The photovoltaic on the roof uses the energy of the sun rays to let electricity flow. Since a long time, different types of photovoltaic modules are available. From silicium based over cadmium-telluride or many other materials. The challenge is to get more efficient modules respectively materials - by research and development - for affordable prices.

The gras in the meadow uses the sun rays in its photosynthesis process, a rather complex biochemical system. The efficiency of the sun energy use in the plant growth is rather low. The advantage is that carbon dioxide can be sequestered in the soil, last but not least the plant species itself.

The fire wood in the picture explains itself. Theoretically it can be used for other purposes. In middle Europe you should dry wood after logging up to 2 years before burning it. If you burn it earlier it can contain huge amounts of water, the heat efficiency would be less.

Furthermore, we see the building probably mainly constructed with wood. As long as a wood building stands, the sequestered carbon dioxide - by the former photosynthesis process in the once living tree - is stored. When the used wood is burnt or rotten, the carbon dioxide goes again to the atmosphere. Then the carbon cycle is closed.

Wood for buildings and other purposes or fire wood should stem from sustainable forestry.

Photovoltaic modules should be used where ever possible, e.g. also in seawater desalination resp. waste water treatment processes.

Some possible links related to the topic, e.g.:

-      Photosynthesis | Definition, Formula, Process, Diagram, Reactants, Products, & Facts | Britannica

-      Uses Of Wood In everyday Life, Examples And Importance - MarNat StudySpace

-      Photovoltaics Report - Fraunhofer ISE        (in German)

-      Photovoltaics - Wikipedia

-      Seawater desalination: A review of technologies, environmental impacts, and future perspectives - ScienceDirect

-      Waste Water Treatment - an overview | ScienceDirect Topics

Last visit: 30. September 2026