5 exercises — Practice green software and sustainable computing vocabulary in English: carbon intensity, carbon-aware workloads, SCI, GreenOps, and Scope emissions.
Tools: Cloud Carbon Footprint, Electricity Maps, CodeCarbon, Green Software Foundation SCI spec, AWS Customer Carbon Footprint Tool
0 / 10 completed
1 / 10
A sustainability engineer explains carbon intensity to the team: "Carbon intensity measures how much CO₂ is emitted per kilowatt-hour of electricity. It varies by grid and by time. In France, nuclear power means the grid has very low carbon intensity — around 50 gCO₂eq/kWh. In Germany, coal means higher intensity — 300–400 gCO₂eq/kWh at peak. The intensity also varies hour by hour as renewable generation fluctuates." What is carbon intensity and why does it matter for software deployment decisions?
Carbon intensity: the amount of greenhouse gas emissions (expressed as CO₂ equivalent, CO₂eq) produced per unit of electricity (gCO₂eq/kWh). It varies by: Grid region — France (nuclear): ~50 gCO₂eq/kWh; Germany: ~300 gCO₂eq/kWh; California: ~200; Poland (coal-heavy): ~700. Time of day — solar peaks midday, wind varies; carbon intensity fluctuates hour by hour. Season — winter often means more gas/coal. Why it matters for software: running the same workload in different regions or at different times can differ by 10× in carbon impact. Tools: Electricity Maps — real-time global carbon intensity by grid region. WattTime — programmatic carbon intensity data with forecasting. gCO₂eq — grams of CO₂ equivalent; accounts for all greenhouse gases (CO₂, CH₄, N₂O) normalised to CO₂ warming potential. In conversation: "We could save 60% of our batch job's carbon footprint just by running it at 2am when the grid is mostly nuclear and wind — same compute, much lower impact."
2 / 10
A cloud architect presents a carbon-aware architecture: "We're making our batch data pipelines carbon-aware. Temporal shifting means we delay non-urgent jobs to run when carbon intensity is lower — say, at night when wind is high. Spatial shifting means we move workloads to a region with lower carbon intensity. Our ML training jobs can wait 4 hours — so we shift them temporally. Our real-time API can't shift temporally, so we don't apply this there." What is the difference between temporal shifting and spatial shifting?
Temporal shifting: delaying a workload to a time when carbon intensity is lower. Requires: the workload to be deferrable (not real-time), carbon intensity forecasting, a scheduling system that can delay and trigger. Example: ML training, batch ETL, video transcoding, backup jobs. Spatial shifting: moving a workload to a geographic region where carbon intensity is currently lower. Requires: multi-region capability, data sovereignty is not a constraint, latency requirements are flexible. Example: global batch jobs, CDN asset processing. Green Software Foundation principles: Demand shaping — designing products to shift user behaviour towards greener times. Example: showing a "lower carbon" option on a download page with a scheduled delivery time. Energy proportionality — a server that's doing 10% of its work should use 10% of its peak power. Most servers are inefficient at low utilisation. Carbon budget — a team's or product's carbon allowance per quarter. Carbon-aware SDK — open-source library (Green Software Foundation) that provides carbon intensity data and shifting logic. In conversation: "Our weekly reports job has an SLA of 'ready by 9am Monday' — we have the whole weekend to find the lowest-carbon 2-hour window. That's temporal shifting."
3 / 10
A developer advocate explains the Software Carbon Intensity specification: "The SCI score measures the carbon emissions of software per functional unit. The formula is: SCI = (E × I + M) per R. E is energy consumed, I is the carbon intensity of that energy, M is the embodied carbon of the hardware used, and R is the functional unit — like per user, per API call, or per GB processed. SCI can't be offset — you have to actually reduce it." What is embodied carbon in the SCI formula?
