Interviewer view · keep this screen to yourself
Cutting emissions 40 percent at a German steel-components maker
You run the case. Read the prompt, answer questions from the notes below, and share data only when the candidate asks for it or gets stuck. Score at the end.
Case timer
00:00
1. Read the prompt aloud
Read it slowly, then pause. Let the candidate ask questions before they structure.
A German maker of forged steel components emits 100,000 tonnes of CO2e a year (Scope 1 and 2). It must cut 40 percent by 2030 at the lowest cost. The exhibit lists its options. What plan do you recommend?
Format note: Interviewer-led: the interviewer shows the lever table and asks you to build the plan.
2. Answers to clarifying questions
Give these answers only if the candidate asks. If they ask something not listed, give a sensible answer or say it does not matter here.
If asked: Is the 40 percent target for Scope 1 and 2 only?
Answer: Yes. Scope 3 comes later.
If asked: What is the baseline?
Answer: 100,000 tonnes a year: 60,000 Scope 1 and 40,000 Scope 2.
If asked: What carbon price should I assume, and are lever costs before or after it?
Answer: EUR 80 per tonne on Scope 1 emissions, likely rising. Lever costs in the exhibit do not include carbon savings.
3. The hypothesis a strong candidate states
Listen for an early, testable guess like this one. It does not need to match word for word.
The first cuts are usually cheap, through efficiency and clean electricity. My hypothesis is that the company can meet 40 percent with low-cost levers and does not need expensive process changes yet.
4. A model structure
Compare the candidate's structure with this one. A different split can be just as good if it is clean and fits the problem.
- Fill the target with the cheapest levers first
- Target in tonnes
- Key: Levers in order of cost per tonne
- Cost of the plan
- Next levers versus the carbon price
Exhibit 1
Reveal to candidate: when they ask for this data, say "Open Exhibit 1" (they press "Show exhibit 1" on their screen).
| Lever | Scope cut | Tonnes avoided a year | Cost (EUR per tonne, before carbon savings) |
|---|---|---|---|
| Efficiency: heat recovery and controls | Scope 1 | 10,000 | -40 |
| Renewable electricity contract | Scope 2 | 30,000 | 10 |
| Electric furnaces for heat treatment | Scope 1 | 25,000 | 90 |
| Hydrogen-ready burners | Scope 1 | 15,000 | 250 |
So-what
The two cheapest levers avoid the full 40,000 tonnes needed and together save money. Electric furnaces are close to paying for themselves at today's carbon price; hydrogen burners are far from it.
5. The working, step by step
Each step shows how a strong candidate works it out. Share a new fact from it only when the candidate asks or is stuck, and let them do the math: the result in the dark box is what they should reach.
Step 1: Target in tonnes
What a strong candidate does: 40 percent of the 100,000-tonne baseline.
Tonnes to cut a year: 100,000 × 0.4 = 40,000
Step 2: Cheapest levers first
What a strong candidate does: Efficiency (heat recovery and better controls, cutting gas use) saves money; renewable electricity through a long-term contract costs EUR 10 per tonne. Together they avoid:
Tonnes from the two cheapest levers: 10,000 + 30,000 = 40,000
Step 3: Yearly cost of the plan
What a strong candidate does: Efficiency saves EUR 40 per tonne; renewable power costs EUR 10 per tonne. A negative result means the plan saves money.
Yearly cost of the plan (EUR): 10,000 × -40 + 30,000 × 10 = -100,000
Step 4: Average cost per tonne
What a strong candidate does: The plan saves a little money on average.
Average cost (EUR per tonne): (10,000 × -40 + 30,000 × 10) ÷ 40,000 = -2.5
Step 5: Counting the carbon saved
What a strong candidate does: The lever costs exclude carbon. The 10,000 Scope 1 tonnes cut by efficiency also avoid EUR 80 each of carbon cost, EUR 800,000 a year. The plan's yearly saving including carbon:
Yearly saving including carbon (EUR): -(10,000 × -40 + 30,000 × 10) + 10,000 × 80 = 900,000
Step 6: Next lever at today's carbon price
What a strong candidate does: Electric furnaces cost EUR 90 per tonne but cut Scope 1 (assuming the extra electricity is renewable; otherwise Scope 2 rises), which carries the EUR 80 carbon price. Net cost for 25,000 tonnes:
Net yearly cost of electric furnaces (EUR): 25,000 × (90 - 80) = 250,000
Step 7: Next lever if the carbon price reaches EUR 100
What a strong candidate does: The same lever would then save money.
Net yearly cost at EUR 100 (EUR): 25,000 × (90 - 100) = -250,000
The recommendation to listen for
At the end, say: "The CEO walks in. What is your recommendation?"
Meet the 40 percent target with efficiency and a renewable electricity contract. First, together they avoid the full 40,000 tonnes. Second, they save about EUR 100,000 a year before carbon savings, and about EUR 900,000 a year once the EUR 800,000 of avoided carbon cost on the 10,000 Scope 1 tonnes is counted. Third, they use proven technology and can be in place well before 2030. Prepare electric furnaces as the next step: at EUR 80 per tonne they cost about EUR 250,000 a year net, but they pay for themselves if the carbon price passes EUR 90. Leave hydrogen burners until costs fall.
Risks a strong answer names: Renewable power contracts depend on electricity prices and supply; Carbon prices may not rise as expected; Efficiency savings may be smaller than engineering estimates.
Next steps: Tender for a 10-year renewable power contract; Run an energy audit to confirm the efficiency savings; Design electric furnaces and set a carbon-price trigger for the decision.
Strong versus weak
A strong answer
Built from the baseline, filled the target from the cheapest lever, and tested the next lever against the carbon price.
A weak answer
Recommended hydrogen because it sounds most advanced, the most expensive option per tonne.
Score the candidate
Score each criterion from 1 to 5. A 2 or a 4 sits between the descriptions.
Total
0 out of 25
Score all five criteria to see the band and the feedback template.