Energy efficiency refers to the use of energy at the same level, performance, comfort, suitability. As the world progresses through technologies, more energy is needed to power the world through various sources. Society has reached a point in our civilization where electricity is used for all purposes and therefore our presence will be impossible without it. However, the increasing amount of energy used will lead to numerous social and economic problems. Demand for electricity is increasing at twice the rate of overall energy consumption and will likely increase by more than two-thirds between 2011 and 2035. In 2012, 42 percent of primary energy used was converted to electricity. In the near future, cities will have to become increasingly energy efficient to cope with these problems. There are three strategies for achieving energy efficiency that have their advantages. First, the introduction of solar energy will substantially increase energy efficiency in ordinary households. Solar energy is completely free once installed and can be converted into electricity or hot water. It is a sustainable resource that does not run out and guarantees a constant supply of energy as long as the sun shines. Furthermore, solar panels are considered as clean and green energy as they are obtained without corroding nature and also do not cause any harm to the environment. (greenhouse gases). The solar credit program is part of Australia's Renewable Energy Target, in which the Australian government has committed to providing 20% ​​of its electricity supply by 2020 from renewable sources such as solar energy. The federal government imposes a mandate on electricity retailers that exceed a certain level of energy consumption. Retailers then choose to pay the penalty or install... middle of paper... an efficient and environmentally friendly energy source used by Norway. 64% of its total energy comes from hydroelectricity. Starkraft is the largest hydroelectric power producer in Europe having contributed to the construction of two hundred and sixty-three hydroelectric power plants in Norway, sixty in Sweden, ten in Germany and four in Finland. The introduction of hydroelectric power plants in Europe brings benefits in terms of higher efficiency and greater respect for the environment. In conclusion, the progress of the world leads to a greater amount of energy used which sacrifices the environment and the economy. To limit and stop all this, numerous strategies must be applied such as the use of solar energy, nuclear power plants and hydroelectric energy. Through these strategies, countries will experience positive effects both economically and socially.