Finance is a field that deals with the study of investments. It includes the dynamics of assets and liabilities over time under conditions of different degrees of uncertainties and risks. Finance can also be defined as the science of money management. Market participants aim to price assets based on their risk level, fundamental value, and their expected rate of return. Finance can be broken into three sub-categories: public finance, corporate finance and personal finance.
Economics is not simply a topic on which to express opinions or vent emotions. It is a systematic study of what happens when you do specific things in specific ways. In economic analysis, the methods used by a Marxist economist like Oskar Lange did not differ in any fundamental way from the methods used by a conservative economist like Milton Friedman.
Thomas Sowell, Ch. 1 What is Economics? in Basic Economics
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.