Black start controls for energy storage
What is black start?
Restart the grid. Restore the load.
Black start is the ability to restart part of the power system after a total blackout, without any outside supply. A black start resource energizes a dead bus on its own, then power flows out along a planned cranking path to restart larger plants and pick up load in islands, until the islands are synchronized back into one grid.
Why batteries, why now
Traditional units are retiring
Hydro, gas and coal units have long restarted the grid. As they retire or are repurposed, operators need new restoration resources, and NERC and FERC are now studying black start availability and readiness.
Fuel is a single point of failure
Gas-fired black start units depend on fuel that can fail in extreme weather. A battery needs no fuel delivery, and NERC notes battery black start adds diversity and remote operation.
Restoration is harder than it looks
Restarting a grid means forming stable islands and synchronizing them. In Iberia some black start units struggled to start, and Chile's February 2025 blackout saw synchronization problems at black start units.
Batteries reach further
Grid-forming batteries ramp voltage up gradually, energizing transformers without tripping protection. CSIRO found they can energize far larger areas of network than an equivalent synchronous generator.
| Conventional black start unit | Grid-forming battery + Fractal EMS | |
|---|---|---|
| Fuel | PJM: 16 h full-load fuel assurance | None; restart energy held in reserve |
| Energizing the network | Sudden transformer inrush | Soft-start voltage ramp, staged energization |
| Operation | Often needs crews on site | Started and sequenced from the control room |
| Emissions | Combustion during restart | Zero at the point of use |
| Everyday value | Idle until needed | Earns market revenue between events |
Black start around the world
Restoration standards are tightening
Restoration standards are tightening at the same time as traditional black start units retire. Grid operators are opening black start and restoration services to storage, and India will require black start capability from new large batteries.
| Market | Status | Requirement or service | Timing |
|---|---|---|---|
| India CEA | Required | BESS of 50 MW or more: grid forming, black start and AGC | From Apr 2027 |
| Great Britain NESO | Paid service | Restoration Standard: 60% of regional demand in 24 h, 100% national in 5 days; technology-neutral tenders | Standard by end 2026 |
| Germany | Paid service | Market-based black start procurement by the four transmission operators; 887 MW contracted in 2025 | Regional tenders 2024–2028 |
| Chile CNE | Defined | All storage grid forming; black start optional, with technical requirements for units that offer it | From Aug 2026 |
| Australia AEMC / AEMO | Standard + trial | New System Restart Standard (islands within 2 h); AEMO trial of black start from inverters | From Jul 2027 |
| PJM | Paid service | Monthly black start payments; qualification rules added for battery storage and hybrids | In force |
| CAISO | Paid service | Competitive black start solicitations; battery-assisted gas plant selected | In force |
| ERCOT | Paid service | Black start procured by RFP every three years | 2027–2029 RFP |
| NERC EOP-005 | Required testing | Black start resources in restoration plans, tested at least every 3 years | In force |
| European Union | Required / proposed | Critical tools 24 h without primary power; experts recommend black start tests every 3 years | In force / proposed |
Status as of October 2026. Summary of public information from grid operators and regulators; not legal advice.
2023 · Scotland
The Distributed ReStart trial used an 8 MW grid-forming battery to energize a 132 kV line, pick up load in blocks and resynchronize.
2026 · Chile
A 228 MW / 912 MWh battery in the Atacama Region, with Fractal EMS controls, is designed for grid forming and black start.
Built for the codes your plant answers to
Black start obligations fall on the plant owner and the system operator. We document to these standards.
NERC EOP-005
Restoration plans, cranking paths, black start resources tested every three years.
Grid codes
Great Britain, EU, Australia, India and Chile restoration and black start rules.
Market qualification
PJM, CAISO, ERCOT and Germany: run-time and test evidence.
Controls standards
Aligned with IEEE 2030.7 and verified by IEEE 2030.8 tests.
Our own posture
ROC run to NERC CIP Medium; ISO 27001; engineered to NIST 800-53 and IEC 62443.
Evidence by design
Every black start test and real event captured at 50 samples per second.
How a battery restarts the grid
Eight steps, programmed in the Site Controller
The grid-forming PCS creates the voltage; Fractal EMS runs everything after it, from the ride-through alarm to the reclose at the point of interconnection.
Energy in reserve, revenue every day
Fractal EMS holds a state-of-charge floor for black start while the plant earns market revenue the rest of the time.
Proven at a black start test bed in Texas
At a battery manufacturer's test bed in Texas, Fractal EMS performed the full sequence: two 4.2 MVA grid-forming PCS units and a 5 MWh ESS black started, formed a 34.5 kV island, energized test units in stages and resynchronized to the utility.
Black start challenges, solved
A battery that can form a grid is not automatically a battery that can restart one. These are the problems that decide whether a black start succeeds, and how Fractal EMS handles each.
Transformer inrush
Soft-start voltage ramps and staged energization keep inrush within inverter current limits.
Cold load pickup
Load is restored in blocks sized to available current and state of charge; non-critical load waits.
Many inverters, one island
Coordinated start-up, load sharing and SOC balancing across every unit on site.
Energy held in reserve
SOC floors keep restart energy available while the plant earns market revenue the rest of the time.
Protection and stability
Island voltage and frequency are monitored continuously, with load shedding if limits are threatened.
Aux power and comms
Local controllers on backup power keep sequencing running even when the WAN is down.
Case study · Atacama Region, Chile
The designated black start resource for a hybrid plant
One of Chile's largest battery systems is being added to a solar park. The BESS has to restart the plant, hold the island and hand it back to the grid cleanly, while answering national dispatch the rest of the year. Chile's rules also require storage to be grid forming and set requirements for any unit offering black start.
In execution COD targeted December 2026
Proven experience
| Project | System | Application | Status |
|---|---|---|---|
| Utility-scale hybrid plant Atacama Region, Chile | 228 MW / 912 MWh BESS with 232 MW solar PV | Black start and grid forming | In execution |
| Black start test bed Texas | 2 × 4.2 MVA PCS, 5 MWh ESS | Black start, island formation and sync-check reconnection | Completed |
One platform, every layer
One controls platform for every black start plant
One stop shop
We design, supply, program, integrate and commission the whole delivery, from black start studies to witnessed testing, with a single point of accountability for the entire controls scope.
Fractal EMS value propositions
Why Fractal EMS for black start
Fractal provides everything a black start plant needs above the inverter, from restoration studies to the equipment, the software and witnessed testing.
Restoration-plan ready
Engineered around the restoration plan and cranking path, with documented procedures and periodic testing.
Hardware-agnostic integration
We know which PCS firmware supports dead-bus start and sync-check transfer.
Model-verified sequences
Inrush, load pickup and island stability studied in PSS®E, PSCAD and DIgSILENT PowerFactory.
Resilience plus revenue
Reserve restart energy while dispatching into markets, and qualify for paid black start services.
Local control, remote operation
Sequences run on site with no cloud dependency, started from the control room and our 24/7 ROC.
Every test and event captured
High-speed capture at 50 samples per second for grid operators, audits and warranty claims.