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The net capacity factor is a unitless ratio comparing an installation's actual electrical energy output to its theoretical maximum output over a specified period.
Answer: True
Explanation: The net capacity factor is defined as the unitless ratio comparing the actual electrical energy output over a period to the theoretical maximum output if the installation ran continuously at its full nameplate capacity.
The capacity factor metric is applicable only to power plants that consume fossil fuels.
Answer: False
Explanation: The capacity factor can be calculated for any electricity-producing installation, including those using fossil fuels, wind, solar, or hydroelectric power.
Under conditions of exceptionally high electricity demand, a power plant's capacity factor can exceed its availability factor.
Answer: False
Explanation: The capacity factor can never exceed the availability factor. A plant cannot produce more energy than it is physically available to produce, regardless of demand.
To average out temporal fluctuations, the capacity factor is most commonly computed over an annual timescale.
Answer: True
Explanation: The capacity factor is typically computed over a year to average out most temporal and seasonal variations, although monthly or lifetime calculations are also used.
In the capacity factor formula CF = E_t / (P_n × t), the term P_n represents the total electrical energy produced.
Answer: False
Explanation: In the formula, P_n represents the nameplate capacity (rated or installed power) of the system, while E_t represents the total electrical energy produced.
What is the primary definition of the net capacity factor?
Answer: A unitless ratio comparing actual electrical energy output to theoretical maximum output.
Explanation: The source defines the net capacity factor as a unitless ratio that compares the actual electrical energy output of an installation over a specific period to its theoretical maximum electrical energy output during the same period.
For which of the following types of electricity-producing installations can the capacity factor be calculated?
Answer: Any electricity-producing installation, including fossil fuel, wind, solar, or hydroelectric.
Explanation: The capacity factor can be calculated for any electricity-producing installation, encompassing those that consume fuel and those that utilize renewable energy sources.
Which of the following is NOT listed as a primary factor causing variation in an installation's capacity factor?
Answer: The age of the plant's construction permits.
Explanation: Primary factors influencing capacity factor include availability, design, location, type of production, fuel, weather, and regulatory or market forces, but not the age of construction permits.
How does the capacity factor relate to the availability factor?
Answer: The capacity factor can never exceed the availability factor.
Explanation: A fundamental principle is that the capacity factor can never exceed the availability factor, as a plant cannot produce more energy than it is physically available to produce.
Over what timescale is the capacity factor most often computed to average out temporal fluctuations?
Answer: A year.
Explanation: The capacity factor is most commonly computed over a timescale of a year to average out most temporal and seasonal variations.
If a 1 MW power plant produces 0.5 MWh in one hour, what is its capacity factor for that hour?
Answer: 50%
Explanation: The capacity factor is calculated as actual output (0.5 MWh) divided by maximum theoretical output (1 MW × 1 h = 1 MWh), which equals 0.5, or 50%.
The primary reasons a power plant's capacity factor is below 100% fall into three main categories: technical constraints, economic factors, and fuel availability.
Answer: True
Explanation: A power plant's capacity factor is typically lower than 100% due to reasons broadly categorized as technical constraints, economic reasons, and the availability of the energy resource or fuel.
Base load power plants are specifically designed to adjust their output quickly in response to demand fluctuations.
Answer: False
Explanation: Base load plants are designed for maximum efficiency and continuous high output; they are difficult to adjust quickly to suit demand fluctuations.
Peaking power plants are characterized by low fixed costs per unit of electricity because they generate power infrequently.
Answer: False
Explanation: The electricity from peaking power plants is relatively expensive because their fixed costs must be covered by a smaller amount of electricity produced due to their limited generation periods.
For renewable energy sources like solar and wind, the primary reason for a reduced capacity factor is typically technical issues with the plant itself.
Answer: False
Explanation: The main reason for a reduced capacity factor in renewable sources like solar and wind is the intermittent availability of their natural energy source (sunlight or wind), not technical plant issues.
Solar, wind, and hydroelectric plants are characterized by low availability factors, meaning they are often unable to produce electricity even when their fuel source is present.
Answer: False
Explanation: These types of plants generally have high availability factors. When their 'fuel' (sunlight, wind, or water) is available, they are almost always capable of producing electricity.
Which of the following is NOT one of the main categories of reasons for a power plant's capacity factor being lower than 100%?
Answer: Public opposition to the plant's location.
