The evolving electricity network

As a producer of renewable energy, you would expect Canadian utility Hydro-Quebec to be a strong supporter of increasing the share of renewables in the global energy mix, and indeed it is. Renewable energy “has to be growing,” Chief Executive Thierry Vandal told delegates at the World Energy Congress. He neverthess said there are other more pressing needs.

“Renewables need to grow in the energy mix, but before we even get to that we need more energy efficiency and a sophisticated transmission grid,” he said. “Energy efficiency has to be No. 1 on everyone’s minds,” he went on. “If you had told me 10 years ago we would get to levels of efficiency we have reached today I would have said you’re mad. There is an ability to go much further in terms of energy efficiency than people thought possible. The potential will only be ‘maxed out’ if we take on the challenge of the transmission grid.”

What the transmission grid challenges are and how they can be tackled by making the grid more sophisticated was explained by Peter Leupp, head of ABB’s Power Systems division, at a meeting of the Young Future Energy Leaders at the congress. One big issue he highlighted is that when traditional grids were built, their designers didn’t think about connecting it to all the remote locations where renewable energy is most plentiful and which are now being developed.

So the first challenge is simply connecting renewable power plants to the grid, but the intermittence of the supply from some sources means that operators face the additional challenge of maintaining balance in the power system, Leupp said. In the power system, supply and demand must be balanced at all times because power cannot be stored, so intermittent power from wind and solar in particular can create real problems with stability.

Leupp explained that since the wind and sun can’t be controlled, supply and demand must be balanced in other ways, for example by managing demand. On top of all this, the grid needs to be strengthened to enable a transition to electric vehicles so that the network isn’t destabilized when large numbers of vehicles are connected to the grid at once, he said. Keeping all these things together requires much more management and control in the electricity grid.

“The future grid will look much more complicated,” Leupp said. “The main discussion is about how we produce electricity, but hardly any attention is focused on how we deliver that electricity.”

Innovation to facilitate the evolution of the grid will concentrate in four areas, Leupp said: AC technology, the backbone of today’s grids; DC technology, which is experiencing a comeback as a technology for low-loss, long distance power transmission; storage; and demand management.

(The image at the top of the story illustrates the transition from a grid with largely unidirectional power flows from large power plants, to a more complex system using a greater variety of power sources.)