Cellsol Energy

What is the Carbon Foot Prints of Solar Panels?

Manufacturing Solar Panels

Electricity produced from solar yields no emissions, no greenhouse gases, and no fossil fuels, but it does require a certain amount of energy to make the solar panels. Luckily, the energy they produce far exceeds what it takes to manufacture them.

The solar power industry pays attention to these details by actively seeking ways to improve this power imbalance. In fact, researchers created a metric called Energy Payback Time (EPBT) to measure the length of time it takes a solar panel to generate the amount of energy equal to what it took to be created.

For multicrystalline-silicon systems (i.e. solar panels), it currently takes 4 years to achieve EPBT, according to the U.S. Department of Energy. 5 Since solar panels last for 20 to 30 years, a single solar panel can generate more than four or five times the energy used to produce. Even better, new technologies arrive every year to reduce EPBT even further. Eventually, the industry wants to shave years off of this time to truly maximize the value of solar!

Around 50g of CO2 per kilowatt-hour is produced during the first years of operating a solar energy system. The solar panel’s carbon footprint is roughly 20 times less than the carbon output of coal-powered electricity sources

Maintaining Solar Panels

Let’s address how much water is used to maintain solar panels vs. how much water is used to process fossil fuels. According to the Solar Energy Industries Association (SEIA), approximately 20 gallons of water per megawatt-hour (MWh) of electricity is needed to clean and wash solar panels.6 That’s less than the amount of water a typical family uses in a year, around 20,000 gallons of water, per the SEIA.

Compare that to coal processing.

Coal created all its electricity from the production of steam, so it naturally needs a lot of water to generate electricity. There are three options to cool coal plants: once-through, wet-recirculating, and dry cooling.

In the U.S., more than 90% of coal plants use once-through or wet-recirculating to cool.

  • For once-through cooling, approximately 20,000 to 50,000 gallons of water is used to produce one MWh of electricity from coal.7
  • For recirculation, 980 to 2,300 gallons are used to produce one MWh of electricity.
  • This translates to 70 to 260 million gallons of water used each day for coal mining (washing and cooling drilling equipment), according to the U.S. Department of Energy.

That’s a lot of water, if we do say so ourselves.