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Utility-scale energy storage

Hours at zero and hours at record prices. Every day.

That volatility is revenue if you have somewhere to store the energy. We integrate multi-MWh standalone BESS that buy when there is surplus, sell when there is shortage and get paid for being available. From the container to the market EMS.

Discuss a projectHow it works
Utility-scale energy storage
Project size
5–188 MWh
Per Powerbolt container
5.015 MWh
Cycles per LFP cell (to 70%)
8,000

The problem

The grid needs flexibility. And it pays for it.

The more renewables enter the system, the more valuable the hours of energy shortage and the ability to respond fast become.

  • Day-ahead prices swing more than ever: hours at zero at midday and peaks as the sun goes down.
  • The system operator needs more balancing reserve that responds within seconds and minutes.
  • A standalone BESS has no regulated remuneration: it lives off the market, so the operating strategy determines profitability.
  • Above 5 MW you must integrate with a control centre and send real-time telemetry to REE (RD 917/2025).
of hours in 2024 with a price below €10/MWh.
26%
of days in 2024 with at least one price above €90/MWh.
25%
of days in 2024 with a spread of more than €50/MWh between hours.
68%
our largest system, in Lianyungang (China).
188MWh

94 MW · Powerbolt containers.

Source: BK analysis of Spanish day-ahead market prices (OMIE), 2024.

How a BK BESS solves it

One battery, multiple revenue streams.

BK EMS stacks revenue: each day it decides how much energy to devote to arbitrage, how much power to offer the system operator and how much to keep firm.

  1. 01

    Day-ahead and intraday arbitrage

    Buys in the cheap hours, sells in the expensive ones, and re-optimises in the intraday market.

  2. 02

    Balancing services: aFRR and mFRR

    Secondary and tertiary frequency control: the battery follows REE setpoints within seconds, faster than any thermal plant.

  3. 03

    Capacity mechanism

    Revenue for firm capacity available when the system needs it.

  4. 04

    System operator compliance

    PPC, real-time telemetry and attachment to a control centre, as required by RD 917/2025.

OMIEDay-ahead · intradayREEaFRR · mFRRCapacityFirm capacityBK EMS MAXStandalone BESSSoC55 %GridSubstationHourly price on a typical daybuyssale00h06h12h18h24h
  • Charging from the grid
  • Discharging to the grid
  • Market and system operator signals

Illustrative diagram. Bars: typical shape of the hourly price; the battery charges in the cheapest hours and sells in the most expensive, and in between it can reserve power for balancing services.

Storage Analytics

How much does a battery earn in Spain? Every day.

Day-ahead market prices, hourly spreads and estimated battery revenue, using public data from OMIE, ESIOS and REE.

Open Storage Analytics

Also: microgrids and communities

Energy shared between several consumers and generators. BK EMS shares, stores and manages the community's energy.

Enquire

Recommended products

What we solve it with.

The full range

Powerbolt

3.34 – 6.25 MWh

20-foot containers with 314 or 587 Ah LFP cells and liquid cooling. Combined in blocks up to tens of MWh.

View product

Racks and packs

172–373 kWh

For bespoke integrations in a plant room or container.

View product
EMS · ONLINE72%

BK EMS Max

EMS · PPC · SCADA

Price forecasting, market strategy, point-of-connection control and system operator compliance.

View product

References

Already up and running.

All projects

BESS system

Lianyungang (China)

188MWh

94 MW · Powerbolt

BESS system

Luoyang (China)

20MWh

Powerbolt

BESS system

Toledo

10MWh

5 MW

References for completed installations: location, energy and power.

Frequently asked questions

What people ask us before deciding.

What battery duration makes sense?
For day-ahead arbitrage in Spain, 2- to 4-hour systems are typical; if the balancing market is the priority, the power-to-energy ratio changes. We set it with simulations on real prices.
What are aFRR and mFRR?
They are balancing reserves managed by REE. aFRR (secondary frequency control) activates automatically within seconds to correct imbalances; mFRR (tertiary control) activates within minutes. Activated energy is remunerated and, for aFRR, so is the reserved capacity band.
How long does a battery of this size last?
The 314 Ah LFP cells are specified for 8,000 cycles to 70% state of health (0.5P, 25 ± 2 °C). BK EMS manages depth of discharge and temperature to extend that service life.
What are my obligations to REE?
Above 5 MW (0.5 MW in non-mainland territories): attachment to a control centre and real-time telemetry, as required by RD 917/2025. Our EMS complies with UNE-EN IEC 62933, UNE-EN 50549-10 and the REE grid codes.
Which part of the project do you handle?
All of it, if you need: feasibility and financial model, engineering and permitting, supply and integration, EPC construction, commissioning and operation with BK EMS. A single point of contact.

Do you have a point of connection?

We help you size the system, build the revenue model and deliver it turnkey.

Talk to our engineersView products