More windpower needed in southern Europe
The best renewable energy strategy for Europe would include coordinated planning for development of wind power. Currently, many countries are pursuing unilateral national strategies that neglect the benefits of regional planning.
Working together to expand capacity in European regions that are currently making very little use of wind power would benefit everyone and minimize impacts from extreme fluctuations, according to energy researchers with ETH Zürich and Imperial College London.
Their study, published in the journal Nature Climate Change, crunched 30 years of weather data together with wind and solar electricity production data in a model that’s now freely available and can be used worldwide. The researchers said it’s part of an effort to improve transparency and openness of science.
They found that the wind is always blowing somewhere, but the bulk of wind capacity is clustered along the northern coast of Europe. It’s critical information because 90 percent of all new power that came online in 2016 was renewable. Solar and wind are being developed on a scale that only makes sense if it’s properly distributed and connected by a smart grid.
The study also addresses the issue whether renewable energy development has taxed the grid and increased “weather-dependent fluctuations in European electricity generation.”
Similar debates are simmering in the U.S., where the Energy Department is releasing a study on grid reliability, and in Australia, where some sought to blame renewables for a power blackout.
In a press release, the researchers explained how “wind power is related to seven prevailing “weather regimes” in Europe and how it will change with the further expansion of wind energy capacity. These weather regimes explain why European wind electricity generation suffers from fluctuations lasting several days.
When storms roll in from the Atlantic, bringing high winds to western Europe, it’s usually calm in the east. When the westerlies die down, winds pick up in southern Europe and Scandinavia.
“There is hardly a weather situation in which there is no wind across the entire continent and thus all of Europe would lack wind power potential” explain Christian Grams, lead author of the study from the Institute for Atmospheric and Climate Science at ETH Zurich.
Because so much of the wind power is along the northern coast, a lull of few days has big European-wide effect on wind power generations, as happened last winter.
If current national strategies are followed, it will concentrate even more wind capacity in the same areas, exacerbating the problem. Additionally, some climate models suggest that weather patterns may be become stuck for longer periods because of global warming.
In a few decades, the fluctuation could be as high as 100 gigawatts during a lull. That’s equal to the power from 10 nuclear reactors and would have to be brought online within just a few days.
If future development of wind power were based on an understanding of the continent-scale weather regimes, fluctuations in future wind energy could be stabilised at the current level of around 20 gigawatts. The Balkans, Greece, the western Mediterranean, and northern Scandinavia are all potential sites.
These locations would all have enough wind if, for example, high pressure led to a lull in the North Sea. Likewise, if a stable high-pressure area slowed wind production in the Mediterranean, the wind farms around the North Sea would produce enough electricity.
“This is why wind capacity in countries such as Greece or Bulgaria could act as a valuable counterbalance to Europe’s current wind farms. However, this would require a paradigm shift in the planning strategies of countries with wind power potential,” said co-author Iain Staffell from Imperial College London.
At this point, storage technology probably couldn’t make up for such large multi-day fluctuations. Current storage technologies are more suited to compensating for shorter fluctuations of a few hours or days.
A wider geographical distribution of wind farms also requires the expansion of the transmission grid. However, such a pan-European renewable energy system could still provide Switzerland with the opportunity to use its hydropower capacities more economically in order to compensate for short-term fluctuations.
Solar energy can be backup at the regional level. To be effective, solar capacity would have to increase tenfold.