgrids, smart grids, power electronics, overhead lines, cables, and gas-insulated lines. The final part discusses the European legal framework for climate protection and for transmission system operator (TSO) cooperation in the new, legally mandated European transmission system operator association ENTSO-E, in particular for joint European grid planning and for R&D. This example shows how UHV technology development can contribute to market integration and economic and environmental goals for continent-wide and internationally coordinated transmission development as one option in international long-term system studies.

A review is given of world-power demands, including energy-resource, environmental, technological, financial, and political aspects. International perspectives on the future of power generation and transmission to early in the next century in Germany, Italy, France, Japan, and the United States are provided. Discussed are nuclear power stations in Eastern Germany that are being closed down on safety grounds and the construction of semifinished nuclear plants that has been halted. Economic use of energy and combined heat and power is also evaluated. The Italian energy sector, which is the most import- and hydrocarbon-dependent of any of the major European economies, is discussed. Distribution of the generation between nuclear and hydro units in France is reviewed. International interconnections between France and European countries are discussed. Three major policy agendas for Japan are reviewed. A 1000-kV trunk line to transmit nuclear power to metropolitan areas that is under construction is also discussed. Proposed changes to Clean Air Acts to reduce SO/sub 2/ emissions from electric power generation in the United States are examined.>

Reviews the physics of tidal power, considering the gravitational effects of the Moon and Sun; semidiurnal, diurnal, and mixed tides; and major periodic components that affect the tidal range. Shelving, funneling, reflection, and resonance phenomena that have a significant effect on tidal range are also discussed. Basic parameters that govern the design of tidal power schemes in terms of mean tidal range and surface area of the enclosed basin are identified. Because energy extracted is proportional to the square root of the tidal amplitude, sites with large tidal amplitudes are best suited for tidal power developments, whereas sites with low tidal amplitudes have sluicing that may be prohibitive. Potential tidal energy developments are mentioned. Existing tidal energy plants are discussed. Tidal barrage design and construction using caissons is examined, as are alternative operating modes, development trends and possibilities, generation cost at the barrage boundary, sensitivity to discount rates, general economics, and markets. Environmental effects, and institutional constraints to the development of tidal barrage schemes are also discussed.>