Sustainability Foundations for AI Infrastructure

Glossary

Additionality

The property of a clean-energy purchase that causes new clean generation to exist that otherwise would not have been built. Additional purchases genuinely green the grid, distinguishing them from buying credit for generation that already exists.

Emissions scopes

A standard division of greenhouse-gas emissions into three categories: scope one from sources the operator directly controls (such as backup generators), scope two from purchased electricity, and scope three from the rest of the value chain including construction and hardware.

Firm clean power

Clean electricity available on demand around the clock regardless of weather — for example nuclear, geothermal, dispatchable hydro, or storage-backed supply — as opposed to intermittent wind and solar. The scarcest and most decisive clean resource for a constant load.

First-order siting driver

A factor that determines whether and where a project can be built at all, rather than merely adjusting a decision already roughly made. The course argues clean power, carbon, and water have all become first-order drivers for data-center siting.

Hourly (round-the-clock) matching

Ensuring that in every hour a campus draws on clean generation actually available in that hour on its own grid, rather than balancing total consumption against total clean generation once a year. A far stricter standard that exposes intermittency and drives demand for firm clean power.

Marginal emissions

The emissions caused by the generator that ramps up to meet an incremental unit of demand — often fossil-fueled — as distinct from a grid's average emission rate across all generation. For a constant round-the-clock load, marginal rates better capture true carbon impact.

Power purchase agreement (PPA)

A long-term contract to buy the output of a specific generation project, often one that would not be built without the contract. Physical PPAs deliver electricity over the same grid; virtual or financial PPAs settle against market prices while supporting a specific project.

Unbundled certificate

A tradable claim to the clean attribute of a unit of generated electricity, bought separately from the electricity itself. The cheapest and weakest form of clean-power procurement because it is geographically indifferent and usually adds no new generation.