Quantifying Greenhouse Gas (GHG) Emissions Intensity of Electricity Grids: Selecting the Right Metric for Net Unit Impact

Sep 4

Decarbonizing electricity systems is essential to tackling climate change.

But while it’s clear that grid emissions intensity is a critical factor in assessing climate solutions, choosing the right version of this metric is less straightforward. Should analysts prioritize precision, usability, or relevance to the specific decision at hand?

This paper explores the critical role of selecting appropriate greenhouse gas (GHG) emissions intensity metrics when evaluating the net impact of decarbonization solutions. It highlights how factors such as geographical location, electricity source, time of use, and assessment timeframe significantly influence the choice of metric, demonstrating why this decision is crucial and how to make it.

Grounded in Project Frame’s GHG impact methodology, this extension introduces a structured workflow to help analysts identify when grid-related effects are material, select metrics that fit the use case, and avoid unnecessary complexity. The approach emphasizes transparency and proportionality, ensuring that results are rigorous yet actionable.

In short: the goal isn’t perfect precision, but clarity that enables smarter climate action. By aligning methods with real-world decisions, this work turns emissions estimates into practical tools for accelerating the transition to cleaner energy systems.

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Frequently Asked Questions

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FAQ: Why is electricity transition planning so complex?

Transition planning is complex because it requires meeting increasing electricity demand with lower carbon intensity electricity sources while maintaining reliability and affordability.

FAQ: To what extent should analysts account for insufficient transmission & distribution (T&D) capacity and curtailment?

T&D capacity and curtailment primarily affect volumes, as opposed to net unit impact. In the example of a renewable energy source displacing a fossil fuel energy source, GHG impact should focus on where the solution and incumbent are different, including in downstream inefficiencies.

FAQ: If a country already has a low average grid emissions intensity, does increasing its renewable electricity generation still result in positive GHG impact — and should investors prioritize it?

Until the grid reaches net zero, there's room for GHG impact if, for example, the intervention displaces fossil generation or has systemic effects (like accelerating coal retirement). Broader impacts may warrant adjustment factors in impact quantification.

FAQ: How do lifecycle emissions of different generation sources compare?

Electricity generation sources, like wind, solar, hydropower, geothermal, and fossil fuels (like coal and natural gas), and nuclear energy, differ in both how emissions are generated and how reliably they supply power. Read more for an overview of how these major generation sources compare, based on the geography of the US.

FAQ: How is electricity created, and how does it get to the user?

There are broadly 3 steps to creating and using electricity: generation, transmission, and distribution. This FAQ provides an overview of electricity generation, transmission, and distribution.

Want to learn more? Read Project Frame GHG Impact Methodology to dive into emissions impact assessment and reporting.

Net Unit Impact

Kelsey Litwin