大型电互连_跨区域互联电网技术发展与展望（英文版）_34页_3mb

Summary of "Large-Scale Electricity Interconnection: Technology and Prospects for Cross-regional Power Networks"

Core Content

Large-Scale Electricity Interconnection is a report that outlines the technological, market, regulatory and policy measures needed to accelerate regional electricity interconnection. It aims to support the development of integrated power systems that are consistent with a clean energy vision, addressing the challenges and opportunities of cross-border electricity networks.

The report highlights the importance of electricity interconnection in enabling a low-carbon energy system, especially with the increasing deployment of variable renewable energy (VRE) such as wind, solar, and hydro. It also explores the role of new transmission technologies, such as high-voltage direct current (HVDC) and flexible alternating current transmission systems (FACTS), in supporting long-distance and flexible power transfers.

The report is structured into several sections, including an introduction, a detailed analysis of current and future interconnection technologies, case studies of regional interconnection efforts in Europe, the Americas, and Southeast Asia, and a discussion on the regulatory and market frameworks necessary for interconnection development.

Main Views

1. Interconnection as a Key Enabler for Clean Energy

• Interconnection supports the integration of VRE by balancing supply and demand across regions.
• It allows for the smoothing of seasonal and daily peak-load variability.
• It reduces the need for new generation capacity by optimising existing resources.

2. Technology Needs for Future Interconnection

• Role #1: Low-cost interconnection over large distances

  • HVDC is more cost-effective for long-distance interconnection compared to HVAC.
  • Break-even distance for HVDC is approximately 600-800 km.
  • Future projects include the North Sea Network (NSN) link with a capacity of up to 1.4 GW.

• Role #2: Connecting asynchronous grids

  • HVDC allows for the interconnection of grids with different frequencies and voltages.
  • Current interconnection capacity for asynchronous grids is nearly 13 GW.
  • Future projects include links between South American countries (Brazil, Uruguay, Argentina) and increased capacity between East and West Japan.

• Role #3: Connecting remote energy resources and loads

  • High-voltage transmission systems (up to 1000 kV) enable the transport of energy from remote renewable sources to densely populated areas.
  • Examples include the Rio Madeira HVDC link in Brazil (2800 km) and the ±1100 kV Xinjiang-Anhui line in China (3300 km).

• Role #4: Accommodating variable renewable electricity

  • Flexible HVDC systems are essential for managing the variability of renewable energy.
  • VSC-HVDC is a key technology, with IGBT costs dropping by 2/3 in the past eight years.
  • The Skagerrak 4 interconnector in Denmark is designed for high wind power integration.

3. Case Studies of Regional Energy Interconnection

Case Study #1: Interconnecting the European Continent

• The UCTE grid (Continental Europe Regional Group of ENTSO-E) is the largest synchronous grid in the world with over 1 TW of installed capacity.
• VRE generation in UCTE countries increased from 12.8% in 2015 to projected 15% by 2021.
• The European Commission has set a target of 10% electricity interconnection by 2020, with a proposed extension to 15% by 2030.
• Key interconnection areas include the Southern Border (Iberian Peninsula and North Africa) and the Northern Border (Nordic countries and Germany).

Case Study #2: Linking the Americas through SIEPAC

• SIEPAC (South American Interconnection Corporation) aims to link the power systems of the Americas.
• The report highlights the need for interconnectors to support the integration of renewable resources and to enhance system flexibility.
• Current interconnections are limited, and future expansion is expected to increase regional energy trade and system resilience.

Case Study #3: Towards an ASEAN Power Grid

• The ASEAN Power Grid (APG) is a long-term project aimed at interconnecting Southeast Asian countries.
• The report outlines the challenges and opportunities for developing this grid, including political, regulatory, and technical barriers.
• Key projects include the proposed interconnector lines between countries, with some currently under construction.

4. Regulatory and Market Frameworks

• Regulatory and market frameworks are essential for the development of large-scale interconnections.
• Cost allocation and merchant investments are critical for the financial sustainability of interconnector projects.
• The report highlights the need for harmonised grid codes and regulations to enable seamless operation of interconnected systems.
• In Europe, the allocation of interconnector capacity is managed through a sequence of electricity markets, as shown in Figure 10.

Key Information

• Current Interconnector Capacity: Approximately 250 GW globally, with plans to increase by nearly a third by 2020.
• HVDC Advantages: No frequency or voltage constraints, no reactive power limitations, and lower cost per unit length for long-distance transmission.
• Regional Demand and Supply Mismatches: Europe has winter peak demand, while North Africa has summer peak demand, creating opportunities for interconnection.
• VRE Growth: VRE is expected to grow significantly in the coming years, especially in the UCTE region.
• Interconnector Projects:
  • NorNed: 600 km undersea link between Norway and the Netherlands, delivering 700 MW.
  • Skagerrak 4: 1.4 GW interconnector in Denmark for high wind power integration.
  • ±1100 kV Xinjiang-Anhui line: 3300 km line delivering 12 GW of power in China.
• Challenges and Opportunities:
  • Southern Border (Europe and North Africa): Need for more interconnection capacity, regulatory alignment, and market mechanisms.
  • Northern Border (Europe and Nordic countries): Existing HVDC links, future expansion for renewable integration.
  • SIEPAC: Potential for regional interconnection in the Americas, with challenges in political and regulatory alignment.
  • ASEAN Power Grid: Long-term vision with significant technical and policy hurdles.

Outlook for 2017

• The report is expected to be launched in April 2017 and will provide policy recommendations for the development of cross-regional electricity networks.
• It will focus on the technological and economic potential of interconnection, as well as the regulatory and market frameworks needed to support it.

References and Acronyms

• IEA: International Energy Agency
• ENTSO-E: European Network of Transmission System Operators
• SIEPAC: South American Interconnection Corporation
• APG: ASEAN Power Grid
• VRE: Variable Renewable Energy
• HVDC: High-Voltage Direct Current
• HVAC: High-Voltage Alternating Current
• VSC: Voltage Source Converter
• IGBT: Insulated-Gate Bipolar Transistor
• TSO: Transmission System Operator
• UTC: Universal Coordinated Time
• UHV: Ultra-High Voltage
• MER: Mediterranean Electricity Market
• BNEF: Bloomberg New Energy Finance
• RES4MED: Renewable Energy Solutions for the Mediterranean
• MedGrid: Mediterranean Grid
• Med-TSO: Mediterranean Transmission System Operator

Conclusion

Interconnection is essential for achieving a clean, secure, and affordable electricity system. The report highlights the need for increased investment in transmission infrastructure, especially HVDC, to support the integration of VRE and to manage regional demand and supply mismatches. It also underscores the importance of regulatory and market frameworks in enabling cross-border electricity trade and system resilience.