Energy and Utilities Renewable Energy 2 — Questions and Answers
Question 1: What does REC stand for in renewable energy markets?
- Renewable Energy Certificate (Correct answer)
- Regional Energy Contract
- Regulated Electricity Credit
- Renewable Equipment Cost
Correct answer: Renewable Energy Certificate
Renewable Energy Certificates (RECs) are tradable instruments representing 1 MWh of electricity generated from a renewable source.
Question 2: What is the 'duck curve' phenomenon in power grid management?
- A pipeline pressure curve shaped like a duck
- A daily load shape with a midday solar dip and steep evening ramp resembling a duck (Correct answer)
- A grid frequency variation pattern
- A wind power output pattern
Correct answer: A daily load shape with a midday solar dip and steep evening ramp resembling a duck
The duck curve describes how high midday solar generation depresses net load, then demand ramps sharply when solar fades in the evening.
Question 3: What is the nameplate capacity of a wind turbine?
- The average annual output in MWh
- The maximum rated power output under ideal conditions (Correct answer)
- The turbine's rotor diameter in meters
- The minimum wind speed needed to generate power
Correct answer: The maximum rated power output under ideal conditions
Nameplate capacity is the manufacturer-rated maximum power output (in MW) a turbine can produce at its rated wind speed.
Question 4: What is 'curtailment' in the context of wind or solar power?
- Shutting down a plant for scheduled maintenance
- Reducing output below what could be generated due to grid constraints or excess supply (Correct answer)
- Ramping up generation to meet peak demand
- Disconnecting a plant during a storm
Correct answer: Reducing output below what could be generated due to grid constraints or excess supply
Curtailment occurs when operators instruct renewable plants to reduce output because transmission constraints or oversupply prevents the energy from being used.
Question 5: Which battery chemistry is most commonly deployed in utility-scale energy storage systems in the US?
- Lead-acid
- Nickel-cadmium
- Lithium-ion (Correct answer)
- Vanadium redox flow
Correct answer: Lithium-ion
Lithium-ion batteries dominate utility-scale storage due to their high energy density, declining costs, and fast response times.
Question 6: What is a Power Purchase Agreement (PPA) in renewable energy?
- A utility's application for a new power plant permit
- A long-term contract to buy electricity from a renewable generator at a fixed price (Correct answer)
- A federal subsidy for renewable energy projects
- An insurance policy for wind turbines
Correct answer: A long-term contract to buy electricity from a renewable generator at a fixed price
A PPA is a long-term contract between a renewable energy developer and a buyer specifying the price and terms for electricity delivery.
Energy and Utilities Renewable Energy 2
What does REC stand for in renewable energy markets?