There is no basis-free carbon number
A carbon-intensity value is the output of an accounting method. Production accounting asks what the generators inside a boundary emitted. Consumption accounting reallocates imported and exported electricity through power-flow assumptions. Operational factors generally count direct generation emissions; lifecycle factors also include supply-chain and construction estimates. Comparing numbers before matching those choices is a category error.
Technology factors are one input
Solar Analytica's source-independent grid layer maps operator fuel categories to a versioned set of IPCC lifecycle median factors. Coal and gas dominate the weighted result when present. Solar, wind, hydro and nuclear are not treated as zero because the method is lifecycle-based. Battery discharge is excluded from direct generation weighting to avoid assigning the stored energy a new generation factor without tracing its charge source.
Six reasons the published values move
| Method choice | Why the result changes |
|---|---|
| Production or consumption | Imports and exports are either left with the producing system or reallocated to users. |
| Operational or lifecycle | Direct stack emissions and full supply-chain medians use different factors. |
| Fuel classification | Mixed, unknown and storage categories may be mapped, excluded or estimated differently. |
| Temporal resolution | An annual average hides hourly changes in generation and trade. |
| Geographic boundary | A balancing area, bidding zone and country are not always the same system. |
| Revision and retrieval time | Operators correct metering and classification after first publication. |
The publication gate matters as much as the formula
The grid-source layer calculates factor coverage before publishing production carbon intensity. If less than 95 per cent of included generation can be mapped to an evidence-backed factor, the carbon value remains blank. Unknown generation is not silently assigned the fleet average. Each observation carries operator, source version, retrieval time, evidence type and confidence.
The same logic powers source reconciliation. Where two independent providers overlap, Solar Analytica records the delta and tolerance result beside the canonical observation. A second source is quality control, not an excuse to average incompatible methods.
Six checks before you compare
- Match the exact location and interval.
- Confirm production or consumption basis.
- Confirm operational or lifecycle factors.
- Inspect import, export and storage treatment.
- Check fuel-map coverage and missing categories.
- Record the source version and retrieval time.
The public Grid Source Registry exposes those fields. The Grid Mix provides annual context, while Methodology explains why blanks are retained when the evidence does not support a comparable value.
Lifecycle medians are inputs, not verdicts
The IPCC figures shown here are lifecycle medians used as stable method inputs. They do not replace plant-specific emissions, marginal-intensity models or consumption-based flow tracing. The method provides a reproducible baseline and a declared confidence boundary, not the only valid carbon accounting approach.