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Solar Energy vs. Fossil Fuels

Profile picture of Kathryn Parkman
by Kathryn Parkman ConsumerAffairs Research Team
solar panels in city

Consumers burn fossil fuels because it's cost-efficient and convenient — for now. Experts don’t consider fossil fuels renewable energy because their global supply is finite. Solar energy, however, is a truly renewable source of natural energy.

The sun won't stop providing sunlight any time soon, and it's available all over the world. However, the amount of sunlight we receive varies depending on location, time of day, season and weather conditions. For instance, if you live in the Northern Hemisphere, it’s ideal to have a south-facing roof. Even if this isn’t the case, though, solar can still work for you, especially if your roof doesn’t get lots of shade throughout the day.

As with all power sources, solar energy has its pros and cons. The two main disadvantages of solar energy are its high upfront costs and its lower energy density. Lower energy density isn’t really a problem, though — it just means more solar panels are necessary for a given energy output. Solar energy output is set by the physics of the panel, because only some frequencies of light hitting the panel can be converted to electrical energy.

Overall, the health, environmental and economic costs of fossil fuels outweigh their value, even if they seem more affordable than solar energy options.

Solar energyFossil fuels
Efficiency rate15% to 22%20% to 40%
CO2 emissions
Long-term availability

Solar energy cost vs. fossil fuels

Going solar is a money-saver in the long term, even though startup costs are higher for the consumer. Electricity from fossil fuels costs between 5 and 17 cents per kilowatt-hour. Solar energy costs average between 3 cents and 6 cents per kilowatt-hour and are trending down, according to the National Renewable Energy Laboratory.

In 2020, the initial installation and setup of a solar energy system in the U.S. cost an average of about $15,000 after state incentives. Luckily, the cost for solar panels has decreased more than 20% in the last five years and is expected to continue declining, according to EnergySage.

Once installed, a solar energy system is easy to maintain and low in cost. Homeowners might even be able to make money by selling excess energy from their solar panels to their local grid.

Full solar panel systems can require a substantial upfront investment, though. Ultimately, solar panels can lower your utility bills, but not everyone is in the financial position to absorb the initial cost of panels until it balances out. To help offset the upfront cost of solar panel installation, many solar energy companies have leasing and solar financing options available.

In order to get a low-maintenance system with maximum energy and low costs, quite a bit of research is required.

  1. First, you need to determine what size system you need for optimum performance. This isn’t a simple calculation, but it has to be done.
  2. Find out what options your utility provider has for buying back solar energy.
  3. Consider a battery storage system rather than selling excess energy to the utility. The utility company won’t buy back solar-produced energy at the same cost they charge for electric energy, so storing energy in batteries may be a more cost-effective option. You can also use utility energy if the batteries run out.
  4. Look for available grants from state, federal and utility agencies, which could reduce installation costs significantly.
  5. The energy output of a solar energy installation can vary significantly. Anything that obstructs sunlight from reaching the panels can affect the output. Dust and dirt, lack of sunlight and the angle of the panel all affect panel performance. Some solar panel supplies have self-cleaning systems and some can track the sun to keep perpendicular to its rays, which increases the energy output.
  6. Try to design and install a solar energy system that returns the investment in about 2 to 3 years — it’s possible to have essentially free energy after this point.

How is solar energy harnessed?

The earth absorbs enough energy from the sun in about an hour to power the world for a year. If you’ve ever had the sun come through your windows and heat your home, you’ve experienced passive solar heating. To use solar energy for your home, however, you have to convert the power into a usable form with solar panels.

Solar panels are made of photovoltaic (PV) cells that convert solar energy into electricity. In a solar panel system, energy from the sun is harnessed and can be stored in solar batteries. Batteries are paired with an electrical control system to provide power after sunset or to offset electricity usage.

A solar panel converts about 20% of the total amount of solar energy impacting it. The panel produces direct-current energy and is converted to alternating-current power by an inverter.

The electrical interface to utility or battery storage systems is fairly complicated. Make sure you ask the solar system installers plenty of questions — it’s also wise to employ electrical engineering consultants to verify details and to avoid additional costs and problems.

There are still some disadvantages to solar energy in terms of the environment; there is some pollution associated with solar energy production, and transporting solar panel systems contributes some to greenhouse gas emissions. Still, the environmental effects of solar energy are pretty insignificant, especially in comparison to fossil fuels.

Where do fossil fuels come from?

