The Answer is Blowing in the Wind
At least that’s where Teichert Aggregates hopes to find a way to lower energy costs at one of its plants.
By Kerry Clines, Senior Editor
California-based Teichert Aggregates began construction of its Vernalis Plant in 1999, completing it in 2000. “It was exciting,” says Paul Mercurio, production manager. “We started a new plant with new people. Fortunately, the economy was good at that time. We went up to double production shifts almost right away with the anticipation of growing the plant in the future. It worked out well.”
The Vernalis Plant replaced Teichert’s Tracy Plant located about 7 miles away, which was being depleted, and began supplying aggregate for the entire area. “Depending on the product, our sphere of influence could be as much as 60 to 80 miles,” says Jerry Hansen, plant manager.
“We go into the Bay area,” Mercurio adds. “Some products go as far as San Jose and some get into San Francisco, but it has to be a special product to get out that far. The majority of the products are centered in Stockton, Livermore, Modesto, Manteca, and all the surrounding area.”
Since 2008, Teichert Aggregates, like every other aggregate operation in California and many aggregate operations nationwide, has been making adjustments to maintain business during the downturn in the economy. One such adjustment addressed not only lowering costs, but being environmentally friendly as well.
“We had been talking about going forward, trying to figure out every way to keep our energy costs down,” Mercurio says. “We talked with Foundation Wind Power about the concept of installing a wind turbine on site. A group of investors put the money up for it, and we provided a site for them to place the turbine. We agreed to purchase the generated power favorable to our utility rate. The investors are responsible for everything else, including turbine maintenance.”
“The computer brain of the wind turbine is monitored in New York,” says Steve Grant, a former Vernalis Plant employee who now works for Foundation Wind Power. “Basically, electricity is generated at the top of the turbine and comes down cables. The blades turn, within reason, as fast as they can to generate as much power as they can. Another device senses what power is being sent and interacts with it to change it into 60 hertz, or 690 volts. That goes out to the transformer just outside the turbine where it is stepped up to plant voltage, which is 4,160 volts.”
There are sensors on top of the wind turbine that send wind speed and direction to the computer, which engages two yaw motors that turn the turbine into the wind. The pitch of the blades is adjustable as well. “The objective is to hold at a steady RPM,” Mercurio says. “They tune it to achieve that level.”
The wind turbine is expected to supply about 25 percent of the plant’s power needs, depending on wind speed and what’s running in the plant. “It’s an effort to have less of an impact [on the environment],” Mercurio says. “We have the land and the wind, and we consume the energy. The neat part is it’s locally provided energy. This is where you’re producing it, and this is where you’re using it.”
Twenty years is the average life span of this wind turbine. “By then, I’m sure there will be a better mousetrap, and we’ll probably want to replace it,” Mercurio says. “The challenging point is that it only produces energy when the wind blows, and usage depends on how much the plant is running. This is just dipping our toe in the water. We will see what it’s like and be sure it makes sense.”
The Vernalis Plant produces all sand and gravel. Larger stones are crushed, but there is no blasting. “We’re mining out of two different pits and blending the materials,” Hansen says. “We mine the pits and then fill them back in with the clay and silt that washes out of the material. The pit is composed of alternating layers of aggregates and clay, and we use scrapers to take the layers out in the reverse order they were put in. So we’re effectively harvesting — taking the good, relatively speaking.”
“That’s why we use scrapers,” Mercurio adds. “We skim horizontally to get the rock off, then remove the clay, then go back to the rock. You can’t be that selective with other types of equipment. We have self-elevating scrapers with paddle wheels, and they can take a relatively thin lift. The paddles rotate, pick up the material, and break up the clumps.”
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