Sustainable Energy Sustains Production

The low cost of traditional energy hasn’t totally eroded profits from the ‘green’ methods available to power production. Manufacturers continue to meter renewable energy into their operations.

Now that fossil fuels are cheaper than they were just a few years ago, some manufacturing companies are quietly abandoning their renewable energy projects—projects that were, in many cases, launched amid some fanfare. Conspicuously absent from this group, however, is Honda Transmission Mfg. of America, which has two wind turbines helping to power its plant in Russells Point, Ohio.

Rather than joining the group quietly expressing disappointment, company vice president Gary Hand did the opposite last summer. He announced that the wind project in Russells Point had exceeded expectations by 6.3 percent.

Studies done before the installation had estimated that the turbines would produce more than 10,000 megawatt-hours (MWh) a year, which is about 10 percent of the plant’s annual power needs. The 260 ft tall structures and their 160 ft blades, however, outperformed the projections in four of the six months since they became operational. At their highest output, in April of last year, the turbines provided 16.26 percent of the plant’s power requirements.

Russells Point may be the first major automotive facility in the U.S. to receive such a substantial amount of its power from on-site wind turbines. This distinction has moved Honda another step toward its goal of reducing the environmental impact of its products and manufacturing operations by 2020. This goal includes reducing carbon dioxide emissions from its products by 30 percent, as well as achieving significant CO2 reductions in its operations, compared with levels in 2000.

One reason behind the success was that Honda had commissioned a feasibility study in advance from Juhl Energy, a renewable-energy developer based in Pipestone, Minn. Unlike most wind development firms, this one develops small installations of one to five turbines. “We’re staffed appropriately to handle smaller solutions,” says Corey Juhl, vice president of project development.

He urges users not to let the small size of one- or two-turbine projects fool them into foregoing a feasibility study in order to save the $10,000 to $25,000 of undertaking one. “A two-turbine solution requires the same amount of work as a 50 MW wind farm,” he explains.

A proper study is necessary to specify the right technology for the wind patterns, terrain and power requirements at a particular site. “You can’t put a small-diameter [of the blade] machine in an area where the wind is not very strong,” Juhl notes. “Otherwise, you won’t get the results that you need.”

The study also should look into obtaining the necessary permits and take the character of the neighborhood into account. In Honda’s case, the Russells Point plant had plenty of space in a large industrial facility.

A question of ownership

Another factor contributing to the project’s success was Honda’s decision to stay out of the energy business and to leave the wind turbines to the experts. Although the two wind turbines are on the automaker’s property, their owner is actually ConEdison Solutions, an energy-services provider based in Valhalla, N.Y. “We stepped in when the project was fully developed and ready to be put out to a long-term investor,” says Jim VanderPas, director of renewables operations at ConEdison Solutions.

Because ConEdison Solutions financed the construction, owns the assets, and operates them with help from subcontractors like Juhl Energy, Honda has no investment risk in the wind turbines. ConEdison Solutions supplies Honda with the electricity generated by the wind turbines through the local power company and bills the automaker through services offered by Juhl Energy.

VanderPas estimates that as many as 85 percent of wind-turbine projects occur through third-party power purchase agreements (PPAs) like the one between Honda and ConEdison Solutions. “We’re talking about a $9.5 million project,” he says. “The payback on this kind of capital investment seldom works for most companies whose primary goal is manufacturing.” Although some manufacturers with an appetite for tax incentives might not mind owning wind turbines, most would rather sink that kind of money into capital assets for their core operations.

Because federal investment tax credits exist for solar power, the situation is just the opposite for this source of renewable energy. “Throughout the U.S., 12 GW of solar energy are produced,” VanderPas says. “It, however, is produced predominantly in very small systems scattered across the rooftops of manufacturing facilities.” A much larger proportion of solar projects is owned by companies that can use the tax shelter.

For solar or wind power, enough sun or wind are natural prerequisites. Their economics otherwise depend most heavily on the local cost of electricity and the governmental incentives available in the state where the power-generating assets are situated (see www.dsireusa.org for a list of incentives by state). “It’s going to be very hard—no matter how strong the sun or the wind is—to make a project return enough revenue in areas where power rates are very low,” VanderPas notes.

Even so, he points out that small-scale wind projects like the one at Honda Transmission are delivering power at attractive rates in various places across the country. “You’ll find that they typically save a penny or two—even up to five cents—a kilowatt-hour, depending on where they are,” he says. Besides that, there is the added benefit of being a good corporate neighbor by reducing your company’s carbon footprint.

