AgBioResearch Scientists Finding Solutions to Rising Greenhouse Energy Costs

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AgBioResearch scientists are traveling the globe and compiling Web sites of information to help Michigan greenhouse growers reduce their energy costs.

Escalating energy costs have strapped greenhouse growers searching for innovative strategies to reduce this monthly expense. Thanks to a new online resource developed by MAES horticultural researchers, growers now have access to a variety of useful information in one convenient location.

The Greenhouse Energy Cost Reduction Strategies Web site was developed by MAES horticulture scientist Erik Runkle and horticulture graduate student Matthew Blanchard to help improve the profitability and sustainability of the state’s greenhouse industry.Erik Runkle

Runkle noted that since 2004, energy costs have escalated by 30 to 50 percent. Increased energy costs reduced the profitability of Michigan’s greenhouse industry by more than $20 million in 2005.

“Energy is usually one of the greenhouse industry’s top two highest priorities because, on average, it accounts for between 8 and 12 percent of a producer’s total expenses,” Runkle said. “Because there is not one single best way to reduce energy costs that’s right for everyone, growers have several options to choose from.”

The site includes a compilation of studies on how to reduce energy costs conducted by researchers from MSU and other universities. Though the site is targeted at Michigan growers, the information is applicable to many other regions of the northern United States with similar climate patterns.

Visitors to the Web site can locate timely information on a variety of topics, such as greenhouse lighting, temperature and scheduling, energy-saving technologies, alternative fuels, and energy grant and loan programs.

Runkle also traveled to Europe with MAES agricultural, food and resource economics scientist Stephen Harsh to gather information on how to curb rising energy costs for greenhouse growers. Runkle and Harsh are spearheading a project to identify alternative energy sources and innovative strategies for reducing energy costs and help the state’s floriculture industry regain its competitive edge.

Harsh and Runkle decided to study how greenhouse operators were dealing with similar situations in other areas of the world. The quest took them to the Netherlands, the top-ranking country in greenhouse crop production, to survey how growers there responded to a government-imposed mandate to reduce climate-warming gases by 40 percent.

Because the climate of the Netherlands is similar to Michigan’s, they were interested in studying the practices that operators there were using to help reduce greenhouse energy costs. The most interesting method that Harsh came across during his weeklong trip was cogeneration, a technique used to produce heat and carbon dioxide for the greenhouses and electricity for the town at the same time.

“The trip to the Netherlands really opened our eyes to how many opportunities exist for generating alternative energy,” Harsh said. “The government of the Netherlands has implemented important regulatory policies to encourage greenhouses to commit to conserving natural resources.”

Although cogeneration systems aren’t used in the United States, Harsh came across other promising methods worth further study. For example, during the warm months, greenhouses in the Netherlands capture solar energy by using heat exchangers in the greenhouses and store it in an aquifer. During the cool months, the stored energy is used to heat the greenhouses. Other alternative energy technologies used include wind energy, biomass (wood pellets), other alternative fuels and different types of glass or plastic.

Runkle is hoping to come up with methods to reduce greenhouse energy costs by developing a better understanding of how crops respond to temperature. The temperature in a greenhouse dictates how long it will take for a crop to reach maturity. Plants grown in cooler temperatures take longer to develop; plants grow much faster in warmer temperatures. Runkle and Blanchard are trying to identify the optimum temperature that would permit energy costs to be lowered without jeopardizing plant growth rate.Stephen Harsh

“We predict that growers may be able to save up to 10 to 30 percent on energy costs by managing greenhouse temperature,” Runkle said.

Because each plant responds differently to varying temperatures, Runkle is partnering with the U.S. Department of Agriculture to build a user-friendly computer program to generate mathematical models to forecast how well various crops can be expected to grow at specific temperatures. Runkle said the computer program, which is still under development, will allow users to select the type of crop they wish to grow and recommend the most profitable temperature at which to grow the plants.

“We hope to contribute to helping Michigan’s greenhouse industry remain a competitive and dominant player,” Harsh said. “Our ultimate goal is to learn how the industry can become more efficient and competitive, and identify the role it can play in reducing carbon emissions.”

This research also is supported by Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs), Michigan’s plant agriculture initiative at MSU, and the Michigan Floriculture Council.

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