Energy from the Sun: Photovoltaics

At this point, solar is everywhere. Your mom said something about solar being advocated on the news the other day, and your friends are probably bragging about how low their electricity bill is after switching to solar. But isn’t solar super expensive and not worth it? Well, that depends; let’s take a closer look.

How Solar Works (sunpower)

Basically solar panels turn sunlight into usable electricity. Typically, they’re placed on roofs and building tops to minimize land usage, but ideas for huge solar farms exist. (Essentially, huge swaths of land in the desert covered entirely by solar panels and stored in batteries.) Technically, there’s enough sunlight hitting the US to power the entire country multiple times over, but it’s a little more complicated than just free energy everywhere.

What is the potential for solar energy?

There is more than enough sunlight in the US to completely cover all of the United States’ energy demand. A roughly 100 square mile patch of desert in California, Nevada, or really anywhere else, completely covered in solar panels, could more than power the entire United States. As ridiculous as this sounds, it’s a great way to think about the implications of solar. It would never make enough sense to use up this great land mass in one centralized location for energy generation and disperse it nationally, but it makes sense to think of a set of solar panels over the roof of one home that could more than meet the energy demands of that building or home daily.

While solar panels used to be an expensive, state-of-the-future idea, it has quickly become an effective way to regularly generate power. To top it off, it is about 20 times cleaner than coal, emitting CO2 in the range of 50-85 grams per kWh of energy generated. [1] If we were to replace 22.5% of the nation’s current electricity generation (via natural gas and coal) [2] with solar over the next 3 decades, that would reduce emissions by about 0.32 GtCO2/year by 2050! (assuming our energy generation amounts stay relatively the same)

Is this technology ready to employ now?

Solar has a Technology Readiness Level of 9, meaning it is commercially available. [3] Numerous companies exist all over California where residents and building owners can install solar panels onto the rooftops of buildings and homes. Though new methods for improving efficiency are still being researched and developed today, it is still a great investment, as installing solar panels will almost always give you a return on your investment within a few years.

For some, this is a hefty investment. The hope is that through policies, we can close down coal and natural gas plants and turn them into photovoltaic manufacturing plants, or even implement solar farms, such as the one pictured below. Many researchers are looking for ways to innovate even further, through the use of green infrastructure including solar windows.

Ivanpah Solar Power Facility, CA (Greenpeace)

Too good to be true?

So, what’s the deal? Why isn’t solar being used everywhere? Well, photovoltaics are a new technology, and skeptics have been pushing back against advocates of renewable energy for a long time. But, solar is on the upswing, and renewable energy has been forecast to continue to rise quickly over the next several decades. And for good reason! At this point, the levelized cost of electricity (LCOE), the cost of electricity by source considering the whole life cycle, is lower for solar and wind than it is for natural gas. (Which includes the subsidies going to the fossil fuel industry) The market is naturally pushing us to implement renewables more and more, so what’s holding us up?

Risk and Public Pushback

The truth is that solar isn’t a perfect technology. It works well for the 3 or so decades it functions, and the solar cells have to somehow be recycled or disposed of safely. (This isn’t a cheap process). [4] With the projected increases in use of solar, especially at the individual level, we would have to have a well-defined recycling or disposal process in place.

Initial investments into could be costly, but honestly, these investments are made up fairly quickly, especially considering that electric companies will buy back excess energy you produce. Perhaps the biggest pushback against solar is the public perception of its intermittency. To be fair, we cannot rely on solar 100% of the time; sometimes, skies are overcast, and nighttime skies aren’t very sunlight productive.

To remedy this, we can support solar energy generation with other renewables, such as wind and BECCS. For the first decade or so, this support will be held by natural gas and coal plants that are slowly phased out by other renewables over time. If we can convince consumers to trust this technology, we would then only need governmental support via policies to support this.

This could happen in a multitude of ways: carbon credits, taxes, cap and trade policies, subsidies for renewable industries, etc. The most straightforward way would probably be to stop subsidizing fossil fuel industries, and to instead supply this support to the emerging wind and solar sectors. Not only would this be a better bang-for-buck in terms of the price of energy, but it would be a cleaner source of energy.

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References:

(1)World Nucelar Association. Comparison of Lifecycle Greenhouse Gas Emissions of Various Electricity Generation Sources.

(2)Frequently asked questions (FAQs) - U.S. energy Information Administration (EIA) https://www.eia.gov/tools/faqs/faq.php?id=74&t=11 (accessed Dec 6, 2020).

(3)Hernandez, R. R.; Hoffacker, M. K.; Murphy-Mariscal, M. L.; Wu, G. C.; Allen, M. F. Solar Energy Development Impacts on Land Cover Change and Protected Areas. Proc. Natl. Acad. Sci. U. S. A. 2015, 112 (44), 13579–13584.

(4)Environmental impacts of solar power https://www.ucsusa.org/resources/environmental-impacts-solar-power (accessed Dec 6, 2020).

(5)Power of Renewables, the: Opportunities and Challenges for China and the United States; National Academies Press: Washington, D.C., DC, 2010.

(6)Clean energy solutions center https://cleanenergysolutions.org/policy-briefs/solar (accessed Dec 6, 2020).