It was a typical mid-April day, and I was enjoying a holiday in China. Back in Switzerland, my husband was hiking through the mountains, capturing the classic scenes of spring inching its way across the landscape. The images he sent were filled with lush greenery and blooming flowers, a testament to the season’s arrival. Yet, just a few days later, I received a starkly different photo from him—this time, it depicted Zurich blanketed in heavy snow. The unexpected shift was a stark reminder of the increasingly unpredictable weather patterns we are facing.

Within just two days, temperatures in Zurich had plummeted dramatically from an average of 24 degrees Celsius to below freezing. Such extreme weather conditions were rarely seen, but are anticipated to become more frequent in the years ahead. According to Intergovernmental Panel on Climate Change (IPCC), the Earth’s climate is warming unequivocally, the various scenarios they outlined show that limiting warming to 1.5°C requires halving emissions by 2030 and reaching net-zero by 2050.

A pivotal strategy to reduce emissions involves transitioning from fossil fuel power plants to renewable energy sources. In Switzerland, the installed capacity for wind and solar energy has risen sharply from almost zero in 2000 to almost 5 GW by 2022. Across the European Union, by 2023, solar and wind generated 27% of the EU’s electricity, while renewables in total accounted for 44%.

Although the pathway to net-zero emissions appears promising, numerous challenges lie ahead. One the main challenges is the intermittency and variability of renewables, which poses a big challenge for the stability of the power system, where supply and demand must be balanced all the time. According to NZZ, on April 22 (Monday), a significant short-term supply deficit, equivalent to the output of the Leibstadt nuclear power plant, occurred in the Swiss power system. Swissgrid swiftly intervened with reserved power to stabilize the grid, yet this event incurred costs estimated between 20 to 30 million Francs, which will ultimately be passed over to the consumers.

What has happened? According to Swissgrid, the weather forecasts didn’t manage to capture the sudden onset of winter after the very warm April days. On that Monday, it snowed down to the lowlands, covering the solar panels in snow. Consequently, solar power production dropped to practically zero, significantly deviating from the forecasted high solar generation, resulting in the sharp supply deficit.

Energy storage plays a crucial role in enabling a sustainable future by balancing supply and demand on the power grid, particularly as we increase our reliance on intermittent renewable energy like solar and wind. By efficiently storing excess energy and releasing it when there is supply deficit, energy storage helps stabilize the grid, minimise electricity curtailment, and reduce the reliance on fossil fuel-based power generation.

According to European Association for Storage of Energy (EASE), storage deployment needs to ramp-up to at least 14 GW/year in order to meet a target of approx. 200 GW by 2030. By 2050 at least 600 GW storage will be needed in the energy system, achieving these targets is essential to ensure a reliable and sustainable energy future, however, given where we are today, there is still a long way to go.