Developments in Solar Cell Efficiency are Fueling Construction of Commercial Solar Farms!

The amount of energy reaching the earth from the Sun every minute is greater than the energy consumed by all of mankind throughout the World in an entire year!  The Sun is a limitless source of energy.  If there was only a way for mankind to capture that energy?

Silicon-based solar cells or panels were first patented in 1954 and were available for sale the following year.  Solar cell efficiency is measured by the ability of the cell to convert sunlight into electricity.  Efficiency is best when the solar cell is oriented 90 degrees to the Sun, and the light rays hit the panel head on.  The original silicon based solar cells were only 2% efficient and the costs of installation averaged $1,785 per watt/hour of electricity.  Since an average incandescent light bulb uses approximately 60 watts/hour the the return on investment upon solar cells was cost prohibitive. 

During the 1960’s and 1970’s efficiency increased to 10% making solar cells slightly more popular.  Meanwhile scientists and politicians took notice of the threats CO2 generated from fossil fuels posed to the ozone layer that absorbs and shields the earth from ultraviolet light in Sun rays.  [See, "Producers and Contractors are Facing Growing Criticism Over the Carbon Footprint of Concrete", posted 6/21/23}.  During the 1980’s the federal government began issuing tax incentives and credits to homeowners for the installation of solar cells.  In 1983, the worldwide sales of solar cells exceeded $250M.  The quality and efficiency of solar cell technology has increased ever since.

Today, silicon solar cells are ±25% efficient, and the costs of installation per watt/hour of electricity is approaching $1.  Since the average LED light bulb uses 6-8 watts per hour, the installation of solar cells is far more practical to both power generators and homeowners.  The improvements in solar cell efficiency and surge in solar farm construction result from two major advances in technology.

Sun Tracking.  Solar cells may now be mounted on devices which track the Sun across the sky. Sun trackers keep the solar cell oriented 90 degrees to the Sun to maintain constant efficiency throughout the day.  Trackers can move in either one axis (east–west) or two axis (east-west, & north-south), with two axis trackers being the most efficient.  Solar trackers are moved by DC motors receiving “parasitic power” generated by the solar cells they serve.  Movement of solar cells  is controlled by either algorithms pre-programed to follow the theoretical position of the Sun or optical sensors that identify and follow the actual position of the Sun.

Perovskite Crystal Cells.  Silicon-based solar cells comprise ±95% of the global marketplace, manufactured from a boron-doped silicon.  The silicon is manufactured by superheating quartz thereby generating a purified silicon that can be doped with boron.  Since silicon is subject to light-induced degradation or LID, silicon-based solar cells suffer an efficiency drop of approximately 2%/year.  Silicon based panels therefor suffer a significant drop in efficiency during over  lifespan, of approximately 30 years.  Solar cells manufactured from Perovskite crystals capture up to 20% more solar energy than silicon-based solar cells and do not suffer from LID.  Unlike silicon, perovskite crystals are manufactured at low heat from readily available materials, that do not require mining.  More importantly. perovskite crystal based solar cells can be fine-tuned to capture multiple wavelengths of light (ultraviolet and infrared) whereas silicon always absorbs the same wavelengths (ultraviolet).

Despite increases in solar cell efficiency, industry experts claim additional advances are in development and that efficiency rates approaching 50% are possible.

The Paris Agreement was signed by 196 countries, including the two largest contributors to the production of CO2 – the US (17.9%) and China (20.09%).  The long term goal of the agreement is to limit the increase in the average global temperatures less than 3.6 degrees F and reach net-zero by 2050.  The continued development and construction of efficient solar farms is just one component of decreasing the release of CO2 to the atmosphere.

Assuming the development of solar cell technology, continues at its current pace, the use of solar power will become a real possibility, and not just an ideal.  While it could eliminate the need for fossil fuels, such as coal, and natural gas to generate power, it is unlikely to negate reliance upon either. However, it will create a new markets for both power generators and homeowners that were not previously attractive because they did not generate the return on investment or ROI.  Only time will tell.