The Limitations of Solar Energy: When The Sun Expires
Posted on October 26, 2021
It will be billions of years until the sun that brightens and produces heat in the world expires. Until then, we have the brightest and most reliable renewable energy technology in the form of solar panels that any Golden, CO homeowner can install.
However, what happens when the sun finally gives up and starts losing energy? Will newer technologies make use of the smaller solar energy amounts their cells are receiving?
It’s no surprise that modern solar panels have achieved so much after a century it was discovered.
The very first solar panel made it possible to see how it’s possible to collect solar energy through technology. Today, we see this discovery’s fruits of labor in the form of highly efficient solar panels capable of powering entire homes even without solar energy storage.
In the tech progression, we’re seeing, the trend for solar panels and energy generation is skyward, which means the future generations centuries ahead may have perfected and gone beyond the capabilities of solar cells we currently have.
Therefore, it’s safe to say that the world, by the end of the sun’s lifespan, the world has advanced technologies that enable them to harness 100% of the sun’s energy — or even beyond.
If you’re curious, Harvard University writes that the future of solar energy is bright. Read more about it below.
The Sun emits enough power onto Earth each second to satisfy the entire human energy demand for over two hours. Given that it is readily available and renewable, solar power is an attractive source of energy. However, as of 2018, less than two percent of the world’s energy came from solar. Historically, solar energy harvesting has been expensive and relatively inefficient. Even this meager solar usage, though, is an improvement over the previous two decades, as the amount of power collected from solar energy worldwide increased over 300-fold from 2000 to 2019. New technological advances over the last twenty years have driven this increased reliance on solar by decreasing costs, and new technological developments promise to augment this solar usage by further decreasing costs and increasing solar panel efficiency.
Solar Cells: Costs, Challenges, and Design
Over the past 20 years, the costs associated with solar cells, the structures capable of converting light energy into electricity, have been steadily decreasing. The National Renewable Energy Laboratory, a US government lab that studies solar cell technology, estimates contributors to the increasing affordability of solar. They estimate that hard costs, the costs of the physical solar cell hardware, and soft costs, which include labor or costs to obtain required government permits, are about equal (Figure 1). Soft costs have decreased because there are more potential consumers and more installation experts for new solar cells, so companies can produce solar cells in bulk and install them easily. Hard costs are less than half of what they were in the year 2000, mostly due to decreasing material costs and an increased ability of cells to capture light. Engineering more cost-effective and efficient solar cells has required careful consideration of the physics involved in solar capture in addition to innovative design.
Because solar cells are used to convert light into electricity, they need to be composed of some material that’s good at capturing energy from light. This material can be sandwiched between two metal plates which carry the electricity captured from light energy to where it is needed, like the lights of a home or machines of a factory (Figure 2). Choosing the right material to capture light involves measuring the difference between two energy levels called the valence band and the conduction band. The lower-energy valence band is filled with many small negatively charged particles called electrons, but the higher-energy conduction band is mostly empty. When electrons are hit with particles of light, called photons, they can absorb enough energy to jump from the low-energy conduction band into the high-energy valence band. Once in the valence band, the extra energy in the electron can be harvested as electricity. It’s as if the electrons are sitting at the bottom of a hill (the conduction band) and being hit by a photon that gives them the energy to leap to the top (the valance band). (Continue reading here to learn more)
