EPRI: Electric Power Research Insitute

Generation Technologies Assessment


Geothermal

Geothermal energy is energy in the form of heat contained within the Earth. The molten interior of the Earth continuously produces high temperatures by the slow decay of radioactive particles. This heat rises to the Earth’s crust and mainly occurs in geologically active areas where continental plates meet. This heat can be recovered as steam or hot water and used to heat buildings or generate electricity.

Geothermal power plants rely on the high temperatures (300-700°F) in underground resources to produce steam and generate electricity. The underground reserves are tapped by drilling wells and piping the steam or hot water to the surface. Because the heat energy is stored underground, it is available at any time, unlike solar or wind power.

Geothermal plants are highly reliable facilities and result in relatively few emissions and waste products. One of the main drawbacks to geothermal energy is its higher capital cost compared to many other large-scale generation options. These costs are highly dependent on the site-specific resource and can be heavily impacted by exploration costs from drilling wells to identify viable resource areas. Geothermal resources are also not uniform, making it a viable option only in certain regions.

Where Does Electricity Come From?

What Plants are Used the Most?

What Plants are Used the Most?

Where Does Electricity Come From?
Geothermal
Construction Cost
New plant construction cost for an equivalent amount of generating capacity
Electricity Cost
Projected cost to produce electricity from a new plant over its lifetime
Land Use
Area required to support fuel supply and electricity generation
Water Requirements
Amount of water required to generate equivalent amount of electricity
CO₂ Emissions
Relative amount of CO₂emissions per unit of electricity
Other air emissions
Relative amount of air emissions other than CO₂per unit of electricity
Waste Products
Presence of other significant waste products
Availability
Ability to generate electricity when needed
Flexibility
Ability to quickly respond to changes in demand
More Favorable Key Less Favorable