Mega returns from microturbines

Despite successes like the one at Honda Transmission, many manufacturing facilities still find that renewable technologies like wind turbines and solar cells are too risky or just not cost-effective at producing the needed quantities of reliable power. The problem with wind turbines, for example, is that their effectiveness varies with the wind, according to Kevin Stevenson, vice president of engineering at F-D-S Manufacturing in Pomona, Calif. A lack of consistent wind discouraged his company, a producer of recyclable packaging products for industry and agriculture, from even considering this source of renewable energy.

Stevenson, however, did start looking at solar energy when brownouts began occurring in California in the early 2000s. Not only would solar panels put 240,000 square feet of roof space to work, but using solar energy would also reduce the company’s carbon footprint and enhance its status among its customers as a green manufacturer. The problem is that payback on the technology was too long. “Without federal subsidies, they are not economically sound,” Stevenson says.

He points to the fact that solar panels contribute to the bottom line only during the daylight hours, which is a limitation for his 24-hour operation. Another limitation is that the capacity of solar cells degrades at about 1 percent a year. “So in 20 years, at the end of the manufacturer’s lifetime warranty—if the manufacturer is still around then—you own a system that runs at only 80 percent,” he says. “I think the money is better spent elsewhere in the company.”

For these reasons, he and his colleagues decided to generate electricity onsite with natural-gas-fired microturbines from Capstone Turbine of Chatsworth, Calif. The microturbines are an environmentally friendly alternative to solar and wind power because the combustion is clean. “Having a continuous combustion process allows us to keep emissions low,” explains Jim Crouse, Capstone’s executive vice president of sales and marketing. The design of the combustion chamber also promotes a highly efficient reaction.

The microturbines help users lower their carbon footprint in other ways, too. “The power that they’re displacing has a higher carbon footprint,” Crouse says.

Because the microturbines work onsite, users can also produce efficiencies through cogeneration—recovering and using heat that would otherwise be lost to the environment. The hot exhaust gases from the turbines can heat water, for example.

“In some cases, they can be used in a direct drying process for tile, bricks or other applications,” Crouse says.

“The exhaust is as clean as or cleaner than the hot air from the old burners, so contamination is not really a concern,” he adds. Air bearings also eliminate the need for lubricating oils and coolants that could be a source to contaminate the exhaust in other turbine designs.

A step beyond cogeneration

Capstone’s technology can take cogeneration a step further by doing what the vendor calls trigeneration. The company offers an absorption chiller that exploits the thermodynamic properties of a sodium bromide solution to cool water. Besides generating electricity and making hot water with the exhaust gases, users also can use some of the hot water to drive the chiller.

By putting the thermal energy in the exhaust to work in these ways, cogeneration drives the overall energy efficiency up. Whereas the overall efficiency of the electricity obtained from the local utility could be as low as 35 percent, according to Crouse, the efficiency of cogeneration applications usually runs between 75 and 85 percent.

Consider the six Capstone C65 MicroTurbines at F-D-S. These turbines generate 320 kW of electricity, which amounts to 20 percent of the electricity used by the manufacturing facility. Besides generating electricity, the microturbines also supply heat for the driers and absorption chillers in a plastics extrusion line making strawberry baskets, fruit clam shells, and other packages.

F-D-S inserted the microturbines into the line for several reasons, but the key deciding factor was cost. “We had just installed a large 6-inch extruder, and it’s an energy hog,” Stevenson explains. “It has a lot of heating and cooling requirements.”

In fact, satisfying these requirements is what made the project pay, he reports. “Because the fastest payback usually occurs when you design the system to match your thermal load, our system is designed for our thermal needs, rather than our electrical requirements,” he says. The electricity savings is just icing on the cake.

The savings in thermal energy come from shutting off the burners on the line. Instead of using the burners, driers at the beginning of the extrusion process now rely on the 280-320 °F exhaust from two of the microturbines to dry the plastic. The exhaust from the remaining four microturbines is deployed at the other end of the line to heat the 198 °F water that an absorption chiller needs to cool the extruded plastic.

Operating at nearly 80 percent efficiency, the natural-gas-fired microturbines have cut the company’s energy bills by a sixth, saving $35,000 to $40,000 a year. Because they also generate fewer emissions than other forms of power production, no permits are necessary from the Southern California Air Quality Management District. “These turbines run cleaner than the AQMD can measure,” Stevenson says.

The electricity is more reliable, too. When the microturbines began contributing to the power grid, F-D-S had to upgrade its main panel and incorporate the appropriate safety features. As a result of that upgrade, the company can now disconnect from the grid during power failures. “If Edison goes down, we go down with them,” Stevenson explains. “But we have the ability to then isolate ourselves and become an island. We can turn back on and produce enough power to run a third of our equipment.”

These results have him thinking about when to exercise his capacity to install six more microturbines in the future.

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