The three main types of fossil fuels are petroleum (also known as crude oil), coal and natural gas. The formation of these fuels is a natural process, but it’s one that takes time. Despite their name, fossil fuels don't come from fossils — instead, energy absorbed millions of years ago remained stored in organisms as they were slowly covered by earth. It takes hundreds of millions of years for buried organisms to decompose anaerobically, and these organisms eventually convert into what we know as fossil fuels.

These fossil fuels are found underground by mining or drilling, both of which have high operational costs. Burning fossil fuels breaks down the atom bonds that store the energy, which releases the energy for use.

Fossil fuel advantages and disadvantages

The most significant advantage of fossil fuels is our well-developed technology for turning them into energy. Historically, nonrenewable fossil fuel energy has been easy to find and reliably used across the globe. We've had centuries to perfect they way we use it.

Though there are innumerable uses for fossil fuels in everyday life, it’s hard to ignore their disadvantages. Fossil fuels are a top contributor to global warming because of their high carbon output when burned. There's also the potential for dangerous accidents during the production and transportation of fossil fuels.

Given the consumption rate of fossil fuels, the world is reaching a point where we’ll have little choice in the matter — nonrenewable fossil fuels are extracted at a rate much faster than the rate of replenishment. Because of this, some fossil fuels, like coal, are on track to be more expensive than solar within the next decade.


  • Cheap
  • Reliable
  • Well-developed technology


  • Less energy independence
  • Production hazards
  • Nonrenewable and unsustainable
  • Contributes significantly to climate change

Solar energy vs. fossil fuels FAQ

How efficient is solar energy compared to fossil fuels?
Solar energy is most efficient in terms of environmental impact. Coal and natural gas are more efficient by reliable applications, though. Solar panels typically have between 15% and 20% efficiency, while coal has an efficiency of up to 40% and natural gas reaches up to 60% — the remaining energy in fossil fuels and coal is lost in the form of heat, and it’s lost forever.

Because only 20% of the total energy impacting solar panels is converted to electrical energy, you’ll have to get more panels if you need more energy output. Optimize your solar panel efficiency by installing a solar concentrator or backup batteries and by not running too many devices at once. Solar energy requires a hefty upfront payment, but it's more efficient in the long run. You also offset electricity costs for the life span of the panels, which can be as long as 35 years.

Why do we use fossil fuels instead of renewable energy?
Our technology and infrastructure for fossil fuels are highly efficient, so phasing them out requires solar infrastructure to be accessible and convenient. The U.S. also grants subsidies to the fossil fuel industry to keep production costs low and incentivize domestic energy sources.

Renewable energy sources also produce inconsistent amounts of power that vary by the season and weather, which makes it more difficult to implement at the scale needed by utility companies and requires additional energy sources to guarantee enough power is produced at any time.

Can renewable energy replace fossil fuels?
Renewable energy can replace fossil fuels, though transitions of such magnitude require time and financial support to implement correctly. More than likely, we will see more mixed-energy usage — some traditional utilities are already becoming renewable. As technology advances, the transition will be a less daunting prospect.
Why is solar energy good?
Solar energy is more environmentally friendly than fossil fuels. It offsets electricity costs and protects against rising utility prices. Best of all, it’s infinitely renewable. Other solar energy benefits:
  • They’re low-maintenance.
  • They provide energy independence.
  • They have diverse applications.
  • They can increase home value.
  • Some states have solar tax incentives.
Why are fossil fuels bad?
Fossil fuels — oil, coal and natural gas or methane — are a leading cause of pollution and inflict nearly irreversible damage on the planet. They also directly damage the land and water where they’re extracted. Fossil fuels also aren’t renewable, and we’re likely to see them run out before too long.

Bottom line: Why is solar energy better than fossil fuels?

When considering the environmental impact of solar power versus fossil fuels, solar power is clearly the more environmentally friendly option. Many consumers prefer fossil fuels for perceived reliability; oil, coal and natural gas have a higher energy density (the amount of stored energy per unit volume) than solar power. However, investing in a battery for solar storage lets you tap into energy even if the sun isn't out and helps provide predictability.

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    Profile picture of Kathryn Parkman
    by Kathryn Parkman ConsumerAffairs Research Team

    As a member of the ConsumerAffairs Research Team, Kathryn Parkman believes everyone deserves easy access to accurate and comprehensive information on products and businesses before they make a purchase, which is why she spends hours researching companies and industries for ConsumerAffairs. She believes conscious consumption is everyone's responsibility and that all content deserves integrity.