Exploring renewable energies - from primary to secondary level

The conversion of our energy supply from fossil and nuclear fuels to renewable energy is already in full swing; in Germany, this is referred to as the “Energiewende” or the “Energy revolution”. In addition to expanding the use of renewable energy, other central areas of focus - and key challenges - include reducing our energy consumption and improving energy efficiency through technological progress. The energy revolution is already affecting our everyday lives in terms of electric mobility on the streets, when we purchase energy-efficient household appliances, or during energy-based renovations of buildings. 

Current, quality-assured data on the development of renewable energy sources in Germany is provided at regular intervals by the German Federal Environment Agency (1).

Therefore, from a strictly scientific perspective, the commonly used phrase renewable energy is not correct. Energy can neither be created nor destroyed; therefore, it cannot be renewed. Energy can only be converted from one form into another. The quantity of energy in a closed system, therefore, remains constant. However, the usable portion of the energy will differ depending on its conversion (2). Overall, the total quantity of energy remains the same. What we call energy usage should more accurately be called the depreciation of energy. The usable value of energy is reduced by conversion and transport. When wood is burned, for instance, the chemical energy stored in the wood is converted into thermal energy and light energy. When heat is dissipated into the environment, it is no longer useful. It has been depreciated – or “used”, as we say.

Our energy consumption continues to grow, even as fossil fuel sources of energy dwindle. This makes experimenting with renewable energy all the more exciting, to understand how solar energy, wind energy and hydropower can be used to convert and store energy and improve the efficiency of energy transmission. 

Hydropower

Hydropower is certainly one of the oldest energy sources ever used. The ancient Mesopotamians were already using water to produce energy 3,500 years ago with the help of water wheels. The journey from water wheel to turbine was a long one. Enlightenment-era engineering resulted in improvements to the water wheel, and ultimately to the construction of new kinds of machines, such as water column systems. In 1824, Claude Burdin invented the first turbine based on this technology. In 1866, Werner von Siemens invented the electrodynamic generator, making it possible to convert hydropower into electric current. The first hydroelectric plant began operations in the English county of Northumberland in 1880. The first German hydropower plant, which was also the first power station to generate alternating current, went online in 1890 in Bad Reichenhall. The world’s first large-scale power station began operating in 1896 at Niagara Falls in the USA.

Wind power

Initial experiments on producing electricity using wind power were conducted in the late 19th century based on windmill technology, alongside the emergency of electricity itself. In the 1950s, engineer J.Juul pioneered the world's first wind power plant to generate alternating current in Vester Egesborg. J. Juul constructed the innovative Gedser wind power plant with an output of 200 kW from 1956-57 for the SEAS electricity company on the coast of Gedser in southern Denmark. Germany's first wind farm was constructed in 1987 on the Growian facility near Marne. 

Photovoltaics

Alexandre Edmond Becquerel discovered the photovoltaic effect in 1839, launching the history of photovoltaics. However, it took over a century for this discovery to be used to produce energy.
Albert Einstein provided the first explanation of the photoelectric effect in 1904. Edmond Becquerel had already demonstrated the association between light and energy generation, but was not initially able to derive any use from this discovery. In 1954, the physicists Chapin, Fuller and Pearson succeeded in building the world's first silicon solar cell. This launched the use of crystalline solar cells to convert sunlight into electrical energy. The first 108 photovoltaic cells were used in the mission of the US satellite Vanguard in 1958. 
However, it took another 20 years for them to be installed on terrestrial systems. In 1976, the Australian government decided to equip the outback telecommunications network with solar cells to charge the installed batteries. In the mid-1980s, Swiss engineer Markus Real was able to install small, decentralised systems on the roofs of houses to demonstrate private usage. Afterwards, many different large-scale solar projects were launched, such as Germany's 1,000 roofs program (1990) or the Japanese 70,000 roofs program (1994). In 2010, Germany exceeded the ten gigawatt threshold for the first time, and in 2012 the country reached 25 gigawatt. As of late 2019, over 49 GW are installed in Germany.

• the fischertechnik solar micromotor is small, but powerful. It is operated with 0.5-2V direct current.

• two solar cells 60x60 1.0V 0.44A deliver the power needed to drive the models, or serve as energy converters for energy storage

• one solar gold cap 10F 2.3V, with stands out for its extremely high capacity

• one hydro cell 0.5V-0.9V 0.5A fuel cell that can be used to convert the chemical energy of a fuel (such as hydrogen) into electrical current

• one voltage converter, which transforms the output voltage of a fuel cell from approx. 0.9V to approx. 2.0V

 

Of course, all of these are perfect for the fischertechnik system, which not only illustrates basic renewable energy issues but also allows students to operate realistic functional models.