Explanation: The main categories of reasons for a capacity factor below 100% are technical constraints, economic reasons, and the availability of the energy resource or fuel.
Which types of power plants are almost always operated as base load plants due to being difficult to adjust quickly to demand fluctuations?
Answer: Geothermal, nuclear, coal-fired, and bioenergy plants that burn solid material.
Explanation: Geothermal, nuclear, coal-fired, and solid-material bioenergy plants are typically operated as base load plants because they are designed for continuous high output and are difficult to adjust quickly.
Why is the electricity generated by peaking power plants relatively expensive?
Answer: Their fixed costs must be covered by a smaller amount of electricity produced due to limited generation.
Explanation: Peaking plants operate only during periods of high demand, so their fixed costs must be recouped over a smaller volume of electricity, making their output relatively expensive.
For renewable energy sources like solar and wind, what is the primary reason for a reduced capacity factor?
Answer: Availability of their natural energy source.
Explanation: The primary reason for reduced capacity factors in renewable sources like solar and wind is the intermittent availability of their natural energy source (sunlight and wind).
What is a key characteristic of solar, wind, and hydroelectric plants regarding their operational availability?
Answer: They generally have high availability factors.
Explanation: Solar, wind, and hydroelectric plants typically have high availability factors, meaning they are almost always capable of producing electricity when their energy source is present.
Nuclear power plants generally exhibit high capacity factors, primarily limited by maintenance and refueling schedules.
Answer: True
Explanation: Nuclear power plants typically have capacity factors at the higher end of the range, ideally reduced only by the availability factor, which accounts for necessary maintenance and refueling.
The Palo Verde Nuclear Generating Station achieved a capacity factor of 90.4% in 2010.
Answer: True
Explanation: In 2010, the Palo Verde Nuclear Generating Station had an annual generation of 31,200,000 MWh from a nameplate capacity of 3942 MW, resulting in a capacity factor of 90.4%.
Each reactor at the Palo Verde station is refueled annually, with a record refueling time of 35 days set in 2014.
Answer: False
Explanation: Each of Palo Verde's reactors is refueled every 18 months, not annually. The record refueling time was 28 days in 2014, not 35.
In 2019, the US nuclear unit with the highest capacity factor was Prairie Island 1, which reached 104.4%.
Answer: True
Explanation: The source confirms that in 2019, Prairie Island 1 was the US nuclear unit with the highest capacity factor, achieving 104.4%.
The Three Gorges Dam, the world's largest power station by installed capacity, had a capacity factor of 45% in 2015.
Answer: True
Explanation: In 2015, the Three Gorges Dam generated 87 TWh from its 22,500 MW installed capacity, resulting in a capacity factor of 45%.
The Hoover Dam has an average capacity factor of 42%, with its highest annual generation recorded in 1956.
Answer: False
Explanation: The Hoover Dam's average capacity factor is 23%. Its highest annual generation was in 1984, and its lowest was in 1956.
Hydroelectric plants are valuable for load following because their high dispatchability allows for rapid adjustments to meet electricity demand.
Answer: True
Explanation: Due to their high dispatchability, hydroelectric plants can be brought from a stopped condition to full power in minutes, making them highly effective for load following.
The worldwide average capacity factor for nuclear power between 2006 and 2012 was 88.7%.
Answer: True
Explanation: Based on data from US plants, the worldwide average capacity factor for nuclear power from 2006 to 2012 was 88.7%.
The worldwide average capacity factor for hydroelectricity is 64%, with a narrow range of variation.
Answer: False
Explanation: The worldwide average capacity factor for hydroelectricity is 44%, and it has a very wide range of variation (10% to 99%) depending on water availability.
What is a general characteristic of the capacity factors for nuclear power plants?
Answer: They typically exhibit capacity factors at the higher end of the range.
Explanation: Nuclear power plants are designed for continuous operation and generally have capacity factors at the higher end of the spectrum, limited primarily by maintenance and refueling schedules.
What was the capacity factor of the Palo Verde Nuclear Generating Station in 2010?
Answer: 90.4%
Explanation: In 2010, the Palo Verde Nuclear Generating Station's annual generation of 31,200,000 MWh resulted in a capacity factor of 90.4%.
How often are the reactors at the Palo Verde station refueled?
Answer: Every 18 months.
Explanation: Each of the three reactors at the Palo Verde station is refueled on an 18-month cycle.
Which US nuclear unit achieved the highest capacity factor in 2019?
