DSR: The Details

What are Demand-Side Response (DSR) services?

National Grid needs the support of businesses (the demand side) to help keep the electricity network in balance. With renewables making up a growing proportion of UK generation capacity, the grid infrastructure needs to be more flexible and responsive than ever to cope with fluctuating supply. Demand-side participants have a major role to play in managing demand or increasing supply (from on-site generation assets) when required, to help National Grid balance the network and keep the lights on.

The services offered by National Grid to help businesses participate in this market-balancing work are known as Demand-Side Response (DSR) services. The more DSR participants there are in the market, the better National Grid is able to cope with fluctuating supply and demand – and ultimately prevent power cuts.

DSR services available from ENGIE

DSR balancing services fall into two broad categories – those that seek to control frequency on the network (response services), and those that seek to control supply and demand (reserve services). A number of services are available under each category, offering opportunities to participate for businesses with different response capabilities and levels of flexibility.

Response services

To maintain system frequency within 1% of 50 Hz, National Grid offers frequency response services that enable it to maintain second-by-second control over electricity demand and generation. The response from participants in these services needs to be instantaneous to enable National Grid to overcome sudden frequency fluctuations and to withstand unexpected faults. Response services include:

• Firm Frequency Response (FFR) 

A monthly tendered service that requires participants to respond by providing a minimum of 1MW to the grid within 30 seconds. It typically involves switching on generation assets rather than reducing demand.

• Enhanced Frequency Response (EFR)

A new, faster service which requires businesses to provide full frequency response in less than a second. It is a dynamic service, which requires participants to continuously vary generation or demand in response to frequency changes – rather than responding to a pre-set frequency trigger.

Reserve services

National Grid also requires access to supplementary sources of power, in the form of small-scale, on-site generation plant, and to sources of demand reduction. It accesses these capabilities through its reserve services. For businesses that cannot meet the required capacity thresholds (outlined below), ENGIE can aggregate your capacity with that of other small generators to enable you to take part.

The response time for these services and the duration of action required are typically longer than for frequency response services. Reserve services include:

• Short-Term Operating Reserve (STOR) 

A vital reserve service for National Grid, procured via three tenders per year. Participation requires a response in under twenty minutes, with actions delivered for up to a potential of four hours. Although National Grid requires a minimum of 3MW of generation or demand reduction to participate in this service, ENGIE can aggregate loads from around 250kW to facilitate a route to market.

• Fast Reserve

A monthly tendered service that provides 50MW blocks of reserve energy, with a response required within two minutes.

• Demand Turn Up 

This service requires participants to increase demand when there is excess generation from wind and solar on the network. You can deliver demand increases either by reducing your on-site generation or increasing consumption. Demand Turn Up is typically required at periods of low demand, such as overnight, at weekends and holidays. A response is required within several hours of notification.

Other demand-side services offered by ENGIE:

• Capacity Market

The Capacity Market aims to ensure there is sufficient electricity capacity available to meet forecast levels of demand in the future – to ensure security of supply. It offers payments to generators and demand-side providers for guaranteeing that they will provide the additional capacity when it’s needed. ENGIE can help you to secure a Capacity Agreement through the Capacity Market auction process.

• Peak Avoidance

This involves reducing energy consumption at times when peak demand is forecast. It includes Triad Avoidance, which involves reducing consumption when peak winter demand periods, known as Triads, are expected. As well as reducing exposure to peak prices, the aim is to reduce the TNUoS (Transmission Network Use of System) charges associated with Triad periods.