Marginal Abatement Cost Curve (MACC)

A Marginal Abatement Cost Curve (MACC) is a visual tool that shows the cost-effectiveness and potential impact of different greenhouse gas (GHG) reduction measures. It plots the marginal cost (i.e., cost per ton of CO₂e avoided) of each action against the total emissions abatement potential.

Each bar on the curve represents a mitigation option:

• Width = how much CO₂e the measure can reduce.

• Height = the cost per ton of CO₂e reduced.

o Bars below the line (negative costs) represent cost-saving options.

o Bars above the line represent cost-incurring options.

MACCs help prioritize investments and policies by identifying the most efficient emissions reduction measures.

1. What is a Marginal Abatement Cost Curve (MACC)?

It is a chart that ranks emissions reduction measures based on their cost per ton of CO₂e avoided and their mitigation potential. It helps visualize trade-offs between environmental impact and economic cost.

2. What does "marginal abatement cost" mean?

It refers to the cost of reducing one additional ton of CO₂e through a specific measure, such as switching to LED lighting or using electric vehicles.

3. What does a MACC tell us?

A MACC shows:

• Which carbon reduction measures are most cost-effective.

• Which measures can deliver large emissions savings.

• The total abatement potential available at various price points.

4. How is a MACC constructed?

It’s typically built using:

• A list of abatement technologies or actions.

• Their implementation costs.

• Their emissions reduction potential.

• Financial and technical assumptions (e.g., energy prices, discount rates).

5. What do negative-cost options mean?

These are actions that save money over time—for example, energy efficiency upgrades that lower utility bills. They're often low-hanging fruit in climate strategies.

6. What are some common measures shown in a MACC?

Examples include:

• Building insulation

• Heat pumps

• Renewable electricity

• Electric vehicles

• Process improvements

• Carbon capture and storage (CCS)

7. Who uses MACCs and why?

Used by:

• Governments for climate policy and carbon pricing decisions.

• Corporates for internal decarbonization planning.

• Investors to identify cost-effective climate solutions.

8. What are the limitations of MACCs?

• They are often static, don’t account for tech evolution or policy shifts.

• May ignore behavioral barriers or infrastructure constraints.

• Usually focus on economic cost, not broader sustainability factors.

9. Are MACCs used for Scope 1, 2, or 3 emissions?

Primarily for Scope 1 and 2, where companies have operational control. For Scope 3, MACCs are harder to build due to data uncertainty and supply chain complexity.

10. Can MACCs change over time?

Yes. As technology costs fall or carbon prices rise, the shape of the MACC can shift, making some measures more favourable. Regular updates are essential for relevance.

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