SynCons for Starters

In the second of our articles examining investment consequences of high renewables penetration, we highlight synchronous condensers, which are transitioning from obscure spelling challenge to emergent infrastructure asset class.
As grid system strength erodes and TSOs hit balance sheet and capex limits, the question is not whether syncons are needed – it is who will fund them.

Spell it out

Synchronous condensers, a form of compensator (also called synchronous compensators), are like large idling electrical motors: like a car in a neutral gear, the engine spins, but does not generate power. Instead it acts as a buffer, ready to deliver stacked services historically provided by large thermal generation units, which decentralised inverter-based equipment cannot replicate at scale. They excel at three stability services, around frequency, current or voltage:

• Inertia: their rotating mass resists frequency deviations, slowing the rate of change of frequency (RoCoF) to buy critical seconds following imbalance. It is not location specific.
• Short‑circuit strength: syncons deliver current to counteract faults, buffering systems from cascading short circuit events. It is location specific.
• Reactive power (aka voltage control): with 2–2.5x field-forcing capability for up to ~10 seconds, they inject or absorb reactive power fast enough to stabilise voltage excursions on stressed networks. It is specific to high voltage locations.

Essentially syncons as a long-established, simple but obscure primary tool to maintain grid stability as thermal plant is displaced by renewables.

There are multiple competing technologies to buy “stability”, but they are not equivalent. Statcoms can only deliver reactive power (but do this well). Thermal units are expensive and carbon intensive. The truest competition is BESS paired with grid-forming inverters (GFI) which can deliver all three services, but the volumetric outputs for SCL and reactive power are like comparing a birthday candle (GFI) with a blowtorch (syncon): they have different use cases.
The UK’s Stability Pathfinder outcomes are telling: in Phase 1, all 12 inertia contracts went to synchronous condensers, and in Phase 3, syncons won all 29 contracts for physical inertia and short circuit resilience. Across all rounds, 90% of all 56 contracts were won by syncons.

Private capital is the answer

These are infrastructure: high upfront capex, long asset life, essential service, contracted or regulated cashflows, and meaningful barriers to entry. For infrastructure funds, the appeal is obvious: low volume risk, zero technology risk, good contract durations and capital recovery, strong contractual counterparties, essential services and long technical lives (30–40 years is typical for well‑maintained machines). Further, they offer an uncorrelated risk.
Currently most European syncons are owned by TSOs but this model may change for the build out of future assets, due to:

1. Competing capex priorities: offshore hubs, new substations, interconnectors, HVAC/HVDC reinforcements, upgrades and digitalisation already stretch TSO balance sheets; stability assets are not optional, and can be outsourced.
2. Unmanageable TSO capex demands: the 15 largest European TSOs are projected to invest around at least €350 bn over the next five years, nearly triple the prior period, with an estimated €250 bn funding gap to 2030. Third party capital may be the solution.
3. Proven contract model: in Great Britain, NESO’s Stability Pathfinders have demonstrated external investors can deliver system needs, just as batteries have for other ancillary services. Germany is following suit while Iberia rues its delays.

Market data already point to syncons transitioning from a UK curiosity to an emerging European asset class as renewables penetration continues. Germany last month initiated the outsourced purchasing of stability services. One recent forecast values the European synchronous condenser market rising 6% pa towards a US$500m market by 2030.

Risks to our thesis

But like its warm ales, the UK contracting model may not be welcomed overseas. Possible reasons include:

• Regulatory conservatism: regulators may insist syncons are owned only by TSOs, excluding third‑party capital. Or TSOs may lobby for more RAB eligible assets.
• Contract tenors and bankability: there is no assurance European regulators will match the 10‑year or fixed contract tenors that make UK syncons attractive.
• Alternatives: regulators may advocate grid‑forming BESS or advanced power electronics to support their local supply chains or if lower whole‑system costs become viable. However these could still be contracted as infrastructure assets.
• Cost inflation: a small group of OEMs – GE, Siemens and ABB – dominate supply. Cost inflation is already a reality, with 20-30% cost increases since 2023. A credible risk is that increasing lead times and costs erode the returns as demand increases.

Conclusion

The lesson of the Iberian blackout is that TSOs need to be more proactive in developing grid resilience. For investors and IPPs, the punchline is simple: syncons will sit alongside BESS as a distinct, contracted grid stability product in ever more markets.
A number of syncon investment opportunities will reach investors in the coming year. Their uncorrelated contracted revenues help rebalance the ever increasing merchant exposure in renewable portfolios, or accompany contracted BESS platforms. Valuing these is straightforward, but a strong advisory suite is critical to accurately pricing the merchant tail on these assets. The locational dynamics are fundamental to value, and an informed advisor knows these before commercial DD costs are incurred. This is where Opus’ syncon expertise and experience is of value in optimising competitive but prudent bids.