Category: Ecological Footprints and Energy


Geothermal projects require a relatively large initial capital investment, with small annual operating costs thereafter. Thus, a district heating project, including production wells, pipelines, heat exchan­gers, and injection wells, may cost several million dollars. In contrast, the initial investment in a fossil fuel system includes only the cost of a central boiler and distribution lines. […]

Heat Pumps

Ground-coupled and groundwater (often called ground-source or geothermal) heat pump systems are being installed in great numbers in the United States, Sweden, Switzerland, and Germany. Ground­water aquifers and soil temperatures in the range of 5-30°C are being used in these systems. Ground – source heat pumps utilize groundwater in wells or by direct ground coupling […]


The fluid state in transmission lines of direct-use projects can be liquid water, steam vapor, or a two – phase mixture. These pipelines carry fluids from the wellhead to either a site of application or a steam – water separator. Thermal expansion of pipelines heated rapidly from ambient to geothermal fluid temperatures (which may vary […]

Downhole Pumps

Unless the well is artesian, downhole pumps are needed, especially in large-scale, direct utilization systems. Downhole pumps may be installed not only to lift fluid to the surface but also to prevent the release of gas and the resultant scale formation. The two most common types are lineshaft pump systems and submersible pump systems. The […]


Standard equipment is used in most direct-use projects, provided allowances are made for the nature of geothermal water and steam. Temperature is an important consideration, as is water quality. Corrosion and scaling caused by the sometimes unique chemistry of geothermal fluids may lead to operating problems with equipment components exposed to flowing water and steam. […]