FACTS, HVDC Key for Renewable Energy Integration

FACTS, HVDC Key for Renewable Energy Integration

Alstom participated in the €30 million Ocean Lider project focused on the integration of marine energy sources into the grid via efficient technologies and solutions. Findings confirm that FACTS (Flexible Alternating Current Transmission Systems) and HVDC (High-Voltage Direct Current) will be key to meeting the technical, economic and environmental requirements of operators.

The aim of this 4-year project, led by Iberdrola Engineering and Construction was to focus on the sustainable use of marine energy resources, and to align priorities with EU 2020 energy sustainability targets.

Alstom Grid conducted the research in collaboration with the University of Madrid. It studied the impact of off-shore power generators, and their integration into the grid network through FACTS and HVDC solutions. Studies took into account different offshore technologies (wind, wave and tidal) with practical applications. The research also assessed the grid codes of various countries for compliance with different generation technologies and electricity transmission systems.

The Ocean Lider Project sheds light on the specific needs of marine energy generation and its integration into the electricity system. Conclusions demonstrate some of the most appropriate technologies, configurations and designs (redundancy levels, type and voltage level, types of compensation, dimensioning) for various applications. Alstom was able to establish more specifically the adequacy of FACTS and HVDC technologies in the context of marine energy generation for fast, flexible control of power delivered into the network.

HVDC to connect offshore projects to onshore infrastructure

One of the key pieces in the Ocean Lider R&D project was to conduct an analysis on the connection of offshore generated electricity with onshore networks.

Offshore generators are, in many cases, located miles away from traditional electricity transmission networks. To maximise efficiency and stability, a high voltage direct current (HVDC) transmission system is desirable.

An HVDC system is able to transmit large amounts of electricity over long distances, up to 5 times more power than traditional alternating current (AC) systems. To integrate offshore- energy, electricity in the form of alternating current is converted into direct current before it is transmitted into an onshore network. Once ashore, it is converted back into AC and integrated into the traditional electrical system.

The connection of HVDC transmission systems to the existing AC grid is known as the “Supergrid” – a vast network of interconnections between electrical transmission and distribution systems. The Supergrid network integrates renewables and balances the transport of bulk power across long distances, providing clean affordable energy with better security.

Alstom has over 50 years of experience in the development of this technology. In March 2013, TenneT (the North Sea electricity transmission system operator) chose Alstom for the DolWin3 offshore project. This project, connecting the North Sea wind farms to the continental electricity network, has an investment volume of over one billion euros.

Press release, February 14, 2014; Image: alstom