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The vital missing links of the energy transition in Europe

No matter how much wind and solar power is generated, the energy transition cannot be achieved without a built-for-purpose electricity infrastructure. Gaps in the interconnections of Europe’s grid network and lack of capacity on the wires where it is needed most will halt green electrification of energy.

Power system operators have a plan. The issue is implementation

NEIGHBOURING NETWORKS
Connecting central Europe’s transmission network to northern Africa and Scandinavia will increase security, but stronger internal infrastructure is also needed

LESSONS FOR THE FUTURE
The Covid-19 pandemic has shown Europe’s grid operators where transmission links need to be strengthened as more electricity from variable sources enters the system

KEY QUOTE
Transmission bottlenecks, both internally and across its national borders, are an increasing problem for the further growth of renewable energy

The stated goals of Europe’s energy transition—32% renewables by 2030 and 50% by 2040—are on shaky ground without radical expansion, robust interconnection and redevelopment of the continent’s electricity transmission highways and distribution networks. The existing grid system is inadequate for the task ahead. At the rate of network upgrades seen to date, the EU would struggle to get even halfway to its goals, no matter how much new wind and solar capacity is built. The grid is not designed to deal with the transition from a limited number of large power stations with controllable output to a system reliant on variable input from many thousands of smaller and dispersed units. The more the power systems of Europe are robustly linked to one another, the more the supply of electricity can be based on variable energy sources, like solar and wind, without compromising security of supply. Indeed, the broader the supplier base, the more secure the system becomes. What is required is completion of plans for 35 GW of cross-border grid investment by 2025, a further 50 GW by 2030 and another 43 GW by 2040, according to the European Network of Transition System Operators for Electricity (ENTSO-E). Its job is to co-ordinate the cross-border power system operations, system development and electricity market activities of 42 electricity transmission system operators (TSOs) across 35 countries.

GERMAN ISSUE

Germany’s location in the middle of the European continent makes its grid investment fundamental to achieving ENTSO-E’s plans. But development of the country’s electricity infrastructure is failing to keep up with the growth of wind and solar capacity. Transmission bottlenecks, both internally and across its national borders, are an increasing problem for the further growth of renewable energy. Over the continent as a whole, transmission of wind power south from the windy locations of northern Europe, on land and offshore, is hampered by lack of sufficient network capacity, as is the transmission of solar electricity to Europe’s industrial heartlands from the sunny south, including from Italy, Spain, Portugal and even North Africa across the Mediterranean Sea.

THE PLANS

ENTSO-E’s 2030 plan seeks to shore up the connections between Germany and Poland, Switzerland and Austria, as well as those across the Belgium-France border, Spain-France, between Turkey and Southeast Europe and various Italian connections. By 2040, connections across the France-Spain border are to be further beefed up as well as those crossing the Portugal-Spain border, helping to better connect the poorly linked Iberian peninsula to the rest of European the grid. Improvements across French borders to Switzerland and the UK are also in the works. North-south power flows will be improved from the Nordic countries and south through continental Europe, Ireland will be better connected to the UK, the UK to the mainland and Italy with the rest of Europe. Some of the new wires involve connecting offshore wind resources to land in a more coordinated way than to date. The 22.1 GW of installed offshore wind capacity at the end of 2020 is expected to rise to 60 GW by 2030 and in November 2020 the EU announced an offshore wind goal of 300 GW by 2050, to be complemented by a further 40 GW of other ocean energies such as wave and tidal projects.

SOUTH AND NORTH

A longer term vision for Europe to increase its renewable energy pool is to tap into the solar potential of North African countries such as Morocco and Tunisia where solar irradiation is as much as 20% higher than southern Spain and Italy. Existing interconnections with Morocco and Spain, with a capacity of 1.4 GW, are mainly used to export European power to Africa because lack of transmission capacity prevents it being sent north. Proposals to improve trans-Mediterranean connections to load centres in the heart of Europe include connections through the islands of Sicily and Cyprus. The Cyprus cable would connect Greece with Egypt. In Europe’s north, longer term plans are for the UK to export abundant offshore wind power to the continent. But energy consultancy Cornwall Insight does not see it being feasible until the 2040s. Meantime, interconnection development will greatly expand transmission capacity, introducing more flexibility for balancing supply and demand on both sides of the North Sea. With 16 GW of additional interconnection to be operational by 2025 and another 25 GW by 2030, transmission capacity between the UK, Scandinavia and France is set to double.

