Additionality

Additionality is the principle that a renewable energy purchase should cause new clean generation capacity to be built, rather than simply reallocating credits from power plants that already existed. A data center operator's solar power purchase agreement is considered additional if it provides the revenue certainty that gets a new project financed and constructed; buying unbundled renewable energy certificates from a decade-old hydro dam is not. Corporate buyers increasingly screen deals for additionality because sustainability disclosures and frameworks like RE100 and the Science Based Targets initiative treat non-additional purchases as weaker evidence of real decarbonization. The concept has become central to data center PPA structuring as hyperscalers compete for a limited pool of new wind, solar and storage projects, and as scrutiny grows over claims of "100% renewable" campuses that in practice draw from a fossil-heavy local grid outside the hours their contracted renewable generator is producing.