Champions of clean energy have long argued that New York City has incredible solar potential. Although Manhattan's vertical skyline may not be ideal, the outer boroughs -- full of broad, flat roofs on low-rise buildings -- have the right physical characteristics to support large solar arrays. Just as important, the demand patterns of the Big Apple also match solar's strengths: New York City's electricity demand is highest on those sunny, sweltering summer days when apartments, offices, and retailers alike are cranking their air conditioners.
Now there's some hard data that supports these theoretical claims. Yesterday, the New York City Solar America City Partnership, led by Sustainable CUNY, released the New York City Solar Map. The map shows existing solar installations (photovoltaic and water heating) in the city and, more importantly, provides detailed estimates for the potential solar gains throughout the five boroughs.
The most impressive takeaway, as Mireya Navarro reported in the New York Times, is that a full two-thirds of New York City's rooftops are suitable for solar power, and these "could jointly generate enough energy to meet half the city’s de`mand for electricity at peak periods."
The map is built on a computer model that uses a massive amount of data, which includes, according to the map's website, "the position of the sun, overall atmospheric conditions, latitude, and most importantly, shading." The amount of shade is determined using advanced LIDAR data that was gathered in some low-altitude flyovers of the city last year. This LIDAR data can be used to create a virtual 3D map of the city, allowing for simulations of the sun tracking through the sky and the resulting shade moving across rooftops.
Technical jargon aside, the end product is incredibly powerful and -- at least if you're an energy dork like me -- awfully fun to play around with. For sake of illustration, I plugged in my last permanent New York City address into the map. I found that it's a little clunky, turning up "449 Vanderbilt Avenue" in Brooklyn rather than "450 Clinton Avenue" when I clicked on my old rooftop.
Even so, the information the map spits out is impressive, and useful. After getting the broad overview of the roof's potential -- in this case, more than $5,000 per year in electricity bill savings off of more than 20 kilowatts of photovoltaics -- you can click through to get even more details about the site itself.
Finally, you can run a customized calculator that tells you all the essential details about actually purchasing and installing a system for that particular building.
The most important thing here for most building owners is probably the payback period. Which, in this case of 450 Clinton Avenue in Brooklyn, is a mere four years. A no-brainer, right? Well, of course, it's not quite so easy. This building, like so many New York City residences, is full of rental units, and the company that owns the building doesn't pay the electric bills. So solar proponents, utilities, and the city will still need to work together to figure out market mechanisms and financing structures that provide incentives for landlords to install these systems. Although this is a tricky economic challenge, it shouldn't prove an insurmountable hurdle.
In the meantime, innovative projects like solar empowerment zones are helping to speed up the installation of photovoltaics. These zones, which I first wrote about a couple years ago, are sections of the city that have been identified as having the best potential for solar power generation. In the zones, building owners are entitled to some special benefits -- unique financial incentives, free data monitoring, techical assistance, fast-tracked permitting -- that should help streamline the purchase and installation process.
With the first three solar empowerment zones recently announced, and this incredibly powerful new mapping tool, New York City's solar future is looking awfully bright.