What you are actually buying
Conventional green supply reconciles annually. You consume a year of power, a year of certificates is retired against it, and the two never have to have happened at the same time. The claim is accurate under the accounting rules and hollow under scrutiny, because a certificate from a windy night in February does nothing for the gas plant that supplied you on a still evening in June.
Hourly matching settles hour by hour against generation that was actually running. Coverage is reported as a percentage. Businesses reporting 100% renewable annually often sit well below 100% when measured hourly, and the figure depends heavily on load shape and location.
What it costs
More. How much more depends on your shape and the stack available, but expect a premium over annual REGO backed supply. You are paying for generation that had to be available in specific hours, plus storage or flexibility to move surplus into the hours that need it.
The premium falls as coverage falls. Getting from an annual claim to a substantial hourly coverage figure is usually more affordable than the last few per cent. Closing the final gap is expensive, because the last hours are the hardest and the cheapest way to cover them is usually storage.
When it is worth it
- You have a reporting commitment that is moving toward hourly or location-based accounting, and would rather move first than be moved.
- Your customers ask questions your current claim cannot survive. This is increasingly common in supply chains with their own targets.
- Your load is flat and substantial, so the coverage figure is achievable rather than aspirational.
- You want the internal number. A coverage score is a thing you can improve year on year. An annual percentage stuck at 100 tells you nothing and motivates nobody.
When it is not
If nobody is asking, your load is small or spiky, and the premium is real money to you, then a well negotiated green supply contract is a perfectly defensible position. Buying hourly matching to be first is a valid strategic choice, but it should be a choice made deliberately rather than sold to you as a necessity.
The thing to insist on
Whatever you buy, insist that the gaps are measured and disclosed. A supplier who will show you the hours they do not cover is telling you the truth about the hours they do.