One of the issues facing preventing more widespread adoption of solar technology is cost concerns. A business merchant, homeowner, or even a corporation with a gleaming downtown office may consider installing solar panels on its roof, but be wary of how expensive it might be.
If they’re mulling it over, they might spend a lot of time on the Internet doing research, or call a few solar companies, but either way, it’s still a significant investment of their time. And even if they decide they are going to switch to solar, they still have questions: How much energy am I really saving? When will my investment pay me back?
Trying to take the hassle out of the process, and encourage more and more people and businesses to invest in solar energy, has been the work of the MIT’s Sustainable Design Lab, led by Christoph Reinhart, an associate professor of building technology, and a new start-up called Mapdwell, which has licensed the technology.
What Reinhart and his colleagues have done is pretty revolutionary, and may signal a breakthrough in solar’s development. They’ve created an application called a Solar Map, in which a simulation-based technique can reliably predict the annual electricity yield from an arbitrarily oriented and obstructed photovoltaic array located anywhere on the planet.
In other words, the app can tell you exactly what your solar output and costs would be on any building, anywhere in the world. The technique considers detailed surrounding geometry such as trees and buildings, hourly direct and diffuse solar radiation data, as well as instantaneous solar cell efficiencies due to varying roof temperatures.
Required simulation inputs are standard local weather station data as well as LIDAR (Light Detection and Ranging) point clouds. In the works for the past three years, MIT did its first test of the system using the city of Cambridge, Mass., and the results are spectacular (see the video below).
“What we were now trying to do is develop a modeling platform that allows you to model 100 buildings at once at the same time,” Reinhart told me in an interview.
The tools being employed are nothing new, and in fact have been around for 40 years.
“Now we want to combine geographic information systems (GIS), large databases that exist for most North American cities,” Reinhart continued. “They contain assessor data, and we wanted to tap into the data to create algorithms that would give us models on how to assess what the cost of solar for buildings would be.”
Reinhart and Eduardo Berlin, who worked under Reinhart previously and is now the CEO of Mapdwell, explained how the system came about, and how the first city, Cambridge, was completed.
The MIT team began using LIDAR data and combining it with weather data and other calculations for 17,000 buildings inside Cambridge, as well as using Google’s satellite imagery of every city. Using all of that information, Reinhart explained, the MIT team was able to create a 3D model of Cambridge, and thus map exactly how much solar radiation would fall on each roof, taking into account trees, hills, and every other possible geographic factor.
“We are also able to predict how hot the building roof is getting,” Reinhart said. “Based on that, we know how hot the solar cell gets, and if the solar cell gets very hot, its efficiency goes down. So that allows us to very finely predict how much energy the solar cell would use over the whole year.”
After MIT finished its mathematical calculations, it licensed the information to Mapdwell, which took the data and designed the online system, and combined all the data into the metric used on the site.
“We translated the kilowatt hours into metrics that people could understand,” Berlin said.
The city of Cambridge was thrilled to have the data, and the cost to the city for MIT to map the city was only $15,000 to $20,000.
To illustrate exactly how the solar map works, Berlin walked me through a random Cambridge building, 579 Massachusetts Avenue.
According to the app data, which can be viewed here, it would cost the building’s owner $314,000 to install 86 kilowatts of solar panels on the roof (MIT consulted with solar companies in the area, and used existing government tax credits on solar, to help come up with the costs). The app also says that the yearly revenue generated per month from the panels is $43,000, and the building would have a carbon offset of 488 trees. It also declares that the payback period (when the owner can make his or her money back from installing solar) would be seven years.
“What we’re doing is absolutely putting the homeowner, or building owner, in control,” Berlin said. “We feel like once people have all the tools, they’ll make the right decision, and see that solar is a very wise investment. But the whole idea is to empower the homeowner.”
As of right now Cambridge is the only city that Mapdwell has completely finished mapping, so only that city’s residents can use the application to gauge the solar cost to their property. But Berlin said that Mapdwell is in “advanced conversations” to bring the Solar System to other cities in Massachusetts, several major U.S. cities, and municipalities in Canada and Latin America. More than 20 cities in all have expressed interest, Berlin said, but he wasn’t at liberty to discuss pending deals until they were closed.
Now, a few caveats for those who are excitedly awaiting the mapping of their town. First, while the app is free to consumers and building-owners, the cost to each city for Mapdwell to map their city, then store the data, is not insignificant. Berlin said that, unlike a smaller city like Cambridge cost less than $20,000 and took about three weeks to complete, a large city like Boston, or Chicago would cost approximately $70,000 (major cities like New York would cost significantly more, Berlin said).
Once the city pays for the mapping, Mapdwell would charge a small fee for the hosting and serving requirements
So there’s no telling if all towns will be willing to spend the money for the service, though Berlin said he was hoping non-profit organizations or other for-profit solar groups in the town would help defray the costs, and he’s been encouraging cities to go that route once they show interest.
Berlin also added that Mapdwell is not in cahoots with any solar companies who want to share the profits from Mapdwell; he says that’s what differentiates Mapdwell from similar companies.
“Of the solar companies we spoke with when developing [the system], all of them were enthused that it could help educate the public,” Berlin said.
Of course, he and Reinhart readily admit that they expect putting the information in the hands of consumers will boost solar installation. Once homeowners see that solar pays for itself within a small amount of time, Berlin and Reinhart expect to see more people talking the plunge toward a renewable energy future.
“You’re able to see that payback times are low because of all the state and government incentives available, including the sustainable renewable energy credits,” Reinhart said. “We expect that this will be a really useful addition to solar power knowledge.”