In addition, transmission system operators Amprion (Germany) and Elia Group (Belgium) have been collaborating on HVDC projects. The Aachen Liège Electricity Grid Overlay (ALEGrO) interconnector also came online in late 2020. A 90 kilometre, 1 GW link, it is the first HVDC power bridge between Germany and Belgium, boosting security of supply to citizens in both countries and smoothing the ups and downs of demand for electricity and the variable delivery of it from renewable energy sources of generation. Elsewhere, however, progress on major interconnectors is ponderous, including high-priority connections for offshore wind projects in the North Sea, which are still a decade away. TenneT has completed the Borssele alpha and Borssele beta connections to transfer 1.4 GW of offshore wind in the Dutch North Sea to the country’s grid. But, a further three of Tennet’s connection projects—BalWin and LanWin in the German North Sea and IJmuiden Ver in the Dutch North Sea for a total of 9.5 GW of transmission capacity—are not due to be wrapped up until 2030. The slow progress either delays offshore wind projects proposed around these connections, or forces the developers to find temporary alternatives.

PANDEMIC LESSONS

As the covid-19 pandemic swept across the globe, the knock-on effect it had on grid management highlighted where grids need to improve. Economic and industrial activity slumped for weeks on end as national lockdowns restricted the movement of people in an attempt to halt the spread of the virus for uptake of renewable energy. In Italy, on a day when demand for electricity was 36% below the 2019 average, 47.6% of total power generation came from renewable energy and 30.6% from wind and solar sources alone. This scenario was repeated across Europe, with power system operators learning-while-doing on how to maintain security of supply while managing the ups and downs of both new demand patterns and much higher proportions of the supply mix based on variable generation. Balancing the two is a challenge.

To help keep the Italian grid secure, operator Terna tapped into existing flexibility resources—mainly natural gas plants, hydroelectric power, pumped hydro storage and grid interconnectors. Italy exported power during hours of excess renewables production and imported during the evening ramp-up as its solar photovoltaic plants stopped producing. The operational changes brought about by the pandemic sharpened Italian focus on how system operations will change as Italy gets closer to its goal of 60.5% electricity from renewables by 2030, with 37.1% from variable renewables. Andrea Marchisio of Italian energy consultancy Elemens, expects batteries will be one essential element to increasing the strength of Italy’s power system, particularly given the prevalence of small distributed solar photovoltaic (PV) capacity in the country. Local storage of PV energy in batteries can help batteries can help avert the need to build out the grid or con- struct additional power generating capacity, he notes.

REPLACEMENT INERTIA

The uptake of renewables requires the adoption of solutions for a range of technical challenges, none of which have proved to be insurmountable. Among them has been finding ways to maintain power system inertia as renewable energy replaces centralised thermal power plants. The huge rotating turbines in thermal power stations cushion sudden changes in frequency caused by changes in demand. Without it, grid stability is weakened. US engineering firm GE installed two synchronous condensers and flywheel units for Italian grid opera- tor Terna at the Brindisi substation in southern Ita- ly. Each unit supplies 1750 MW of inertia to provide grid stability. Similarly, in South Wales, Germany’s Siemens Energy is building a rotating grid stabilisation technology, which is basically a form of electronic synchronous condenser and a flywheel. The UK’s TSO, National Grid, also intends to line up synthetic inertia tools by 2025 to enable it to remove gas generating plants from the grid. In the north of Scotland, two rotating stabiliser synchronous machines are being installed. The same methodology has been adopted in Denmark, which with well over 50% of electricity supplied from variable renewables, tends to be further ahead with power system innovations.

TEXT Drew Robb ILLUSTRATION Hvass & Hannibal