Google’s Project Sunroof has estimates on a lot more rooftops than it did a year ago! My house didn’t have a sqft roof estimate last year, and now it does: 2,001 sqft with 2,009 hours of usable sunlight per year! Most of my neighbors have between 1,700 and 2,500 sqft of roof space available for solar panels according to Google’s estimates.
My wife and I are quite conservative when it comes to energy usage. We haven’t gone full-home energy efficient, but our thermostat settings are optimized, windows are shaded, and we even went tankless (and gas) on our water heater. Our typical electric bill is between $100-200, and that’s even having a Volt that is typically in need of a full charge 3-4 times per week.
On the low side, Google estimates that using 247 square feet for solar would save 98% of our electricity costs. That’s 12.34% of my available rooftop. On the high side, Google estimates that using 423 square feet for solar would save 100% of our electricity costs. That’s still less than 1/4 of my total roof space. In other words, I could generate enough solar power for slightly more than 4 houses in my neighborhood. More importantly, my entire neighborhood could generate enough solar power for 4x as many houses! I postulated this idea years ago but didn’t have the tools until now to show how easy it would be.
That’s roughly 588 houses (similar to my very average house) worth of energy that my grid-tied neighborhood could produce! While this one neighborhood won’t be able to power the entire planet, it’s pretty easy to see how blanketing rooftops could be a giant leap forward for solar energy. Instead of building small solar arrays to cover the individual homes’ energy needs, an entire city’s homes can be powered by roughly 25% of it’s homeowners.
However, there is very little incentive for a property owner to blanket their rooftop with solar panels to generate excess electricity. Without getting into details about all the legal aspects of it, economically it doesn’t make any sense, and net metering ends up limiting this as an option anyway. But it shouldn’t.
Utilities have a cost associated with maintaining their network, and self sustaining homes eat into their ability to cover the entire costs of the utilities’ network. Net metering has energy companies overpaying for energy. If net metering was limited to the going wholesale cost of energy, that erases any incentive for homeowners to put a larger solar array on their rooftop. Still, homeowners could be persuaded with stronger tax rebates, with the goal being to make the tax rebate enough to help turn the wholesale rate of electricity into something the property owner makes her/his money back on within 7-10 years.
That long term ROI wouldn’t be much of an incentive for a house flipper, but it would be a great incentive for someone living in their lifetime home. It would likely increase the value of a rental property as the properly owner could get more money in rent due to the fact that the renter would never have to pay for electricity!
This could help drive down the cost of electricity for everyone while creating a boon for the home energy efficiency and roofing & solar installation industries.