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Real-time gas network nears field trials

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Antony Green Antony Green
Vice president, utilities and infrastructure, DNV GL

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Real-time gas network nears field trials
UK gas networks will need to use and account for a wider range of gases
Networks to handle mixed-source gas with varying energy content in a lower-carbon world need to be cost-effective, flexible, safe and secure. An innovative project involving a major UK gas distribution network operator aims to pave the way for this to become reality.

Industrial, commercial and domestic customers of SGN, the UK’s second largest gas distribution network operator, are being asked to host logging instruments to record and communicate how and when they use gas in a bid to understand energy demand in the company’s network of pipes. 

SGN hopes hundreds of volunteers in southern England will engage in the GBP8 million (circa USD10m) Real-Time Networks (RTN) project, developed in partnership with DNV GL. 

The goal is to create a new modelling technique to accurately measure energy flows within the network. Combining logging devices in customer premises with sensors in the network and external data on local weather conditions and consumer behaviour will enable the creation of a software tool to better understand a representative part of the modern gas network (see figure 1).   

The tool could ultimately be used across the entire UK gas network, enabling it to meet current and evolving needs. Gas meets around 80% of UK peak-time energy demand and is the main energy source for 85% of households. However, the long-term trend for natural gas production from the UK Continental Shelf is one of decline, forcing networks to use alternative sources, each with its own composition, physical properties, and energy content as indicated by the Wobbe Index (see figure 2). Networks to handle mixed-source gases need to be cost-effective, flexible, safe and secure. 

”The Real-Time Networks project will show that gas networks have very real and significant roles to play in the future energy mix,” said Angus McIntosh, SGN’s project director for the RTN programme. 

”To support transition to a lower-carbon economy, networks must be flexible to accommodate different compositions of gas without significant technical, safety or cost barriers, such as a need for expensive processing,” he explained. 

”At the applications level, we must adapt to the performance and functioning of modern gas boilers, cookers, heaters and fires, and the spread of newer downstream renewable technologies, such as combined heat and power (CHP) and hybrid systems. We also need to optimize use of renewable gas, such as biomethane in existing gas networks,” McIntosh added.

Figure 1: SGN real-time network project
Figure: Heating power of gases in the UK

Looking more closely at network modelling

With more than 74,000 kilometres of pipelines and 5.9m customers spread across contrasting geographies, demographics, and climates in southern England and Scotland2, SGN has a clear strategic interest in achieving the RTN project’s goals. 

How operators model and manage distribution networks underpins all decisions on investment in the network. In recent years, SGN has spent GBP500m upgrading its network. 

”As part of the RTN project, we are going back to first principles to look at how we model the network and how to ensure that it is fit for today and the future,” McIntosh said.  

SGN is leading UK research into real-time gas networks through this project, but learnings will be shared with the industry under the terms of the project’s funding from Ofgem, the UK gas and electricity markets regulator. 

The RTN proposal3 developed by SGN and DNV GL attracted the largest share of funding from Ofgem in an oversubscribed bidding process in the regulator’s annual Gas Network Innovation Competition in 2015. In a competitive tendering process, SGN chose DNV GL as project partner for the bid to Ofgem. ”DNV GL is now fully engaged with SGN in executing the project itself,” said McIntosh. 

The ’Opening Up the Gas Market’ project conducted by SGN has already shown that varying qualities of gas could be used safely by appliances supplied by its Oban gas network in Scotland.4 As a consequence, a request to UK regulators to allow a greater range of gas sources into the network, without expensive processing, is already in progress. 

”A key thing about the future energy mix is not to back only one horse. We need real options. The gas network plays an important role currently, and will continue to do so if it can be flexible to changing applications and sources such as LNG, shale gas, coal-bed methane, biomethane and hydrogen,” explained McIntosh.

What the future holds

The majority of gas distribution networks are not fitted with flow or gas quality sensors, so there is uncertainty in understanding exactly how they operate. Currently, there is only a rudimentary capacity to gather and communicate data. ”In the future, we will not only know the energy content entering the network, but will be able to understand energy flow and better predict customer demand,” said Antony Green, vice president, utilities and infrastructure, DNV GL.

Implementing the RTN project

DNV GL and SGN researched technology requirements for measuring flow and gas quality in the network. They have since examined and validated, pre-installation, the latest logging equipment and sensors available, and communications technologies to relay data to a novel software platform.  

There are big challenges in measuring flow in the network because of the low pressures, range of pipe sizes and materials, lack of power supplies and the roadside locations. Novel applications for flow measurement will be trialed using ultrasonic technology. Gas quality will be measured by an inferential device that is cheaper and easier to manage than traditional gas chromatography. 

”Further down the line, far less costly gas quality measurement solutions will be needed by the industry,” Green observed. ”Once such sensors are widely used, market forces will bring lower-cost devices.”     

On the IT side, the project combines innovative applications of data cloud technology, big data, and real-time network modelling. DNV GL’s experts are drawing on its broad insights from data handling in transmission and other utility distribution sectors to design the concept for the RTN project’s data handling and analytics solutions from the ground up.

Challenging assumptions

The project may challenge existing assumptions and definitions. ”Networks are currently designed using averages of aggregated demand at particular times of day and the year – these are based on data that is 30 to 40 years out of date. Accurate real-time modelling will allow networks to optimize their operations and understand the energy content to a more granular level,” Green said. 

This could allow future networks to be designed differently, he explained: ”It is currently supposition, but quite possible, that we may be over-designing networks for a projected peak demand in energy use that may be higher than would ever occur in reality.”

References

  1. ‘DNV GL partners with SGN to deliver innovative project for UK regulator’, DNV GL, June 15, 2016 
  2. Delivering on our customer promise: annual report and accounts 2016’, SGN, 2016 
  3. ‘Gas network innovation competition: real-time networks’, SGN, October, 2015 
  4. ‘Opening up the gas market’, SGN, October 2016.