Terms like “eco-friendly” and “cost-saving” don’t always go together, but Connecticut-based O&G Industries found a sweet spot for the two.
O&G Industries installed a 1.3-megawatt (DC) solar array to power its quarry in Southbury, Connecticut. According to the company, the 3,762-panel array sits on five acres and produces the energy equivalent of powering 150 homes.
Solar company Solect Energy provided O&G with the panels needed for the array, which features 16 inverters that each produce about 60 kW of energy – totaling to a nameplate rating of 960 kW (AC).
Matt Tobin, engineering manager at O&G Industries, was heavily involved in the solar array project since its conception years ago. He worked with surveyors and engineers to choose the location for the array.
“[The location we chose is] where we had deposited a bunch of overburden, created a large berm and then planted trees on the berm to shield our operations from residences to the west of us,” Tobin says. “So we didn’t really disturb the area too much [with the installation].”
The array has a 280-kW battery to assist in powering the quarry. It’s particularly useful during the early morning hours, when the sun’s rays are still too weak to produce the energy necessary for the startup of the on-site machinery.
The company designed and sized the array to be able to power its various on-site components, including its rock crushing equipment, concrete plant and assets in the quarry. While O&G Industries had completed two other solar installations previously, the array at the Southbury Quarry is the first of its size, magnitude and scope at the company.
“From a solar perspective, it was interesting getting involved with it and learning more about it,” Tobin says. “This is the biggest solar project I’ve done by far.”
Long-term cost savings
Says O&G Industries’ TJ Oneglia: “There is money to be saved by producing your own solar power.”
The company has been pursuing ways to reduce its carbon footprint and be eco-conscious in as many areas as possible, says TJ Oneglia, vice president of construction materials at O&G Industries.
To make environmental goals more feasible, the state of Connecticut offers economic incentives for projects such as O&G’s known within the ZREC (Zero Emission Renewable Energy Credit) program. While companies make upfront investments, the program presents an opportunity for cost savings.
In addition, O&G Industries took into account the federal renewable investment tax credit, which was 30 percent at the time of installing the Southbury Quarry array.
“You look at the money you’re spending up front, coupled with the incentives, coupled with the energy savings, and it shortens the payback period on the array to the point that it makes economic sense,” Oneglia says.
Also, the array’s battery will ultimately aid in saving on energy costs because of its ability to keep instantaneous kilowatt demand down, Tobin says.
“The storage battery will allow us to peak shave,” Tobin says. “Since our billing is based not only on electrical energy consumption, but also on our highest point of demand, the battery will help us to keep our demand charges down.”
The future of solar energy
The installation at the Southbury Quarry was the largest solar project engineering manager Matt Tobin has been a part of at O&G Industries.
Tobin estimates the solar panels will last about 25 years. When the time comes to replace them, the panels’ mounts are already in place so the reinstallation process should be simplified.
The quarry in Southbury is not the first quarry to be powered by solar energy, and it won’t be the last, according to Oneglia.
With government incentives in place, the potential for solar-powered quarries is much greater. Tobin believes a solar-powered future is based largely on economics. If states continue to incentivize, then the way is paved for other to use solar power – and this could help reduce the aggregate industry’s carbon emissions.
“There is money to be saved by producing your own solar power,” Oneglia says. “It is also the right thing to do for the environment. We are interested in lowering our carbon footprint, as well as that of the overall industry. This is a great opportunity to try new technology, see it perform in service and hopefully utilize it in other locations in the future.”
To read the full story, visit the Pit & Quarry magazine website.