30 April 2012
The Mojave Air & Space Port in Mojave, California (US) motto is “Imagination flies here.” Many firsts have launched from its runways: the first non-governmental rocket ship, the first plane to circle the globe without refuelling, the first rocket-based plane. Today it’s home to Richard Branson’s Virgin Galactic’s SpaceShipTwo, Paul Allen’s StratoLaunch, the National Test Pilot School and many other businesses.
Officials at the Space Port are taking steps to make it an attractive place for businesses to locate and part of that plan is renewable energy.
Officials at the Space Port are taking steps to make it an attractive place for businesses to locate and part of that plan is renewable energy. Not only are huge wind turbines built here, but hundreds of spinning turbines dot the nearby Tehachapi Mountains. Solar is also playing a role, yet it’s not without its challenges.
Sunny, hot and windy
For most of the year the solar resource in the Mojave desert is very strong, with direct sun and clear skies. But there’s also high heat and winds. And, being an airport, reflectivity from solar panels is not an option. When the Air & Space Port operators wanted to power the administration building with solar energy, the choice, according to Kevin Wojkiewicz, Contracts Administrator, was concentrated photovoltaics. “CPV was the best technology because we couldn’t have glare.” He explained that the ground-mounted system with dual-axis tracking has no reflectivity, which would interfere with the test flights conducted at the Port. Another challenge is wind of up to 40 knots, but to date the CPV system has held strong even in winds of over 100 mph. And in the heat of the desert, CPV has proven itself. The multijunction CPV cells operate well in high heat conditions, as opposed to traditional PV in the same conditions.
Being an airport, reflectivity from solar panels is not an option.
After consulting with multiple vendors with varying technologies the Space Port chose GreenVolt’s CPV system, which Wojkiewicz said has been installed and operating at high efficiency for more than a year with no issues.
The 64kW system is configured in two, 32 kW columns, each about 160 feet long and spaced about 50 feet apart. The installation had to accommodate existing structures in an operating airport and a custom electrical connection was required for integration to an emergency diesel generator.
GreenVolt's 64kW CPV System
The grid-connected CPV system includes solar modules (consisting of concentrating Fresnel lenses, secondary optics, multijunction photovoltaic cell, and passive thermal management), two-axis trackers, bi-polar ± 600V inverters, energy management software, networking, AC and DC disconnects, and all DC wiring. Wojkiewicz said the advantages of going with a single system supplier was a big reason they chose GreenVolts. All the parts and pieces were designed from the ground up to work together optimally. For example, the CPV modules are pre-wired and pre-fabricated into 2kW assemblies that install directly from the shipping pallet to the array with only four bolts and two electrical snap-in connections.
Time lapse video of the CPV system tracking the sun
Wojkiewicz said another impressive part of the system are the monitoring capabilities. The system comes with a video camera for live feed from the site. A solar and weather monitoring station, and Internet-based, energy management software provides sophisticated, remote monitoring, diagnostics, reporting and control. With the real-time monitoring not only do operators know how much energy is being produced, but they can see if there are any problems with the system, identify the problem location, produce diagnostics and reports, and maintain inventories and more. And this can all be done remotely from an Internet-based PC or a mobile device.
Solar proving ground
The CPV system provides enough energy to fully power the administration building and a few others at the airport. To pay for the system, the non-profit Mojave Air & Space Port provided an up-front contribution toward the capital outlay for the system and have a long-term agreement to purchase power at a low rate from the system owner., according to Wojkiewicz. This investment pays dividends in many ways, beginning with a low, fixed rate for energy, but also by sending a message about the benefits of using cutting edge, highly efficient technologies.
Written by Anne Fischer, Managing Editor, Solar Novus Today