Carbon convergence has emerged as a key timing risk for power trading across South-East Europe, with markets focusing on when carbon costs, coal and lignite exits, and deeper market coupling will align. Seasonal system assessments by ENTSO-E are used to frame adequacy under current assumptions. Trading desks price the possibility that those assumptions change abruptly as carbon convergence progresses.
The mechanics of convergence in the region differ from fully ETS-integrated markets. Several systems still run dispatchable coal and lignite outside the full cost of EU carbon pricing. That structure anchors marginal energy costs in the €25–35/MWh range in some cases, while neighbouring markets internalise carbon costs that can lift gas- or coal-set prices to €70–120/MWh under normal conditions.
This pricing asymmetry has supported cross-border arbitrage and helped dampen prices during stress periods. Convergence can erode the gap through CBAM exposure, market coupling, or domestic carbon pricing. The central trading question is whether convergence arrives before or after replacement capacity and grid reinforcement are commissioned.
Carbon costs, dispatchable depth and winter availability
Timing becomes critical because convergence can remove dispatchable support before new resources replace it. Coal and lignite units provide coincident availability during winter stress when demand rises and renewables underperform. If carbon costs price these units out of the merit order or accelerate closures, dispatchable depth can fall immediately.
Replacement assets cited for the region include storage, pumped hydro upgrades, grid-forming inverters, and new interconnectors. These projects typically operate on multi-year timelines. If carbon convergence outruns build-out, markets anticipate a gap period marked by higher volatility, wider spreads, and more frequent scarcity pricing.
Forward curves already incorporate this risk. Winter peak products across South-East Europe show persistent premiums of €40–60/MWh over baseload that are not solely attributed to demand patterns. Beyond Y+2, bid–ask spreads widen materially and liquidity thins, indicating disagreement over how quickly convergence will occur.
How forward curves price uncertainty
Traders price a range of outcomes rather than a single path for policy-driven change. One scenario described involves slower convergence with lingering lignite anchors. Another involves faster convergence with abrupt repricing as marginal economics shift.
The convexity embedded in winter products reflects insurance against policy-driven shocks. As carbon costs rise unevenly, congestion economics can also change as flows reorient toward zones with lower effective marginal costs until transmission corridors bind. Early phases may increase congestion frequency as markets exploit remaining differentials between areas.
Later phases are described as potentially reversing congestion patterns when coal exits accelerate. In that case, scarcity can propagate upstream and previously exporting zones may import during stress events. Trading desks that do not separate these phases risk mispricing corridor exposure.
Stress outcomes under partial versus faster convergence
Quantitative differences appear in stress outcomes described for winter events under partial convergence. Deficit zones clear at €250–400/MWh day-ahead in those episodes. Intraday and balancing prices are reported to exceed €500–600/MWh when response is scarce.
Under faster convergence scenarios where coal availability is economically constrained, models point to higher activation volumes of +30–50%. The same scenarios indicate more frequent corridor saturation, with commercial capacity compressing from 1.5–2.0 GW to 500–700 MW on key interfaces.
The probability of these scenarios is priced rather than waiting for them to materialise. Markets described in the source treat uncertainty as an input to pricing across products rather than a single deterministic trajectory for policy alignment.
CBAM exposure and lumpy availability shifts
A non-linear element is introduced through CBAM exposure. Even without domestic ETS alignment, export exposure to carbon costs can alter dispatch behaviour abruptly. Assets that were marginally profitable can become loss-making at the border, changing availability during peak hours.
The effect is described as lumpy rather than gradual. A policy threshold crossed in one year can remove hundreds of megawatts from winter availability overnight. Trading books exposed to such step changes face asymmetric downside if they assume smooth adjustment in generation retirements or dispatch patterns.
Inertia decline and volatility in balancing markets
The interaction with system inertia deepens the risk profile described for the region. Carbon convergence is expected to retire synchronous units first, accelerating inertia decline before grid-forming alternatives scale up. As inertia falls, balancing prices spike and intraday volatility increases.
An empirical comparison cited links low synchronous online capacity with higher intraday variance. Days with low synchronous online capacity show 2–3× higher intraday variance than comparable demand days five years earlier. The source frames this as increasing not only energy prices but also the cost of risk through imbalance charges, higher margins, and reduced liquidity.
Investment sequencing: grid reinforcement, storage and pumped hydro
Whether convergence is disruptive or manageable depends on investment sequencing relative to policy timing. Grid reinforcement is cited at €0.8–1.2 million per kilometre for new 400 kV lines. Storage is cited at €500–700 thousand per MWh, while pumped hydro modernisation is cited at €1.5–2.5 million per MW.
The source links volatility compression to commissioning ahead of or alongside carbon convergence rather than after it begins. Where approvals lag, markets are said to price a gap period reflected in congestion rents of €30–70 million per year on key interfaces.
Treatment of convergence risk in trading and procurement
The source describes carbon convergence as a calendar risk for trading strategies across time horizons. Near-term books are said to benefit from residual low-carbon-cost baseload and dampened volatility, while mid-term books face the highest convexity as policy timing uncertainty peaks. Longer-term books depend on infrastructure delivery timelines.
A layered approach is described as protecting winter peaks, diversifying corridor exposure, and valuing flexibility as a hedge against policy shocks. For industrial offtakers, procurement is described as shifting away from fixed-price baseload structures that can become punitive when peak exposure remains unhedged.
The source reports buyers moving toward contracts that cap peak risk, index balancing exposure, or secure access to flexibility. The premium paid for such structures is described as functioning like an insurance premium against convergence timing risk.
Remuneration gaps and transition misalignment
The risk is framed as misaligned transitions rather than high prices alone. If carbon costs rise faster than flexibility and grids arrive, volatility becomes chronic; if infrastructure leads policy, markets absorb convergence more smoothly according to the source description.
A structural mismatch in remuneration is described as compounding the challenge by reducing returns for assets that stabilise the system through lower peak scarcity and reduced balancing needs. Without explicit recognition of stability value, investment lags are said to make convergence shocks harder to manage.
Threshold effects across regional policy timelines
The source describes carbon convergence in South-East Europe as a sequence of thresholds approached with caution by markets rather than a distant endpoint. Each policy announcement, closure schedule change, or grid delay shifts probabilities and reprices curves used by traders.
The final set of dynamics described links dispatchable depth exits with potential price spikes if alternatives have not arrived before those exits occur. It also notes that if investment and policy align credibly, volatility would compress and premiums would fade within the market framework referenced in the source.