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 energy is a largely untapped, renewable energy source based largely on lunar gravitation. While the potential of tidal hydroelectricity has long been recognized, compared to river dams, tidal power projects are expensive because massive structures must be built in difficult saltwater environments.here are relatively few coastal locations in the world where the tidal range (i.e., the difference between high and low tides) is large enough to justify exploitation of the available tidal energy. There must be a sufficiently high tidal range (at least 5 m) for construction of an economically feasible plant.