What is life cycle assessment (LCA) and why is it used in evaluating energy systems?

• A. LCA measures only greenhouse gas emissions during operation.
• B. LCA predicts future energy prices.
• C. LCA assesses environmental impacts from resource extraction to end-of-life and is used to compare sustainability.
• D. LCA ignores resource extraction impacts.

Answer: (C)

Life cycle assessment looks at environmental impacts across the entire life of an energy system, from resource extraction through manufacturing, construction, operation, maintenance, and end-of-life disposal or recycling. It’s used to compare the sustainability of different energy options by accounting for multiple impact categories (like greenhouse gas emissions, air and water pollution, resource depletion, and land use) over the full life cycle, not just during operation. This broader view reveals trade-offs that aren’t visible when focusing on one stage alone, helping identify where improvements have the biggest effect. For example, a system might have low emissions during use but high emissions from material production or end-of-life disposal, and LCA captures all of that to inform comparisons. The option that limits itself to operation is too narrow, and treating prices or ignoring extraction impacts misses the purpose of evaluating overall environmental performance.