What is a hotspot in LCA terms?

A hotspot is a lifecycle stage, process, or input that contributes a disproportionately large share of total environmental impact. Identifying hotspots early focuses improvement effort and tells you where a full quantitative LCA will deliver the most value, rather than spreading data collection evenly.

How are the scores normalised?

Within each impact category the tool divides every stage's score by the sum of all five stage scores, giving each stage a percentage share of that category's total. This turns your relative estimates into comparable shares regardless of the absolute numbers you entered.

What threshold counts as a hotspot?

By convention a stage holding 20 percent or more of an impact category is flagged as a hotspot, since a single stage exceeding a fifth of the total is material. With five stages an even split would be 20 percent each, so anything above that share signals concentration worth investigating.

Why combine CO2e and energy?

Carbon and primary energy often, but not always, peak in the same stage. Looking at both helps you spot trade-offs, such as a use phase that is energy-heavy but low-carbon on a clean grid, and prioritise stages that are hot in either or both categories for the deeper study.

Is a simplified hotspot screen a substitute for full LCA?

No. This is a screening step to direct effort. A full ISO 14040 and 14044 LCA quantifies impacts across many categories using inventory data and characterisation factors. The hotspot screen tells you which stages most deserve that rigorous treatment.

Simplified LCA Hotspot Identifier

A full life cycle assessment is data-intensive and expensive, so practitioners screen for hotspots first — the lifecycle stages that dominate environmental impact. This simplified tool takes your relative intensity estimates for five lifecycle stages across two impact categories, normalises them into comparable shares, and produces a hotspot matrix plus a prioritised list of stages that justify a deep, quantitative LCA.

How it works

For each impact category the tool converts your raw stage scores into percentage shares of the category total:

share(stage, category) = score(stage, category) / Σ scores(category) × 100%

Any stage whose share reaches the hotspot threshold (20 percent, the point above an even five-way split) is flagged. To rank stages for a deep LCA the tool sums each stage’s CO2e and energy shares, so a stage that is hot in both categories rises to the top:

priority(stage) = CO2e share + energy share

This dual-category view surfaces both stages that dominate one impact and stages that are moderately significant across both.

Example and tips

For many durable electronic products the use phase dominates energy while raw materials dominate embodied carbon — two different hotspots that a single-category view would miss. Enter your honest relative estimates even if rough; the screen is about direction, not decimals. Once the matrix points to one or two stages, commission a full ISO 14040 and 14044 study focused there, where inventory data and characterisation factors will turn your screening hunch into a defensible quantified result.