Learn vocabulary for carbon-aware computing: carbon intensity, demand shifting, and time-shifting workloads.
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What is 'carbon intensity' in green computing vocabulary?
Carbon intensity (gCO2eq/kWh): the greenhouse gas emissions per kilowatt-hour of electricity. Low-carbon periods: when more renewables (solar, wind) are generating. High-carbon periods: when fossil fuel peaker plants are running. Carbon-aware software moves workloads to low-intensity times or regions. APIs like Electricity Maps provide real-time carbon intensity data.
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What is 'demand shifting' in carbon-aware computing vocabulary?
Demand shifting (temporal): delay a batch training job until 3am when wind power is high and carbon intensity is low. The work still happens — just at a lower-carbon time. Examples: CI/CD builds, ML training, backup jobs, report generation. The Green Software Foundation calls this 'temporal demand shifting.'
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What is 'spatial shifting' in carbon-aware computing vocabulary?
Spatial shifting: if your workload can run in multiple cloud regions, choose the region with the lowest carbon intensity at the time of execution. Example: run a batch job in a region where it is currently windy (low carbon) rather than a region running on coal. AWS, Azure, and GCP now provide per-region carbon intensity data to enable this.
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What is 'energy proportionality' in green IT vocabulary?
Energy proportionality (Barroso & Holzle, Google): a system with 10% utilization should use approximately 10% of its peak energy. In practice, servers at 10% utilization may consume 50%+ of their peak energy due to idle overhead. Better utilization (consolidation, workload scheduling) is often more carbon-efficient than buying more efficient hardware.
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What is 'Scope 3 emissions' in IT sustainability vocabulary?
GHG Protocol scopes: Scope 1 (direct — burning fuel on-site), Scope 2 (indirect — purchased electricity), Scope 3 (all other value-chain emissions — hardware manufacturing accounts for a large portion of tech industry Scope 3). For software: the embodied carbon of manufacturing hardware is often larger than operational energy over the hardware's lifetime.
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David: 'The new microservice deployment is triggering a high carbon intensity alert on the East Coast region. We need to investigate immediately.' What does 'carbon intensity' likely refer to in this context?
'Carbon intensity' measures the amount of carbon dioxide emitted per unit of energy produced. In this case, a high value indicates that the majority of the power source driving the East Coast servers is fossil fuels, leading to increased emissions for each request. Option B correctly identifies the key factor – the proportion of renewables directly impacts this ratio.
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Sarah (in a Slack channel) writes: 'To reduce peak load and lower our carbon footprint during business hours, let's consider shifting some of the reporting tasks to off-peak times.' What strategy is Sarah advocating?
'Demand shifting' focuses on adjusting workloads to times when energy grids are less stressed and often utilize more renewable sources. This directly reduces peak demand and consequently lowers carbon emissions. Option A describes query optimization; B accurately reflects the core concept.
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David: 'The new microservice deployment is triggering a high carbon intensity alert on the East Coast region. We need to investigate immediately.' What does 'carbon intensity' likely refer to in this context?
'Carbon intensity' measures the amount of carbon dioxide emitted per unit of energy produced. In this case, a high value indicates that the majority of the power source driving the East Coast servers is fossil fuels, leading to increased emissions for each request. Option B correctly identifies the key factor – the proportion of renewables directly impacts this ratio.
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Sarah (in a Slack channel) writes: 'To reduce peak load and lower our carbon footprint during business hours, let's consider shifting some of the reporting tasks to off-peak times.' What strategy is Sarah advocating?
'Demand shifting' focuses on adjusting workloads to times when energy grids are less stressed and often utilize more renewable sources. This directly reduces peak demand and consequently lowers carbon emissions. Option A describes query optimization; B accurately reflects the core concept.
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Reviewer Comment: 'This deployment seems to be causing a spike in CPU utilization on the Azure West Europe region. Considering the current carbon intensity data, it's worth investigating if we can optimize resource allocation here.' What is the reviewer primarily concerned about regarding this deployment?
The reviewer is focusing on the carbon intensity, which directly relates to the environmental impact—specifically, the amount of energy consumed and its associated emissions. While performance metrics are important, the core concern here is the deployment's contribution to a high carbon intensity alert. Cost overruns and regulatory compliance are secondary considerations in this specific comment.
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Team Lead (Alex) writes in the #devops channel: 'We're seeing a significant increase in API requests from our mobile app during peak hours. To mitigate this and reduce our carbon footprint, let's explore strategies for demand shifting – primarily offloading some of these requests to lower-carbon regions.' What does 'demand shifting' most likely refer to in this context?
'Demand shifting' refers to strategically redistributing workloads – in this case, API requests – to locations where the environmental impact (carbon intensity) is lower. It's about optimizing resource utilization based on demand and location-specific energy sources. Rate limiting is a separate optimization technique; a complete architectural redesign would be overkill for this scenario.
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PR Description: 'This commit introduces a new feature that processes user data asynchronously. We've configured the worker queue to utilize servers in AWS Frankfurt and Dublin, which currently have lower carbon intensity compared to our primary US East region servers. Monitoring these regions' carbon intensity is crucial for ongoing optimization.' What key aspect of 'carbon-aware computing' does this PR description highlight?
This description emphasizes the core concept of 'carbon-aware computing' by detailing the strategic placement of workloads in regions with lower carbon intensity. The goal isn't simply performance; it's about minimizing the overall environmental impact of operations. The other options represent secondary considerations or unrelated aspects.
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Developer (Ben) reports in the daily stand-up: 'I've been working on shifting some of the nightly database backups to our European data center. This has reduced the peak load on our US servers and, according to the monitoring dashboards, lowered our carbon intensity during those hours.' What is Ben's primary approach to achieving a more sustainable computing environment?
Ben's strategy involves 'spatial shifting' – moving workloads (database backups in this case) to locations with a lower carbon intensity. This directly addresses the environmental impact by leveraging regional differences in energy sources and grid emissions profiles. The other options represent alternative optimization strategies or security measures.
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API Response (from the Carbon Intensity Monitoring Service): 'Request POST /api/v1/metrics – Region: AWS US East - Current Carbon Intensity: 350 gCO2e/req. Request POST /api/v1/metrics – Region: AWS EU West - Current Carbon Intensity: 180 gCO2e/req.' What does this API response primarily illustrate regarding carbon-aware computing?
This API response directly demonstrates how carbon intensity can be tracked and compared across different regions. This capability is fundamental to carbon-aware computing—allowing for informed decisions about where to run workloads to minimize environmental impact. The other options represent related but distinct aspects of infrastructure management.
What will I practise in "Carbon-Aware Computing — Vocabulary and Language"?
Learn vocabulary for carbon-aware computing: carbon intensity, demand shifting, and time-shifting workloads.
How many exercises are in this module?
This module has 14 multiple-choice exercises, each with instant feedback and a full explanation of the correct answer.
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Where can I find more Green IT exercises?
Browse the full Green IT hub for related drills, or check the "Next up" link below to continue with a connected topic.
How is this different from reading an article on the same topic?
Articles explain vocabulary and concepts in prose; this exercise tests and reinforces that vocabulary through active recall with immediate feedback — the two work best together.
Who writes these exercises?
Every exercise is written by the CoderSlingo team, drawing on real workplace English used in IT roles, then reviewed for accuracy and clarity.