Hamster wheel of renewable energy, symbolizing wasted effort.

Renewable Energy's Hidden Flaw: Are Storage Systems Cycling Out of Control?

Nico Varela in Climate & Environment December 2025 • 4 min read.

"Discover how unintended storage cycling in renewable energy systems can lead to increased costs and inefficiencies, and what steps can be taken to mitigate this growing problem."

The global movement toward decarbonization has spurred many governments to set ambitious targets for renewable energy sources. These targets are often framed as specific percentages of electricity demand or supply that must come from renewables. However, implementing these seemingly straightforward constraints in energy models can lead to unexpected and undesirable outcomes.

One such outcome is the phenomenon of 'unintended storage cycling,' where electricity storage systems are used excessively, resulting in simultaneous charging and discharging. This seemingly innocuous artifact can have significant implications for the cost-effectiveness and overall efficiency of renewable energy systems.

This article will explore the complexities of unintended storage cycling, examining its causes, consequences, and potential solutions. By understanding this often-overlooked aspect of energy modeling, policymakers, energy professionals, and everyday citizens can work together to ensure a smoother, more sustainable transition to a renewable energy future.

Understanding Unintended Storage Cycling: A Closer Look

Hamster wheel of renewable energy, symbolizing wasted effort.

Unintended storage cycling arises when energy models, used to plan and optimize renewable energy systems, produce a peculiar result: storage systems that simultaneously charge and discharge electricity. This means energy is being drawn from the grid to charge batteries or other storage devices, even as those same devices are releasing energy back onto the grid. This behavior, while seemingly counterintuitive, can occur due to the way minimum renewable energy share constraints are implemented in these models.

To achieve renewable energy targets, energy models must often include constraints that ensure a certain percentage of electricity comes from renewable sources. There are different ways to implement these constraints. However, some approaches inadvertently incentivize the model to use storage systems in a way that increases overall energy production from renewables, even if it means creating inefficiencies. In essence, it's like spinning the wheels—generating more energy than necessary simply to meet a quota.

Zero SLCR: Storage losses are covered by conventional energy sources.
Proportionate SLCR: Storage losses are shared between renewable and conventional energy sources.
Complete SLCR: Storage losses are completely covered by renewables.

The problem is that not all these approaches fully account for storage losses—the energy lost when converting electricity into a stored form and back again. When models don't properly account for these losses, they can create situations where it becomes 'cheaper' to cycle energy through storage than to curtail (or reduce) renewable energy production during times when supply exceeds demand.

Charting a Course to Renewable Energy

As the world continues its transition to renewable energy sources, it is crucial to address the issue of unintended storage cycling. By implementing more comprehensive energy models, policymakers and energy professionals can unlock the full potential of renewable energy. This includes lowering costs, improving efficiency, and paving the way for a truly sustainable energy future.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.isci.2022.104002,

Title: Renewable Energy Targets And Unintended Storage Cycling: Implications For Energy Modeling

Subject: econ.gn q-fin.ec

Authors: Martin Kittel, Wolf-Peter Schill

Published: 28-07-2021

Everything You Need To Know

What is unintended storage cycling in the context of renewable energy?

Unintended storage cycling refers to the excessive use of electricity storage systems, causing them to simultaneously charge and discharge. This behavior, observed in energy models, can occur when the models are designed to meet specific renewable energy targets. It leads to inefficiencies and increased costs within the renewable energy systems. The models might draw energy from the grid to charge batteries while the same batteries are also releasing energy back onto the grid, creating a cycle that is often more expensive than alternative methods.

What causes unintended storage cycling in energy models?

Unintended storage cycling arises primarily from the way energy models implement minimum renewable energy share constraints. Certain approaches do not fully account for storage losses, the energy lost during the charge-discharge cycle. The lack of accounting for these losses incentivizes the model to cycle energy through storage, even when curtailing renewable energy production would be more efficient. The way storage losses are handled in these models – whether they are covered by conventional energy sources (Zero SLCR), shared between renewable and conventional sources (Proportionate SLCR), or covered completely by renewables (Complete SLCR) – significantly impacts the likelihood and extent of unintended storage cycling.

Why is addressing unintended storage cycling important for the future of renewable energy?

Addressing unintended storage cycling is critical for the cost-effectiveness and overall efficiency of renewable energy systems. By identifying and mitigating this issue, policymakers and energy professionals can ensure a smoother, more sustainable transition to a renewable energy future. It helps in lowering costs and improving the efficiency of the systems, paving the way for a truly sustainable energy future. If left unaddressed, unintended storage cycling can undermine the economic and environmental benefits of renewable energy adoption.

How do storage losses contribute to the problem of unintended storage cycling?

Storage losses play a crucial role in causing unintended storage cycling. When energy is stored and then released, there's always some energy lost in the conversion process. If energy models do not properly account for these losses, they might indicate that it's cheaper to cycle energy through storage, even if curtailing renewable energy production during times of excess supply would be more efficient. Without accurately accounting for these losses, the models can create situations where the cycling of energy becomes an unintended consequence.

What steps can be taken to mitigate unintended storage cycling?

To mitigate unintended storage cycling, it is necessary to implement more comprehensive energy models. Policymakers and energy professionals should focus on improving how these models account for storage losses. Accurately modeling storage losses and considering different approaches to handle Storage Losses Covered by Renewables (SLCR) are essential steps. By refining the models, it is possible to reduce the incentives for excessive cycling and unlock the full potential of renewable energy sources, leading to lower costs and improved efficiency.