To prevent a climate catastrophe, we will need to change to renewable energies, and rightly so. The variety of renewable energy choices is wide. Let us try to categorize them.
This graphic shows that energy derived directly from the sun provides the most options. Looking at the availability of the energy on earth, it is also obvious that solar energy has the biggest share of energy.
Hansen University Rostok 1EJ=10^18Joules
As these figures show, geothermic energy is an important renewable energy source, but the direct use of solar energy will dominate.
Hydropower and head pumps have achieved a high level of maturity. These technologies are followed by wind power, solar thermic power, and concentrated solar power. These three technologies have development possibilities, but we are considering them for optimization.
With photovoltaics, ocean power, and biomass, the need for some basic developments remains. Ocean power and biomass have the advantage of being continuously or nearly continuously available. This gives them a solid place in the energy sources environment. However, with photovoltaics, there are two issues: price and storage (due to their limited availability). Nevertheless, these developments play an important role in many projects, focusing on optimization of the thin film technology and the development of H2-storages. The advantages of this technology are great:
- No mechanically moving parts
- Easy to install and becoming a part of architecture
- Nearly no environmental impact if used on buildings
Due to the above-mentioned facts, I would expect that the largest growth of renewable energies will occur on these three energy sources: photovoltaics, ocean energy, and biomass. The mature energy sources will further contribute to energy sourcing. The growth rate for photovoltaics, ocean energy, and biomass will surpass that of the mature technologies.