Exactly how much sunlight hits the five boroughs?
That question prompted researchers at the City University of New York to spend months poring over terabytes of data, part of a project to quantify the city’s potential for solar electricity. To solve the sunlight riddle, the researchers dispatched a laser-wielding airplane on low-flying missions over the city.
The ultimate goal is to motivate more New Yorkers to install solar panels on more rooftops. The city already doubled the use of solar panels in 2010, according to Con Edison’s recent report, surpassing a mark officials had projected would not be reached until 2015.
“We’re creating a solar map where, on the front end, consumers could plug in their addresses and see how much solar they could get,” said Tria Case, CUNY’s director for sustainability. There will also be a financial component to the map, showing New Yorkers how a particular solar array installed atop their building might reduce utility bills.
The project website will allow users to draw hypothetical shapes of solar panels on their rooftops, said Sean Ahern, whose center for spatial information at Hunter College has been analyzing the data and creating the sunlight map. An online prototype is currently in testing.
The map, similar to one used in San Francisco and another in Boston, is due to be released in the spring. The total cost of the project is about $640,000, with federal stimulus funds covering about a third.
As part of the project, Sanborn Map Co. gathered comprehensive data on New York City’s architectural topography by sending a low-flying airplane on two dozen missions, each lasting about nine hours. The airplane, equipped with lasers, shot harmless rays to the ground; its sensors measured how long each ray took to touch down and return to the plane.
The data gathered calculates the elevation of millions of points throughout the city. You can see a short visualization of the data in video format. The colors in the video represent relative change in elevation. The blues are closer to the ground, while the reds are higher.
The technology, called Light Detection and Ranging, or LIDAR, offers a level of detail unavailable in similar maps created via aerial photography. The height of water towers and air-conditioning units on rooftops — which cast shadows big enough to affect solar-power calculations — are revealed in the map, Ahearn said.
The solar map is just one of several initiatives to increase the city’s solar power. Activists are also trying to reduce the time it takes to install an array — from the initial decision to completion – to just 100 days . The effort aims to create a single online portal for solar installers to schedule building inspections, file applications with Con Ed and satisfy safety regulations.
Con Ed said that there are now 8.5 megawatts of solar power on the grid in the region — a big improvement over the 1 megawatt generated in 2007. But that total still represents only about 0.1% of the average power used by the city.