Geothermal Energy Quiz

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Questions and Answers

What percentage of the global installed capacity does Volcanic Geothermal represent?

96% (correct)

50%

Enhanced Geothermal Systems (EGS) currently have a significant portion of global installed capacity.

False

What is the primary substance used in the fracking fluid for geothermal stimulation?

water

Geothermal stimulation is also known as __________.

hydraulic fracturing Signup and view all the answers

Match the geothermal types with their corresponding global installed capacity percentage:

Enhanced Geothermal System (EGS) = 0% Hot Sedimentary Aquifer (HSA) = 4% Volcanic Geothermal = 96% Signup and view all the answers

What is the approximate temperature gradient found in the Earth's crust per kilometer?

30 K/km Signup and view all the answers

Geothermal power locations are typically away from tectonic plates.

False Signup and view all the answers

What is the estimated global geothermal electricity capacity as of 2013?

around 12,000 MWe Signup and view all the answers

Geothermal energy is primarily generated from the heat flux driven by _______ in the Earth's crust.

temperature gradients Signup and view all the answers

Match the following geothermal characteristics with their descriptions:

Temperature gradient = 30 K per km Tectonic plates = Locations for geothermal exploitation Global capacity = 0.2 to 0.5% of total global generation Ring of Fire = A prime example of geothermal regions Signup and view all the answers

What temperature is considered necessary for a geothermal power plant to operate using dry or superheated steam?

300°C Signup and view all the answers

The emissions from geothermal plants include higher levels of sulfur dioxide (SO2) compared to conventional fossil fuel plants.

False Signup and view all the answers

What are two environmental issues associated with the operation of geothermal power plants?

Induced seismicity and contamination of groundwater. Signup and view all the answers

In a flash geothermal power plant, impurities are concentrated into _____ after processing.

brine solutions Signup and view all the answers

Match the following geothermal plant components with their functions:

Flash unit = Separates steam from water Moisture separators = Removes excess water from steam Turbines = Converts steam energy into electricity Geothermal reservoir = Source of heat energy Signup and view all the answers

What is a common consequence of direct cycle geothermal power plant operations?

Heavy metals and salts may deposit on turbine blades Signup and view all the answers

Geothermal reservoirs can be classified as renewable resources regardless of how they are managed.

False Signup and view all the answers

The geothermal reservoirs in Northern California are being _____ at a faster rate than they can replenish.

cooled Signup and view all the answers

Signup and view all the answers

Study Notes

Renewable Energy Sources

Renewable energy sources rely on energy from the natural environment, not finite resources, making them effectively infinite.
Renewables typically exhibit ubiquity (widespread availability), low power density (slow rate of energy extraction), and an intermittent nature (fluctuating energy fluxes).
Solar energy, wind power, and geothermal energy (except for tidal/geothermal) are derived from the sun's energy. The sun heats the atmosphere unevenly, driving wind patterns.
Geothermal energy is heat from Earth's radioactive core and crust.
Tidal energy is created by the moon's gravitational pull.

Renewable Energy Technologies

Hydro power includes conventional hydroelectric dams, tidal barrages, wave power, and pumped storage.
Wind power is generated by turbines, and it includes onshore and offshore installations.
Solar power encompasses photovoltaic cells, collectors, and solar thermal technologies.
Geothermal technologies include binary cycle power plants, which use heat from hot rocks to produce electricity.
Biomass includes landfill gas collection, which harnesses the biogas created by decomposing waste and geothermal technologies which use heat from deep underground. Hydrogen and Fuel cells are discussed along with steam methane reforming and water electrolysis.

Typical Power Densities of Renewable Technologies

A table details the typical power densities for various renewable technologies, including solar photovoltaic, hydroelectric, wind, geothermal, biomass, ocean tidal, and ocean wave energy.

Installed Capacity Costs (2010)

A graph displays the estimated levelized costs of new electricity generation technologies in 2016, showing costs for different technologies in 2007 dollars per MWh. This data shows costs for various technologies.

U.S. Average Levelized Costs (2007-2016)

A table presents average levelized costs for different plant types, including various types of coal, natural gas, advanced combined cycles and others, in 2007$/megawatt hour for plants entering service in 2016. This includes data on factors like capacity, levelized capital cost, fixed O&M, etc.

2009 vs 2019 Costs

A graph compares the installed capacity costs for different technologies in 2009 vs 2019.

2022 Costing

A table provides estimated levelized costs for different power sources, including new nuclear (SMR), coal, and various gas-based plants. Costs are shown in 2022 Canadian dollars (MWh).

Hydro Power Diagram and Examples

A diagram illustrates the components of a hydroelectric power station, including a headpond, intake, penstock, powerhouse, turbine, generator, and transformer.
Examples include Mactaquac Dam, Hoover Dam, and Three Gorges Dam which are all conventional hydroelectric dams.

Tidal Power & Concerns

A diagram explains tidal barrage operation which uses the tides flowing in and out of a basin to power a turbine.
There are environmental concerns about tidal turbines in the Bay of Fundy.

Wave Power

Wave power systems use the kinetic and potential energy of the ocean to generate electricity with a Wells' turbine that turns consistently regardless of the airflow direction.
The Pelamis wave energy converter is a semi-submerged, articulated structure used for wave energy conversion with hydraulic rams.

Wind Power Description & Components

Surface winds are created by uneven heating of the Earth via solar radiation, generating density gradients. The Earth's rotation dictates the direction of air flow. Local factors complicate this.
Early wind turbines were used for applications like grinding, pumping water.
Horizontal axis wind turbines using cloth sails were developed over time. Modern designs have numerous components including: rotor, hub, gearbox, generator, control unit, and tower. Components like sensors, anemometers, wind vanes, and yaw mechanisms monitor conditions.
Wind turbine design accounts for continuous variability in wind speed and optimizes for capacity factor in the performance of the wind turbine.
There are minimum and maximum wind speeds wherein energy extraction is inefficient or impossible. A wind turbine's power depends on its blade size and the cube of the wind speed.
There is a maximum feasible efficiency (~59%). Actual systems have much lower efficiency.

The Power Coefficient (Cp)

The power coefficient, also known as the theoretical wind turbine efficiency, Cp is the ratio between the actual power produced by a wind turbine and a theoretical maximum.
The optimum relationship between upstream and downstream wind speeds is 1:3.
Actual power coefficients of observed systems are significantly below this optimum theoretical value.

Wind Resource Maps

Maps show the distribution of wind resources across specific geographic regions helping to locate potential sites for wind farms.

Solar-PV

Solar-PV plants can produce large amounts of electricity via solar energy (a photoelectric effect).
Solten project in Spain is an example.
Solar thermal power plants collect solar energy to generate heat using heliostats (mirrors) to focus sunlight onto a central point for electricity generation. These plants use molten salt for heat storage. Parabolic Trough uses mirrors to focus sunlight onto pipes which then act as the heat exchange fluids to power steam turbines.
The efficiency of solar energy conversion is typically below 20% which is a major limitation in its use.