Back in 2015, Google launched a clever venture called Project Sunroof that used Google Maps data to assess the solar potential of individual roofs, giving homeowners a better idea of whether or not they should take the plunge. From humble beginnings in a few select cities the project has now expanded to cover every US State, and the data collected in the process makes a compelling case for solar indeed.
The upfront costs of installing rooftop solar might cause many to hesitate, particularly considering the unknowns around how much energy it would actually produce. Project Sunroof is Google's attempt to remove some of the guesswork, combining aerial images from Google Maps with 3D modeling of the roof and even taking into account sun position, weather patterns and shade from nearby objects.
From this information, Google can calculate how many hours of usable sunlight your roof receives along with how much is available for placement of solar panels. It can then estimate the resulting energy production and, based on current solar industry pricing, the costs and savings involved if you decide to go ahead.
The project started in Boston, Fresno and the San Francisco Bay Area in August 2015 and has now analyzed around 60 million buildings across the country. All this data has revealed some very useful insights about the state of solar power in the US. For starters, 79 percent of all roofs analyzed are technically viable for solar power. That's four out of every five homes.
In Hawaii, Arizona, Nevada and New Mexico, more than 90 percent of the homes are technically viable. In Pennsylvania, Maine and Minnesota, just over 60 percent are viable. As far as the total solar potential of US cities go, Houston tops the list with an estimated 18,940 gigawatt-hours (GWh) of generation per year. Google says if the country's top ten cities hit their rooftop potential, it would produce enough energy to power eight million homes.
If you're interested in seeing what your rooftop has to offer, you can check out the Project Sunroof explorer tool here.
Source: Google
There are lots of reasons PV panels aren't widely adopted yet even though the panels are about $1 per watt or less. The PV panels are only part of the cost. The inverters that convert the DC 12V electricity from the panels to AC 120V household cost as much as the panels. And the electricity is only available during sunlight hours. With grid-tied inverters (the vast majority) if there's a power blackout you can't access the electricity generated by your PV panels. Crazy, right? Off-grid inverters are even more expensive, then there's the huge cost of installing battery banks. Battery backup inverters are tied to the grid and can feed power back to the grid, but are the most expensive and they also require expensive battery banks.
Grid-tied PV panel installations are the only ones so far that are cost-effective for a lot of homeowners...with federal and local subsidies and utility companies required to buy excess electricity generated by your panels. When about 5% or so of homeowners have installed PV panels, the utility companies begin to grouse about paying for the electricity you generate and state legislatures begin reworking the rules so utilities are not required to buy the excess electricity. Then the savings go poof.
then if you want it to work at night, you need batteries.
both of which are very expensive, then all of it wears out at different times.
the problem is not 'lobbying' [though for a lot of issues (HEALTH CARE) it is]