Network Code on Demand Connection (DCC)
Historically, the ways in which generators and customers connected to electricity transmission systems were based on national (or occasionally regional) rules. Because electricity was generated by a small number of large generators, these rules were often specific to individual generators (or large customers) and in many cases were not legally binding. Other customers were seen as passive receivers of electricity and the lower voltage electricity distribution networks traditionally took power from the higher voltage transmission networks to supply homes and businesses. This is changing.
As ever increasing numbers of small solar and wind-powered generators are installed – for example on house roofs – distribution networks, at times, are becoming suppliers of electricity. Perhaps the biggest change is in the role of the customer. Smart grid technology (like smart meters) is enabling intelligent and active electricity usage – with customers able participate in deciding when and how they use electricity. This is called demand side response.
TSOs would not be able to manage the changes the system is experiencing without clear rules for everyone connecting to the grid (whether large or small, generator or customer). Without these connection rules it would be impossible to plan the system effectively or to manage it securely. Put simply, changing and aligning Europe’s connection rules is a prerequisite for the secure operation of Europe’s electricity sector in the years ahead.
The Network Code on Demand Connection (DCC) is one of three network codes (i.e. “Connection Codes”) which will set out these rules.
The DCC’s objectives
Offering a reliable source of energy to consumers is the objective of any power system. To keep an electricity system stable, electricity supply and demand need to remain in balance at all times.
Most European countries already have basic requirements in place for connecting to transmission grids. These requirements can take the form of a national grid code, contractual agreements or a set of common practices. However, a common set of rules for users across Europe has until now, never been developed. The development of a pan-European electricity market, an increase in the use of energy from renewable sources, and ambitious targets for realising the potential of customers to contribute to managing the energy system using smart grids all make a consistent set of rules necessary.
The DCC will ensure that all distribution networks and demand facilities (suppliers and customers) contribute effectively to the stability of the system across Europe.
Achieving the Demand Connection Code objectives
The Demand Connection Code (DCC) will set transparent European rules on how large demand interacts with the transmission system. This code will set out the capabilities that parties connecting to the system will be required to provide and will need to take into account when planning their connection.
The DCC clarifies the role that demand response will play in increasing the proportion of energy from renewable sources. The code specifies the basic functional requirements for electricity users who want to feed power back into the system from small-scale renewable generation technologies.
It provides a framework for making different household appliances ‘DSR ready’ (able to adjust their electricity usage automatically), making it easier for consumers to provide demand side response. Given that domestic demand makes up 30-40% of electricity use, giving consumers the opportunity to reduce their consumption at certain peak periods (and save money in the process) would enable renewable energy to provide clean secure supply.
Changes following implementation of the DCC
As with all network codes, the Demand Connection Code is legally binding. All parties connecting to Europe’s transmission grids are obliged to comply with the requirements as set out in the DCC. The code contains a mix of harmonised pan-European rules and national requirements, which will be decided on, by each country’s TSOs and regulator (following ranges set out in the code).
The first step will be to work with industry to specify these values. Each Member State will also need to review current standards, codes and requirements to ensure that their national rules are compatible with the cross-border rules in the DCC. The extent of change to national rules will depend on the arrangements which currently exist in a given country.
How the DCC links to other codes being developed
The Demand Connection Code is closely linked to the Network Code on Requirements for Generators (NC RfG). Many of the demand requirements principles are closely related to those for generation requirements. The code is also closely linked to the Network Code on Electricity Balancing and the Network Code on Operational Security. The former stipulates requirements for market actors to keep the system in balance, while the latter specifies how the capabilities defined in the DCC are used to maintain the correct balance of electricity networks.