Distributed electricity generation is increasingly applied in the electricity grid. This generation can be more energy efficient than conventional generation; however, a large scale introduction of distributed generators implies possible instability in the grid. A Virtual Power Plant (VPP) deals with this problem by controlling the distributed generators in such a way, that the complete group a...

The power system requirements for wind power mainly depend on the power system configuration, the installed wind power capacity, and how the wind power production varies. Wind resources vary on every time scale: seconds, minutes, hours, days, months and years. On all these time scales, the varying wind resources affect the power system. An analysis of this impact will be based on the geographic...

Radioactivity in nuclear power effluents is negligible compared to that in retained wastes to be disposed of as solids. Two basic waste categories are those for which shallow disposal is accepted and those for which more extreme isolation is desired. The latter includes "high level" wastes and others contaminated with radionuclides with the unusual combined properties of long radioactive half-l...

Static stretching, consisting of holding muscles at lengthened positions for typically 15-45 seconds, has been recommended before participating in physical activity. Gymnasts historically have performed static stretches, such as splits, during the warmup portion of training. Recently however, data has been presented from studies on adults which have shown that static stretching immediately prio...

Electricity cannot be conviently stored. Thus there should be sucient production at all times to meet the demand for electric power. If a low-cost generating unit fails this will lead to its substitution by a higher cost unit. The cost of producing electric power is a random variable because it depends upon two uncertain quantities, demand and the availability of the generating units. Analytic...