Author: Derek Michalski, Editor.
Part I can be viewed here
Part II: Why This Auction Could Redefine Europe’s Flexibility Market
When Portugal opens bidding for more than 1 GW of battery storage this September, the government will officially be procuring electricity infrastructure. In reality, however, it will be testing something much bigger.
The auction will become one of Europe’s first large-scale attempts to answer a question that every electricity system is now facing: how should governments encourage investment in flexibility once renewable energy becomes the dominant source of generation?
For years, policymakers focused on building wind farms and solar parks as quickly as possible. That strategy has been remarkably successful. Portugal now produces a substantial share of its electricity from renewable sources, while periods of exceptionally high renewable generation are becoming increasingly common.
Yet the success of renewable deployment has exposed a new constraint.
Electricity systems increasingly need assets capable of absorbing surplus generation, responding within seconds to fluctuations in supply and demand, and supporting grid stability during periods when conventional power stations are operating less frequently.
Storage is no longer an optional addition to renewable energy. It is becoming one of the foundations upon which high-renewable electricity systems will operate.
A Different Conversation After the Iberian Blackout
Portugal’s storage ambitions did not emerge overnight. Battery deployment had already become part of the country’s long-term energy planning.
However, the widespread power outage that affected Portugal and Spain on 28 April 2025 changed the political narrative surrounding electricity security.
Although investigations continue to examine the sequence of technical events, the blackout demonstrated how rapidly disturbances can propagate across highly interconnected electricity systems.
For policymakers, the lesson extended beyond the specific causes of the incident.
The resilience of future electricity systems will depend not only on generation capacity but increasingly on fast-response technologies capable of balancing supply, maintaining frequency stability and supporting network recovery after unexpected events.
Battery storage cannot prevent every blackout. It is not designed to replace transmission infrastructure or conventional system protection. But strategically deployed storage can significantly improve operational flexibility and strengthen the overall resilience of modern power systems.
That reality is shaping investment priorities across Europe.
Developers Are Competing for More Than Capacity Contracts
Portugal’s auction is expected to attract interest from many of the companies already active across Europe’s renewable energy sector.
Established Iberian utilities are well positioned thanks to existing development pipelines, grid connection experience and extensive renewable portfolios that could be paired with storage.
International independent power producers are also expected to participate, viewing Portugal as one of the continent’s most attractive emerging battery markets.
Alongside them will be a growing number of specialist battery developers and infrastructure investors whose business models focus almost entirely on storage assets rather than electricity generation.
For these companies, the auction represents more than a procurement opportunity.
It offers an early chance to secure positions in a market that is likely to expand significantly throughout the remainder of the decade.
As more renewable generation enters Portugal’s electricity system, the commercial value of flexibility is expected to increase accordingly.
Winning the Auction Is Only the Beginning
Securing capacity support does not automatically guarantee attractive project economics.
Battery developers must still navigate construction costs, equipment procurement, financing, network connection timelines and long-term operational performance.
Revenue stacking remains essential.
Beyond any support secured through the auction itself, operators are expected to rely on multiple income streams including wholesale electricity arbitrage, balancing services, ancillary markets and congestion management where available.
The ability to combine these revenue sources efficiently is increasingly becoming one of the defining competitive advantages within Europe’s battery sector.
In many respects, developers are evolving from renewable energy companies into sophisticated operators of flexibility assets.
Investors Are Looking Beyond Portugal
Institutional capital has become increasingly comfortable financing battery storage across Europe.
As technologies mature and operational experience expands, infrastructure funds, pension investors and specialist energy financiers are treating battery assets as an increasingly mainstream infrastructure class.
Portugal therefore enters the market at an advantageous moment.
Battery costs have fallen dramatically over the past decade while financing conditions for well-structured storage projects continue to improve.
At the same time, governments are recognising that private investment alone may not deliver storage deployment quickly enough to meet national decarbonisation targets.
Competitive auctions are emerging as a mechanism to reduce investment uncertainty while maintaining market discipline.
Part of a Much Bigger European Shift
Portugal is not acting in isolation.
Across Europe, governments are experimenting with different approaches to accelerate investment in flexibility.
Italy is developing its long-term MACSE procurement mechanism for electricity storage.
Germany continues to rely largely on merchant investment supported by increasingly attractive balancing markets.
Spain is expanding storage deployment through a combination of incentives and hybrid renewable projects.
The United Kingdom has built one of Europe’s most mature battery sectors through participation in multiple electricity markets, including the Capacity Market.
Despite these differences, the underlying objective is remarkably consistent.
Every country is attempting to solve the same problem: how to operate electricity systems where renewable generation increasingly becomes the default rather than the exception.
The Risks Remain Significant
Despite growing optimism, battery investment remains far from risk-free.
Grid connection delays continue to affect projects across much of Europe.
Market revenues remain volatile, particularly as more storage assets compete within balancing markets.
Technology continues to evolve rapidly, raising questions about long-term asset competitiveness and replacement cycles.
Meanwhile, regulatory frameworks continue to adapt as policymakers refine market rules for flexibility services.
Perhaps the greatest uncertainty is that electricity markets themselves are changing.
The commercial strategies that prove successful today may require significant adjustment before the end of the decade.
For developers, adaptability may become just as valuable as technical expertise.
The Next Phase of the Energy Transition
Portugal’s September auction is important not because it is Europe’s largest battery procurement programme.
Larger initiatives are already under way elsewhere.
Its significance lies in what it represents.
For much of the past two decades, success in renewable energy was measured primarily by installed generation capacity.
That era is ending.
The next phase of Europe’s energy transition will increasingly be measured by the ability of electricity systems to integrate renewable generation efficiently, maintain stability under rapidly changing operating conditions and provide reliable electricity regardless of weather patterns.
Storage sits at the centre of that transformation.
The countries that develop effective market frameworks for flexibility today are likely to become the leaders of tomorrow’s low-carbon electricity systems.
Portugal’s auction is therefore more than a national procurement exercise.
It is an early indication of how Europe intends to build the electricity system of the 2030s – one in which batteries, digital technologies and flexible resources are no longer supporting renewable energy but enabling it.
