VA Alternative Energy System Contracting
Practice Exam 300 Questions with Verified
Answers & Detailed Rationales Updated for
2025/2026/2027 — A+ Pass Guarantee
This comprehensive exam is designed to mirror the official Virginia Alternative Energy
System (AES) Contracting licensing exam. The actual exam consists of 60 questions
(open-book, 150-minute time limit, 72% passing score). This expanded 300-question
practice exam covers every topic area in depth, ensuring you are fully prepared for the
2025, 2026, and 2027 testing cycles.
Part 1: Core Concepts & Alternative Energy Terminology
Questions 1–30
1. What is the primary function of a photovoltaic cell in a solar energy system?
A) To store electrical energy for later use
B) To convert sunlight directly into direct current (DC) electricity
C) To convert direct current to alternating current
D) To track the sun’s movement across the sky
Correct Answer: B
Rationale: A photovoltaic (PV) cell absorbs photons from sunlight, which excites
electrons and creates a flow of direct current (DC). This is called the photovoltaic effect.
Storage, inversion, and tracking are performed by other components.
2. What does a solar combiner box do in a photovoltaic system?
A) Converts DC to AC
B) Combines the output of multiple PV strings into a single circuit
C) Disconnects the system during a power outage
D) Measures energy production
Correct Answer: B
Rationale: The combiner box is a junction box where the outputs of multiple PV strings
are connected in parallel, consolidating them into one main DC feeder before the
inverter. This reduces wiring complexity and costs.
,3. Which of the following best defines an “alternative energy system” under the Virginia
AES Contracting exam?
A) Any system that uses fossil fuels
B) Any method of generating electricity from renewable resources, including solar, wind,
and geothermal
C) Only solar photovoltaic systems
D) Any system that produces heat without electricity
Correct Answer: B
Rationale: For the purposes of the Virginia AES Contractor license, “alternative energy
system” encompasses renewable energy technologies such as solar (PV and thermal),
wind, geothermal, and bio-energy, excluding traditional fossil-fuel generation.
4. What is the minimum passing score for the Virginia Alternative Energy System
Contracting exam?
A) 65%
B) 70%
C) 72%
D) 75%
Correct Answer: C
Rationale: According to the PSI examination bulletin for Virginia’s AES Contracting exam,
the minimum passing score is 72%, based on a 60-question, open-book, 150-minute test.
5. How many questions are on the actual Virginia AES Contracting exam?
A) 40
B) 50
C) 60
D) 80
Correct Answer: C
Rationale: The official PSI examination consists of approximately 60 multiple-choice
questions. This is confirmed by both the VA licensing board and the exam bulletin.
6. Which electrical parameter is critical when configuring PV modules in parallel?
A) Voltage
B) Current
C) Frequency
D) Resistance
Correct Answer: B
Rationale: When PV modules are connected in parallel, their currents add while voltage
,remains constant. Therefore, matching current ratings is critical to avoid imbalances and
potential equipment damage.
7. A “string” in a solar PV system refers to:
A) The wire connecting the inverter to the main panel
B) A series of PV modules connected together
C) The mounting hardware for rooftop panels
D) The software that monitors production
Correct Answer: B
Rationale: A PV string is a specific number of modules wired in series, producing a
combined DC voltage that is fed into the inverter or combiner.
8. What device is used to maximize energy harvest from a PV array by varying the
operating point of the modules?
A) Rapid shutdown device
B) Maximum Power Point Tracker (MPPT)
C) Surge protection device
D) Disconnect switch
Correct Answer: B
Rationale: An MPPT is an electronic DC-to-DC converter that continuously adjusts the
electrical operating point of the PV array to deliver maximum available power under
varying sunlight and temperature conditions.
9. Which of the following is NOT a renewable energy source?
A) Solar
B) Wind
C) Natural gas
D) Geothermal
Correct Answer: C
Rationale: Natural gas is a fossil fuel and is not considered renewable. Renewable energy
sources are naturally replenished on a human timescale and include solar, wind,
geothermal, hydro, and biomass.
10. The time between a noon solar reading and a reading of 90% of the noon value is
known as:
A) Insolation
B) Peak sun hours
C) Sunrise duration
D) Solar azimuth
, Correct Answer: B
Rationale: Peak sun hours represent the number of hours per day when solar irradiance
averages 1,000 W/m². They are used to estimate energy production from a PV system.
11. A kilowatt-hour (kWh) measures:
A) Power at an instant
B) Energy consumed or produced over time
C) Voltage multiplied by current
D) Sunlight intensity
Correct Answer: B
Rationale: A kilowatt-hour is a unit of energy equal to one kilowatt (1 kW) of power
sustained for one hour. Utilities bill customers based on kWh consumption.
12. The primary advantage of a grid-tied PV system is:
A) Complete independence from the utility
B) The ability to store large amounts of energy on-site
C) Lower cost because no batteries are needed
D) Higher efficiency in cloudy conditions
Correct Answer: C
Rationale: Grid-tied systems (without battery storage) are less expensive and simpler
because they rely on the utility grid for backup, eliminating the need for expensive
batteries.
13. A “bi-directional meter” is used in grid-tied PV systems to:
A) Measure both incoming and outgoing electricity for net metering
B) Reduce voltage fluctuations
C) Isolate the system during maintenance
D) Convert DC to AC
Correct Answer: A
Rationale: A bi-directional (or “net”) meter can record both electricity drawn from the
grid and excess electricity exported to the grid, enabling accurate net metering billing.
