Ancillary Services: Balancing Energy with Battery Storage

Earn from grid stabilization. Your battery storage delivers balancing energy for Swissgrid and generates predictable revenue. Fully automated, around the clock.

What Are Ancillary Services?

Ancillary services ensure the stability of the Swiss power grid. Swissgrid, the national grid operator, procures balancing energy from approved providers. Whenever generation and consumption in the grid are not in balance, balancing energy is activated to keep the frequency at 50 Hz.

Battery energy storage systems (BESS) are particularly well suited for ancillary services. They respond to frequency deviations in milliseconds, can both absorb and deliver energy, and provide exactly the required power. Compared to conventional power plants, BESS is faster, more precise, and more flexible.

FCR and aFRR

The most important ancillary service products for battery storage are FCR (Primary Control Reserve, activation within 30 seconds) and aFRR (Secondary Control Reserve, activation within 5 minutes). Both are tendered and compensated by Swissgrid.

Frequency Regulation with BESS Tolerance band 50.000 Hz Hz Time Without BESS With BESS (stabilized)

Why Battery Storage for Ancillary Services?

Conventional power plants need minutes to adjust their output. Battery storage responds in milliseconds. For frequency regulation, this speed is decisive: the faster the response, the less balancing energy is needed overall, and the more stable the grid remains.

BESS can operate symmetrically, meaning it can both feed in and absorb energy. This flexibility makes battery storage ideal for ancillary service provision. Additionally, the entire control runs automatically via the energy management system (EMS). No manual intervention required.

Multi-Use Strategy

A storage system providing ancillary services can simultaneously perform peak shaving, self-consumption optimization, or arbitrage during call-free periods. The intelligent control automatically maximizes overall revenue.

Response Time: BESS vs. Conventional 0 ms 100 ms 1 s 30 s 5 min Time after frequency deviation BESS Full power in <100 ms Gas turbine Minutes Hydropower Seconds Faster = less balancing energy needed = more stable

Three Benefits at a Glance

24/7

Automated Participation

The energy management system controls ancillary service delivery fully automatically. The battery storage responds to frequency deviations in milliseconds and delivers exactly the required balancing power.

CHF

Attractive Compensation

Participation in the ancillary services market generates predictable revenue. Swissgrid compensates both the reservation (capacity price) and the activation (energy price) of balancing energy.

Multi

Combinable with Other Use Cases

Ancillary services can be intelligently combined with peak shaving, self-consumption optimization, or arbitrage. The EMS automatically prioritizes the most economically advantageous application.

From Prequalification to Marketing

FCR (Primary Control Reserve)

Frequency Containment Reserve: The storage responds within seconds to frequency deviations in the European interconnected grid. Full activation within 30 seconds. BESS is ideally suited for this, as response time is in the millisecond range.

aFRR (Secondary Control Reserve)

Automatic Frequency Restoration Reserve: Automatic activation by Swissgrid within 5 minutes. The storage follows the setpoint signal and restores grid frequency. Compensation via capacity and energy prices.

Prequalification by NRG

NRG Solutions handles the entire prequalification process with Swissgrid. From technical documentation through verification tests to approval. You do not need to deal with the regulatory requirements.

Marketing and Pooling

NRG bundles storage capacities and markets them as a pool on the ancillary services market. Even smaller storage systems can participate in the balancing energy market this way. Revenue optimization is handled automatically by the EMS.

Find all use cases in detail on our use cases page.

Is ancillary service provision right for your storage?

Together we assess whether your location meets the requirements for ancillary service participation.

Or directly:

Headquarters

NRG Solutions AG
Platz 4
6039 Root D4

Branch Office

Rue des Moulins 51
2000 Neuchâtel
30 minutes, free & non-binding. Online via Microsoft Teams.

Member of

VSEAEE SuisseSwiss CleantechIHZNELUCNCIEnergie HubNachhaltigkeitsnetzwerk

Frequently Asked Questions

Ancillary services ensure the stability of the power grid. Swissgrid procures balancing energy (FCR, aFRR, mFRR) to keep the grid frequency at 50 Hz. Battery storage is particularly well suited for ancillary services because it responds in milliseconds and can both absorb and deliver energy.

Prequalification involves technical documentation, verification tests, and formal approval by Swissgrid. NRG Solutions handles the entire process: from preparing the documentation through conducting the tests to successful approval. The storage must meet defined requirements for response time, accuracy, and availability.

Revenue depends on the ancillary service product, market conditions, and storage size. Compensation consists of a capacity price (for reservation) and an energy price (for activation). By combining with other applications such as peak shaving or arbitrage, the overall return on the storage can be further increased.

Yes. An intelligently controlled battery storage can serve multiple applications simultaneously. The energy management system automatically prioritizes deployments: ancillary service calls typically take precedence, while peak shaving, self-consumption optimization, or arbitrage run during call-free periods.

Swissgrid sets minimum requirements for direct participation in the ancillary services market. Through pooling, i.e., bundling multiple systems, even smaller storage units can participate. NRG Solutions assesses in the initial consultation whether your storage meets the requirements or can be integrated into an existing pool.

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