Answer: Prairie Island 1
Explanation: In 2019, Prairie Island 1 was the US nuclear unit with the highest capacity factor, reaching 104.4%.
What was the capacity factor of the Three Gorges Dam in 2015?
Answer: 45%
Explanation: In 2015, the Three Gorges Dam generated 87 TWh, which resulted in a capacity factor of 45% for that year.
What is the average capacity factor of the Hoover Dam?
Answer: 23%
Explanation: Based on its nameplate capacity of 2080 MW and average annual generation of 4.2 TWh, the Hoover Dam has an average capacity factor of 23%.
What makes hydroelectric plants particularly useful for load following?
Answer: Their high dispatchability, allowing quick power adjustments.
Explanation: Hydroelectric plants are useful for load following due to their high dispatchability, which allows operators to bring them to full power in just a few minutes to meet demand changes.
What was the worldwide average capacity factor for nuclear power between 2006 and 2012, based on US plants?
Answer: 88.7%
Explanation: Based on data from US plants, the worldwide average capacity factor for nuclear power between 2006 and 2012 was 88.7%.
As of January 2017, the Horns Rev 2 offshore wind farm had an average capacity factor of 37.7%.
Answer: False
Explanation: The Horns Rev 2 offshore wind farm's production data translates to an average capacity factor of 47.7% as of January 2017.
Wind farms with lower projected capacity factors are generally not considered economically viable.
Answer: False
Explanation: Sites with lower projected capacity factors can still be deemed feasible for wind farms, as exemplified by the 1 GW Fosen Vind project in Norway, which had a projected capacity factor of 39%.
In Finland, the capacity factor for wind farms is significantly higher during the cold winter months than in July.
Answer: True
Explanation: Seasonality significantly affects wind farm capacity factors in Finland, where the factor during cold winter months is more than double that of July, correlating with higher heating energy demand.
A wind turbine's capacity factor is directly related to Betz's coefficient, which limits the energy extracted from wind.
Answer: False
Explanation: The capacity factor, which measures actual production relative to potential production, is unrelated to Betz's coefficient, which is a theoretical limit on the energy that can be extracted from wind.
The capacity factor of a wind farm is determined exclusively by the availability of wind.
Answer: False
Explanation: While wind availability is a primary factor, a wind farm's capacity factor is also determined by the turbine's swept area, the generator size, transmission line capacity, and electricity demand.
Typical capacity factors for contemporary wind farms globally are in the range of 25% to 45%.
Answer: True
Explanation: The source material states that typical capacity factors for current wind farms range between 25% and 45%.
As of 2022, the typical global range of capacity factors for wind farms is between 21% and 52%.
Answer: True
Explanation: The source indicates that as of 2022, the typical range of capacity factors for wind farms globally is between 21% and 52%.
What was the average capacity factor of the Horns Rev 2 wind farm as of January 2017?
Answer: 47.7%
Explanation: Based on its total production since commissioning, the Horns Rev 2 offshore wind farm had an average capacity factor of 47.7% as of January 2017.
What was the projected capacity factor for the 1 GW Fosen Vind project in Norway as of 2017?
Answer: 39%
Explanation: The Fosen Vind project in Norway, under construction as of 2017, had a projected capacity factor of 39%, indicating its economic viability.
How does seasonality affect wind farm capacity factors in Finland?
Answer: Capacity factors during cold winter months are more than double compared to July.
Explanation: In Finland, the capacity factor for wind farms during the cold winter months is more than double the factor in July, aligning with higher demand for heating energy.
Which of the following onshore wind farms achieved a capacity factor exceeding 60% in 2015?
Answer: Eolo plant in Nicaragua
Explanation: The 44 MW Eolo plant in Nicaragua generated 232.132 GWh in 2015, which is equivalent to a high capacity factor of 60.2%.
As of 2022, what is the typical global range of capacity factors for current wind farms?
Answer: 21% to 52%
Explanation: The source states that as of 2022, the typical range of capacity factors for wind farms globally is between 21% and 52%.
Due to their continuous operation during daylight, photovoltaic power stations typically have higher capacity factors than nuclear plants.
Answer: False
Explanation: Photovoltaic power stations have inherently lower capacity factors due to the requirement for daylight, whereas nuclear plants operate continuously and exhibit some of the highest capacity factors.
The capacity factor for photovoltaic power stations is usually computed on a monthly basis to capture seasonal variations.
