Safety is the state of being "safe" (from French sauf), the condition of being protected from harm or other non-desirable outcomes. Safety can also refer to the control of recognized hazards in order to achieve an acceptable level of risk.
The amount of energy potentially available from the difference in the salt concentrations of seawater and river water around the world is 1.4 to 2.6 terawatts, or about 20 % of local electricity consumption. This natural process does not produce carbon dioxide or any other polluting combustion emissions, nor does it result in thermal pollution.