Benefits of interconnecting regional utilities

Interconnection of regional utilities means linking the grids of two or more regions or countries by tie-lines so that power can flow between them and they can operate in synchronism (or through HVDC links).

Benefits

1. Reduced reserve requirement: The utilities can share spinning and standby reserve. Since the chance of large outages occurring in both at the same time is low, total installed reserve is less than the sum of separate reserves.
2. Higher reliability and security: If one region loses a large unit or line, power flows in from the neighbour, avoiding load shedding and blackout.
3. Use of load diversity: Peaks of different regions occur at different times (time zones, climate, consumer type), so combined peak demand is less than the sum of individual peaks; less capacity is needed.
4. Economic dispatch over a wide area: Cheaper plants (e.g. hydro) in one region can replace expensive thermal plants in another; production cost falls.
5. Seasonal exchange: A hydro-rich region with wet-season surplus can export, and import in the dry season. Example: Nepal–India interconnection (Dhalkebar–Muzaffarpur 400 kV) lets Nepal export surplus ROR energy in monsoon and import in winter.
6. Larger, more efficient units: A large grid can absorb bigger units, which have lower cost per kW.
7. Better frequency stability: Larger combined inertia reduces frequency deviation after a disturbance.
8. Integration of renewables: Variable solar and wind are smoothed over a larger area and balanced by hydro in other regions.
9. Power trading: Creates a regional electricity market and revenue (e.g. BBIN power trade).

Points to manage

Tie-line power control, faults spreading between areas, need for coordinated protection, and commercial agreements.