Renewable Energy Systems Flashcards

What is the Levelized Cost of Energy (LCOE) used for in renewable energy project analysis?

Answer: Comparing the lifetime cost-competitiveness of different energy technologies on a per-kWh basis

LCOE represents the average revenue per kWh needed to recover all costs over a project's lifetime, enabling apples-to-apples comparison across technologies with different cost structures and lifetimes.

Which commercially available solar panel technology typically achieves the highest conversion efficiency?

Answer: Monocrystalline silicon

Monocrystalline silicon panels, made from a single continuous crystal structure, achieve the highest commercial efficiencies (typically 18–22%) among mass-produced solar panel types.

What is a Renewable Portfolio Standard (RPS) as used in US energy policy?

Answer: A government mandate requiring utilities to supply a defined minimum percentage of electricity from eligible renewable sources

An RPS (also called a Renewable Energy Standard) legally requires electric utilities to source a specified and often increasing percentage of their power sales from renewable energy.

What is the primary energy production benefit of installing a single-axis solar tracking system compared to a fixed-tilt array?

Answer: Increases annual energy capture by 20–40% by keeping panels perpendicular to the sun throughout the day

Single-axis trackers rotate panels to follow the sun's east-to-west path, maximizing irradiance capture and typically increasing annual yield by 20–40% versus fixed-tilt systems.

What does the Betz limit of approximately 59.3% represent in wind energy engineering?

Answer: The theoretical maximum fraction of kinetic wind energy that any turbine can extract

The Betz limit (16/27 ≈ 59.3%) is a fundamental fluid dynamics result showing that no turbine can capture more than 59.3% of the kinetic energy in the wind, regardless of design.

What is a Power Purchase Agreement (PPA) in the context of commercial renewable energy procurement?

Answer: A long-term contract to buy electricity at a pre-negotiated price from a renewable energy generator, often with no upfront capital cost to the buyer

A PPA is a financial contract where an energy buyer agrees to purchase power at a fixed or escalating rate from a third-party owner who finances, installs, and operates the renewable system.

Which metric expresses the proportion of a building's total annual energy consumption that is met by its on-site solar energy system?

Answer: Solar fraction

The solar fraction is the ratio of solar energy contribution to total building energy demand, expressed as a decimal or percentage, and is a key design target for solar thermal and PV systems.