The Energy Industry is a category of stocks that relate to producing or supplying energy, including companies involved in the exploration and development of oil or gas reserves, oil and gas drilling, and refining. One of the largest, most dynamic, and often most controversial industries in the world, the Energy sector has gone through a rapid transformation by responding to the new trends and changing needs of customers. The Energy sector can be classified into two: nonrenewable and renewable. Non-renewable are petroleum and oil industry, natural gas, gasoline, diesel fuel, heating oil, and nuclear. Renewable energy contains hydropower, biofuels, wind power, and solar power.