Transcontinental and global power grids

Background and context

Diverse geopolitical, market integration and techno-economic dynamics push for further interconnecting the higher voltage systems across countries and continents. 

The best locations for the generation of renewable electricity are not uniformly distributed across the European continent and worldwide. Sizable renewable energy potential is concentrated in sites far from the power grid (e.g. offshore sea) or where grid transfer capacity is low. The energy production from renewable sources also greatly depends on local weather conditions.

To fully utilise these resources, the power grid must be enhanced to allow electricity to be transported to the main demand and storage centres. A more flexible, yet robust, transmission grid may be instrumental to interlink distant electricity markets and take advantage of the low-carbon resources temporal and spatial complementarity. 

All the above may drive the realisation of a transcontinental higher transfer capacity system to transport large amounts of electricity over long distances. High Voltage Direct Current (HVDC) technologies, due to their lower losses and smaller environmental impact, promise to be the cornerstones of such global power grid.

Europe has been at the forefront of HVDC research, development and deployment since the beginning of large-scale pilot projects in 1950s-1960s. All the major companies in the field that innovated and set the standards are located in Europe. The same companies built or extensively contributed to projects worldwide. All the HVDC projects deployed in Europe are “unique”, that is all the equipment is sized to that specific project; no two projects are alike. All the HVDC projects in Europe (with one exception) are point-to-point with specific parameters meeting the local conditions (grid connection, voltage levels, capacity). Other countries and continents worldwide have lately emerged as growing markets for HVDC technology. In particular, China, although lacking a proper (interconnected) HVDC grid, has built in the last two decades more than 30 HVDC lines. European HVDC equipment producers have started and built the first projects but through technology transfers China is able now to produce almost the entire set of equipment and to manage also the planning and designing phases. Many of these HVDC links are built (or are in building phase) as standardized systems in terms of parameters (nine systems of 500 kV / 3000 MW, 11 systems of 800 kV / 6400 MW).

Our role

Against this background, we assess building blocks and progress towards the development and interconnection of the European electricity transmission grid. More in detail, we conduct research on:

  • the feasibility and sustainability of alternative options to interlink neighbouring continent's power grids.
  • the geopolitical dynamics driving the transcontinental grid developments.
  • the technological progress towards higher transfer capacity architectures.
  • the techno-economic challenges for redesigning the trans-European electricity networks.
  • the impacts on power exchanges of more strongly interconnected extra high voltage grids.

2020 - Optimal Paths for Electricity Interconnections between Central Asia and Europe

The European Union is increasingly considering energy cooperation with Central Asia as this is a relatively nearby and stable region with tremendous energy resources. Locally produced electricity – i.e. predominantly from gas and hydro and potentially from solar and wind energy – offer opportunities for beneficial electricity trade, both among the Central Asian countries and with the European Union. As such, Central Asia may contribute to the European Union’s security of electricity supply and the achievement of its renewable energy targets. Underpinning policies and strategies for improved energy connectivity with Central Asia and the use of renewable energy sources in this region have been developed. However, efficient electricity interconnections are still lacking, hindering the full potential of Central Asia’s energy resources. Against this background, this report presents a methodology for the computation of optimal electricity transmission routes, crossing Central Asia, the Caspian Sea and the Transcaucasia towards the European Union. This methodology, which is based on the concept of friction maps, makes use of a set of 13 input variables and is implemented in geographic information system software. For each pixel of the friction map, covering the addressed countries, a crossing cost is calculated from semi-quantitative friction scores, which are locally attributed to the variables. Starting from the final cost surface, which represents a composite weighted map of the constituent variables, the software model successfully evaluates the least-cost paths for electricity transmission throughout the considered region. It is found that the evaluated route is most sensitive to the renewable energy potential across the considered region and not to the already existing electricity assets.

