Spain’s shady spring highlights solar challenge

At the end of March, a huge Saharan dust storm saw residents of southern Spain waking up to skies tainted with an intense orange hue and ‘red rain’, caused by tiny particles of dust in the air that had travelled hundreds of miles across the Mediterranean.  

As extreme weather events continue to break records globally, 2022 has seen Spain experience its wettest March in 61 years. Coupled with the dust storm, this resulted in the country’s biggest decline in solar irradiance in 28 years. 

With Europe undergoing a rapid energy transition following Russia’s invasion of Ukraine, the case for clean energy has never been stronger. Policymakers are determined to slash the EU’s Russian gas dependence by increasing the continent’s reliance on renewables. With Spain doubling its solar capacity in the last three years, the country is implementing measures to achieve a 100 percent renewable electricity mix by 2050.  

As solar specialists, we regularly look at historical, recent, and forecasted data. After the dust storm, Solargis’s team of experts found on their maps a 50 percent decrease in Spanish solar irradiance – the most extreme decrease since the beginning of their satellite-based records in 1994. By contrast, Germany and the Balkans saw solar irradiance during the month of March at levels about 45 percent higher than long-term averages. 

With Spain one of Europe’s sunniest countries and with Germany looking to triple its solar energy capacity to 215GW, these significant deviations from average values reflect the weather anomalies and our changing climate, making it increasingly difficult for project developers and investors to accurately calculate return on investment and support solar integration into the continent’s grid at a time when renewable energy is in extremely high demand. 

Variability 

A recently conducted 10-year analysis highlighted the fact that solar irradiance levels have deviated from the long-term averages that are often used to underpin production estimates and financial models. North America, India and Australia have witnessed significant variation both above and below these averages, illustrating the variability challenge that solar poses. It is a promising yet intermittent renewable energy source. 

In Europe, as mentioned, this year the Spanish Meteorological Agency recorded the country’s least sunny March since records began. This was preceded by the fifth driest January and second driest February, although winter is usually a wet period. While such deviations may not be too unnerving for investors with project portfolios distributed across multiple countries, it does highlight the seasonal variability inherent in renewables and the strain faced by utilities required to make up the energy shortfall from temporarily underperforming, weather-dependent sources such as hydropower plants and solar farms.  

“Improved grids
spanning countries
will enable regional
utilities to compensate
for local variability
through clean
energy sources”

Although renewables are now significantly undercutting fossil fuels as the world’s cheapest source of power, during periods of weather intermittency, renewable energy deficits are still usually balanced out by conventional power. It is therefore essential that we manage regional variability better across regions of Europe by improving the quality and interconnection of grids. Doing so would help reduce the continent’s energy dependency on fuel imports. 

Interconnected European grid 

The record low solar irradiance noted across the Iberian peninsula this March serves to highlight that we are dealing with a variable power source and one that is subject to seasonal, monthly and short-term fluctuations. For Europe to best manage this variability without relying on fossil fuels, there is a need for improved regional grids, as well as for cross-continental infrastructure.  

It is well-known that grid interconnection in Europe isn’t sufficient to accommodate the growth in renewables required to meet climate targets. Insufficient interconnection hampers the ability of neighbouring solar- and wind-rich regions to compensate for anomalous low generation capacity in markets such as Spain during the recent winter period.  

Interconnectors allow the import of electricity when there is not enough generation capacity in the home market but excess generation is available in interconnected markets. Improved grids spanning countries will therefore enable regional utility companies to compensate for local variability through clean energy sources rather than by reverting to fossil fuels. 

The modernisation of the grid faces significant challenges. However, we are seeing that there is a clear push for a more coordinated energy policy and coordinated approach to interconnection between countries across Europe. 

Digitalisation of the grid 

While the power sources of our future require an innovative approach to grid interconnectivity, so too do they require increased digitalisation to support their integration. Currently, new simulation and data analysis tools are being developed to optimise the design and operation of complex power systems and entire portfolios on a large geographic scale.  

As we transition to more weather-reliant means of power generation, we need to invest more in hardware and software able to react to the associated variability. This can be done in part by relying on Europe’s world-leading meteorological services. However, we need more sophisticated forecasting to ensure a steady energy source across grids. 

A new generation of forecasting models allows grid operators to maintain balance between variable and flexible energy sources through flexible trading and energy exchange. The digitalisation of our grids coupled with increased interconnectivity ultimately will allow larger generators to react faster and more efficiently to regional variability in renewables. In addition, these technologies unlock the unexploited potential of solar power portfolios to provide grid-balancing services. 

As margins tighten for solar asset owners and investors, investment in high-quality solar and weather data and software services is crucial to understanding – and managing – the impacts of resource variability on performance and profitability. 

With solar performance coming under increased scrutiny because of changing global energy market conditions, investment in robust resource data throughout the lifetime of solar projects has become a prerequisite for asset owners and operators seeking to manage the financial impacts of power generation variability. 

Ultimately, high-quality solar data helps to better understand and address deviations from expected production, forecast short-term performance, and support effective integration into modern, digitalised grids. 

Through our work, we hope to highlight the variability challenge in key markets to best support policymakers, planners and consultants and encourage the adoption of high-quality, real-time weather data into renewable energy decision making. 

Controlling the weather is beyond our capabilities, but what solar developers, owners and operators can control is their knowledge. Vital, trusted intelligence on the solar resource and the specific geographical conditions at project sites can be the difference between an asset that retains its value through its life cycle and one that fails to live up to its potential.  

The author is the chief executive of Solargis, a data and software company based in Bratislava, Slovakia, that specialises in solar energy assessments.