Question

the costs to generate solar and wind power continue to fall, according to a 2019 report published by the international renewable energy agency.

chart: power generation cost over time (years 2010–2021, y - axis: 2019 usd/kwh; lines: onshore wind, offshore wind, photovoltaic, concentrated solar power)

which of the following types of technology has experienced the greatest decrease in cost per kilowatt hour since 2010, and how do you know?

choose 1 answer:
a) photovoltaic (pv), because the cost was lower than the other energy types in 2021.
b) concentrated solar power (csp), because the cost fluctuated the most between 2010 and 2021.
c) onshore wind power, because the cost was lower than the other energy types in 2010.
d) photovoltaic (pv), because the cost was higher than the other energy types in 2010 and lower than the other energy types in 2021.

Explanation:

To determine the technology with the greatest cost decrease, we analyze the start (2010) and end (2021) costs:

• Option A: Wrong. A low 2021 cost doesn’t show the decrease (needs 2010 comparison).
• Option B: Wrong. Fluctuation ≠ greatest decrease (decrease is about start - end, not variation).
• Option C: Wrong. A low 2010 cost means less room to decrease (decrease = 2010 cost - 2021 cost; lower 2010 → smaller decrease).
• Option D: Correct. Photovoltaic (PV) had a higher cost in 2010 (so more room to decrease) and a lower cost in 2021, meaning the total decrease (2010 cost − 2021 cost) is the largest.

Answer:

D. Photovoltaic (PV), because the cost was higher than the other energy types in 2010 and lower than the other energy types in 2021.