2018 - Submarine power cable between Europe and North America: A techno-economic analysis

This article addresses the potential of interconnecting electricity systems to geographically aggregate remotely located variable power sources. Increasing the deployment of power generators using variable renewable power sources, such as wind and solar, brings power balancing challenges in electricity systems. One mean to achieve power balancing and to share balancing resources, is to interconnect.

The article provides insights for electricity trading through a submarine power cable between Europe and the eastern part of North America. While such ambitious power interconnection concepts appear in recent literature, this article is the first to present a techno-economic analyses. This article concludes that, a 4000 MW cable between Europe and North America could bring an annual socio-economic benefit of 177 M€ in 2030. In addition to the differences in generation costs, mutual benefits from electricity trading between Europe and North America derive from different daily peak demand times, low correlation in generation from renewable energy sources, and in seasonal demand variations. The results of the cost-benefit analysis indicate that the benefit for society is sufficient to cover the investment costs. Thus, the proposed interconnector is welfare improving.

2017 - A China-EU electricity transmission link

This report looks at the potential routes for a future power interconnection between EU and China. China has launched in 2016 the idea of transmitting electricity as far as Germany via an Ultra High Voltage Direct Current (UHVDC) link. China intends to exploit its Renewable Energy Sources (RES) from north-eastern regions both for domestic use and for export. The country has the capabilities to design and build long and powerful systems to transmit electricity across the country for thousands of kilometres.

Three route scenarios are considered and analysed, all starting in RES-rich areas in western China and heading towards Europe on three different paths. High voltage direct current technology is considered and its potential is assessed.

The renewable energy sources in the countries along the potential routes as well as the power sector and power grid in the countries crossed are analysed.


2015 - HVDC Submarine Power Cables in the World

This report provides an extensive study on the availability of the technologies required for the realisation of a HVDC interconnection between the European and North American Alternating Current (AC) transmission grids.

High Voltage Direct Current (HVDC) interconnections started to spread across land and underwater becoming longer and more powerful. The advance of this technology makes them the prime option for bulk power transmission in future. While on land the length can reach thousands of kilometres underwater they measure less than 600 km. The constraints but also the future developments must be addressed in order to assess the perspectives of this technology.
JRC is performing a study to identify and analyse the technical and geopolitical challenges for building an offshore electricity transmission interconnection between Europe and North America.
The report revises the main submarine power cables in the world along with their characteristics. Special attention is given to the installation of HVDC submarine cables. Techniques for laying a cable are discussed. Also issues such as protection measures and maintenance aspects are dealt with. The operation of HVDC submarine cable is treated as well. Reliability and accident risk issues are discussed in a dedicated paragraph as well as environmental aspects.

2014 - It's a Bird, It's a Plane, It's a...Supergrid!

This article discusses the emerging challenges facing the European transmission grid as it contributes to meeting the EU's energy and climate change policy goals. We focus on the European ultra-high-voltage system, which is already considered to be a “smart” system but is expected to evolve toward architectures offering higher transfer capacities (a so-called “supergrid”).

We address the challenges of making power distribution systems smarter only insofar as transmission-distribution interfaces are concerned, in the course of illustrating the tensions and complementarities within the smart grid and supergrid concepts.

In this light, the article presents the main policy objectives and visions for electricity in the European Union, key figures and trends relating to the European energy and electricity systems in a worldwide context, and technological options and design challenges for the pan-European transmission grid. The article ends by summarizing various needs and potential solutions for the EU transmission grid in view of its long-term evolution.

2014 - Electricity exchanges with North Africa at 2030: The European and the Italian approaches

This chapter provides a first preliminary analysis on the effect of African solar energy import on the Italian system at 2030. In particular, the aim is to provide a first preliminary answer to questions like:

- what flow will prevail in Italy at 2030 (wind from the Northern border or solar from the Southern border);

- how could the market prices be modified as the effect of Renewable Energy Sources (RES) import from North and from South.

The scenario analyses presented in this study are the result of collaboration between the Joint Research Centre of the European Commission and Ricerca sul Sistema Energetico, which developed, respectively, a pan-European approach and a detailed model of the Italian system.


