2.2 Renewable Energies
This chapter discusses renewable electricity as the central raw material for green hydrogen production. It highlights the three origins of renewable energy: geothermal heat, solar energy, and gravity. Technologies such as photovoltaic systems, wind turbines, and hydropower plants are used to generate renewable electricity. Hydropower and biomass have limitations, making photovoltaic systems and wind turbines the main options for large-scale green hydrogen production.
Overview
Electricity from renewable energy sources is, along with water, the
central raw material for the production of green hydrogen. In addition,
the most important technologies used for this purpose will be briefly
presented.
As the figure below shows, all renewable energy flows or
energy sources that can be converted into electrical energy come from
one of three origins. These three basic origins are geothermal heat, solar energy and the gravity between the celestial bodies,
basically between the moon, the earth and the sun. The sun's radiation
energy is not only an energy stream itself but is also converted into
various other renewable energy flows and energy carriers through a
variety of natural processes inside the earth's atmosphere. Examples of
this are wind energy and biomass. In case of biomass, the radiation
energy of the sun is converted into a usable energy carrier by the
photosynthesis of plant organisms. Wind is an energy stream that occurs
due to spatial differences in the atmospheric air pressure distribution,
which, in turn, result from variations in solar radiation.
- Photovoltaic systems
- Solar thermal power plants
- Wind energy turbines
- Hydropower plants
- Biomass power plants