|White stakes mark out where a tomato|
greenhouse will be built. The ethanol plant is
shown in the background.
The two waste products are hot water and CO2. Both are going to be pumped across the street. The CO2 will increase the growth rate of the tomatoes, and the heat from the water will help keep the greenhouse warm in the winter. The water will then be pumped back to the ethanol facility (cooled off) and reused.
Quoting from an article in Ethanol Producer Magazine:
When complete, tomato greenhouses will cover a total of 90 acres sitting on 120 acres of land located across the street from the ethanol plant. The first phase, construction of a 22.5 acre greenhouse, is under way now, with an expected completion date in July...
The idea of building a greenhouse next to the Chatham ethanol plant is one the two companies have been working on for a while. Greenhouses require year-round heat, which adds up to 40 percent of the cost of operation. Natural gas boilers are used to produce hot water and CO2 is captured from boiler exhaust to help increase plant health and yield. A big challenge, however, is that the largest demand for CO2 is in the summer, which is also the time of the lowest demand for heat, DeVriers said (Greg DeVriers is part owner of Truly Green). That problem is solved with working with the ethanol plant, which can supply the greenhouse with all the heat and CO2 it needs all year long.
Another neat part of the story is that the farming operation produces corn and also includes a feedlot, he said. This means the company could deliver a load of corn to the ethanol plant, leave with distillers grains for its feedlot — all at the same time that heat and CO2 is being used to grow tomatoes in the greenhouse. “It’s an amazing story,” he said, adding that it’s beneficial for the local economy, the farming operation, the greenhouse and the ethanol plant. “I get goose bumps thinking about it,” he said. Once the project is proved out, DeVriers sees it as something that could develop into partnerships between other ethanol plants and greenhouse operations.