By Steve Donohue
On a recent sunny Sunday (appropriately enough) the meter for the solar photovoltaic (PV) system on our home showed we had produced 50,000 kWh of clean renewable electricity!
This is a major milestone to me but what does it really mean? The EPA Greenhouse Gas Equivalencies Calculator helps translate abstract measurements like these into concrete terms. In our case the carbon dioxide emissions we avoided with our solar panels were equal to the amount captured and stored, or sequestered, by over 33 acres of forest in a year.
That’s a big benefit for the planet and, closer to home, enough “juice” to supply over 85% of our annual electricity needs. We installed the PV system back in July 2010 and I originally wrote about it in 2012 https://blog.epa.gov/blog/2012/07/energy-independence-day/. The table below shows the results of our conservation and efficiency improvements and solar production since we first moved into our house.
Our average annual electricity bill for the last five is about $250 and in 2015 we got it down to $182. Since installation we have also had zero maintenance or operating expenses and with no moving parts I expect our system to last a long time.
That’s good since we still have about another 3 years or so until we re-coup the cost of our initial investment and the system is paid off by our savings.
Sustainability often means taking the long view and in our case it was like paying 10 years of electricity bills upfront so we could get our power from the sun and essentially never pay another bill.
Even more good news is that our system today would be about half of what we paid. This is the penalty we paid for being “early adopters” but I am happy to see my neighbors have started to join the bandwagon. In the last year I am seeing panels sprouting on roof tops all over my neighborhood. One family uses their panels to charge their electric car!
And what I’m seeing locally is a microcosm of what is happening in the world. I read that in 2015 for the first time there was more installed renewable power generating capacity, like solar and wind, than any single fossil fuel powered generating capacity. I’m hopeful that we’ve finally reached a tipping point and there is a bright future ahead for renewable power.
About the author: Steve Donohue has been a senior environmental scientist at EPA for over 25 years. Currently, he works in the Office of Environmental Innovation in Philadelphia where he is focused on improving the sustainability and climate change and improving the efficiency of EPA facilities.