Publishing inside information under REMIT Article 4

What this is about

Ofgem is targeting a specific loophole in how generators and transmission owners decide what outage information to disclose under REMIT Article 4. The problem: many market participants have adopted a blanket 100MW threshold, below which they treat outage and availability data as immaterial and do not publish it. Ofgem's position is that this is not compliant with the regulation, which requires a market-conditions-based assessment, not a fixed numerical cutoff.

The economic logic is straightforward. Whether a 90MW outage constitutes inside information depends on when it happens, what else is out, and what the margin looks like — not on whether it clears an arbitrary bar. A 90MW unplanned trip during a tight winter evening is price-moving. The same trip on a mild Sunday in May is not. Fixed thresholds ignore this entirely, and that is the point: they are designed to minimise disclosure obligations, not to comply with them.

Key points

The 100MW threshold has no regulatory basis. REMIT Article 4 requires publication of information that would be likely to significantly affect wholesale energy prices. The test is market impact, not capacity size. Ofgem states explicitly that no fixed MW threshold can substitute for the case-by-case assessment the regulation demands.

Cumulative and portfolio effects matter. A participant with three units each losing 80MW has 240MW offline but may have published nothing if each unit falls below its internal threshold. Ofgem expects participants to assess their portfolio position in aggregate, not unit by unit. This is a meaningful tightening: it means trading desks cannot silo information across assets to stay below disclosure triggers.

Prevailing market conditions must inform the assessment. The guidance requires participants to consider system margin, time of day, season, and concurrent outages when deciding whether information is price-sensitive. This converts the disclosure decision from a simple lookup (is it above 100MW?) to a judgement call that must be documented and defensible. Compliance costs rise, but the alternative — systematic non-disclosure of price-moving information — is worse for market integrity.

OFTOs are now explicitly in scope. Offshore Transmission Owners have apparently been operating as though REMIT disclosure obligations do not apply to them, or apply only loosely. Ofgem clarifies that transmission availability is inside information when it affects wholesale prices, regardless of who owns the asset. Given that offshore wind farms are functionally curtailed when their OFTO link is unavailable, this closes a gap where significant generation reductions were going unreported because the constraint sat on the transmission side rather than the generation side.

Problematic practices flagged. Ofgem identifies specific patterns it considers non-compliant: applying fixed thresholds without reference to market conditions; failing to aggregate across portfolios; delaying publication beyond what is justified; and treating planned outages differently from unplanned ones for disclosure purposes. The last point matters because planned maintenance schedules, if not published promptly, give the holder an information advantage in forward trading.

What happens next

This is guidance, not a consultation — Ofgem is stating its position, not asking for views. Market participants are expected to review and update their internal REMIT compliance procedures immediately. There is no implementation timeline because, in Ofgem's framing, the obligation already exists and participants should already be complying with it. The guidance merely clarifies what compliance looks like.

The practical implication is enforcement risk. Ofgem has laid down a marker: if a participant suffers an outage below 100MW and does not publish it, and the outage turns out to have been price-moving given prevailing conditions, the participant cannot defend non-disclosure by pointing to its internal threshold. The threshold was never a safe harbour, and Ofgem has now said so in writing.

For generators, this means compliance teams need to build (or buy) real-time assessment tools that cross-reference their own availability against system conditions. For OFTOs, it means establishing REMIT disclosure procedures that many may not currently have. For traders, it means the information environment around GB wholesale power should improve — more outage data published sooner, which tightens spreads and reduces the value of proprietary availability intelligence.

The wider context is Ofgem's post-Brexit REMIT enforcement posture. The UK retained REMIT after leaving the EU, and Ofgem has been progressively asserting its role as the sole enforcement authority for GB wholesale markets. This guidance is consistent with that trajectory: raising the compliance bar and signalling willingness to act against participants who treat disclosure as optional.