Supporting Solar Energy Installations from Massive Farms to Pocket Arrays

Although solar energy only fulfills around one percent of our nation’s current power demands, a combination of high visibility, public incentives, and lower component costs have fueled an increase in installations coming online over the last 12 months and continuing into this year. KCI is supporting the solar industry by providing a host of services for installations ranging from massive farms to urban pocket arrays.

Wide Open Spaces

In the South, where large, flat tracts of land are plentiful, scientists, surveyors and utility engineers are working with engineering, procurement and construction (EPC) developers on large solar farms. At a site in Central Florida, a due diligence study helped identify geophysical concerns prior to design and construction of a proposed six megawatt power plant. (According to the Solar Energy Industries Association, one megawatt of solar photovoltaics can power an average of 164 homes.)

“We have a lot of experience in this region, which is prone to sinkholes,” said project engineer Prashanth Vaddu, PE. “We used ground-penetrating radar over the entire site in conjunction with soil testing to identify subsurface anomalies.”  In this case, where areas of concern were identified, geotechnical borings helped confirm that anomalies had no association with sinkholes.

ALTA-ACSM-surveys
In addition to traditional and GPS survey equipment, KCI crews use four wheel all-terrain vehicles, pickup trucks and even farm tractors to safely navigate the fields and meet aggressive schedules.

Among the farm fields in eastern North Carolina, surveyors focus on the land surface itself instead of beneath it. KCI has provided ALTA/ACSM (American Land Title Association/American Congress on Surveying and Mapping), boundary, topographic and wetland surveys for three multi-tract sites ranging in size from 400 to 600 acres. “We conduct ALTA/ACSM surveys to provide a clear chain of title on these tracts, including research on every easement, every road, every land owner, and just about everything that touched the property back to when the dirt was new,” said Practice Leader Matthew M. Crawford, PLS. Field crews locate the physical features, property corners and elevation data for each property. The resulting boundary and topographic mapping helps facilitate land and easement purchases as well as civil design for the solar facilities.

Renewal Equals Reuse

Further up the eastern seaboard, in the urbanized and highly developed metropolitan area that makes up much of the country’s Northeast corridor, properties of similar size and topography are in short supply. Instead solar energy providers and facilitators have to look for alternative installation sites. KCI is working with contractors, EPCs and utility companies on projects throughout the Northeast to capitalize on opportunities to generate solar power within existing land uses.

“Photovoltaic panels don’t generate a significant amount of lease revenue per square foot of land,” said Brendon Quinlivan, Director of Origination – Distributed Energy for Constellation, an Exelon company.  “As such, many of the ground-mounted arrays are located in non-urban areas, or in surplus land adjacent to a customer-owned commercial or industrial facility. In addition to these applications, re-use of existing facilities like rooftops and parking lots offers strategic locations for a variety of photovoltaic solar arrays for municipal customers.”

At the New Carrollton Federal Building, headquarters of the IRS, in Lanham, Maryland, KCI is providing surveying services for a solar array structure that will sit above the building’s immense radial parking lot. Once completed, more than 3,300 panels will be capable of generating up to 875 kilowatts of energy. Working for contractor John E. Kelly &

IRS Financial Service Center
The General Services Administration estimates that the $45 million Deep Energy Retrofit Project, which also includes a new geothermal system, rain gardens and conservation upgrades within the IRS headquarters building, will reduce the facility’s energy consumption by 60 percent with a first-year savings of more than $2.5 million. KCI’s survey crews are helping lay out the steel structure for an array over the existing parking lot. image courtesy of Carol M. Highsmith

Sons Electrical Construction Inc., crews are laying out the infrastructure for the project, specifically the horizontal and vertical position of the columns that will support the nearly two-acre solar farm. “When working with steel, we use specialized equipment that enables us to locate points with a high degree of precision and accuracy, in many cases to one second of a degree and five one-thousandths of a foot,” said senior surveyor D. Clark Johnson Jr., PLS. “We

were tasked with calculating design positions of the array columns based on geometry shown on the plans, laying out the positions in the field, and later conducting an as-built survey on the installed column foundations.” Engineers use the information to finalize the design of the steel supports that tie together into the final array, a large frame structure covering much of the parking lot.

 

Fitting In

In and around Boston, KCI worked with Phoenix Solar to expedite the installation of solar arrays ranging in size from 290 to 640 kilowatts atop five department store roofs. “They were dissatisfied with their current consultant, and to facilitate building permits, they needed a letter from a structural engineer stating that the roofs were strong enough to carry the weight of the photovoltaic panels,” said Practice Leader Kenneth G. Dill, PE. “Phoenix contacted us late on a Tuesday night and I was on site at two locations by the following Monday with reports delivered that Thursday.” The last three sites were completed over the next week followed by development of staging plans for material pallet placement. KCI also provided personnel to serve as site managers, responsible for documenting construction progress and coordinating between client and subcontractor personnel during construction at two locations.

Boston-Area-Department-Store-Solar-Panels-Partial-Construction
Phoenix Solar called on KCI to conduct a structural analysis in support of building permits for new solar arrays atop five department stores in and around Boston.

Phoenix contacted KCI based on a recommendation from Constellation, who owns and will operate and maintain the five Boston-area arrays. Dill has been working directly with the energy giant to implement a much larger multi-site solar power initiative as part of Constellation’s merger with Exelon in 2012.

KCI is supporting Constellation by providing structural, electrical, geotechnical, civil, and public utilities engineering, as well as surveys, for multiple small sites that include roof, open ground and parking lot installations. In addition to structural analyses, design for rooftop locations often requires highly accurate 3-D scan (LIDAR) surveys to locate every possible obstruction and feature that could affect the layout or potentially create shaded areas. Ground-based sites can be developed using traditional topographic surveys, but also require underground utilities to be located as well as geotechnical studies to evaluate soil conditions and resistivity or heat absorption, which can limit the size of transmission cables. All sites require power distribution design including electrical equipment boxes and cabling.

The firm has 19 sites in process that range from 189 to 2,319 kilowatts, with at least three more in the pipeline. The Constellation work is KCI’s largest solar project to date, but with the market expanding and set for a banner year, KCI is poised to support owners, developers and contractors with any suite of services they require. The firm has proposals pending for sites in Rhode Island, New York and Illinois and continues to look at other opportunities around the country.