Photovoltaics is the most efficient renewable energy source. Some of the cleaner and safer renewable energy sources in the world today are solar, wind, hydroelectric, geothermal, and biomass. This is demonstrated below by a brief introduction to these major energy sources.

(1) Solar energy system
Solar energy does not emit any greenhouse gases or produce harmful by-products when used. Solar panels are also very reliable and have a long lifespan; it has a failure rate of only 0.05%. Since it only relies on capturing solar energy and converting it into electricity for home use, solar energy does not produce any greenhouse gases that contribute to global warming, which is friendly to our environment. However, solar power systems can only supply electricity when there is sufficient sunlight, so it is not a good choice for areas with insufficient sunlight resources.
(2) Wind Power
Wind energy has long been utilized in ancient China, and it has a long history that continues to this day. It is a relatively cheap energy source. Wind turbines can be easily installed in the sea and wind turbines have a recyclable rate of 80-90%.
(3) Hydroelectricity
Hydroelectric system uses water as an energy source to generate electricity and it is more cost-effective and renewable source of electricity and is also very economical. Hydroelectric power generation is carried out by utilizing the self-renewal capacity of rivers, so it is both economical and efficient. However, it also has hazards and sometimes dams are built that can flood nearby communities. As a result, people living near reservoirs have to move to other places.
(4) Geothermal Energy
Geothermal energy, as the name suggests, utilizes the heat of the earth to generate electricity. Geothermal energy is more suitable for high-temperature areas because the difference in temperature between the hot rocks underground and on the ground creates an electric current. Geothermal energy is a virtually unlimited resource in comparison, but it is still relatively unexplored by mankind, so there are challenges to be faced in order to utilize it. We need to overcome problems such as the fact that geothermal energy production releases greenhouse gases stored under the earth’s surface.
(5) Biomass Energy
Biomass energy is produced by burning biomass, which is a variety of organisms, including plants, animals and microorganisms, that are formed through photosynthesis. It is also a more cost-effective source of energy, but growing biofuel crops requires a lot of land and pesticides, which are harmful to the environment.
What is the best renewable energy source?
Experience has shown that solar energy is the most efficient and cleanest source of energy in comparison, and it is not harmful to the environment. Solar energy is so abundant in the world that it tends to have a small restricted range.
Currently the use of solar photovoltaic cells is increasing in the world due to the decreasing cost of solar photovoltaic cells. However, with human development and research, more problems will be solved. Energy sources that are currently harmful to the environment may later be beneficial to the environment, and we can often choose more favorable energy sources by avoiding restrictions. In this way, we can magnify its advantages and avoid its disadvantages. The future development will be unpredictable, follow the changes of the times, choose the more favorable energy for the environment and human beings.