Renewable Energy Flashcards
7 cards from real Agricultural/Bioengineering 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 flashcards as text
Which type of biofuel is produced by transesterification of vegetable oils or animal fats?
Answer: Biodiesel
Transesterification reacts triglycerides with an alcohol (usually methanol) and a catalyst to produce biodiesel (fatty acid methyl esters).
In photovoltaic systems, what is the function of a maximum power point tracker (MPPT)?
Answer: Continuously adjusts operating voltage to extract maximum power from panels
An MPPT algorithm adjusts the electrical load impedance to keep PV panels operating at their peak power point under varying conditions.
Which agricultural waste stream has the highest energy content per dry tonne for direct combustion?
Answer: Rice husk
Rice husk has a higher silica-adjusted heating value (~15 MJ/kg dry) compared to other crop residues, making it favorable for combustion.
What is the primary role of a digestate separator in a farm biogas system?
Answer: Separates digestate into liquid fertilizer and solid fiber fractions
A screw press or centrifuge separator divides digestate into solid fiber (compost feedstock) and liquid (nutrient-rich fertilizer).
A wind turbine has a rotor diameter of 20 m and operates in 8 m/s wind. Using Betz's law, what is the theoretical maximum power extractable (air density = 1.225 kg/m³)?
Answer: ~77 kW
P_Betz = 0.593 × 0.5 × ρ × A × v³ = 0.593 × 0.5 × 1.225 × π×100 × 512 ≈ 77 kW.
Which US federal program provides financial support to agricultural producers installing renewable energy systems?
Answer: USDA Rural Energy for America Program (REAP)
REAP provides grants and loan guarantees specifically to agricultural producers and rural small businesses for renewable energy and energy efficiency improvements.
In lignocellulosic ethanol production, what is the main purpose of the pretreatment step?
Answer: Disrupts the lignin-hemicellulose matrix to improve cellulose accessibility for enzymes
Pretreatment (steam explosion, dilute acid, or alkali) breaks apart the recalcitrant lignocellulosic structure so cellulase enzymes can access and hydrolyze cellulose.