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.
Tidal Power. The gravitational pull of the moon and sun along with the rotation of the earth cause the tides. In some places, tides cause water levels near the shore to vary up to 40 feet. People harnessed this movement of water to operate grain mills more than a 1,000 years ago in Europe. Today, tidal energy systems generate electricity. Producing tidal energy economically requires a tidal range of at least 10 feet. Barrage of the tidal power plant on the estuary of the Rance River in Bretagne, France Source: Stock photography (copyrighted)