Renewables need high-performance grids

How can we work together to reach climate goals?

The long-term conversion of Europe’s electricity supply from fossil fuels to carbon-free sources of energy is picking up speed.

  • Germany is leading the way with its green electricity subsidy offensive, which has created a real boom in wind and solar power in recent years.
  • Austria, with its strong hydropower tradition, is already starting out at a high level with around three-quarters of its electricity supply coming from renewable sources. However, the country still needs to push expansion of renewable energy sources if it is to meet climate change targets.

The next factor is the necessary grid development, which is far from keeping pace with the expansion of “new” renewables, especially wind and solar power. The slow progress is mainly due to the length of the approval process for major projects – such as the 380-kV Salzburg line – which is out of the control of system operators. The project has undergone one of the lengthiest reviews of any infrastructure project in Austria, with court proceedings having lasted a total of 77 months between the first instance and the proceedings before the Federal Administrative Court. For many years, European power grid operators have been pointing out that the energy transition can only go as far as the grid infrastructure will permit, in a reference to the necessary development and reinforcement projects. This is because renewable power plant facilities place different demands on the power grid than conventional systems. For one thing, large-scale wind farms are usually located in remote areas away from major power transmission routes, and photovoltaic systems rely on decentralised feed-in points to connect to the distribution system.

Grid extensions are needed to integrate PV systems into the main power grid and to transport the power generated. Whereas most wind farms in Austria’s primary wind regions are already connected to the 380-kV grid, solar power is initially fed into the distribution system, which then connects to the transmission grid. Secondly, the generation behaviour of the “new” renewables is not like that of conventional (including thermal) power plants. These renewable energy sources are not designed to supply electricity based on consumer demand, but rather when the weather conditions are favourable for generation. Under the right weather conditions, the quantities of electricity transmitted to the grid are often greater than it can absorb or transmit to their destination.

What goes for all of Europe also goes for Austria:

  • Over the next ten years, investments of up to €2.9 billion in APG’s supraregional electricity transmission network alone will be required to move ahead with grid development.
  • Around 220 km of new, high-performance power lines will be built, 400 km of existing power lines modernised and 100 km of lines upgraded to higher voltage levels.

Network Development Plan (NDP) 

APG has been updating its network development plan (NDP) every year since it was first drawn up in 2011. The NDP is an integrated planning tool aimed at compiling all developments in the electricity sector that affect grid expansion requirements in Austria. It describes all of the grid projects to be implemented or that are to undergo further planning over the next ten years. APG prepares the NDP in a transparent process that both involves and informs market participants. Feedback is requested from the distribution system operators (DSOs) in the Austrian federal states, and the relevant projects involving power plants or other market participants are taken into consideration. After the draft planning document has been prepared, it is subjected to a public consultation process, and feedback from market participants is incorporated into the planning document after review. The NDP is then officially approved by E-Control, the Austrian regulator, in autumn of each year and published on the APG and E-Control websites at year-end.

Ten-year network development plan (TYNDP)

The NDP projections are synchronised with the ten-year network development plan (TYNDP) for Europe issued by the European Network of Transmission System Operators for Electricity (ENTSO-E). This ensures that grid projections are coordinated between all European TSOs and are based on common scenarios as well as on developments in Europe’s energy markets. The current 2018 TYNDP specifies the pan-European grid expansion requirements as amounting to an investment volume of around €115 billion between 2018 and 2030.