Renewable Energy Systems Flashcards
7 cards from real HERS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Renewable Energy Systems flashcards as text
What is 'net metering' and why is it relevant to residential solar PV installations?
Answer: A billing arrangement where excess solar generation offsets the homeowner's utility bill
Net metering allows homeowners with PV systems to send excess electricity to the grid and receive bill credits, making solar more economically attractive.
What is the primary advantage of a building-integrated photovoltaic (BIPV) system over a rack-mounted system?
Answer: Dual function as both building envelope material and electricity generator
BIPV products such as solar roof tiles or facade panels serve as both the building skin and a power-generating system, replacing conventional building materials.
Which type of battery chemistry is most commonly used in modern residential energy storage systems paired with solar PV?
Answer: Lithium iron phosphate (LiFePO4)
Lithium iron phosphate batteries dominate residential storage because of their high cycle life, safety, energy density, and declining cost compared to older chemistries.
A home has a 6 kW DC solar array. If the system performance ratio (PR) is 0.80 and annual peak sun hours are 1,500, what is the estimated annual energy production?
Answer: 7,200 kWh
Annual production = DC capacity × peak sun hours × PR = 6 kW × 1,500 h × 0.80 = 7,200 kWh.
Which federal incentive program most directly reduces the upfront cost of installing a residential solar PV or battery storage system in the US?
Answer: Investment Tax Credit (ITC) / Residential Clean Energy Credit
The Residential Clean Energy Credit (ITC) allows homeowners to deduct a percentage of qualified solar, wind, and battery storage installation costs from their federal income taxes.
What does 'capacity factor' mean when applied to a residential rooftop solar PV system?
Answer: The ratio of actual annual energy output to the maximum possible output if the system ran at full capacity 24/7
Capacity factor is the ratio of actual energy produced over a period to the theoretical maximum if the system operated at full nameplate capacity continuously; rooftop PV typically has a capacity factor of 10–25%.
When a HERS rater evaluates a home with a ground-source heat pump, how is the system classified from a renewable energy perspective?
Answer: It qualifies as a renewable energy system because it extracts thermal energy from the earth
Ground-source heat pumps extract renewable thermal energy stored in the earth and are recognized as a renewable energy technology under most rating standards and incentive programs.