Can we meet global energy demands just from renewable energy sources?

Wind turbines use wind to spin turbines which generates electricity. A single large wind turbine could only generate around 2MW when it is windy so thousands of wind turbines would be needed to replace a single power station. This requires land as wind turbines are very large, which some people complain “spoils the landscape” although there is also potential to have offshore wind farms. The cost of building and maintaining wind turbines would be expensive and they are also noisy so couldn’t be located near residential areas.

Energy can also be generated by water. A tidal power station covering an area of 100km2 could have a power output of 250 MW if released over about six hours. However, there would be significant environmental damage and fish populations would plummet. Also, the start-up costs of a tidal power station are high although the maintenance costs are low.

Similarly, a hydroelectric power station requires a large sum of money to build and damages the environment – killing wild life. Unlike the other forms of renewable energy, hydroelectric energy can be controlled so that the water flows through the dam when more energy is needed.

To conclude, making all of our energy renewable would require an extremely large investment for the start-up costs for all of the various types of power station. Also, with the exception of hydroelectric power, the other forms of renewable energy cannot be controlled (you can’t decide when it’s sunny, it’s windy, the tide is, etc.) so the energy would need to be stored somehow. This could possibly be done by electrolyzing water turning it into hydrogen and storing it, although this isn’t very efficient. Furthermore, large areas of land will be required and some forms of renewable energy can damage the environment badly.