Government Technology - January 2009 - (Page 51)

units, skylights, perimeter walls or an adjacent building that’s taller. “It takes out the unusable space,” Partin said. “It takes out the north-facing side of the roof if it’s a pitch roof. It takes out the shaded areas; it takes out roof obstructions and those kinds of things.” CH2M HILL uses “stereo-pair aerial imagery” — taking side-by-side photographs to view three-dimensional features — to build models of the buildings, which are run through a computer rendering that determines where the sun is throughout the year in relationship to the building. This determines the ideal location for solar panels. San Francisco chose Google Maps as the platform, but Hermann said Microsoft Virtual Earth can be used, and the company is working on implementations using ESRI solutions. According to Miller, there are two features to the Solar Map. First is the mapping of existing solar installations, which required cityprovided data for geocoding — the process of determining geographic coordinates. These data points are mapped through the Solar Map Web portal and incorporate characteristics of each installation, such as system size, the amount of electricity it generates, the installer, a link to the installer’s Web site, and photos and comments posted by the home or business owner. This information is displayed after users click on a dot on the map that represents each location where photovoltaic (PV) systems are installed. Information that’s publicly available is posted for each solar installation, but Partin said about 1 in 500 owners chose not to participate in the Solar Map. The second feature of the Solar Map is for people who are interested in installing solar panels. “They enter their address, and that address hits a database that contains their building-specific characteristics. That information is then rendered on the page and includes the PV potential and computations based on that PV potential, such as the amount of CO2 [carbon dioxide] that would be reduced, the [power] output, the estimates of cost, etc.,” Miller said. If users want a more detailed price, they may click on “get cost estimates” and the information is tied into Clean Power Research’s Clean Power Estimator. According to Jeff Ressler, product line manager of Clean Power Research, the company was approached by CH2M HILL and San Francisco, who asked Miller added that there’s a cost-accuracy tradeoff depending on how detailed the client wants the data to be. The less detailed, the less expensive the map will be. San Francisco first launched the site in low resolution for it to display quickly and then updated the portal with high-resolution information. The site was expected to be updated to high resolution by November 2008. It takes about 45 days to launch a lowresolution solar map, as long as there isn’t a backlog, Miller said. Made-to-Order Maps Examples of cities that will be launching their own solar maps are: San Diego; Berkeley, Calif.; Sonoma County, Calif.; Portland, Ore.; Salt Lake City and Austin, Texas. that solar economics analysis be added to the map. The information provided by the Solar Map is shared with the estimator. “The Clean Power Estimator Web services can produce a total energy output, and that energy output can dictate what incentives are paid out and thus the overall cost of the system,” Ressler said. Environmental Investment Hermann said the Solar Map’s accuracy is dependent on the data because cities can choose between a low-resolution or a highresolution map. The map’s assessments have been compared with those made by a solar installer who does the measurements inperson. The installer tells CH2M HILL the information meets their needs and the technology can be used in place of physical assessments, though the installer didn’t reveal the exact results. According to Hermann, the high-resolution version of the Solar Map costs about $4,000 per square mile, which is a one-time fee and covers approximately 2,500 buildings in an urban area. The low-resolution version costs about $25,000 for a 50-square-mile city or county. “The low-res version is really a great marketing tool and is a great one-stop shop for all your solar information as a city or county,” he said. Clients can add unique details to their solar map. CH2M HILL has cities that are interested in allowing users to draw solar panels on their rooftop in the Solar Map; for example, if users add three solar panels, the map will determine the details and then they can see what the difference would be compared to two solar panels. According to Hermann, Los Angeles County is customizing its solar map with high-resolution imagery for county buildings, and each city within the county can decide whether to fund the high-resolution imagery. The Solar Map site can also match the colors and structure of a government’s overall Web page style. “The goal is to have the Solar Map feel like a part of their existing city presentation,” Miller said. San Francisco hasn’t yet received feedback from citizens that the Solar Map led directly to solar installation, Partin said, but the Department of Environment has heard that potential customers use information garnered from the site when speaking with solar installers. She suspected city grants for residents who install solar power is the main driver of solar installations. The Web site receives about 200 page hits per month, according to Partin. However, the number increases after a big announcement is made about solar. In the future, San Francisco will add measurements of solar water heating potential to the map and eventually make it a wind power resource. Hermann said estimating wind power depends on if cities can measure the wind microclimate — the climate of a specific place in contrast to the climate of an entire area — but San Francisco has some capability to do that. 41 http://www.govtech.com

Table of Contents Feed for the Digital Edition of Government Technology - January 2009

Government Technology - January 2009 Contents Point of View On the Scene Big Picture Four Questions for... Stemming the Retirement Tide Getting the Picture Fact of Matter Money Trail Rays the Roof Trick or Tweet? The Modern Way to Vote Products signal:noise

Government Technology - January 2009

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