Germany's energy grid is outmoded. For decades its job was simply to transport electricity from generator to consumer. But now, with the energy transition in full swing, Germany is forecast to be generating 80 percent of its total requirement from renewables by 2050 . In fact, by 2016 renewables already accounted for 29.5 percent of the country’s total energy mix . "One of the big challenges is to reliably feed renewable energy into our grid and transport it to where it is needed," says Hans Koch, Chief Commercial Officer Prysmian Group Germany. Prysmian is a global market leader in the manufacture of electric power transmission and telecommunications cables. Meeting this challenge requires major infrastructure changes, because with renewables, electricity transmission and distribution is no longer a one-way street from centralized power stations to customers. Increasingly, electricity customers are also electricity producers ('prosumers') who need to be able to feed their solar and wind power into the grid.

What are the power grid implications of Germany’s big central power stations being joined by a multiplicity of small decentralized producers seeking to generate and sell electricity from renewable sources? More importantly, what happens during times of peak renewable production? In summer when the entire country is bathed in sunlight? Or in the depths of winter when a storm over the north of the country is turning the wind turbines at full speed? These situations already push Germany’s power grid to its limits. If the feed-ins from these volatile sources are too high, the country’s grid operators are forced to step in and throttle them back in order maintain grid stability. So, what does Germany need to do in order to enable its power grid to accommodate renewable energy?

Key components of future-proof power grids

Germany’s national grid currently comprises two main parts: the transmission system, in which power is transported over long distances at ultra-high voltage, and the distribution system, in which power is transported over shorter distances at high, medium and low voltage to regions and individual customers. These systems consist mainly of cables, so investment in cable infrastructure is one of key requirements for a future-proof energy grid.

"Future-proof, sustainable energy systems need HVDC (high-voltage, direct current) transmission cables rather than the more conventional overhead alternating-current cables," says Prysmian Group’s Hans Koch. HVDC cables are laid below ground, so they are much more expensive than overhead lines. But "they are 'electrical super highways' that enable the transmission of very large volumes of power over very long distances, often across national borders." HVDC systems would thus be a very efficient way of transporting large amounts of wind power from northern Germany to southern Germany and of integrating off-shore wind farms into the national grid, for example.

Innovative cable systems for higher voltages

Among the most exciting innovations on the transmission cable market are Prysmian's polyethylene cable systems. They are ideal for electrical super highways because they support the very high voltages that are needed in order to maintain stability in decentralized power grids. "In 2016, we achieved voltages of 600 and even 700 kV. These are the highest HVDC voltages ever achieved. The higher voltages permit an increase in transmission capacity of up to 15 percent beyond that of our previous 525 kV technology."

Of course, Germany's energy grid also needs to get smarter. As well as transporting more power more efficiently, the smart grid of the future uses sensors and meters to collect and transport data. The purpose of making grids smart is to enable grid operators to know at any given point in time exactly how much power is being consumed and generated, and by whom. The ultimate aim is to manage the increased complexity of decentralized energy consumption and generation so as to keep both in balance and maintain grid stability at all times. The smart meters that Germany started phasing in this year are the first step towards achieving this aim .

Real-time facts and figures on the energy transition

How many smart meters have been installed worldwide so far? How much solar energy reached the Earth today? How much oil does the world actually have left? For answers to these questions and more, check out the Real-time infographic on the new world of energy .

These energy and energy transition themes will be explored in depth in an extensive lineup of forums, conferences and special events at Energy, the leading trade fair for integrated energy systems and mobility. Energy is part of the HANNOVER MESSE industrial technology trade show. Prysmian Group will be there, presenting its HVDC cable innovations at Stand H50 at the Integrated Energy Plaza (Hall 27).