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.

What is the Simplified LCA Hotspot Identifier?

Enter relative intensity scores for five lifecycle stages — raw materials, manufacturing, logistics, use phase, and end-of-life — across CO2e and energy impact categories to build a hotspot matrix and a prioritised list of stages for a deep LCA. It runs free in your browser on Gera Tools, with nothing uploaded.

Simplified LCA Hotspot Identifier

Name: Simplified LCA Hotspot Identifier
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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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.

Scoring guidance for each lifecycle stage

Your scores are relative, not absolute — they reflect where you estimate impacts concentrate compared with the other stages. You are answering: “If I had 100 points of impact to distribute across these five stages, how much goes where?”

Stage	What to consider for CO2e	What to consider for energy
Raw materials	Mining/refining, upstream transportation, material mass and carbon intensity	Extraction energy, primary material processing (aluminium, steel, concrete are high)
Manufacturing	Energy source of factory, process steps, waste, packaging	Electricity and heat consumed in production processes
Logistics	Transport mode (air >> sea), total distance, load efficiency	Fuel per tonne-km; sea freight is ~50× lower than air per tonne
Use phase	Grid carbon intensity × kWh consumed over product lifetime	Total kWh drawn over product lifetime
End of life	Landfill methane, incineration, recycling avoidance credits	Energy to recycle or process; transportation to disposal

Worked example: laptop computer

Stage	CO2e score	Energy score	CO2e share	Energy share
Raw materials	40	35	40% — HOTSPOT	35% — HOTSPOT
Manufacturing	25	30	25% — HOTSPOT	30% — HOTSPOT
Logistics	5	5	5%	5%
Use phase	20	25	20% — threshold	25% — HOTSPOT
End of life	10	5	10%	5%

In this example, raw materials and manufacturing dominate both categories — the expected result for a device with aluminium body and lithium battery. The use phase is a hotspot for energy (and borderline for CO2e) because the device draws power for several years. Logistics and end-of-life are low-priority for a deep study.

How to use the output

The hotspot screen tells you where to spend LCA budget, not what the actual emission values are. Once the top one or two stages are identified, a full ISO 14040 / 14044 quantitative LCA focuses primary data collection and inventory analysis on those stages. Secondary data (literature averages, EcoInvent database figures) can handle the low-priority stages without materially affecting accuracy.

If a stage is borderline — exactly at the 20% threshold — include it in the deep study anyway; the score uncertainty from rough relative estimates is typically larger than the gap between hotspot and non-hotspot at the boundary.