Solar energy is rapidly transforming the energy landscape, but excess production strains grid capacity. Solutions such as storage, demand flexibility, and overbuilding could turn this challenge into a pathway to greater resilience.

When the sun outshines the grid
Solar power is expanding at an incredible rate. Ironically, this success creates new challenges for power systems. With the surge in photovoltaic capacity, solar curtailment is becoming more common – where surplus energy generated by solar plants can’t be absorbed and must be “switched off.”
These cuts in production signal a lack of flexibility in the energy system. It highlights that grid infrastructure – both transmission and consumption – was not designed to handle large-scale renewable output.
This underscores the need for new, adaptive solutions. However, curtailment isn’t a failure of solar energy; it’s a technical reality that calls for smarter management.
In 2024, solar energy made up 11% of electricity consumption in the European Union, surpassing coal-based power (which dropped to 10%) for the first time.
Understanding solar curtailment
When solar generation exceeds demand and there aren’t enough batteries or transmission lines to store or move the electricity, the system must be balanced. Operators achieve this by temporarily reducing output from large-scale solar plants or limiting household prosumers.
Globally, solar power has seen remarkable growth, with 239 GW of new capacity installed in 2022 – a 45% increase over the previous year, the highest since 2016. In Romania, solar generation rose by over 60% in the first eight months of 2024 compared to the same period in 2023.
Often, output control proves more economical than investing heavily in new infrastructure. But, long-term strategies that integrate surplus solar energy are essential to sustain renewable expansion.
Managing solar variability with smarter grid solutions
Variability is another challenge for solar power. Short-term fluctuations – like cloud cover – can cause sudden drops in output across thousands of systems, straining local grid stability.
To counter this, countries with high solar penetration are implementing advanced measures such as:
- Forecasting technologies to predict output fluctuations
- Load management, where utilities temporarily limit non-essential consumption (e.g., air conditioning)
- Controlling battery and EV charging cycles
Additionally, reinforcing transmission networks between production hubs and demand centers helps smooth supply-demand imbalances.
A 2021 study introduced a hierarchical control system for large-scale solar plants. This system enables plants to proactively adjust their output based on real-time conditions, stabilizing the grid without relying on non-renewable resources.
A setback or a driver of progress?
One risk posed by curtailment is reduced profitability for solar projects. Investors may hesitate if they know a significant portion of production could be curtailed, introducing uncertainty around returns.
To mitigate this, various grid flexibility measures are being adopted, such as:
- Energy storage solutions (batteries, pumped hydro)
- Demand-side flexibility (adjusting consumption patterns)
- Grid expansion and optimization
- Flexible use of dispatchable renewable sources (e.g., hydropower)
- Adjusting fossil-fuel power plant operations
These strategies enhance the integration of surplus energy, reduce financial risks, and improve the resilience of power systems.
Why overbuilding solar capacity works
One increasingly adopted strategy is overbuilding solar capacity – installing more photovoltaic panels than the expected demand. While this may lead to periodic curtailment, the long-term benefits often outweigh the losses.
Why is overbuilding effective?
- Stability and predictability: Extra capacity ensures consistent output, even on less sunny days or during peak demand. This reduces reliance on alternative energy sources.
- A virtual form of storage: Surplus capacity acts as a buffer, smoothing out fluctuations in production and giving grid operators greater flexibility to balance supply and demand.
- Cost-effective compared to large-scale storage: As photovoltaic costs continue to fall, it’s often more economical to install extra capacity than to invest in expensive storage or transmission infrastructure.
Progress through adaptation, not restriction
Solar curtailment isn’t a barrier but a transitional phase in the evolution toward a renewable-driven energy system.
Solar energy will remain central to the global energy mix. The real challenge lies not in reducing output but in building smarter grids, crafting adaptive policies, and developing economic models that maximize renewable potential for a sustainable future.