Solar power is a great way to help you save money on energy, but it’s also a great way to help protect the environment. Going solar empowers families and businesses to make a concrete positive impact on the planet, by curbing climate change and safeguarding precious water and air resources.
When shopping for solar panels, many people are specifically curious about the net carbon impact of their investment. In other words, how much planet-warming CO2 pollution can their solar panels help avoid?
Of course, solar panels’ conversion of sunlight into electricity doesn’t involve any carbon pollution at all – a big improvement over carbon-intensive fossil fuels. But savvy consumers rightfully point out that the process of making and transporting solar panels does have its own (albeit small) carbon footprint. Therefore, they want to be sure that their solar panels will produce a net environmental benefit.
It turns out they can rest assured.
SolarCity’s 2015 Impact Report directly addressed the question of a solar power system’s net carbon impact, and arrived at some striking results. Here are a couple of highlights related to the report’s findings.
Over 30 years, the net carbon reduction of a typical system deployed by SolarCity is equivalent to leaving more than 166,000 pounds of coal unburned
How much is 166,000 pounds of coal? It’s more than the weight of 11 full-size African elephants 🐘 (the largest land-based animal in the world)!
By providing an affordable and clean alternative to conventional grid electricity, solar panels can avoid a huge amount of fossil fuel use and carbon pollution.
Here’s another way to think about the net carbon impact of a typical solar power system over 30 years: it’s equivalent to avoiding the use of 17,000 gallons of gasoline (roughly enough to fill a backyard in-ground swimming pool), or offsetting 125 roadtrips (by conventional car) from San Francisco to New York.
Calculating the net carbon reduction of going solar means carefully considering the carbon emissions associated with making and shipping solar panels. That includes activities like raw material extraction, transport to manufacturing facilities, manufacturing solar panels, delivery to customers, and recycling of a solar system after its expected 35+ years of use.
Those lifecycle emissions, however, are tiny compared to the emissions that a solar power system ultimately avoids, thanks to its pollution-free electricity production. We calculate that while the total carbon footprint of a typical panel system may amount to 5 or so metric tons of CO2, its lifetime carbon savings (relative to using energy from the existing U.S. power grid) is at least 150 metric tons. That suggests that the carbon benefit of a solar panel system is around 30 times greater than the carbon cost.
What about the “carbon payback period” of solar panels?
Another way to think about the net carbon impact of a solar panel system is to ask a related question: how many months must you use clean electricity from a solar system (in lieu of consuming electricity exclusively from the grid) to make up for the system’s imbedded carbon footprint (from manufacturing, transportation, and so on)?
Our recent Impact Report also rigorously examined this question “carbon payback period,” and found a reassuring result. Even accounting for the lifecycle carbon footprint of solar technology, the typical SolarCity system starts delivering net carbon reductions in less than 1 year.
Since our solar panels are built to last, it means that after a relatively brief carbon payback period, a system installed by SolarCity can generate significant net carbon reductions year after year, for decades. Even with the most conservative lifecycle accounting of a solar panel system’s carbon footprint (see the bottom bar in the chart), a typical home can look forward to decades of being green and slashing carbon pollution.
As sure as the sun rises, the net carbon impact of SolarCity customers is unambiguously positive and significant. Together, they are making a historic impact in creating a bright future for the planet.
For more details (and all the nitty-gritty calculations) on how SolarCity customers are reducing carbon pollution, you can download our 2015 Impact Report.
Calculations for net carbon impact correspond to a 6-kilowatt solar panel system producing 8,418 kWh of electricity in its first year, with an annual degradation rate of 0.5%, and a 30-year term (20-year initial term plus 10-year renewal). Business-as-usual carbon emissions correspond to average non-baseload emissions factors for the U.S. electric grid, as for the EPA Greenhouse Gas Equivalencies calculator.
Calculations of avoided carbon pollution and equivalencies (e.g. pounds of coal, gallons of gasoline) are based on eGRID 2010 and current values generated by the EPA’s Greenhouse Gas Equivalencies Calculator.
For the purposes of our 2015 Impact Report and this blog post, we have identified the carbon reductions and environmental benefits that originate from the systems we have installed. However, we cannot and do not necessarily claim legal ownership of those reductions or benefits. That ownership contractually resides with the party that owns the Renewable Energy Credit (REC) associated with a given unit of solar energy production — whether it is another organization, a customer, or in some cases, SolarCity. For more details, see “What Are Renewable Energy Certificates (RECs)?” on page 28 of report.