The planet's energy mix is changing. Renewable sources of energy have become increasingly important, with the International Energy Agency expecting renewable electricity generation to rise by over one-third by the year 2022.

In order to harness these types of energy solar panels, turbines, batteries and a range of other materials are needed. Here are five.

Lithium-ion batteries are used in electric and hybrid vehicles. They are also crucial for renewable energy storage.

The U.S. Department of Energy describes lithium-ion battery technology as growing in popularity because of "its lightweight, high-energy density, and ability to recharge."

Cobalt is playing an increasingly important role in the transition to renewable sources of power. On its website, the United States Geological Survey states that the leading use of cobalt is in rechargeable battery electrodes.

The Cobalt Institute, a non-profit trade association, adds that cobalt plays a "crucial role in the cathode of lithium-ion batteries." Cobalt is also present in the magnets used in wind turbines.

Copper is important across the renewable energy sector. In photovoltaic solar cells, for example, the European Copper Institute (ECI) states that copper is used in cabling, earthing, inverters and transformers, among other things.

The ECI adds that in wind energy, copper is used in the "coil windings" in a generator's stator and rotor portions, as well as high-voltage power cable conductors and transformer coils.

The U.S. Department of Energy (DOE) describes silicon as "the most common material used in solar cells." Cells made from silicon, the DOE adds, offer low costs, high-efficiency and a long lifetime.

It may seem counterintuitive, but water plays a crucial role in the production of solar power. Large scale technologies — parabolic troughs and power towers — require water to produce electricity both cost-effectively and efficiently, according to the Solar Energy Industries Association (SEIA).

Solar technologies need water to clean surfaces such as mirrors, panels, dishes and troughs, according to the SEIA, using around 20 gallons per megawatt hour.

A large-scale facility that sits on 360 acres, the Nevada Solar One plant uses 850 gallons of water per megawatt hour, the SEIA states. This works out at around 300,000 gallons per acre annually.