2013 - Effects of North-African electricity import on the European and the Italian power systems

This paper, based on the combination of two methodologies, presents a first techno-economic analysis of the effects of electricity imports from North Africa on the European and the Italian power systems in 2030.

Several European initiatives consider the electrical integration of the Euro-Mediterranean region a key priority for meeting future European Union (EU) energy policy goals. Ambitious plans include the development of Renewable Energy Sources (RES) in the region as well as transmission interconnectors between the two shores of the Mediterranean Sea. 

Within a common framework, the adopted approach has proved its feasibility with coherent results showing a decrease in electricity prices in Europe. The European study shows how net electricity exchanges tend to follow the direction from South to North. The impact of North-African electricity on the Italian system is relevant. Also, Italy’s potential of becoming a Mediterranean electricity hub is emphasised. National internal grid congestion results to be a crucial issue for the Euro-Mediterranean electrical integration.

2012 - Behaviour of Multi-Terminal Grid Topologies in Renewable Energy Systems Under Multiple Loads

This paper identifies and analyses by means of MATLAB or NEPLAN models transient responses of four representative Multi Terminal Grids topologies for renewable energy systems.

Decarbonization policies adopted worldwide are leading to a steadily increasing deployment of renewable energy sources (RES). In Europe, for example, a multitude of wind farms is built at (predominantly) onshore and (increasingly) offshore sites. The connection of offshore wind farms is expected to promote the realization of Multi Terminal Grids (MTG), which include High Voltage DC (HVDC) transmission systems requiring high voltage inverters. Due to the semiconductor components used in the inverter systems, voltage and current fluctuations occur before and after the inverters, producing harmonics, voltage oscillations and power loss in the transmission system.

The study escalates the complexity of the simulation starting from a point-to-point HVDC connection up to the interconnection of five (5) inverter terminals. In order to address all the possible connection options the authors examine different topologies for grid having more than three points. The different responses of the network configurations under study are analyzed and compared. Simulation results are then validated with hardware-in-the-loop experiments in the Smart Grid Simulation Centre of the European Commission's Institute for Energy and Transport (IET).

2011 - A European supergrid for renewable energy: local impacts and far-reaching challenges

This paper assesses the impact of extensive deployment of indigenous and external renewable energy sources on a local electricity system (Sardinia Island) and discusses the main challenges faced by the European power grids in integrating high shares of renewable-based generation technologies. It presents the 2030 scenarios for the Sardinian power system and the results of steady-state analyses in extreme (renewable) generation and consumption conditions.

These results are eventually combined with the assessment of key technology development trends to explain how this can affect the development of a European supergrid.

In general, the article stresses that rendering the bulk-power system capable of accommodating high renewable energy penetration not only requires reinforcing the electricity highways but also demands carefully planning the architecture of and the interface with regional power systems.

2011 - Evolutions and Challenges towards a Potential Pan-European HVAC/HVDC SuperGrid

This paper investigates the role of HVDC towards the development of the future transmission system in Europe: particular attention is paid to current evolutions and challenges ahead of the potential realisation of a pan-European (mixed HVAC and HVDC) SuperGrid in a long term view, also in line with the recently issued European Commission’s Energy Infrastructure Package.

In presence of several issues more frequently constraining the realisation of new High Voltage Alternating Current (HVAC) overhead infrastructures, the need for evolution in the design and operation of transmission system towards a re-engineering process emerges in Europe. Among the different measures to support such shift, there may crucially be the use of High Voltage Direct Current (HVDC) technologies for advanced power transmission.

After introducing key technical, economic and environmental characteristics of HVDC technologies, this paper reports some specific long-distance HVDC applications for bulk power transmission in extra-European systems towards potential SuperGrid implementations in Europe. The developments at the eastern and southern edges of the European system as well as across the North Seas, the Baltic Sea and the continental network are then specifically investigated in their evolution stages as potential building blocks of a long term pan-European SuperGrid.


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