Google's Project Sunroof Tells You How Well Solar Would Work On Your Roof

An anonymous reader writes: Google's Project Sunroof aims to make the task of installing solar panels easier by providing financial advice and stats on what solar energy could do for you. The project is only available in San Francisco, Boston, and Fresno for now. Techcrunch reports: "To get started, you simply plug in your address and some data about your monthly electricity bill, and the tool will tell you what the recommended solar installation size is and how much it would cost to buy or lease the hardware. In case you want to go ahead with a solar install, the tool also lets you reach out to local solar providers. Google says these listings are sponsored, so chances are it'll get a bit of a kickback when it generates a sales lead for these companies."

Comments

Might as well ...

[PPH]

... just contact a local system installer. The insolation data for a particular region is already known and publicly available. What will affect your particular system are things like local shading, roof pitch and orientation and cost of installation as affected by your house and lot particulars. Local installers will also be familiar with your utilities solar programs.

Re:Might as well ...

[Anonymous Coward]

Yeah, but the most important number is the cost of electricity, which is _assumed_ to hold constant, rather than go up in price. Given the shit to natural gas which is historically cheap right now, and the difficulty of going back to coal for baseload, that's not a very good assumption on balance.

We opted not to get solar, but we live in San Francisco. Our home doesn't even have an A/C, just an old furnace. The one thing that almost persuaded us was that if we got solar this year we'd be locked into a favorable, 20-year contract with PG&E which would require them to purchase our excess capacity at market prices. That program will end sometime this year or next, when the number of participants hits the statutory cap.

Here in California electricity prices are relatively low. They've remained constant for almost a decade, and are just beginning their inexorable rise as PG&E begins the decades-long replacement of ancient infrastructure. If we lived outside San Francisco, especially in South Bay or East Bay in a home with A/C, we'd get solar without hesitation.

As we live in SF, and our biggest expense is for gas for the furnace during the winters and spring, the risk just wasn't worth it. Our average electricity bill is less than $75/month, and our peak electricity use in the winter is at night (when we use a space heater upstairs). So our exposure to increased prices isn't that great. Our payback at current prices was in 20 years. However, it would have increased the value of our home substantially (because of the "eco" factor, because of the PG&E lock-in), so including increased equity the payback would have been almost immediate. But we have other, higher priority home improvements to worry about right now. Solar installation contractors are almost universally shady; it's exceptionally difficult to find a reputable one. I just didn't like the idea them causing damage to our roof, however minimal the risk, given our current budget.

This already Exists

[Anonymous Coward]

There is already a the PVWatts calculator at on NREL's website. You input your location, the type and placement of the solar panels and it tells you how much power to expect based on local weather measurements. Since these are the people gathering the data, I can't imagine google's project does anything than access this same database.

http://pvwatts.nrel.gov/

Re:This already Exists

[hawguy]

There is already a the PVWatts calculator at on NREL's website. You input your location, the type and placement of the solar panels and it tells you how much power to expect based on local weather measurements. Since these are the people gathering the data, I can't imagine google's project does anything than access this same database.

http://pvwatts.nrel.gov/

The NREL site just looks at location and weather to estimate solar availability -- The Google site attempts to calculate usable roof area and take into account shading from nearby trees and other structures.

Re:Not available yet...

[thinkwaitfast]

Try pvwatts. It's very accurate in my experience.

http://pvwatts.nrel.gov/

Re:Strange limitations

[swillden]

Annual insolation, even after considering weather, counts as a well-documented stat across the entire US. Why would they limit this to just a few key cities?

Because this provides dramatically more detail than regional average insolation. It tells you how much insolation each portion of your roof receives, accounting for local geography, flora and other buildings. That takes some moderately-detailed 3D models and heavy number crunching. The 3D models come from Google's project to build 3D models of all population centers using low-flying aircraft with angled cameras, so Sunroof will only be available in regions where the models are available (zoom in in Google Maps in your area to see if it's already 3D-ifiied) and even then it will take time to crunch all the data.