The Network Codes on Load Frequency Control & Reserves (NC LFCR) and Electricity Balancing (NC EB) can be thought of as two sides of the same coin. They form an important bridge between the operation of the system and the operation of the European market. The NC LFCR sets out the conditions from which a pan-European balancing market can be constructed. In simple terms, the NC EB sets out the way in which reserves and system services will be procured on a pan-European basis, while the NC LFCR determines the levels of reserves which TSOs need to hold.

The NC LFCR and NC EB can be thought of as two sides of the same coin. They form an important bridge between the operation of the system and the operation of the European market. The NC LFCR sets out the conditions from which a pan-European balancing market can be constructed. In simple terms, the NC EB sets out the way in which reserves and system services will be procured on a pan-European basis, while the NC LFCR determines the levels of reserves which TSOs need to hold.

The existing rules reflect the specificities of countries and not necessarily of Europe as a whole. Hence, there is a need for a more coordinated “top down” approach to setting clear expectations on all parties active in the sector so that they all contribute to the common goal of secure electricity supplies. This is particularly important in the case of load frequency control, which is at the heart of ensuring security of supply.

The vast majority of countries have their own rules to regulate the operation of the transmission network (and sometimes, as in the Nordic region, these are applied to several countries). Until today, the most extensive of the rules was the “operational handbook” used in the continental European synchronous area.  This voluntary agreement provided the basis for cooperation between all countries within this area.

In developing the NC LFCR, ENTSO-E has drawn on existing rules and best practice while taking into consideration the future challenges which the transmission system will face.

Frequency is the term used to describe the normal oscillations of alternating current (AC) in an electric power grid. The frequency of the transmission system is a continuously changing variable that is determined and controlled by the second-by-second (real time) balance between production and consumption. If demand is greater than generation, the frequency falls while if generation is greater than demand, the frequency rises.

Frequency quality is a requirement for electricity transmission systems to operate correctly; a balance of electricity between power production and consumption is a requirement to maintain the system frequency at the required frequency of 50 Hz. This process is load frequency control.

The vast majority of countries have their own rules to regulate the operation of the transmission network (and sometimes, as in the Nordic region, these are applied to several countries). Until today, the most extensive of the rules was the “operational handbook” used in the continental European synchronous area. This voluntary agreement provided the basis for cooperation between all countries within this area.

In developing the NC LFCR, ENTSO-E has drawn on existing rules and best practice while taking into consideration the future challenges which the transmission system will face.

Frequency is a common value for a synchronous area (a group of connected countries). Therefore, all TSOs must work together to maintain frequency across the synchronous area. This is done by each TSO ensuring that there is no error in its transfer of electricity to neighbouring TSOs. If the transfer error is zero then the system is balanced. If all the TSOs systems are balanced, then the frequency within the synchronous area will be at the required 50Hz.

When the transmission system operators (TSOs) see either their transfer error increasing or the system frequency changing from the standard value of 50 Hz, they act to control it and restore the system to the required value. This may happen, for example, because a power plant has broken down or because a demand or generation forecast was inaccurate.

TSOs need to ensure that sufficient generation and/or demand is held in automatic readiness to manage all circumstances that might result in errors or frequency variations. This is referred to as reserves.