In its recently released GeoVision report, the U.S. Department of Energy provides a great chapter only on explaining What Geothermal Energy is.
The report goes through the different geothermal resources classes, heat pump resources, hydrothermal resources and enhanced geothermal systems.
In an overview chapter it further looks into geothermal energy production, providing a great iteration of the Lindal Diagram on the different temperatures and possible utilisation of geothermal heat resources.
In the geothermal energy benefits, the chapter looks at available resources in the United States, the economic benefits, the reliability of power generation and grid services, highlighting the great capacity factors provided by geothermal plants.
The chapter than continues looking into environmental and efficiency benefits, but also sharing technical and n0n-technical barriers to geothermal development.
The non-technical barriers section provides a rather interesting analysis showing a great uphill battle for geothermal energy in the context of social acceptance and perception towards geothermal energy.
The chapter also highlights the rather long lead time for geothermal projects on federal lands, illustrating that a single location could trigger legislative-based analysis six separate times.
With a focus – naturally – on the United States, this chapter is though a great resource.
The chapter can be read and downloaded here (pdf).