Network Modelling Software Review

2. Network Modelling Software Review A presentation to Transmission Workstream Angus Paxton 5th February 2009

3. About Pöyry Energy Consulting • 42 energy consulting staff based in Oxford • 250 energy consulting staff throughout Europe • 15 European offices from Madrid to Moscow • Provide a wide range of advice to a wide range of clients • Gas, power, carbon, renewables and associated markets (oil, coal) • Due diligence, group strategies, market modelling and simulation, regulatory support, business process design, policy making, trading tactics, technical auditing, price projections, market training • Government departments, regulators, monopolies, producers, generators, retailers, consumers, associations • Pöyry plc group company adds many other dimensions, e.g. • oil and gas engineering – IGL Consultants (Aberdeen) • capital financing – Pöyry Capital (London) National Grid Network Modelling Software Review

4. Network Model Software Review • Driven by the Network Model Obligation • Requires NGG to maintain and make available a Network Model • Requires independent proof to Regulator of fitness for purpose • What is the purpose? • Gas Act obligation – develop…economic and efficient • Licence obligations • 1 in 20 • Transmission Planning Code • Network Model Obligation • Information requests • Network code obligations • Safety Case • IGE/GL/2 National Grid Network Modelling Software Review

5. GL/2 and network analysis • GL/2 sets out requirements for network analysis • GL/2 implicitly acknowledges pressure and flow relationship is not linear • Empirically derived, thermodynamic formula • Requires consideration of Joule Thompson coefficient, i.e. considers that natural gas is not an ideal gas – formulae are very complicated • Mathematics: • In-flows must equal out-flows • Loops require algorithms & computation • Compressors and optimisation make computation more difficult • Overarching requirement to validate against actual measured network performance – network validation • Flows & pressures within 5% National Grid Network Modelling Software Review

6. Falcon replacement • Thorough procurement process • Short-list • Shorter-list • Single product • New product (Simone) used by • E.On • BEB • VNG • GdF Suez / GRTgaz • Gaz-System • NGG considered that Ofgem/industry may require assurance, per Network Model Obligation & Transmission Planning Code • HAI • Energienet.dk • AGGM • Transgas (Portugal) National Grid Network Modelling Software Review

7. Observation and validation • Series of tests independently created by Pöyry Energy Consulting • Based on the Transmission Planning Code • Incorporating consideration of other analytical requirements • Considered: • Basic functionality • Supply and demand flows • Capacity discovery • Energy/volumetric conversion • Gas component tracking • Pöyry Energy Consulting granted unfettered access to equivalent models in both Simone and Falcon • We ran through the series of tests • We also examined the validation work undertaken in both products • Compressors • Flow control valves & other plant • Error handling, analysis • Configurations, reinforcement • Management and other functionality National Grid Network Modelling Software Review

8. Mathematical depths • Pöyry also briefly checked the underlying maths • Momentum term was neglected in Falcon – not requried to model transients • Momentum term included in Simone – underlying equations therefore different • Differences in compressor model specification – surfaces, not a set of coordinates – better compressor modelling • Differences in computation algorithm – more efficient and far more stable • Software documentaion references have been cross-referenced to independent, academic literature • Variables required/decribed are usual for fluid dynamics National Grid Network Modelling Software Review

9. Findings • New product very stable • Fit for existing network analyses (offline, long-term) • Simulation of NTS as good as, if not better than, GF • One minor finding: • Compressor inlet temperature reset under a very particular situation • Short compressor loop - very unusual configuration • Unlikely set of conditions • Response from software vendor (within 2 weeks) is apparently: “ah... yes… now fixed for the next release!” • Additional functionality could be very useful • Subject to licensing, Ofgem or other third party could do some limited examination/audit of network analyses National Grid Network Modelling Software Review

10. Report published • Available (now/shortly) through National Grid and Pöyry Energy Consulting (UK) websites www.nationalgrid.com www.ilexenergy.co.uk • Questions? National Grid Network Modelling Software Review

11. Angus Paxton angus.paxton@poyry.com +44 1865 812263 Andy Morris andrew.morris@poyry.com +44 1865 812212 Pöyry Energy Consulting King Charles House Park End Street Oxford, UK OX1 1JD +44 (0)1865 722660 www.poyry.com www.ilexenergy.com Pöyry Energy (Oxford) Ltd. Registered in England No. 2573801. King Charles House, Park End Street, Oxford OX1 1JD.

12. National Grid Network Modelling Software Review