Embodied carbon (also: embedded carbon): the greenhouse gas emissions generated across a hardware component's full lifecycle — manufacturing (mining raw materials, fabrication), shipping, installation, and end-of-life disposal. For a server, manufacturing accounts for 50–80% of its total lifecycle carbon. Operational carbon: emissions from the electricity consumed while running the hardware. SCI formula: E — Energy consumed by the software (kWh). I — Carbon intensity of the electricity grid (gCO₂eq/kWh). M — Embodied carbon allocated to this software (based on hardware utilisation share × hardware lifecycle carbon). R — Functional unit (per user/call/GB). Why embodied carbon matters: using a smaller instance doesn't just save electricity — it uses less of a server's embodied carbon. Keeping hardware longer amortises its embodied carbon over more use. Cloud has lower embodied carbon per workload due to higher utilisation rates than on-premises. Vocabulary: PUE (Power Usage Effectiveness) — data centre efficiency metric: total facility power / IT equipment power. 1.0 = perfect; typical: 1.1–1.5. GreenOps — applying FinOps principles to carbon: measure, optimise, govern. In conversation: "Our on-premises servers run at 15% utilisation — most of their embodied carbon is wasted. Moving to cloud gets us to 60% utilisation and much lower embodied carbon per unit of computation."
4 / 10
An SRE explains Scope emissions to the sustainability team: "Scope 1 emissions are direct — fuel we burn ourselves, like diesel generators. Scope 2 are indirect from purchased electricity — the biggest category for most tech companies. Scope 3 are all other indirect emissions: our supply chain, the flights our employees take, the devices our customers use to access our product. For most software companies, Scope 3 is 70–90% of total emissions." What are Scope 3 emissions and why are they the hardest to measure?
Scope 3 emissions: all indirect emissions in a company's value chain that are not Scope 1 or 2. The GHG Protocol (greenhouse gas standard) defines 15 Scope 3 categories including: upstream (purchased goods, supplier emissions, capital goods) and downstream (use of sold products, end-of-life treatment). GHG Protocol Scopes: Scope 1 — direct emissions from owned/controlled sources (on-site generators, company vehicles, gas heating). Scope 2 — indirect emissions from purchased electricity, heat, steam, cooling. Location-based vs. market-based accounting. Scope 3 — all other indirect emissions. For a cloud provider: chip manufacturing (supply chain), employee flights, customer energy use. Why hard to measure: data comes from thousands of suppliers and customers; methodologies differ; requires estimation and supplier engagement. For software companies: Use of sold products — the electricity customers use to run your software. Example: streaming video is a major Scope 3 source for Netflix-type services. Employee commuting and business travel. In conversation: "Our product runs on 200 million customer devices — the energy those devices use to run our app is Scope 3. We can influence it through efficiency, but we can't control it."
5 / 10
A cloud cost engineer introduces GreenOps practices: "GreenOps applies FinOps principles to carbon. Just like FinOps makes cloud cost visible and accountable, GreenOps makes carbon emissions visible and actionable. We have zombie instances — servers that are running but doing nothing. Rightsizing for cost also helps carbon. We're adding carbon as a column next to cost in our infrastructure dashboard." What is a zombie instance and why does it matter for both cost and carbon?
Zombie instance: a cloud resource that is running (incurring costs and consuming energy) but performing no useful work. Common zombie types: stopped EC2 instances with attached EBS volumes still charging, unattached load balancers, unused Elastic IPs, development environments left running over weekends, orphaned databases from cancelled projects. Zombie impact: financial waste (direct billing) + operational carbon (idle electricity) + embodied carbon (hardware allocated but unused). GreenOps vocabulary: GreenOps — applying FinOps's Inform → Optimise → Operate cycle to carbon emissions. Cloud Carbon Footprint — open-source tool that calculates carbon emissions from cloud usage data. AWS Customer Carbon Footprint Tool — AWS's built-in carbon dashboard. Rightsizing for carbon — oversized instances waste embodied carbon and electricity. Right-sizing reduces both cost and carbon. Sustainability KPI — e.g., carbon per API request, carbon per active user. AWS Graviton — ARM-based instances with up to 60% better energy efficiency than x86. Choosing Graviton reduces both cost and carbon. In conversation: "Our zombie instance audit found $18K/month in waste and approximately 40 tonnes of CO₂eq per year — the fixes are identical: terminate the unused resources."
