1000 Days of Solar
Wednesday September 4, 2013: Updated November 30, 2013
1000 Days of Solar
July 5, 2013 marked the 1000th day since I installed the solar panels on our home roof.
During that time, my entire environmental belief system has changed. Solar panels truly are a gateway drug that leads to more energy efficiency, increased cost savings and a higher standard of living. Because of this addictive addition to our house, we have been nothing but blessed.
Solar panels typically lose about 1% of their capacity each year. Oddly, the panels on our roof have performed better each year over the precious year. 2012 was better than 2011 and 2013 has been better than 2012. I attribute this odd outcome to increasingly less cloudy days each year. Some may pin this trend on climate change but it is happening way too fast for that to be the case. I believe this trend is an anomaly and I doubt it will continue.
While the solar panels were originally sized to cover only 90% of our home’s electrical needs, through minor efficiency improvements, by early 2011, they quickly supplied over 140% of our electrical needs.
With all that extra “free” energy, I decided to use it to offset gasoline usage in my commuter vehicle. I converted a Toyota pickup truck (and later a Geo Metro) to an all-electric vehicle. I started driving the EV pickup truck back and forth to work in September 2011. The truck used about 15-16 kWh per day, in turn bringing my total electric usage back above what the solar panels were producing.
This further motivated me to further increase the energy efficiency of the house and the EV Truck.
Throughout 2011-2012, home efficiency was further increased through the following:
- Air sealing (windows, doors, electrical outlets and recessed light fixtures)
- Blowing in more insulation in the attic
- Adding insulating shutters on all south-facing windows on the main floor
- More efficient lighting (LED and lower wattage CFL/LED bulbs where appropriate)
- Powering down PCs when not in use (and more efficient PC power supplies)
- More efficient appliances (reduced phantom power)
- Better habits of turning off lights and TVs when not in use
During the same time period, electric vehicle efficiency was increased through:
- Aero-mods
- Improved driving technique
- Higher tire pressure
- Reduced friction gear and transmission fluid
- Better planning and combining trips to reduce miles driven
Both of these improvements (home and EV) collectively reduced our total annual electrical usage to nearly what the solar panels were producing in a year.
Switching from the EV pickup to a Geo EV, actually pushed the total annual usage to almost exactly what the solar panels produced.
From March 2012 to February 2013 total electricity consumed beyond what was produced by the solar panels was 11 kWh or $1.10 in electricity. A dollar and ten cents! FOR THE YEAR!
It's quite a feeling to be able to power all the lighting and appliances in your house for a year plus drive over 12,000 miles in an electric vehicle, all for only $1.10 in energy costs.
By the way, removing snow is a snap with a roof rake. I use this one here. No need to climb on the roof.
During this year, I was charging up the EV at work for half of my commute. In February 2013, I felt it was time to go all in and only drive on clean, renewable energy. I stopped charging at work and now only plug in at home.
Concurrently, in February 2013, we had a geothermal heat pump installed. It directly replaced the air conditioner and gas furnace, plus supplements most of our home’s hot water needs.
In May 2013, I leased a Nissan leaf for my wife to drive. Now both of us can commute in truly emission free, all-electric vehicles. We shamefully keep the gas van around for those very rare but necessary trips when we drive farther than 100 miles at a time, carry more than 5 people or need to haul something bulky. These energy-dependent, polluting gas trips occur 1-3 times a month.
Oh we also still have an old gas powered television and VCR. Just kidding :)
Now, the only remaining non-solar-powered appliance in our home is the gas powered clothes dryer. With 10 loads of laundry a week, it consumes 3 therms of natural gas each month (equivalent to about 80 kWh).
In full disclosure, we still have a gas fireplace which we almost never use and a propane barbecue grill that we use every couple of weeks during the summer. Lawn equipment (lawn mower, trimmers and leaf blower), as always, are electric.
Oh we also still have an old gas powered television and VCR. Just kidding :)
In June 2013, we finished a basement apartment for my mom. The additional HVAC loads are essentially negligible, but one more occupant and another full set of kitchen appliances does add about 1-3 kWh per day in energy usage.
While it was my hope to have the power meter on the house roll back to zero by 2014, with all the additional electrical equipment (especially the geothermal heat pump and another electric car), this will no longer be the case.
By July 2013, it became apparent that the solar panels were not going to completely cover all our energy needs. I calculate that in 1 year, the solar panels will be about 2300 kWh short of what we consume.
While that is nothing to complain about, still, it would be really cool to be a true, net zero energy consuming family.
Looking Back
In less than 3 years, the solar panels went from supplying 90% of our electricity (or 15% of our total energy needs) to supplying 100% of our electricity (or 80% of our total energy needs).
In 2010, our family consumed 63 Megawatt-hours of energy (natural gas heating, air conditioning, lights, appliances and driving 2 gasoline vehicles about 18,000 total miles per year). All this energy (gasoline, natural gas and electricity) cost about $5500.
Today, we consume 11.7 Megawatt-hours of energy and the solar panels produce 9.3 Megawatt-hours annually. Our total energy bill is now only $200 per year.
With further home energy improvements, the same 26 solar panels on our house roof could in theory supply 100% of our total energy needs (HVAC, domestic hot water, lighting, appliance and 2 electric cars).
This could suffice until climate change brings higher average temperatures, the solar panels slowly degrade over time, our children start driving their own EVs and new cool energy sapping toys come out.
Just to be on the safe side, perhaps I will install another 2-3 kW of solar panels on the roof in the spring.
But before we rush out and put up more panels, I want to quantify the house performance (especially the geothermal heatpump) through the winter months.
Plus, there are still so many more improvements to be made.
- Double cell blinds in basement south-facing windows
- Drain-water Heat-recovery unit on the sewer stack
- Solar Tubes in kitchen and hallway
- Water-saving/water-recovering devices (potable and culinary)
- Awning on the south-side of the dining room
- Whole-house fan?
- Bidet (not everything has to be about energy efficiency).