Millburn, New Jersey:
Water Treatment Plant Uses Solar Panels to Generate Power
Suzanne Chiavari Jul 27, 2012
Aiming to lower energy costs and decrease our carbon footprint, New Jersey American Water, a wholly owned subsidiary of American Water, is investing in solar technology. Most recently, the company installed solar modules on a reservoir at the Canoe Brook Water Treatment Plant in Millburn, N.J. This is the first solar array on a body of water on the East Coast designed to withstand a freeze/thaw environment.
American Water treats, pumps and delivers one billion gallons of water a day. This takes a substantial amount of energy. The company’s goal is to lower greenhouse gas emissions per volume of water produced by 16 percent by the year 2017. A large portion of this reduction will come from increasing pump efficiencies, but six percent is slated to come from increasing the use of renewable energy sources in New Jersey.
Solar energy generates electricity without producing harmful greenhouse gases and produces maximum output at times of peak demand, when electricity is of highest value. Solar energy can be purchased from a third-party supplier or owned outright. After analyzing the incentives, energy cost savings and other factors, New Jersey American Water chose to invest in owning the system.
Looking to generate energy for use at the plant, the space needed for traditional ground-mounted solar arrays was lacking. The plant sits on more than 500 acres of protected land and only a small portion of the property can be used for construction and/or operational purposes. With such little space available, a 735 million gallon reservoir nearby was the most viable place to install solar panels.
The 400 solar modules measure 110 ft by 110 ft and rest on a docking station designed to float on the water’s surface. The array will generate 112 kilowatts of direct current (DC) power, which will then be converted to alternating current (AC) power. Annually, the solar field will produce 135,000 kilowatt hours per year, or approximately two percent of the plant’s power.
The solar panels are fixed at a 15-degree angle and specially made to endure severe weather conditions —heavy wind, rain, snow and ice — allowing this pilot project to be monitored for the effectiveness of the solar station during inclement weather changes.
Because the reservoir has a 6- to 9-in. thick liner, the array needed to be secured without penetrating the reservoir lining. The project team designed a unique mooring system that allows it to rise and fall with the water level of the reservoir. A system of elastic bands connects the docking system to anchors at the bottom of the reservoir, preventing twisting or turning, but allowing it to move up and down in response to changes in the water level or laterally as a result of ice. On the underside of the docking system, special connection details are used to attach the elastic bands. The anchors consist of 25 concrete blocks, each weighing four tons.
The project was constructed for about $1.35 million. While tax credits and other inducements are expected to help defray some of the costs, New Jersey American Water has applied for a tax rebate of up to 30 percent of the total project cost as a result of the federal American Recovery and Reinvestment Act of 2009 (ARRA), also known as the Stimulus Package. The ARRA has a progressive clean energy program that provides incentives for alternative power projects. Meanwhile, the state of New Jersey also offers economic incentives for renewable energy projects, which are key for solar projects.
Environmental and Social Benefits
Renewable energy technologies are clean sources of energy that have a much lower environmental impact than conventional energy technologies. By producing 135,000 kilowatt hours per year, this equivalent energy doesn’t have to be produced by other traditional electric generation, such as equipment fired by coal, natural gas or oil.
Two additional benefits of the system are currently being evaluated. Since the solar panels eliminate the sun’s rays from reaching the water, algae growth is reduced. This can lead to a reduction in chemicals required to the reduce algae growth as part of the water treatment process. Additionally, since solar panels operate more efficiently when cooler, the effect of the water beneath the array keeps the panel temperature cooler, which thereby can increase efficiency and ultimately, production of the system.
Over the next year, New Jersey American Water will continue evaluating the performance of the array and the extent of maintenance required. Once the system operates for a year, the company will decide whether to expand the array and by what amount. The system is expected to be essentially maintenance free and is monitored constantly via the internet with monthly inspections planned.
By exploring new ways to use green energy to help power the Canoe Brook plant and other facilities, the company will generate approximately 3.5 million kilowatt hours per year by the power of the sun, which benefits the customers and the company.
Water companies throughout the U.S. should investigate local incentives for renewable energy as well as implement energy efficiency programs as this can reduce environmental impacts, energy costs and future exposure to higher electricity costs.
Suzanne Chiavari is vice president of engineering for New Jersey American Water, responsible for the planning, design and construction of water and wastewater system improvements.