Answer: False
Explanation: Due to significant variations in sunlight throughout the day and across seasons, the capacity factor for photovoltaic power stations is typically computed on an annual basis.
The Agua Caliente Solar Project in Arizona achieved a capacity factor of 29.1%.
Answer: True
Explanation: With a nameplate capacity of 290 MW and an average annual production of 740 GWh, the Agua Caliente Solar Project had a capacity factor of 29.1%.
In 2005, the Sacramento Municipal Utility District observed a 25% capacity factor for solar energy.
Answer: False
Explanation: The Sacramento Municipal Utility District observed a 15% capacity factor for solar energy in 2005, not 25%.
Geothermal power typically has a lower capacity factor compared to other power sources due to inconsistent resource availability.
Answer: False
Explanation: Geothermal power generally has a higher capacity factor than many other power sources because the resource is typically available consistently throughout the day and year.
Which of the following is an inherent limitation affecting the capacity factor of photovoltaic power stations?
Answer: Requirement for daylight, preferably unobstructed.
Explanation: Photovoltaic power stations have inherently lower capacity factors because they require daylight and are affected by clouds, shade, latitude, and local weather, limiting their operational hours.
What was the capacity factor of the Lauingen Energy Park?
Answer: 12.0%
Explanation: The Lauingen Energy Park in Bavaria, with a 25.7 MW capacity and 26.98 GWh/year average production, achieved a capacity factor of 12.0%.
What capacity factor for solar energy did the Sacramento Municipal Utility District observe in 2005?
Answer: 15%
Explanation: In 2005, the Sacramento Municipal Utility District observed a 15% capacity factor for solar energy, highlighting its variability.
What is the general characteristic of a geothermal power plant's capacity factor?
Answer: It generally has a higher capacity factor compared to many other power sources.
Explanation: Geothermal power typically has a higher capacity factor than many other sources because the geothermal resource is consistently available throughout the day and year.
In 2018, the US EIA reported the capacity factor for Solar PV in the United States as 26.1%.
Answer: True
Explanation: According to US EIA data, the capacity factor for Solar PV in the United States was reported as 26.1% in 2018.
Coal-fired power stations in the UK experienced a consistent increase in capacity factors from 2007 to 2021.
Answer: False
Explanation: Coal-fired power stations in the UK saw a general and sharp decline in capacity factors over this period, falling from 46.7% in 2007 to just 7.8% in 2019, reflecting a move away from coal.
What was the range of annual capacity factors for wind farms in the United States from 2013 to 2016?
Answer: 32.2% to 34.7%
Explanation: During the period from 2013 through 2016, annual capacity factors for wind farms in the United States ranged from 32.2% to 34.7%.
What capacity factor did the US EIA report for Geothermal power in 2018?
Answer: 77.3%
Explanation: According to the US Energy Information Administration (EIA), the capacity factor for Geothermal power in the United States was 77.3% in 2018.
In the UK, what was the peak capacity factor for Nuclear power stations between 2007 and 2021?
Answer: 80.1% in 2016
Explanation: Data for UK power stations shows that the capacity factor for Nuclear power peaked at 80.1% in 2016 during the 2007-2021 period.
What was the lowest capacity factor observed for Combined Cycle Gas Turbine (CCGT) stations in the UK between 2007 and 2021?
Answer: 27.9% in 2013
Explanation: The capacity factor for CCGT stations in the UK saw considerable variability, reaching a low of 27.9% in 2013.
What was the capacity factor for Coal-fired power stations in the UK in 2019?
Answer: 7.8%
Explanation: Reflecting a significant move away from coal, the capacity factor for UK coal-fired power stations dropped to just 7.8% in 2019.
What was the highest capacity factor achieved by Hydroelectric power stations in the UK between 2007 and 2021?
Answer: 41.5% in 2015 and 2020
Explanation: UK Hydroelectric power stations reached a peak capacity factor of 41.5% twice during this period, in both 2015 and 2020.
What was the capacity factor for Offshore wind power in the UK in 2020?
Answer: 45.7%
Explanation: Offshore wind power in the UK reached a high capacity factor of 45.7% in 2020, indicating improved performance over time.
What was the highest capacity factor for Photovoltaic power stations in the UK between 2007 and 2021?
Answer: 11.8% in 2015
Explanation: Photovoltaic power stations in the UK consistently had low capacity factors, peaking at 11.8% in 2015.