Batteries and Flexible Demand Are Eroding European Power Market Transparency, Montel Says
Growing behind-the-meter storage and price-responsive load are obscuring the wholesale signals European traders rely on for short-run price discovery.
Europe's power markets are losing visibility as batteries and flexible demand take an expanding share of grid activity, according to a Montel analysis published Wednesday (2026-09-23) by Andre Bosschaart, head of analytics at Montel. Growing volumes of price-responsive assets are making European energy markets less transparent. They dispatch in ways that do not surface in the public data feeds underpinning short-run price formation.5
Bosschaart grounded the observation in Dutch terms. The Netherlands, he noted, is known for its large front windows and open curtains. The cultural image of openness sits awkwardly alongside a power market where an expanding share of consumption and storage capacity operates behind meters, outside the visibility of public price data. Dutch power day-ahead priced at €195.07/MWh in Wednesday's (2026-09-23) auction, with German day-ahead at €210.07/MWh. Neither cleared price captures what flexible assets below the public market layer actually did.5
Europe spot prices spiked above EUR 500/MWh on June 17 (2026-06-17) during a period of low wind output, Montel reported. How behind-the-meter storage behaves in the next tight-supply episode has direct consequences for whether future spikes of that magnitude moderate or intensify. That dispatch decision does not surface in current public reporting frameworks.3
TenneT, the Dutch transmission system operator, described the broader grid situation as "a crisis in slow motion" at POLITICO's Energy and Climate Forum on Monday (2026-06-01), warning that the energy transition was outpacing the ability to expand and reinforce networks. Distributed flexibility can ease physical congestion. But it does so without the transparency that day-ahead and intraday market participants need to price risk.2
Commercial storage volumes are now large enough to register. Ore Energy, the Netherlands-based iron-air storage company, agreed in June (2026-06-22) to deploy 1 GWh of long-duration storage with Budget Thuis, one of the largest Dutch energy suppliers, in what the company described as the largest iron-air energy storage agreement globally. Iron-air systems cycle over multiple days rather than intraday windows, meaning their effect on cleared prices falls outside patterns that most day-ahead forecast models are built to capture.4
Solar adds a parallel layer of opacity. Montel EnAppSys director Jean-Paul Harreman observed on Thursday (2026-04-30) that a forecast solar surge over a bank holiday weekend might trigger a first-ever downward adjustment to the spot power price floor. Behind-the-meter solar reduces metered grid demand without appearing in published generation forecasts, compressing the spread between expected and cleared prices in ways that only become apparent after settlement.1
ICE Endex TTF front-month gas fell to €72.30/MWh on Wednesday (2026-09-23), down 1.45% on the session. That reference price anchors the fuel-switching calculation for thermal generation. Yet it says nothing about how flexible demand-side assets will charge or discharge across individual delivery hours, the dimension of the supply-demand balance that public order books are increasingly unable to reflect.5
For traders active in Dutch and German intraday and day-ahead markets, the practical consequence is growing uncertainty in residual load forecasts, the number that sets short-run prices. Settlement data eventually captures flexible dispatch, but only in arrears. Whether European regulators move to require real-time reporting from large batteries and demand-response aggregators, or whether commercial aggregators voluntarily disclose, sets the pace at which the blind spot closes. Every new GWh of long-duration storage commissioned in the Netherlands or elsewhere widens that blind spot a little further until those disclosure requirements arrive.5,4