ERAC ERAC Renewable Energy Systems & Technologies 2 — Questions and Answers
Question 1: What is a Renewable Energy Certificate (REC) and what does it certify?
- A government permit required to install solar panels
- A tradable certificate representing 1 MWh of electricity generated from a renewable source (Correct answer)
- An equipment warranty for solar inverters
- A compliance document for utility interconnection
Correct answer: A tradable certificate representing 1 MWh of electricity generated from a renewable source
A Renewable Energy Certificate (REC) is a market-based instrument certifying that 1 megawatt-hour of electricity was generated and delivered to the grid from a qualified renewable energy source.
Question 2: In solar energy systems, what does 'peak sun hours' represent?
- The hours per day when the sun is above the horizon
- The equivalent number of hours per day at a solar irradiance of 1,000 W/m² (Correct answer)
- The hours of maximum electricity demand at a facility
- The optimal hours to run solar-powered equipment
Correct answer: The equivalent number of hours per day at a solar irradiance of 1,000 W/m²
Peak sun hours represent the equivalent hours per day during which solar irradiance averages 1,000 W/m² (1 kW/m²), used to estimate daily energy production from a PV system.
Question 3: What is the primary risk factor that an ERAC auditor assesses when evaluating a wind energy project's revenue stability?
- Equipment manufacturer credit risk
- Wind resource variability and associated generation uncertainty (P50/P90 analysis) (Correct answer)
- Local zoning regulation changes
- Carbon credit market fluctuations
Correct answer: Wind resource variability and associated generation uncertainty (P50/P90 analysis)
Wind resource variability is the primary risk factor; P50/P90 analysis quantifies the probability that annual generation will exceed a given threshold, informing lender and investor risk assessments.
Question 4: Which type of energy storage technology is most commonly paired with utility-scale renewable energy projects in the US to manage intermittency?
- Compressed air energy storage (CAES)
- Pumped hydroelectric storage
- Lithium-ion battery energy storage systems (BESS) (Correct answer)
- Flywheel energy storage
Correct answer: Lithium-ion battery energy storage systems (BESS)
Lithium-ion battery energy storage systems (BESS) have become the dominant technology for utility-scale renewable energy storage due to their declining costs, scalability, and rapid response capability.
Question 5: In a Power Purchase Agreement (PPA) for renewable energy, who typically owns and maintains the generation equipment?
- The electricity customer (offtaker)
- The local utility company
- The renewable energy developer or third-party investor (Correct answer)
- The state energy office
Correct answer: The renewable energy developer or third-party investor
In a PPA, the renewable energy developer or third-party investor retains ownership of the generation equipment and sells electricity to the customer (offtaker) at a contractually agreed price.
Question 6: What does 'interconnection' refer to in the context of on-site renewable energy projects?
- Linking multiple buildings in a campus microgrid
- The technical and administrative process of connecting a renewable energy system to the utility grid (Correct answer)
- Installing parallel redundant solar inverters for reliability
- Combining solar PV with wind generation at the same site
Correct answer: The technical and administrative process of connecting a renewable energy system to the utility grid
Interconnection is the process by which a distributed generation system is reviewed, approved, and physically connected to the utility grid, governed by the utility's interconnection tariff and IEEE 1547.
ERAC ERAC Renewable Energy Systems & Technologies 2
What is a Renewable Energy Certificate (REC) and what does it certify?