Made in the Shade

New Jersey's National Guard - along with help from the US Army Corps - constructs two solar power projects.

During President Barack Obama’s inauguration speech on January 20, 2009, he said, “We will harness the sun, and the winds, and the soil to fuel our cars and run our factories.”

President Obama and the new administration believe that renewable energy is part of our nation’s successful future, possibly because the federal government has already experienced positive results in the past.

Under the Federal Government’s Energy Policy Act of 2005, all federal government agencies are required to use some renewable energy. One agency that’s continuing to do this successfully is the US National Guard, with the assistance of the US Army Corps of Engineers.  

Recently, the Guard’s New Jersey branch sought the expertise of the Army Corps’ New York District to construct two solar power projects for them. These projects will not only help the Guard meet the country’s energy laws, but also save money on electricity and earn a profit from the State of New Jersey.

The State of New Jersey requires its citizens to support the use of renewable energy. Under the New Jersey Solar Renewable Energy Certificate Program, solar system owners that generate over 1,000 kW of electricity per year, that’s connected to the public power grid, receive certificates. These certificates are then publicly sold and traded to New Jersey businesses and individuals, enabling them to receive solar power benefits without building a solar power system themselves. The revenue is returned to the solar system owners.

The New Jersey National Guard is an owner of several solar power systems. They have benefited from the SREC Program and will continue to with the assistance of the Army Corps.

The Army Corps is constructing two open panel Photovoltaic Carport solar power projects for the New Jersey National Guard—one for their agency’s Joint Forces Headquarters at Fort Dix, NJ, and the other for their National Training Facility Headquarters at Sea Girt, NJ.

The carport solar power projects are being erected over two existing parking lots at both locations. The energy generated will power these two buildings that are less then 200 feet away from the parking lots.

The Army Corps is erecting the carport structures above the parking lots and then setting up area lighting, inverters, transformers, switchgears, and electrical metering equipment. When the projects are completed, they will restore the parking lot pavements, which are already in good shape, by restripping and sealing cracks.

The steel carport structures will stand 16 feet above the parking lot pavement and will be supported by web steel joists and joist girders. On top of these structures, the solar Photovoltaic Power Panels arrays are being installed.

The panels are composed of modules. Each module is made up of several solar cells or photovoltaic cells that absorb the sun’s light and produce electricity. The larger the size of the panel, the more electricity will be produced.

Incorporating panels into existing structures can mitigate the space requirement attendant to most onsite solar installations.

The panels produce electricity in the form of Direct Current (DC), which is not directly usable energy for a building. Most buildings require Alternating Current (AC) at a higher voltage. To make usable building power, the solar panel’s DC is fed into an inverter that transforms it into AC at a higher voltage.

This AC power is then sent to the building’s main transformers where it can be used by the buildings for their energy needs. The New Jersey National Guard’s solar power system is tied into the public’s power grid and excess power is shared with the community.

When completed, both structures including the panels will roughly be the size of a football field. The Fort Dix project will generate approximately 240 kW and the Sea Girt project approximately 238 kW. Both projects are also being designed in a way that will save the National Guard considerable energy savings during the high-energy demand months of summertime.

At Fort Dix, the panels are being placed at a 25-degree angle and Sea Girt at a 15-degree angle, to allow for optimum performance. This will provide the Fort Dix building 40% of its summer energy needs and the Sea Girt building 80%. Placing the panels on an angle also facilitates runoff of rain and snow.

The New Jersey National Guard will earn considerable money from electric bill savings and the state’s SREC Program. In total, the agency will save approximately $116 K in electric bill savings and earn approximately $350 K from the SREC Program.

Besides these financial benefits, there are additional plusses that come with constructing solar power projects on new open panel carports that are on existing parking lots.

If you install a solar power system on an existing building roof and not a new roof, you will most likely have to remove these panels in the future to repair the roof as it gets old and leaks, which can be very expensive and time-consuming. The solar power system will also add weight or roof load to the existing roof, increasing its deterioration.

“You don’t want to install panels that can last 20–25 years on top of a roof that has only one year left,” says Armando Jimenez, project manager, US Army Corps of Engineers, New York District. “By placing panels on new roof tops, you also don’t have to deal with building or roofing permits to reinstall roof mounted solar power systems.”

Constructing on existing parking lots also has its benefits. By doing this, you aren’t impacting the stormwater runoff, so there are minimal impacts to the environment. In addition, vehicles using the parking lot receive some shading from the sun.

An open panel carport design is also a smart way to go. An open panel as opposed to a solid ceiling structure prevents debris, such as bird nests and snow, from accumulating on the carport, which would require regular maintenance. Also, a solid ceiling adds additional weight to the structure that would require a stronger and more expensive structural support.

Jimenez says that he envisions an increase in solar power project construction in the future and has the following suggestions for builders who plan on embarking on them:

Before you begin a solar power project, seek advice from experts in solar and renewable energy, because they can save you considerable time and money. In the case of these projects, the Army Corps’ New York District collaborated with the Army Corps’ Engineer Research and
Development Center, that has extensive experience working on solar power projects with Army Corps districts, Department of Defense, and other Federal agencies throughout the world.

When designing the project, make sure the buildings you want to provide the solar power are large enough to be able to use most of the energy or have a “big load,” and are situated near the solar power panels. The further a building is to the panels, the more energy you will have to use to transport the solar power energy to the buildings.

“For example, it doesn’t make sense to have solar power panels way out in a desert, because you will lose efficiency by using the energy to transport electricity from there to where buildings are that will use the energy,” he adds. “Due to power transmission lines having inherent resistance and capacitance, energy is always wasted when transporting power.”

You should also calculate ahead of time how much money your customer will be saving in electric bills in the long run, as well as try to find out if there are any energy credit programs they can benefit from, such as the State of New Jersey’s SREC Program, so that the project is economically justified. 

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Both solar power projects are expected to be completed sometime this fall, and, according to Jimenez, the New Jersey National Guard has asked the Army Corps to perform additional solar power projects in the near future.

Jimenez says, “These solar power projects are a win-win for the community, US National Guard, and the Nation. We are meeting the Nation’s environmental goals and President Obama’s renewable energy vision.             

Author's Bio: Dr. JoAnne Castagna, Ed.D. is a technical writer-editor for the US Army Corps of Engineers, New York District, and can be reached at joanne.castagna@usace.army.mil.