14. Which component in a standalone PV system prevents batteries from overcharging?
A) Inverter
B) Charge controller
C) Disconnect switch
D) Combiner box
Practice Exam 300 Questions with Verified
Answers & Detailed Rationales Updated for
2025/2026/2027 — A+ Pass Guarantee
This comprehensive exam is designed to mirror the official Virginia Alternative Energy
System (AES) Contracting licensing exam. The actual exam consists of 60 questions
(open-book, 150-minute time limit, 72% passing score). This expanded 300-question
practice exam covers every topic area in depth, ensuring you are fully prepared for the
2025, 2026, and 2027 testing cycles.
Part 1: Core Concepts & Alternative Energy Terminology
Questions 1–30
1. What is the primary function of a photovoltaic cell in a solar energy system?
A) To store electrical energy for later use
B) To convert sunlight directly into direct current (DC) electricity
C) To convert direct current to alternating current
D) To track the sun’s movement across the sky
Correct Answer: B
Rationale: A photovoltaic (PV) cell absorbs photons from sunlight, which excites
electrons and creates a flow of direct current (DC). This is called the photovoltaic effect.
Storage, inversion, and tracking are performed by other components.
2. What does a solar combiner box do in a photovoltaic system?
A) Converts DC to AC
B) Combines the output of multiple PV strings into a single circuit
C) Disconnects the system during a power outage
D) Measures energy production
Correct Answer: B
Rationale: The combiner box is a junction box where the outputs of multiple PV strings
are connected in parallel, consolidating them into one main DC feeder before the
inverter. This reduces wiring complexity and costs.
,3. Which of the following best defines an “alternative energy system” under the Virginia
AES Contracting exam?
A) Any system that uses fossil fuels
B) Any method of generating electricity from renewable resources, including solar, wind,
and geothermal
C) Only solar photovoltaic systems
D) Any system that produces heat without electricity
Correct Answer: B
Rationale: For the purposes of the Virginia AES Contractor license, “alternative energy
system” encompasses renewable energy technologies such as solar (PV and thermal),
wind, geothermal, and bio-energy, excluding traditional fossil-fuel generation.
4. What is the minimum passing score for the Virginia Alternative Energy System
Contracting exam?
A) 65%
B) 70%
C) 72%
D) 75%
Correct Answer: C
Rationale: According to the PSI examination bulletin for Virginia’s AES Contracting exam,
the minimum passing score is 72%, based on a 60-question, open-book, 150-minute test.
5. How many questions are on the actual Virginia AES Contracting exam?
A) 40
B) 50
C) 60
D) 80
Correct Answer: C
Rationale: The official PSI examination consists of approximately 60 multiple-choice
questions. This is confirmed by both the VA licensing board and the exam bulletin.
6. Which electrical parameter is critical when configuring PV modules in parallel?
A) Voltage
B) Current
C) Frequency
D) Resistance
Correct Answer: B
Rationale: When PV modules are connected in parallel, their currents add while voltage
,remains constant. Therefore, matching current ratings is critical to avoid imbalances and
potential equipment damage.
7. A “string” in a solar PV system refers to:
A) The wire connecting the inverter to the main panel
B) A series of PV modules connected together
C) The mounting hardware for rooftop panels
D) The software that monitors production
Correct Answer: B
Rationale: A PV string is a specific number of modules wired in series, producing a
combined DC voltage that is fed into the inverter or combiner.
8. What device is used to maximize energy harvest from a PV array by varying the
operating point of the modules?
A) Rapid shutdown device
B) Maximum Power Point Tracker (MPPT)
C) Surge protection device
D) Disconnect switch
Correct Answer: B
Rationale: An MPPT is an electronic DC-to-DC converter that continuously adjusts the
electrical operating point of the PV array to deliver maximum available power under
varying sunlight and temperature conditions.
9. Which of the following is NOT a renewable energy source?
A) Solar
B) Wind
C) Natural gas
D) Geothermal
Correct Answer: C
Rationale: Natural gas is a fossil fuel and is not considered renewable. Renewable energy
sources are naturally replenished on a human timescale and include solar, wind,
geothermal, hydro, and biomass.
10. The time between a noon solar reading and a reading of 90% of the noon value is
known as:
A) Insolation
B) Peak sun hours
C) Sunrise duration
D) Solar azimuth
, Correct Answer: B
Rationale: Peak sun hours represent the number of hours per day when solar irradiance
averages 1,000 W/m². They are used to estimate energy production from a PV system.
11. A kilowatt-hour (kWh) measures:
A) Power at an instant
B) Energy consumed or produced over time
C) Voltage multiplied by current
D) Sunlight intensity
Correct Answer: B
Rationale: A kilowatt-hour is a unit of energy equal to one kilowatt (1 kW) of power
sustained for one hour. Utilities bill customers based on kWh consumption.
12. The primary advantage of a grid-tied PV system is:
A) Complete independence from the utility
B) The ability to store large amounts of energy on-site
C) Lower cost because no batteries are needed
D) Higher efficiency in cloudy conditions
Correct Answer: C
Rationale: Grid-tied systems (without battery storage) are less expensive and simpler
because they rely on the utility grid for backup, eliminating the need for expensive
batteries.
13. A “bi-directional meter” is used in grid-tied PV systems to:
A) Measure both incoming and outgoing electricity for net metering
B) Reduce voltage fluctuations
C) Isolate the system during maintenance
D) Convert DC to AC
Correct Answer: A
Rationale: A bi-directional (or “net”) meter can record both electricity drawn from the
grid and excess electricity exported to the grid, enabling accurate net metering billing.
14. Which component in a standalone PV system prevents batteries from overcharging?
A) Inverter
B) Charge controller
C) Disconnect switch
D) Combiner box
