What is Demand Response (DR) | different types - FCR, aFRR, & mFRR programs

Demand response might sound like a complicated topic and the terminologies used around it’s technologies can be confusing too. But the concept of demand response is simple. This article may explain it in simple terms.

Our power grid systems to work smoothly, the electricity being injected into the grid and consumed should be balanced all the time, but finding this balance is the challenge!. On the demand side (i.e: on the consumer side), electricity demands are continuously changing due to various factors. On the other hand, the supply side also continuously shifting - especially since more and more “unpredictable” renewable energy sources like solar and wind are involved.

Gratefully, the demand response technologies help to resolve this issue, by ensuring supply and demand stay balanced.

What is Demand Response?

Demand response is a system used by grid operators to regulate electricity consumption by consumers (such as commercial and industrial businesses) to help keep the supply and demand of electricity in balance. Demand response (DR) services are often referred as demand-side flexibility services too, they are the same.

Demand response mechanisms

Different types of demand response programs are available. Frequency reserves include FCR, aFRR and mFRR, each operating in slightly different ways that allow TSOs to choose the most appropriate service. The main difference between them is the time it takes for each service to be activated.

1. Frequency Containment Reserve (FCR) :  is the “primary reserve”, may be you can consider it as a safety mechanism to provide a short-term balancing service to keep the grid frequency at 50 Hz. Whenever there is an outbreak in the system (e.g: due to a major power plant outage) FCR will pitch-in automatically within 30 seconds to help restore safety and security of the grid by balancing supply and demand of electricity.

2.  Automatic Frequency Restoration Reserve (aFRR): is a ‘secondary balancing’ service that pitches in when the grid imbalance can’t be solved by primary reserve / FCR and issue persists over 5 minutes. It’s mostly 5 mins time, and in several countries this margin is also coupled with +/- 0.2 Hz either side of 50 Hz. Unlike, FCR, this doesnot initiate automatically, but the grid aggregators working with TSO’s are responsible for activating this aFRR.

3. Manual Frequency Restoration Reserve (mFRR): Once a signal is received by the TSO, it can be activated manually or semi-automatically by an aggregator or by customers possessing the required software technology. mFRR is generally used when longer lasting events – or deviations in the grid frequency, cannot be rectified by other upstream balancing services, such as FCR or aFRR. According to European guidelines, mFRR must be fully deployable after 12.5 minutes with a minimum duration period of 5 minutes.

Image: Clean Horizon