Stepping up the voltage levels
Ultra high-voltage technology and the power of change
On 29 October 1969 two computers share a message for the first time over ARPAnet, a wobbly academic communications network that later morphs into the global ‘Internet’, which many of us now access each day on our smart phones.
It`s a reminder that change is not only constant, but that it’s happening at a constantly faster rate. Even in the relatively conservative world of power grids big changes are happening.
Ultra high-voltage direct current transmission (UHVDC for short) is a typical example of this development. Just six years ago, ABB was testing components for this milestone DC transmission technology, with the goal of delivering large amounts of power (+6,000 megawatts) at ultra high voltages (+800 kV ) across very long distances (+2,000 km).
By 2010, UHVDC was a working reality, implemented and transmitting power one year ahead of schedule. The Xiangjiaba-Shanghai project in China with a power rating of 6,400 megawatts (MW) – a huge amount of electrical power – was the world`s first commercial UHVDC line, spanning a distance of 2,000 km.
Two years after that milestone, we have developed 1,100 kV converter transformers which together with the next steps in converter technology make it possible to transmit as much as 10,000 MWs of power over distances exceeding 3,000 km.
Interconnected installations of wind power, solar panels and hydroelectric power plants, in combination with storage power capacity, are expected to potentially provide more and more of the power needed on earth.
UHVDC technology is an exciting prospect, because it brings into play renewable power resources like hydro on an unprecedented scale that until now has simply been out of reach – too far from the centers that need power.
In order for such a scenario to become reality, a new kind transmission system with high capacity, controllability and efficiency is required. This future transmission system can indeed benefit from ultrahigh-voltage direct current technology in many ways, and in the end these sophisticated DC transmission links are the technically and economically preferred solution to address the challenge of integrating and elevating renewable energy to the top of our energy mix.
FYI: Hydropower provides 16.3 percent of the world’s electricity (about 3,500 terawatt hours (TWh) in 2010), more than nuclear power (12.8 percent), much more than wind, solar, geothermal and other sources combined (3.6 percent), but much less than fossil fuel plants (67.2 percent). The percentage of undeveloped hydroelectric potential is highest in Africa (92 percent), followed by Asia (80 percent), Australia/Oceania (80 percent) and Latin America (74 percent). Even in the most industrialized parts of the world, the undeveloped potential remains significant, at 61 percent in North America and 47 percent in Europe. (Source: International Energy Agency, Technology Roadmap, Hydropower, 2012)