Ancillary Services Market Size, Share & Growth Forecast (2026-2031)

The Ancillary Services Market is forecast to grow at a CAGR of 8.0%, reaching USD 17.64 billion in 2031 from USD 12.02 billion in 2026.

Ancillary services help to provide the operational flexibility that ensures the reliability and stability of electricity networks. These services are utilized by transmission and distribution operators to manage fluctuations in electricity demand, the availability of generation resources, transmission limitations, voltage behavior, and unanticipated disturbances affecting system performance.

Electricity generation and consumption need to be instantaneously balanced at all times, but due to disruptions in energy supply such as solar power intermittency, frequency regulation is one of the critical categories. According to California ISO, regulation energy keeps system frequency close to 60 Hz and requires resources that participate in the market to automatically respond to control signals.

Reserve services are extra generation or controllable capacity that can be turned on in response to contingencies. In California, spinning and non-spinning reserves are identified within the ISO's ancillary-service products, while voltage support and black start are procured as distinct reliability services.

The market is also getting more technology-neutral. This service was traditionally only supplied by fossil, hydro, and other classical generation. The growth of BESS, demand response, distributed generation, virtual power plants, and advanced inverter technologies is expanding the range of possible service providers.

Developing nations like India are creating a separate market for this. According to GRID-INDIA, its ancillary-services mechanism is intended to keep frequency near 50 Hz, bring frequency back within the acceptable band, alleviate transmission congestion, and assure safe and secure system operation.

Market Dynamics

Market Drivers

• Rise in Integration of Renewable Energy: As solar and wind generation proliferate, ancillary service needs rise commensurately since renewable output is dependent on the weather. With high renewable penetration, net load can change quickly and for multiple consecutive hours prior to an event requiring flexible resources to respond.

• Fast-tracking in Battery Energy Storage Systems (BESS): BESS is becoming one of the key enabling technologies driving ancillary services. Batteries can provide rapid power adjustment upward and downward, and participate in ancillary services such as frequency regulation, spinning and non-spinning reserves, renewable firming, congestion management, among others

• Increasing Demands of a Reliable and Resilient Grid: Factors such as extreme weather events, equipment failures, cyber risks, growing electricity demand, and more aging grid infrastructure are pushing utilities and system operators to fortify grid resilience. Ancillary services fulfil the role of ensuring sufficient reserves, as well as recovering electricity supply from a disturbance.

• Increasing Electricity Demand: Transportation, heating, industrial processes, and digital infrastructure are being electrified as well, leading to an increasing demand for electricity and more variable load profiles. Data centers and other facilities with large loads can create significant variation in demand in a very short time. This trend is putting a premium on flexible generation, storage, demand response, and other resources that can ramp output or consumption whenever needed by the grid operators.

• Expansion of Competitive Ancillary-Service Markets: Many electricity markets are implementing more structured mechanisms for procuring ancillary services. An example is ERCOT's 2026 ancillary-service methodology, which establishes minimum requirements for various reliability products, including a 1,377 MW minimum capacity requirement for Responsive Reserve Service with Primary Frequency Response.

Market Restraints & Opportunities

• High capital costs continue to be a key restraint, particularly for BESS, synchronous condensers, advanced power-electronic systems, black-start facilities, and grid-automation infrastructure.

• Volatility in project economics can also arise through revenue, as ancillary-service prices are market-specific and can adjust over a longer time frame as more flexible resources enter the market.

• Yet another constraint is the growing difficulty of coordinating thousands of disparate resources. Distributed assets must be able to respond reliably when dispatched, and aggregators and system operators need a communications and cybersecurity infrastructure that supports it.

• However, the market offers vast prospects for multi-service energy-storage systems. These applications can use a single BESS for frequency regulation, reserve services providing contingency and no-contingency reserves, renewable integration, congestion management, and energy arbitrage.

• Virtual power plants also create portfolio opportunities that can be made available to the market by aggregating batteries, flexible loads, EVs, distributed solar, and other resources together. Another factor is the development of grid-forming inverters, which presents an opportunity for inverter-based resources to provide some voltage and frequency stability in grids that are increasingly losing synchronous generation.

Key Developments

• July 2026: Aksa Energy commissioned the first standalone battery-energy-storage system in Türkiye and entered the ancillary-services market. In ?anl?urfa, the RASA facility featured 50 MW of operational power and 61.9 MWh of storage capacity.

• August 2025: CheckWatt integrated solar self-consumption, enabling all household customers with rooftop PV to participate in ancillary services. This functionality was rolled out automatically to customers employing the Currently Optimized operating mode, and could also be turned on by those operating in Self Consumption mode simply by updating their setting.

Market Segmentation

The market is segmented by service type, application, end user, and geography.

By Service Type: Frequency Regulation Services

Frequency regulation services demand is one of the services that will comprise a large portion of the ancillary-services market because generation-demand balance must be maintained in real time for any electrical system with connected loads.

