Geothermal power age is an entrenched and moderately develop type of business sustainable power source. One of its vital attributes is a high load factor, which implies that each MW of capacity delivers essentially more electricity a year than a MW of wind or solar capacity.
Geothermal energy—energy derived from the heat of the earth—can be harnessed both as a source of renewable electricity as well as directly for heating and cooling applications.
Geothermal energy can provide heating, cooling and base-load power generation from high-temperature hydrothermal resources, aquifer systems with low and medium temperatures, and hot rock resources. Each geothermal source is unique in its location, temperature and pool depth, and various geothermal technologies have been developed to best specific resources. Flash steam, dry steam, binary and enhanced geothermal systems (EGS) are the leading geothermal technologies for power generation.
Advantages of Geothermal Energy
Low Cost of Electricity Generation
Geothermal energy is a very attractive source of electricity, based on recent data published by IRENA. Geothermal represents the lowest levelized cost of electricity in comparison to other sources of energy.
Geothermal electricity generation is a mature, base-load generation technology that can provide very competitive electricity where high quality resources are well-defined. The LCOE* of conventional geothermal power varies from $0.05 to $0.13/kWh for recent projects. Yet the LCOE can be as low as USD 0.04/kWh for the most competitive projects, such as those which utilize excellent, well-documented resources and are brownfield developments.
* Levelized cost of electricity (LCOE) is often cited as a convenient summary measure of the overall competitiveness of different generating technologies. It represents the per-kWh cost (in real dollars) of building and operating a generating plant over an assumed financial life and duty cycle. Key inputs to calculating LCOE include capital costs, fuel costs, fixed and variable operations and maintenance (O&M) costs, financing costs, and an assumed utilization rate for each plant type. The importance of the factors varies among the technologies.
Flexible Power: Geothermal Power’s Ability to Adapt to Variability
Geothermal power can supplement variable resources to counteract and balance some of the changes needed to transition to a clean energy economy by acting as a firm and flexible power source.
Geothermal power has the ability to operate in a flexible mode that can quickly adapt to variability in the power system. Geothermal power plants can provide regulation, load following or energy imbalance, spinning reserve, non-spinning reserve, and replacement or supplemental reserve.
Some geothermal power plants can ramp up and down multiple times per day to a minimum of 10% of nominal power and up to 100% of nominal output power. A geothermal plant can operate as Real Power Regulation, allowing the geothermal plant to support the grid frequency during disturbance thereby improving the ability of the utility system to ride through the disturbance.
Reliability: Predictable and Long-lasting
Geothermal power production represents predictable output and long-lasting resources.
Having no reliance upon transitory environmental states such as wind and sunlight, geothermal facilities can produce electricity 24 hours a day, 7 days a week. As a result, geothermal power plants have a high capacity factor, demonstrating a level of consistency not found in other sources. According to EIA*, geothermal power has the highest capacity factor (91%) of all the energy sources, higher even than gas (87%), or biomass (83%). For comparison’s sake, the capacity factors for wind (onshore), solar PV and hydroelectric are listed as 43%, 33%, and 65% respectively.
* U.S. Energy Information Administration, Annual Energy Outlook 2018, New Generation Resources Entering Service In 2022
Geothermal power’s reliability is also demonstrated by the longevity of the resource and its history of successful exploitation. The first electricity from geothermal steam was produced in 1904 by Prince Piero Ginori Conti in Larderello, Italy, and it went into operation as the first commercial geothermal power plant in 1913. This field is still producing today. In fact, with the exception of a few years during World War II, this field has been producing continuously for more than a century. Similarly, The Geysers field in California has been exploited consistently since the 1960s, and thanks in part to the wastewater injection practices which were enacted to sustain the resource, this field accounts for approximately one-fifth of the clean energy produced in California today.
Examples such as these demonstrate the dependability of the resource, and the technology used to exploit it. Since geothermal exploitation is focused on harvesting a fluid, underground resource, much of the technology involved is similar to that which has been successfully used for decades in oil and gas drilling. Also, geothermal power is not burdened by many of the integration issues which plague variable energy sources and is compatible with existing transmission technology.
Small Land Footprint
Geothermal power has a very small land usage compared to other energy sources, particularly when weighed against other renewables. Unlike solar, wind, and biomass sources, which are predicated upon gathering diffuse ambient energy over large tracts of land, geothermal exploits a concentrated, subterranean resource. This plant design equates to less planetary surface area needed to produce comparable levels of power.
A paper* estimates the intensity of land use associated with various energy sources based on the anticipated state of technology in the year 2030. Geothermal power’s estimated usage of 7.5 km2/TWh-year is better than coal (9.7), solar thermal (15.3), natural gas (18.6), solar voltaic (36.9), petroleum (44.7), hydropower (54.0), wind (72.1), and biomass (543.4).
* Energy Sprawl or Energy Efficiency: Climate Policy Impacts on Natural Habitat for the United States of America (Robert I. McDonald et al, 2009)
Near Zero Emissions
Geothermal power boasts extremely low emission rates, especially when compared with traditional fossil fuels that involve direct combustion of the primary resource. Binary power plants, which represent most of the geothermal plants that have come online recently, have near-zero GHG emissions and minimal particulate matter emissions. When considering life cycle emissions, Argonne National Laboratory found binary geothermal power plants to be one of the cleanest forms of energy.
Employment and Economic Development
Geothermal power production creates a variety of jobs throughout its lifecycle. Consultants and geoscientists perform the initial exploration; drilling engineers and construction teams develop the facilities; and an O&M staff ultimately runs the power plant. These steps, and many more in the process, create quality, professional positions. In addition to the jobs created directly, geothermal development also indirectly increases employment in a variety of industries that provide services to the companies performing exploration, construction, or operation and maintenance. Examples of these indirectly- created jobs include equipment service personnel, security guards, lawyers, and government regulators.