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Curtailment, receiving a payment for shutting off

This may sound strange, but sometimes one can earn money by shutting off wind turbines. This is how it works.

TenneT is responsible for preserving the balance on the Dutch Electricity Network. In a situation of shortage TenneT will compensate producers of energy for delivering extra electricity on the network, but also when consuming less. In the event of surpluses they will reward producers of energy to deliver less on the network or to consume more energy. A few times a day the surplus reaches a level where producers of energy will even receive a payment for completely shutting off the production. In moments like these it’s sensible to fully shutdown the wind turbine for a certain amount of time. This phenomenon is also know as ‘curtailment’.

The need for accurate predictions

The moments where prices become negative are unknown in advance. The challenge here is to execute accurate predictions. Therefore Senfal developed software which is able to conduct predictions with a high level of certainty about the correct imbalance moments combined with negative market prices. The prediction of the dynamics of the energy markets is one of our core activities. The predictions of imbalance moments are underpinned with the use of our smartest mathematical models and privately developed artificial intelligence. The result is a well performing predictor which achieves the best results compared to other solutions. 

How it works

But how does it work? TenneT publishes minute-to-minute information concerning the exertion of balancing power with which the network operator preserves a balance between supply and demand. It also includes information regarding the present volumes and the price they pay. This information, together with other data, is the foundation for the predictions of the price per 15 minutes. Even during these 15 minutes we may sometimes alter our predictions, in order to make use of the remaining time to possibly, temporarily disconnect the turbine. Together with the wind park manager we decide on possible curtailment scenario’s. To arrive at possible scenario’s, we look at the technical specifications of the wind turbine, the SDE-price and the price of green certificates. All these factors are taken into account to make the right decisions.

Predicting & Adjusting

When our ‘peak caller’ predicts high imbalance prices, our system communicates with the wind park’s controller. Depending on the wind turbine the output of the turbine is curbed by pitching the blades or controlling the torque of the turbine. When the end of the imbalance period is predicted, then the turbines will be switched upward again to enable full production afterwards.

Higher return

The merits are highly dependant on market circumstances, however they eventually result in a higher return. Although this can run up to several thousands of Euro’s per MW annually. In addition we also apply our imbalance-predictor for industrial companies. For these clients we take care of both upward and downward regulation of consuming and generating installations.

The future

We at Senfal we believe that we need to generate as much energy as possible from sources. It’s somewhat of shame that the free-of-charge energy from a wind turbine isn’t used from time to time. That’s why you may not always want to curtail, but prefer to use your energy more usefully. For example by allowing an industrial process to consume more -or to charge your electric vehicle when wind power is available. We see these kind of systems being developed more and more. Currently, oversupply by sustainable sources sometimes results in negative prices. Then you are actually paid to consume energy! Controlling industrial processes and/or the moment people charge their electric vehicle could potentially counteract negative prices, by ensuring consumption on those moments. If and when this will result in the disappearance of negative prices is hard to tell. On the other hand there is an increasing amount of sun and wind energy on the network, which then also increases the demand for more flexibility. Currently we still see negative prices several times a day which apparently makes it economically more efficient for society as a whole to temporarily switch-off turbines. At least if a larger fraction of our energy can be sustainably generated by occasionally upward and downward regulation of sun and wind energy, we will be happy to contribute to that!