Postings without closing dates are often positions that are difficult to fill or ones that come open frequently. An example of a position that is difficult to fill is a psychologist at a small-town state hospital. If the hospital left the job open for a month, it is unlikely to get a sufficient number of applicants.
The Disadvantages of Tidal Power Tidal power is growing rapidly in interest as countries look for ways to generate electricity without relying on fossil fuels. Tidal schemes have a number of advantages, including their lack of greenhouse gas emissions and 100% renewable nature.
As there are two high and two low tides each day, electrical generation from tidal power plants is characterized by periods of maximum generation every twelve hours, with no electricity generation at the six hour mark in between.arrages can be designed to generate electricity on the ebb side, or flood side, or both. Tidal range may vary over a wide range (4.5-12.4 m) from site to site. A tidal range of at least 7 m is required for economical operation and for sufficient head of water for the turbines.