Review of Large City & Metropolitan Area Power System Development Trends

Considering New Generation, Grid and Information Technologies

Introduction

Urbanization is reshaping global energy demand. As more people move into Large Cities and Metropolitan Areas (MA&LC), these regions become dense hubs of economic activity—and of electricity consumption.

Power systems that support these critical urban centers face unique challenges:

• Increasing load concentration
• A need for higher reliability and resilience
• Integration of renewable and distributed generation
• Aging infrastructure
• Short circuit limitations
• Space constraints for grid expansion

The 2024 CIGRE Technical Brochure 922 provides an in-depth review of how MA&LC power systems are evolving to meet these challenges through new technologies and coordinated planning.

Defining Large City and Metropolitan Area Power Systems

Metropolitan Area (MA) power systems support a capital or major city with >3 million residents and >5 GW peak load. They include the urban core and surrounding suburbs and rural zones tied economically to the city.
Large City (LC) power systems support dense urban areas with >1 million residents and >2 GW peak load.

Both systems must deliver sustainable, resilient electricity in environments with limited physical space and increasing decarbonization pressures.   

These are key considerations in our Power System Studies service.

Key Development Trends and Drivers

1. Energy Transition and Carbon Neutrality

MA&LC power systems are at the forefront of the global energy transition:

• Moving away from fossil fuel-based generation
• Electrification of heating and transportation
• Integrating renewable energy and storage
• Examples include London’s gas phase-out and New York’s EV infrastructure—placing new demands on urban grids.
  

2. Space Constraints in Urban Environments

Urban environments lack space for traditional infrastructure expansion:

• Use of underground cabling
• Deployment of GIS substations
• Compact grid components

This mirrors design considerations found in Substation Design projects.

3. Coordinated Planning Across Stakeholders

Modern grid planning involves:

• TSO and DSO coordination
• Municipal energy policies
• Transport electrification
• Distributed generation and storage

City-driven climate mandates now shape long-term utility investments.

4. Short Circuit Current Management

Meshed grids in urban centers require advanced solutions:

• Fault current limiters (FCLs)
• Optimized topology
• Smart breakers

Examples from Bangkok and New York City highlight innovations in this space.

5. Replacement of Aging Infrastructure

Most urban infrastructure dates back to mid-20th century. Upgrades focus on:

• Resilience
• Digitalization
• Compact substations (GIS, GIL)
  

Power System Technologies for MA&LC

1. Renewable Energy, DG, and Storage

Urban systems increasingly use:

• Rooftop solar, wind farms, BESS
• Microgrids for resilience

This aligns with our expertise in Utility-Scale Battery Storage and RES integration.

2. HVDC and FACTS Integration

Used to manage:

• Power flow
• System stability
• Inter-regional supply

Projects like NYC’s Champlain Hudson Express demonstrate this trend.

3. Underground Infrastructure

Adopted technologies include:

• Gas-insulated lines (GIL)
• High-Temperature Superconducting (HTSC) cables
• Underground substations (e.g., Tokyo, Paris)
  

4. Smart Grid and Demand Response

Digitalization enables:

• Smart meters
• Active network management (ANM)
• Large-scale demand response

5. Fault Current Limitation Technologies

To handle short-circuit issues:

• Superconducting Fault Current Limiters (SFCL)
• Grid segmentation
• Optimized protection systems

6. Electric Vehicle Integration

EVs increase peak demand—mitigated through:

• Smart charging
• Vehicle-to-grid (V2G) systems
  Urban planning must now incorporate these dynamics.
  

Reliability and Resilience

Blackout Mitigation

Urban centers have seen major blackouts. Strategies include:

• Grid resilience planning
• Enhanced local generation
• Storage integration
  

Planning and Coordination Best Practices

Cities like Rome, Toronto, and Moscow integrate resilience into their master grid planning. This reflects our national focus on advanced NERC Compliance strategies.

Conclusions

The evolution of MA&LC power systems is driven by:
✅ The global energy transition
✅ Decarbonization mandates
✅ Urban resilience imperatives
✅ Digitalization and demand response



To meet these demands, stakeholders must adopt:

• Integrated planning
• Advanced technologies (HVDC, FACTS, BESS)
• Compact, modular infrastructure
• Coordinated strategies aligned with national reliability standards

Frequently Asked Questions (FAQ)

1. What is an MA&LC power system?

A grid system serving >1M or >3M residents in urbanized environments, often with complex demands and high resilience expectations.

2. What are the key challenges in MA&LC power systems?

• Aging infrastructure
• Limited space for expansion
• Short circuit current management
• Resilience against extreme events
• Integrating renewables and storage

3. How do cities manage space constraints for power grids?

• Underground cables (HV and UHV)
• GIS substations
• GIL and HTSC cables
• Underground substations

4. Why is coordinated planning important?

It ensures that city energy policies (EV adoption, heating electrification) are aligned with grid capabilities and investment plans.

5. How are cities integrating renewable energy?

• Rooftop PV
• Suburban wind
• Offshore wind (NYC, London)
• Microgrids and BESS

6. What role does HVDC play?

HVDC provides efficient long-distance power transmission and helps manage cross-regional flows into dense urban centers.

7. What are FACTS devices used for?

FACTS improve grid stability, control power flows, and mitigate voltage/reactive power issues.

8. What is the impact of EV adoption on urban grids?

EVs add significant peak loads; smart charging and V2G help manage this impact.

9. How is fault current managed?

With FCLs, optimized grid topology, and advanced protection systems.

10. What is Active Network Management?

ANM allows dynamic control of loads, generation, and grid assets to optimize performance.

11. What is the role of BESS in MA&LC grids?

BESS provides grid flexibility, peak shaving, and fast response capabilities.

12. How do cities handle voltage rise issues?

Using reactive power compensation devices (SVC, STATCOM, synchronous compensators).

13. What is a GIS substation?

A compact substation using gas-insulated switchgear, ideal for space-constrained environments.

14. How does underground cabling affect grid design?

It reduces visual impact and land use but requires careful management of reactive power and fault levels.

15. Why is resilience planning critical?

Urban grids must withstand extreme weather, cyber threats, and other disruptions with minimal downtime.

16. What are non-wires alternatives?

Solutions like DERs, demand response, and BESS that defer traditional grid investments.

17. How does distributed generation impact fault levels?

It can raise local fault current, requiring advanced management solutions.

18. What technologies help manage short circuit levels?

• FCLs
• SFCLs
• HVDC back-to-back
• Grid reconfiguration

19. What are city-specific decarbonization strategies?

• Heat electrification (London, NYC)
• Electrified transport
• Integrated RES deployment

20. What software is used for planning urban grids?

Commonly used tools include PSS®E, CYME, and local proprietary tools.

Is your city or utility preparing for a resilient and decarbonized future?

Contact Keentel Engineering to consult with our experts on advanced transmission and urban grid solutions across the U.S.