Have you ever heard the term “zero feed-in” in solar energy discussions and wondered what it actually entails?

You’re not alone.

In the Dutch energy industry, more and more grid operators are imposing contracts that require zero feed-in, yet they rarely define it in precise technical terms. Is absolute zero feed-in even possible?

Let’s explore the realities behind this requirement, the technical challenges, and how we might work toward a clearer industry standard.

The rise of zero feed-in requirements

In recent years, Dutch grid operators have increasingly required that solar installations deliver no surplus electricity back to the grid. But if you ask them what “zero” truly means, you’ll typically get a one-word answer: “zero”.

For asset owners and energy management system (EMS) providers, that raises many follow-up questions, and no one seems to agree on a standard interpretation. Despite these contracts, there’s no unified certification or guideline. And without consensus, those enforcing zero feed-in risk creating more confusion than clarity.

Is absolute zero feed-in really possible? (spoiler: not really)

Technically speaking, an absolute zero feed-in – where not a single watt ever flows back into the grid – is nearly impossible to achieve: every control system reacts to the real-time flow of energy with a slight delay.

This delay occurs because the system must first measure what’s happening, then make a decision (is an adjustment needed? If yes, which one?), and finally take action by reducing or increasing the output of your solar system. During those fractions of a second, a small (but measurable) quantity of power could still slip through to the grid.

Modern EMS technologies can shrink that delay to almost nothing, but never truly to zero. This means that if we’re serious about meeting a “zero feed-in” target, we should be talking about a small, allowable margin of error rather than a hard-and-fast zero.

Three key factors influencing local control loops

In understanding why zero feed-in is so difficult, it helps to zoom in on the control loop – the automated process that measures energy flow and adjusts power output accordingly. Three primary elements cause delays and small inaccuracies:

1. Deadband

You can think of this as a “quiet zone” in your system. This is a range within which small fluctuations in input do not immediately trigger an adjustment in output. This prevents the system from making constant micro-adjustments, which can cause instability and unnecessary switching actions. In the context of zero feed-in, this means the system has a certain margin within which it only adjusts if the deviation exceeds a specific threshold.

2. Response time

Every component in the control chain has a processing time, meaning adjustments never happen instantly:

• The meter takes about 100 milliseconds to sense real-time energy data.
• The EMS processes that data and calculates new instructions, also in under 100 milliseconds.
• The solar inverter receives this new setpoint and adapts its power output. Depending on the system, this can take from a few milliseconds to several seconds before the effect is visible.
3. Local load variations

On-site energy consumption can fluctuate suddenly: for example, when a large machine is turned off or a heavy load is switched on. The control system tries to compensate, but can’t do so instantly, leading to brief deviations from the zero feed-in target.

Understanding these factors is key to designing a stable, reliable control loop that can perform well under real-world, changing conditions.

The absence of clear standards

Another part of the zero feed-in puzzle is the lack of a recognized Dutch standard or certification. If an asset owner wants to check whether their system meets a grid operator’s requirement, to which specification can they turn? So far: none, at least not domestically. 

This absence of shared guidelines can lead to varying interpretations and inconsistent applications across projects.

Defining zero feed-in

To find a workable solution, we need clear guidelines. At the very least, we need to align on:

• What is a zero feed-in system?

A clear definition of how a zero feed-in system should behave in practice and the operational boundaries it needs to respect.

• What is an acceptable deviation?

A realistic threshold for negligible feed-in (for example, a few watts or a short interval of kilowatts) that reflects technical limitations.

• How to measure and verify?

A standardized approach to testing and confirming whether a system is performing within that allowed margin.

Without these core elements officially defined, zero feed-in remains more aspiration than reality.

Learning from existing international standards

Why reinvent the wheel when other countries have traveled this road already?

For example, Spain has the UNE 217001 standard,The UNE 217001:2020 standard in Spain specifies the testing requirements for systems designed to prevent the injection of energy into the distribution grid (zero feed-in). This standard is crucial for ensuring that renewable energy systems, such as photovoltaic (PV) installations, do not export excess energy to the grid, thereby complying with local regulations like ITC-BT-40 and RD 244/2019.

Key aspects of the standard include:

• Testing for compliance: Systems must be tested to ensure they can reduce power production within two seconds when surplus energy is detected, preventing grid injection.

• Technical specifications: The standard outlines the technical requirements for inverters and other components to meet zero feed-in criteria, including redundancy in control systems and communication protocols.

• Certification: Equipment must be certified according to internal procedures, such as SGS PE.T-ECPE-51, to confirm compliance with UNE 217001:2020. which precisely defines how zero feed-in systems should work and what deviations are acceptable. Studying and adopting established standards could help the Netherlands build a robust framework in less time, bringing much-needed clarity to the market.

Crafting the ideal zero feed-in setup

Achieving a stable, reliable zero feed-in arrangement demands a well-planned control architecture. This typically includes:

• Closed-loop control

Real-time feedback from the grid connection point enables fast and stable power adjustments. High-accuracy metering ensures you’re capturing the actual flow of energy as it happens. Dynamic calculation of the active power setpoint considers the current load and solar energy production.

• Fail-safe measures

Communication failures and technical glitches are inevitable, so fail-safe protocols are essential. These systems detect errors automatically and switch to a fallback mode.

The Teleport: A practical zero feed-in solution

One real-world example of a system designed with these requirements in mind is the Teleport Gateway.

Withthegrid built it around closed-loop control so that it constantly monitors grid feed-in and adjusts power output in near real-time.

High-precision meters validate the actual flow of electricity, minimizing feed-in beyond the acceptable margin.

Crucially, Teleport also integrates with ABB protection relays for fail-safe operation. That means if the communication link or the EMS itself encounters a critical fault, the system can:

• Automatically switch to a fallback mode
• Retain the last known setpoint
• Apply a default setting (like 0% output)
• Completely disconnect if necessary

It is also possible to apply zero feed-in using a battery by configuring a peak shaver.The Teleport peak shaver manages battery and PV systems to maintain grid limitations at a single measurement point. It prioritizes PV generation over battery discharge and can perform peak shaving to correct grid consumption or feed-in violations, which can be independently disabled.

The controller supports 15-minute contractual limits, dynamic power reduction via schedules, and state of charge (SoC) management with primary and secondary limits for optimal battery usage. The battery will be first used to charge / absorb the excess PV power. It will allow the PV to be curtailed only if the battery is full. 

In a context where zero feed-in is increasingly required but seldom clearly defined, the Teleport aims to bridge the gap by combining advanced controls with robust fail-safe options.

Conclusion: Calling for clarity

Zero feed-in is fast becoming a standard expectation in Dutch solar projects, yet the industry lacks a common blueprint. Without clear guidelines, asset owners and EMS providers remain uncertain about how to comply with grid operators’ demands.

The solution lies in unifying our technical understanding (grounded in feasibility), and in following or adapting standards that already work in other regions of the world.

It’s time for grid operators and the industry to make clear agreements on this issue. By aligning on concrete definitions and acceptable margins, we can transform an ambiguous requirement into a practical, reliable approach that benefits everyone involved.