6 / 10
Sarah (Lead Developer) writes this comment on a code review:
`@john.doe - This function is efficient but could be more carbon conscious. Consider batching API calls to reduce the overall energy consumption of the service. Also, investigate using a serverless architecture for intermittent tasks to avoid idle compute resources.`;
What does Sarah primarily mean by 'carbon conscious' in this context?
Sarah's comment focuses on reducing the *impact* of the function's energy consumption, not just its speed. By suggesting batching and serverless architecture, she's advocating for strategies that minimize the total amount of energy used by the service over time – a core principle of Green Software Engineering. The incorrect options misinterpret her focus on overall impact versus immediate performance.
7 / 10
During a standup meeting, David (SRE) says: "We're seeing a significant increase in carbon emissions from our database queries. A lot of them are running on older, less efficient VMs."
What does David likely mean when he refers to 'carbon emissions' in this context?
David's statement highlights a critical connection between inefficient code and environmental impact. In this scenario, 'carbon emissions' refers to the energy consumed by the servers running the database queries—the more intensive the queries, the higher the carbon intensity, directly linked to server resource utilization. The other options represent different aspects of database performance or storage that don't directly translate to carbon emissions.
8 / 10
You're reviewing a PR description for a new feature: "This microservice handles user authentication. It uses Node.js and Express, runs on AWS Lambda, and is deployed to Kubernetes. We've optimized the code for performance but haven't explicitly considered carbon efficiency."
What key area should the developer have addressed in this PR description regarding Green Software Engineering?
While performance optimization is important, a Green Software Engineering approach requires considering the *source* of energy used by the infrastructure. AWS Lambda's pay-as-you-go model and serverless architecture inherently offer more carbon efficiency than running traditional VMs in Kubernetes – this should have been explicitly mentioned to drive further optimization.
9 / 10
Maria (Cloud Engineer) sends this Slack message:
`@team - Just noticed a spike in carbon usage from the staging environment. Seems like we have several VMs still running even though no deployments are happening!`;
What is Maria referring to when she mentions 'carbon usage'?
Maria's message focuses on a concrete metric – energy consumption. 'Carbon usage' in this context refers directly to the energy consumed by the servers in the staging environment; this is the primary driver of carbon intensity and therefore environmental impact. The other options represent related but distinct aspects of cloud infrastructure management.
10 / 10
You are reviewing a code review comment from a sustainability consultant:
`'Consider using asynchronous processing for tasks that don't require immediate results to reduce the overall energy consumption of your system. This will allow you to offload non-critical workloads during periods of low carbon intensity.'
What does this comment suggest regarding Green Software Engineering?
This comment highlights a key strategy in Green Software Engineering: workload shifting. Asynchronous processing allows tasks to be deferred until periods of lower grid carbon intensity (e.g., nighttime when renewable energy is abundant), minimizing the system's overall energy consumption – directly addressing the core principle.
What does the "Green Software Engineering Vocabulary" vocabulary exercise cover?
This exercise tests real IT vocabulary related to green software engineering vocabulary through 10 multiple-choice questions, each built from realistic workplace sentences rather than abstract definitions.
Is this vocabulary exercise free to use?
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How many questions does this exercise have?
This exercise has 10 questions. Each one shows a real-world sentence or scenario with multiple-choice options and an explanation once you answer.
What happens after I answer a question?
You'll see immediate feedback showing whether your answer was correct, along with a short explanation of why — then a button to move to the next question, and a full results screen at the end.
Can I retry the exercise if I get questions wrong?
Yes. Once you reach the results screen, click "Try again" to reset your answers and go through the exercise from the start as many times as you like.
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No account is needed. Your answers are scored in your browser during the session — nothing is saved to a server, so you can jump straight in.
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No — progress within an exercise resets if you navigate away or reload. Each exercise is short enough to complete in a few minutes in one sitting.
Are these vocabulary exercises connected to other topics?
Yes — browse the full vocabulary exercises hub to find related modules covering adjacent IT topics and roles.
How is this different from reading a glossary or blog article?
Exercises like this one are active recall drills — you have to choose the correct term or phrasing yourself, which builds retention faster than passively reading a definition.
Where can I find more vocabulary exercises?
Browse the full Vocabulary exercises hub for hundreds of modules covering Agile, DevOps, security, databases, architecture, and more — organised by IT role and skill.