Utilising geothermal energy for dehydrating onions – a unique plant in Fernley, Nevada

Olam Spices and Vegetables, Inc. (Olam Group), is a large farming, buying and processing company and the largest vertically-integrated processor of garlic and dried onion in the world.

In Fernley, Nevada, the company operates the world’s only onion dehydration facility utilizing direct geothermal energy. Nevada’s Division of Environmental Protection shared a few more details in a production report.

“It uses geothermal water to wash down processing equipment and clean and dehydrate onions during their processing season, which generally runs from May to December each year.

During the non-processing period, the facility uses a reduced flow of the geothermal water to heat the facility in order to keep the building and their processing equipment from freezing. Surrounding areas are generally undeveloped property, with the exception of the Brady Power Plant.

The Brady Power Plant, through contractual agreement, supplies Olam with geothermal water via a dedicated pipeline. Upon delivery to the facility, the geothermal water is first used to operate two dehydration units. The water enters the units at a temperature near 300° F and exits the units at a temperature around 160° F. After the non-contact process water exits the dehydrators the flow stream is split. A portion of the water (approximately 20% ) is cooled to no more than 110° F, and then stored for use as onion and equipment wash water. After use, the wash water is filtered through a 0.054-inch Hydro-sieve screen to remove vegetable matter, the water is collected in a detention sump, and intermittently discharged to any of 18 onsite infiltration basins (Outfall 001). The remaining non-contact process water (approximately 80% of inflow) is diverted into a pond to cool prior to release into an unnamed ditch (Outfall 002) that discharges to an alkali flat.”

In its 2018 report on the Global Reporting Initiative, there are though indications the use of geothermal has fallen in 2018 compared to 2017. (see report, pdf)

The Brady geothermal power plant has been in operation since 1992 is now operated by Ormat Nevada.

Source: Olam, Nevada Division of Environmental Protection (pdf)