Tdworld 957 Hvdc Abb Grid Opt

HVDC: A Revolution Ahead

April 1, 2012
The power engineering industry is facing tremendous challenges worldwide. Countries such as China, Brazil and India have experienced a massive demand

The power engineering industry is facing tremendous challenges worldwide. Countries such as China, Brazil and India have experienced a massive demand increase, which needs to be covered; North America is seeking a more reliable energy system; and in Europe, we are predominantly looking for a more sustainable energy supply, based on liberalized market principles. This editorial will focus on the developments in Europe.

The European power system is operated ever closer to its limits. Links between countries are now serving the liberalized electricity market, whereas they have only been developed in the past to help neighboring countries. Investments are heavily needed, whilst transmission system operators are facing an increasing opposition when it comes to the construction of new overhead lines.

The drastic need for transmission system upgrades and the inability to upgrade the European electricity system in past years using traditional solutions is well demonstrated when one observes the evolution of the so-called TEN-E priority development plans.

The Future Will Be Ever-More Challenging

The TEN-E plans have been pinpointing the missing links that had been recognized as being important for Europe and the European electricity market in the long run. Most of these prioritized links kept popping up whenever the TEN-E brochure was updated, meaning that those heavily needed links were still missing and, unfortunately, not too much had changed. The new infrastructure package, “Energy Infrastructure Priorities for 2020 and Beyond,” provides a blueprint to tackle the challenges in a coherent way.

The ambitious 20-20-20 targets of the European Union — aiming to increase the share of renewable energy sources in the overall energy mix to 20%, cut greenhouse-gas emissions by 20% and increase the energy efficiency by 20% in the year 2020 — will definitely be reflected in the way the European energy system will evolve in the years to come.

Nowadays, we are talking about a massive integration of intermittent renewable energy sources such as wind and solar, with part of the wind energy coming from offshore wind energy. Germany alone has an installed capacity of more than 40 GW in wind and solar combined.

Industry is Changing

It has become more and more apparent to the power engineering community that a real change of paradigm is needed in order to make the step forward that policy makers would like. This is well reflected by the smart grid initiatives popping up all around the world, as well as the plans that have been put forward by different institutions and groups to construct offshore grids interconnecting the wind farms to be built, or even a new overlay grid, both onshore and offshore, as a backbone structure for the European power system.

But while rethinking the power system, our community is faced with the same challenges when it comes to social acceptance as a decade ago. Therefore, opportunities have to be discussed to tackle those issues: What about a change on the technology front?

It's no secret that the power engineering community has primarily been thinking in terms of ac overhead lines as the standard solution, because this is what we have been taught to do. The industry still is very much concentrated on ac technology (high-voltage lines, switchgear, transformers, etc.). The material has been optimized over the years, with improved efficiency, lower prices and increased reliability and lifetime.

European companies have invested massively in the development of HVDC during the last years, and although the turnover in dc applications is still low, compared to ac installations, the growth is immense. New challenges such as deep offshore wind parks, interconnecting of asynchronous ac zones, and the development of the dc grid overlay of the existing 400-kV ac grid are being addressed.

Voltage source converter HVDC is seen as one of the key enabling technologies in developing the renewable energy sector in Europe and as the prime candidate for a new European overlay grid or “super grid.”

European players are making investments in new manufacturing units with the aim of increasing the capacity for cables and high-rated power electronic components. New systems are becoming ready for the market, such as dc current breakers. Others are still on the drawing board, such as flow-control devices for meshed dc grids. SCADA systems have to be developed to operate with these new devices.

The step is use, the investments in the grid are massive, but it is clear “no grid, no party.” If we will not be able to deploy the new grid, the party to celebrate the future CO2-free electric energy system will not take place.

Ronnie Belmans is a professor with the K.U. Leuven, teaching electric power and energy systems. His research interests include techno-economic aspects of power systems, power quality and distributed generation. Belman is hononary chairman of the board of directors of ELIA, the Belgian transmission grid operator.

Voice your opinion!

To join the conversation, and become an exclusive member of T&D World, create an account today!