What is curtailment?
Curtailment is an English term from the energy sector for the conscious and temporary reduction or discontinuation of electricity production or return from an energy installation.
This usually concerns renewable energy installations, such as solar panels and wind turbines. The available power is then set lower than is technically possible.
Why does curtailment exist?
Solar and wind installations produce electricity based on the weather, not based on direct demand or available grid capacity. This creates times when more electricity is generated than the system can handle safely or economically.
At such times, limiting production is not a choice, but a necessary control tool to keep the system stable. Curtailment prevents the electricity grid from becoming overloaded, the grid frequency from coming under pressure or from having to sell electricity at very unfavorable conditions.
The design of the current energy system also plays a role. The grid was historically designed for central, highly predictable production and one-way traffic. Due to the rapid growth of decentralized generation, this infrastructure is reaching its limits in more and more places.
1. Grid congestion and physical limitations
Grid congestion occurs when the electricity grid has insufficient local capacity to transport all the generated electricity. This mainly occurs in areas with a lot of simultaneous generation from solar panels or wind installations.
The grid has physical limits: cables and transformers can only handle a limited amount of power. Once that limit is reached, production must be temporarily limited to prevent overload and disruptions.
Because grid congestion is often location and time dependent, curtailment is used as a temporary means as long as structural solutions are lacking.
2. Overproduction of solar and wind energy
When many solar and wind installations produce simultaneously, the supply may temporarily be higher than what the grid or customers can absorb.
This oversupply mainly occurs on sunny afternoons or in periods with a lot of wind. Curtailment then keeps the system in balance and prevents uncontrolled surpluses.
3. Market incentives such as negative prices
On the electricity market, a temporary surplus of power can lead to very low or even negative electricity prices. Returning costs money instead of yielding anything.
In that situation, curtailment is an economic choice: limiting production is financially more favorable than putting electricity on the market at a negative rate.
When is curtailment applied?
Curtailment is applied at times when electricity production is temporarily undesirable or not possible. This may be technically forced or strategically planned, depending on the situation.
The deployment varies per type of installation, scale and degree of automation. In practice, curtailment mainly occurs with renewable generation that produces simultaneously and is difficult to control.
How does the technology behind curtailment work?
Curtailment is not an administrative measure, but a technical intervention in the control of an energy installation. The core is simple: the available power is actively limited via hardware and software.
How this is done depends on the technical structure of the installation and the degree of automation.
1. Power limitation via inverters
With solar panels and many wind installations, curtailment takes place via the inverter. This converts the generated direct current into alternating current and determines how much power is actually supplied.
With a set power limit, the installation produces less than is technically possible. The installation remains active, but returns in a controlled manner.
2. Control via an energy management system
In professionally managed installations, curtailment takes place via an energy management system (EMS). This system centrally controls inverters, batteries and other assets.
An EMS automatically applies curtailment based on grid load, market prices or preset rules. This means that the power is adjusted dynamically, without manual intervention.
What is more effective: manual or automated curtailment?
Manual curtailment, for example with fixed power limits, is simple but not very flexible. Automated curtailment responds to conditions in real time.
The system only limits production when necessary and allows maximum generation as soon as space becomes available again. This is how you achieve optimal curtailment.
Can anyone curtail energy assets?
Not everyone with energy assets can apply curtailment independently. This depends on the technical design, the grid connection and the degree of control of the installation.
Small installations without active control are often dependent on the grid operator or fixed settings in the inverter. Larger or professionally managed installations can use curtailment themselves, for example via power limitation or automated control with an energy management system such as the Smartbox.
Smartbox
Responding intelligently to curtailment starts with Smartbox
Smartbox is an innovative energy management system (EMS) with proprietary software, developed by our R&D team in the Netherlands. The system connects solar panels, wind installations, batteries] and other assets with real-time market and grid signals and controls them fully automatically.
As a result, curtailment is no longer an emergency measure, but a strategic instrument within the total energy management of end users.
- Automatic power limitation to prevent negative feed-in.
- Curtailment only when technically or economically necessary.
- Real-time control within 20 milliseconds based on market prices and grid conditions.
- Combination of curtailment with storage and market optimization.
- Live data in the clear Smartbox Portal.
- Maximum return from the same energy assets.
Do you want to get maximum return from your customers' energy assets? We are always looking for new energy companies and energy installers who want to offer the Smartbox in their customer portfolio. Contact us and become a partner.