Both routes give you a formal DNO position on the project. The question is at what cost and at what point in the project lifecycle.
Choose feasibility first when
- Project size is significant (typically above ~500 kW, always above ~1 MW).
- You're not yet committed to spending on a full application.
- Customer is evaluating multiple sites.
- You suspect the local network might be constrained.
- You want an indicative cost before scoping investment.
Go straight to G99 when
- Project is small to mid-scale and within Fast Track thresholds.
- Site is in an area you know is unconstrained.
- Customer is committed to proceeding at this site regardless.
- Timeline is tight and the G99 route is faster than sequential feasibility then application.
What feasibility doesn't do
Feasibility gives you an indicative view of the network, not a formal connection offer. If the project is definitely going ahead, you'll still need a full application afterwards — the feasibility work informs it but doesn't replace it.