Solar energy is a renewable source of limitless energy, which is expected to last about another five billion years or so according to scientific research (Sherman, 2003). There are about three different modes of harvesting solar energy, but the two most popular are orienting a structure towards the sun to enable maximum utilization of the sun’s energy, and the other is the use of photovoltaic cells and solar panels to harvest solar radiations into electrical or mechanical energy (Royal Society of Chemistry, 2007).
Credit is given to the most famous scientist, Albert Einstein, for establishing the close relationship between photochemistry and photoelectric effect. It is due to his research in the early 20th century that we set the laws of photochemistry that represent the starting point for understanding and exploiting solar energy. Due to the scarcity of fossil fuels and the expenses incurred in the mining of fossil fuels, it is important that we find a new source of energy to fulfill the energy needs of the world.
Harnessing solar energy
People have been using sun’s energy in countless ways since time immemorial and it is practically impossible to determine who actually discovered solar energy.
We can however appreciate milestones in the use of sunlight in the previous inventions such as the sundial and the utilization of solar energy by Auguste Mouchout to power the world’s first solar-powered motor engine. Moreover, Charles Fritz set a milestone when he invented solar cells which converted sunlight (around 1 to 2 percent) to electrical energy. Silicon is used in most solar panels as a semi-conductor though recent development of cheaper-to-produce silicon crystals which has not outdone the previous original silicon crystals (Sherman, 2003). The crystals are however fit into larger panels which produce about the same amount of electricity or more for the same investment. However, only about 30% of the sun’s light is absorbed and optimum efficiency is reached when the solar panel is oriented at 90o to the sun. Nevertheless, a new trend has emerged which involves making semi-conductors out of plastic and allows cheaper and more durable cells instead of silicon. It is done using a juxtaposition of two different polymers where each takes in a different charge after absorption and the charge is collected to give a working cell. With photovoltaics generally, there is a need to prevent fluorescence after absorption thereby, maximizing energy conversion (Sherman, 2003).
There has been a new replacement for the lowering supply of silicon crystals. This is the Dye Sensitized Solar Cells (DSCs) which, utilizes relatively inexpensive organic dye molecules as light harvesters which carry away charge in inorganic nanoparticles such as titanium dioxide (Institution of Engineering & Technology, 2008). These DSCs can last up to thirty years and undergo numerous turnovers with minimal damage.
Nano-crystalline structures harvest up to 11% of solar energy due to their improved conversion efficiencies via a rapid diffusion across the inorganic polycrystalline network which generate current. Through this technology large amounts of electric current can be harvested to drive motor vehicles and even light households. Imagine an electricity-powered car fitted with photovoltaic cells on the roof or incorporated into the windows. While parked it could be used in recharging its battery similar to a house fitted with photovoltaic cells which is more environmentally friendly.
Another field of research in which the world may achieve a milestone could be the designing of an artificial leaf to harness solar energy similar to an ordinary organic plant leaf in the process of photosynthesis. The leaf would be expected to break down water molecules to hydrogen and oxygen atom and at the same time form oxygen-oxygen bonds to form exhaustible oxygen molecules for combustion thus, creating fuel when combined with the hydrogen molecules (EVISA , 2008). Such an achievement is possible through the incorporation of ruthenium and manganese complexes to mimic photosynthesis. The artificial leaf could as well be used to reduce carbon levels by mimicking the dark reaction where adenosine tri-phosphate is converted back into adenosine di-phosphate and releasing energy in joules plus an inorganic phosphate a process which requires no light. In this way we could realize the use of water as a fuel in the coming future via an artificial photosynthetic process (Gratzel, 2003).
The harnessing of solar energy may be taken as the world’s next step to reduce carbon emission from burning of fossil fuels.
The new techniques developed in the harnessing of solar energy have made it easy for more and more companies to come up with solar powered devices that will go into the market soon. The developments made have been made possible through funding from organizations around the world that have a goal of reducing energy costs and carbon emission while at the same time developing local communities where infrastructure hasn’t accessed (ECOS Magazine, 2003). With bottom-up influence and motivation, a global community that operates primarily on solar energy could be achieved when young scholars and scientists are made aware of such advances.
ECOS magazine (2003). One golden pond. Ecos , 8 – 9. European Virtual Institute for Speciation Analysis (EVISA) (2008).
Advances in nanomaterials. American Ceramic Society Bulletin, Vol. 86 , 9. Gratzel, M. (2003). Journal of Photochemistry and Photobiology. New Jersey: Elsevier B.
V. Institution of Engineering & Technology (2008). Power solar power. Engineering & Technology , 56 – 58. Royal Society of Chemistry (2007). Harnessing Light.
London: Burlington House. Sherman, J. (2003). Solar Power. Washington: Capstone Press.