The field of alternative energy has developed a lot in the last 50 years and mostly because man has started to realized more and more that we have to use better, renewable and non-pollutant types of energy. Renewable energy should be even more popular then the production of oil and coal, as the extraction and exploitation process is easy and undemanding and the resources regenerate, which is a massif advantage. Here we have geothermal waters, wind, rain, tides, the power of rivers and many more that are or should be used more.
Wind energy is probably one of the easiest and cheapest types of energy to exploit, especially if there are strong currents in your country’s area and is one of the 100% pollution freeways. More recently, wind has been used over waters as well, as we have wind turbines placed in many places in the world (for example, there are some near Copenhagen).
Solar energy is also easy to obtain, although solar plants are not as cheap as the ones used for wind energy. Solar panels for home use have become more popular in the last 20 years though as the price dropped, and more and more houses and hotels have switched to this type of energy while still being connected to the power grid, to have backup for when the solar activity is insufficient).
Atomic energy has been largely considered in the last 2-4 decades, but there have been many accidents that affected and polluted a lot (we can include the Chernobyl incident here as well as the more recent Fukushima plants incident, that followed after the powerful earthquakes and tsunamis in the Japan area).
In the field of transportation, alternatives exist and thus we now have hybrid cars that use two or more distinct power sources for moving. Best known car of hybrid design is the one using an electric engine and a combustion fueled engine. Apart from hybrid cars, another actually used alternative is represented by liquefied gas cars, that have lost the need for gasoline altogether.
We also have alternative energy cars with a single propulsion type like solar powered cars (that have solar batteries, also known as cells that recharge during the day) and electric charged battery cars, that have to be connected with a power plug for a time after eight hours (for example) of functioning. However, people are still searching for alternatives that are commercially and environmentally friendly when compared to what is used today.