Getting started: key terms

In this course, we will use a variety of terms related to computing and environmental impact, as well as units of measurement associated with energy consumption.

Before you start, it may be useful to familiarise yourself with some key terms that will recur throughout the course. You can return to this page at any time as needed.

Carbon footprint: the total amount of greenhouse gases (including CO₂ but also other greenhouse gases -GHGs- such as methane and nitrous oxide) that are added to the atmosphere by an activity, person, or entity. Measured as a quantity of CO₂ equivalent (CO₂e).

Carbon intensity (of electricity): the amount of CO₂e emitted per kilowatt hour of electricity consumed. In gCO₂e/kWh.

CO₂ equivalent (CO₂e): The standard unit used to measure a carbon footprint. It takes into account the varied global warming potentials of different greenhouse gases so that the footprint of different activities can be compared. For more details, you can visit this Glossary page from Eurostat. 

Cluster: a computing cluster is a set of interconnected computers (referred to as nodes) working together as a single machine, allowing them to perform larger, more complex, or faster calculations than any one computer could handle on its own.

Data centre: a physical facility that houses IT infrastructure, such as servers, storage systems, and network equipment, to store, process, and manage data and applications.

Environmental impacts/footprint: the effect a person, entity, or specific activity has on the environment. It accounts for all the impacts on the environment (such as water usage, resources extraction, etc), therefore it includes but is not limited to GHG emissions.

E-waste: an abbreviation for electronic waste, it generally refers to all disposed electronic equipment.

Greenhouse Gas (GHG): the set of gases which absorb the radiation emitted by the planet, trapping it in the atmosphere and generating the greenhouse effect. The most abundant GHGs on Earth are water vapor, carbon dioxide, methane, nitrous oxide and ozone. 

High Performance Computing (HPC): In the context of this course, it refers to the kind of computational analyses that require more hardware than a personal computer typically has, and therefore require specialist computing resources (typically found in dedicated data centres/Digital Research Infrastructures).

Watts: The standard unit of power being consumed at any point in time. Not to be confused with energy (watt-hours) which is the measure of power consumed over a period of time.