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 process converts biomass into a combustible gas mixture (CO, H2, CH4, CO2) through partial oxidation at high temperatures?
Answer: Gasification
Gasification reacts biomass with a controlled amount of oxygen or steam at 700–1000°C to produce syngas (producer gas).
A biochar soil amendment is a co-product of which biomass energy process?
Answer: Pyrolysis
Slow pyrolysis of biomass in the absence of oxygen produces biochar as the solid co-product alongside bio-oil and pyrolysis gas.
What is the primary advantage of using a biogas combined heat and power (CHP) unit on a farm?
Answer: Simultaneously generates electricity and recovers waste heat for use in farm operations
CHP (cogeneration) captures both electrical output and thermal energy from combustion, raising overall system efficiency to 80–90%.
In agrivoltaic systems, crops are grown beneath solar panels. What is the main observed benefit for the crops in hot, arid climates?
Answer: Reduced water evapotranspiration due to panel shading
Agrivoltaic shading lowers crop canopy temperature and reduces soil evaporation, cutting irrigation water needs by 20–50% in arid conditions.
Which microbial group is responsible for the final step of methanogenesis in anaerobic digestion, converting acetate and H2/CO2 to methane?
Answer: Methanogens (Archaea)
Methanogenic archaea (e.g., Methanosaeta, Methanobacterium) perform the terminal step converting acetic acid and hydrogen gas into CH4 and CO2.
What does 'levelized cost of energy' (LCOE) represent for a farm-scale renewable energy system?
Answer: The average cost per unit of electricity generated over the system's lifetime, including capital and operating costs
LCOE normalizes total lifecycle costs (capital, O&M, financing) over total lifetime energy production, enabling fair comparison of different technologies.
Which federal standard in the US requires transportation fuel sold to contain a minimum volume of renewable fuel, driving demand for farm-produced biofuels?
Answer: Renewable Fuel Standard (RFS)
The RFS (administered by EPA under EISA 2007) mandates annual volumetric targets for ethanol, biodiesel, and advanced biofuels blended into transportation fuel.