Direct Use Geothermal for Industrial Applications

Many industries need steam or hot water for their operations. Geothermal water is an excellent low-cost source of this basic item. Industries generally need very hot water, hotter than the water used in agriculture or aquaculture, though there is much variation. Plants can be built right next to geothermal reservoirs and pipe the water or steam straight into the operation.

Current uses of industrial applications

Geothermal water is useful in any industry that requires steam or hot water. Some uses include:
- Timber processing
- Pulp and paper processing
- Washing wool
- Dyeing cloth
- Drying diatomaceous earth (a light, abrasive soil used as a filtering material and insecticide)
- Drying fish meal and stock fish
- Canning food
- Drying cement
- Drying organic materials such as vegetables, seaweed and grass
- Refrigeration

Benefits and drawbacks of industrial applications

Using geothermal water and steam saves companies the cost of heating water and saves the environment some of the pollution that would be caused by heating the water. However, geothermal water is only available in a few places, so most industries cannot use it.

Direct Use Geothermal for Industrial Applications copyright

Geothermal Dye Works

In most cases an industry uses geothermal water because it is a cheap source of heat and/or water. In a few cases, however, industries take advantage of the unique mineral properties of geothermal water. In Iwate Prefecture, Japan, there is a geothermal dye factory that uses the minerals in geothermal water as a mordant, a substance that makes dye pigments stick to cloth, and also as a substance that can remove dye from cloth. The factory uses a method of folding and tying the cloth with string, soaking it in dye made with geothermal water, and then rinsing it and unfolding it. The combination of steam, heat, and the hydrogen sulfide in the geothermal water leaves beautiful and unique patterns on the cloth.