Four lit gas rings partially in view against a near-black background

Understanding within-day behaviour

We highlighted last November that for certain supply and demand patterns, how gas is put on and off the network within-day could create operationally challenging conditions in the South East. During this study, we found that the frequency and level of operational challenges varied depending on assumptions made around how customers will use their capacity within-day  in the future.

We want to work with you to further refine our assumptions and undertake enhanced network capability studies. This will help to ensure you can continue to flow gas at the most efficient profile for you, with minimal restrictions.

2000 –> 2018  How has within-day behaviour changed

Throughout the gas day, supply and demand are rarely in balance. If demand exceeds supply, levels of linepack within the National Transmission System (NTS) will decrease along with system pressures. The opposite is true when supply exceeds demand.

We have seen an increasing trend in:

  • the range between minimum and maximum linepack in the NTS within a gas day (linepack swing)
  • market imbalance between supply and demand at the start of the gas day
  • the time taken for the network to be in balance by the end of the day.

These trends reflect how some of our customers are changing the way that they want to put gas on and off our network within-day.


2020 –> 2035 How will it continue to evolve

Some of you have told us through face-to-face meetings and our February 2018 webinar that you believe levels of supply and demand volatility, and thus linepack swing could increase for several reasons. To better understand the level of operational risk this could create, we want to further refine our current within-day modelling.

This will help to:

  • increase the accuracy in assessments of our current network’s capability to meet your future needs
  • maximise the value we get from our current network before we begin to consider investing in solutions
  • ensure we continue to make informed decisions that are right for the end consumer

Maximising our capabilities to benefit your operation

We are looking to publish a document in February 2019 which takes a deeper look at:

  • how within-day behaviour could evolve in the future
  • the impact it could have on network operation
  • whether current and future network capability can continue to meet future within-day customer needs
  • what potential options we could consider if we find this not to be the case

To do this, we want to further refine our current within-day modelling and solution optioneering assumptions by understanding:

  • what factors impact how you use your capacity currently and how these factors could change in the future
  • what impacts the accuracy and notice-periods of your day-ahead and within-day flow notifications and how this could change in the future
  • What benefit having optionality to flow gas at an efficient profile, with minimal restriction, has commercially and operationally for you.

By actively working with you to ensure we understand your needs, together we can make informed decisions that continue to facilitate efficient market operation and are right for end consumers.

About the authors: Imran Abdulla ([email protected]is a Senior Gas Network Strategy Analyst in the Future Networks team in Warwick, where Adeolu Adesanya ([email protected]) is a Lead Economics Analyst.