Short Term Operating Reserve (STOR): Supporting Grid Stability with Standby Power
A contracted service where a provider delivers a contracted level of power to the National Grid.
Short Term Operating Reserve (STOR) is a demand-response service where generators, battery storage systems, or flexible power plants provide extra power to the National Grid during periods of unexpected demand spikes or generation shortfalls. STOR ensures grid stability by supplying rapid-response electricity when required.
Why Is STOR Important?
Balancing Supply and Demand
- Helps the National Grid maintain frequency stability when demand exceeds supply.
- Provides reserve power when renewable sources (like wind and solar) fluctuate.
2. Supporting Emergency and Peak Demand Situations
- Activated during power plant failures, sudden demand surges, or extreme weather events.
- Typically required during early evenings and winter months when energy usage is highest.
3. Enabling Revenue Generation for Power Providers
- Businesses with standby generators, battery storage, or small power plants can earn revenue by providing power to the grid when needed.
- Participants receive availability payments (for being on standby) and utilisation payments (for actual power delivery).
How Does STOR Work?
- Contracting – The National Grid contracts STOR providers for a specific power capacity.
- Availability Periods – Providers agree to be on standby at designated times.
- Activation – When demand increases, the provider is instructed to supply power (usually within 10 minutes to 2 hours).
- Power Delivery – The provider supplies electricity for a set duration (often 30 minutes to 2 hours).
- Payment & Settlement – The provider receives payments based on availability and energy supplied.
Who Can Participate in STOR?
STOR is open to a variety of power generators and storage systems, including:
| Type of Provider | Common Use Cases |
|---|---|
| Diesel & Gas Generators | Standby power in industrial & commercial facilities |
| Battery Storage Systems | Grid-scale energy storage & renewable backup |
| Flexible Gas Peaking Plants | Rapid-response power stations |
| Industrial & Commercial Sites | Businesses with backup generators |
STOR Requirements & Eligibility
To participate in STOR, providers must meet National Grid requirements, such as:
- Minimum power capacity – Typically 3 MW or more (smaller units can aggregate).
- Fast response time – Must be able to supply power within 10-20 minutes.
- Availability periods – Commitment to be on standby during peak demand hours.
- Reliable fuel supply – Diesel, gas, or battery storage must support extended operation.
Benefits of STOR for Generator Owners
- Additional Revenue Stream – Earn money for providing reserve power.
- Optimised Generator Usage – Avoid long periods of standby inactivity.
- Grid Stability Contribution – Help prevent blackouts and voltage fluctuations.
- Flexible Participation – Businesses can integrate existing backup power into the STOR scheme.
Conclusion
Short Term Operating Reserve (STOR) plays a crucial role in maintaining grid reliability and energy security. By contracting backup generators, battery storage, and flexible power plants, the National Grid ensures quick access to extra power when needed.
For businesses with standby generators, participating in STOR offers a valuable opportunity to earn revenue while supporting the national electricity network.
