An interconnector (also known as a DC tie in the USA) is a structure which enables high voltage DC electricity to flow between
electrical grid
An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:Kaplan, S. M. (2009). Smart Grid. Electrical Power ...
s. An electrical interconnector allows electricity to flow between separate AC networks, or to link synchronous grids. They can be formed of
overhead power line
An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy across large distances. It consists of one or more uninsulated electrical cables (commonly multiples of three for three-p ...
s.
The longest interconnection as of July 2022 was the 2,210 km Hami - Zhengzhou delivering 8 GW of
high voltage direct current
A high-voltage direct current (HVDC) electric power transmission system (also called a power superhighway or an electrical superhighway) uses direct current (DC) for electric power transmission, in contrast with the more common alternating curre ...
power. The longest proposed connector is the 3,800 km, 3.6 GW
Xlinks Morocco-UK Power Project
The Xlinks Morocco-UK Power Project is a proposal to create 10.5 GW of renewable generation, 20 GWh of battery storage and a 3.6GW high-voltage direct current interconnector to carry solar and wind-generated electricity from Morocco to the United ...
.
Economy
Interconnectors allow the
trading
Trade involves the transfer of goods and services from one person or entity to another, often in exchange for money. Economists refer to a system or network that allows trade as a market.
An early form of trade, barter, saw the direct exchan ...
of electricity between territories. For example, the
East–West Interconnector
The East–West Interconnector is a 500MW high-voltage direct current submarine and subsoil power cable which connects the Irish and British electricity markets. The project was developed by the Irish national grid operator EirGrid.
Aim
The ...
allows the trading of electricity between the UK and
Ireland
Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...
. A territory which generates more energy than it requires for its own activities can therefore sell surplus energy to a neighbouring territory.
Interconnectors also provide increased resilience. Within the
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
there is a movement towards a single market for energy, which makes interconnectors viable. As such, the Nordic and Baltic energy exchange
Nord Pool Spot
Nord Pool AS is a pan-European power exchange. Nord Pool has a main office in Oslo and further offices in Stockholm, Helsinki, Tallinn, Berlin and London. The company is owned by the European exchange operator Euronext as well as TSO Holding, ...
rely on multiple interconnectors. The fullest possible implementation of this is the proposed
European super grid
The European super grid is a possible future super grid that would ultimately interconnect the various European countries and the regions around Europe's borders – including North Africa, Kazakhstan, and Turkey – with a high-voltage ...
which would include numerous interconnectors between national networks.
Interconnectors are used to increase the security of the energy supply and to manage peak demand. They enable cross-border access to the producers and consumers of electricity, thus increasing the competition in energy markets. They also help integrate more electricity generated from renewable sources,GB/France : un projet d’interconnexion dans les tuyaux... de la justice www.lemondedelenergie.com thus reducing the use of fossil fuel power plants and emissions. Interconnectors aid adaptation to changing demand patterns such as the uptake of electric vehicles.
Infrastructure
Interconnectors may run across a land border or connect two land areas separated by water. As of July 2022 there are at least 35 international connectors and many more intra-national connectors, see high-voltage direct-current (HVDC) projects.
Variable-frequency transformer
A variable-frequency transformer (VFT) is used to transmit electricity between two ( asynchronous or synchronous) alternating current frequency domains. The VFT is a relatively recent development. Most asynchronous grid inter-ties use high-voltage ...
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Solid-state transformer
A solid-state transformer (SST), power electronic transformer (PET), or electronic power transformer is actually an AC-to-AC converter, a type of electric power converter that replaces a conventional transformer used in AC electric power distrib ...