Renewable Energy Systems Flashcards
7 cards from real EMP 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 the primary purpose of a Maximum Power Point Tracker (MPPT) in a photovoltaic system?
Answer: Continuously adjust the load impedance to maximize energy harvest
An MPPT controller dynamically adjusts the electrical operating point of PV modules so they always operate at peak power output regardless of varying irradiance or temperature.
Which wind turbine configuration is most commonly used in utility-scale onshore wind farms?
Answer: Horizontal-axis upwind three-blade turbine
The horizontal-axis upwind three-blade design dominates utility-scale wind because it offers the best balance of aerodynamic efficiency, structural reliability, and noise characteristics.
A solar farm in the US Southwest produces 8 GWh annually from a 5 MW DC installation. What is its capacity factor?
Answer: 18.3%
Capacity factor = 8,000 MWh ÷ (5 MW × 8,760 h) = 8,000 ÷ 43,800 ≈ 18.3%.
In a geothermal binary cycle power plant, what fluid is used to drive the turbine?
Answer: A low-boiling-point working fluid heated by geothermal brine
Binary cycle plants use a secondary organic working fluid (e.g., isobutane) with a low boiling point, allowing electricity generation from moderate-temperature geothermal resources without flashing brine.
Which metric best describes the ratio of usable energy output to total energy input over a renewable technology's lifetime?
Answer: Energy Return on Energy Invested (EROI)
EROI measures how many units of energy a technology delivers for every unit consumed during manufacturing, installation, operation, and decommissioning.
What is the Betz limit, and what does it represent for wind turbines?
Answer: Theoretical maximum aerodynamic efficiency of 59.3% for any wind turbine
The Betz limit (16/27 ≈ 59.3%) is the theoretical maximum fraction of kinetic energy that any turbine can extract from free-flowing wind, derived from conservation of momentum.
Which interconnection standard must US distributed solar inverters typically comply with for anti-islanding protection?
Answer: IEEE 1547
IEEE 1547 sets the US standard for interconnection of distributed energy resources, including mandatory anti-islanding functions that disconnect the inverter when grid power is lost.