
Hydropower: For centuries, people have harnessed the energy of river currents, using. . Cities, states, and federal governments around the world are instituting policies aimed at increasing renewable energy. At least 29 U.S. states have set renewable portfolio standard. . The impact of the growing use of renewable energy is a subject of ongoing debate and research. Many fossil-fuel producing countries, such as , , and , are currently able to exert diplomatic or geopolitical influence as a result of their oil wealth. Most of these countries are expected to be among the geopolitical "losers" of the energy transition, althoug.