Frequency regulation resources adjust their output or consumption automatically based on signals from system operators. Regulation is defined by CAISO as a service to which the certified resources respond automatically to control signals that direct them to raise or lower their operation levels.

BESS is increasingly supplying the segment because batteries can respond in both directions, and quickly. This trait proves especially beneficial in high-solar and wind-dominant markets.

Among its ancillary-service products, ERCOT has it structured to provide Regulation Up and Regulation Down, continuing designated requirements for regulation service.

Additionally, battery resources are participating in increasing numbers of regulation services markets since they can respond to dispatch signals multiple times while also remaining high power-control accurate.

By Application: Frequency Regulation & Grid Balancing

Frequency Regulation & Grid Balancing is expected to continue to be the largest application segment because ancillary services are essentially needed to continuously balance electricity generation and demand.

Regulation and reserve products allow system operators to correct deviations between the scheduled and actual generation or consumption of power. For instance, this necessity is reflected by CAISO's market framework, which includes Regulation Up, Regulation Down, Spinning Reserve, and Non-Spinning Reserve products.

ERCOT monitors Regulation Up, Regulation Down, Responsive Reserve Service, Contingency Reserve Service, and Non-Spinning Reserve as reliability products for the support of the bulk power system. Similarly, BESS is gaining in importance as a means of providing fast balancing response because it can support renewable-energy integration.

By End User: Transmission System Operators

Transmission System Operators segment is expected to dominate the market owing to their direct accountability for maintaining bulk-system reliability, generation and demand balancing, transmission constraints, and procuring various categories of ancillary services.

Ancillary services are used by transmission operators to maintain system frequency and balancing reserve requirements, as well as voltage conditions or controlled responses to unexpected generation or transmission outages.

CAISO directly procures ancillary services to support reliability within its controlled grid, and handles the resources through day-ahead, hour-ahead, and real-time processes. Likewise, the ancillary-service framework in GRID-INDIA also plays a crucial role in terms of providing support for frequency restoration and transmission-congestion relief.

Regional Analysis

North America Market Analysis

The North America region has an enormous, yet well-established ancillary-services market due to the presence of multiple organized wholesale electricity markets with clear procurement and settlement processes. The US has major organized market players like CAISO, ERCOT, ISO-New England, NYISO, PJM, and MISO operating variably combined sets of regulation, reserve, voltage, and reliability services.

South America Market Analysis

South America is a growing new ancillary-services market supported by a growing installed capacity of renewables and the need to complement existing interconnection and transmission networks. Brazil is the largest opportunity because its electricity system features a large hydroelectric generation base and quickly growing solar and wind capacity.

Europe Market Analysis

Europe is leading in the ancillary-services market because of high penetration of renewables, interconnection between various electricity systems, and a relatively sophisticated balancing market features. Major regional markets for frequency containment, reserve, balancing, and other system services are Germany, France, the UK, Italy, and the Nordic Countries.

Middle East and Africa Market Analysis

The Middle East & Africa market is growing with new generation and transmission and distribution infrastructure modernization. Saudi Arabia and the UAE are booming regional markets because of significant solar investments and long-term plans for modernization of electricity sectors.

Asia Pacific Market Analysis

Asia Pacific is anticipated to register rapid growth over the coming years owing to high electricity-demand expansion, massive renewable deployment, grid modernization, and growing energy storage investment. The largest regional market is China due to its immense electrical grid, fast-growing renewable resource base, and rising energy-storage system deployment.

List of Companies

• California ISO

• ERCOT

• ISO-New England

• NYISO

• Energinet

• Snowy Energy

• Transelectrica

• NESO

• GRID-INDIA

California ISO

California ISO, which operates the California electricity grid and a competitive wholesale electricity market. CAISO manages ancillary-service products such as Regulation Up, Regulation Down, Spinning Reserve, and Non-Spinning Reserve. Regulation resources track automated control signals to change their levels of operation in order to maintain system frequency.

ERCOT

The company monitors the bulk electricity system and wholesale electricity market for most of Texas. Regulation Up, Regulation Down, Responsive Reserve Service, Contingency Reserve Service, and Non-Spinning Reserve are part of its ancillary-service framework. ERCOT maintains a real-time dashboard on deployment and awards of its reliability products.

Transelectrica

Transelectrica is the operator of Romania's electricity transmission system and provides support for the country to integrate into the interconnected European electricity network. The firm also performs the transmission-system balancing and system-security tasks that require reserve capacity and other ancillary services.

Analyst View

The ancillary services market is transitioning from a generator-dominated reliability model to a dynamic flexibility ecosystem solution involving BESS, demand response, renewable generators, distributed energy resources, and digital aggregation platforms. Frequency Regulation remaining the leading service type category because constant generation-demand balancing is required for a grid to operate, while frequency regulation & grid balancing continue to remain the largest application. The most mature market structures are expected to be in North America and Europe, while Asia Pacific is poised for robust growth as China, India, Australia, and other nations continue to expand renewable generation and storage.

Ancillary Services Market Scope: