_20201019_010851論文igu2009docswgcfinal00820

1、NETWORK PLANNING METHODOLOGY,FROM AN INTEGRATED COMPANY TO AN INDEPENDENT TSOPiet Nienhuis, Gas Transport Services (part of N.V. Nederlandse Gasunie)Keywords: 1. Network Planning Methodology; 2. Integrated Company; 3. Independent TSO; 4.Decoupled Entry - Exit system; 5. Open Season.1Introduction/Bac

2、kgroundThe structure of the gas market in North West Europe has undergone major changes in the recent past. Liberalization of the gas market forced that roles of existing market parties changed and new market parties were created. This paper describes the challenges of the network planning departmen

3、t in an independent TSO.2Objectives of the paperThis paper describes the changes in network planning methodology that a gas company has to implement when moving from an integrated company to an independent TSO and under which circumstances these have to be carried out. Hopefully by means of this pap

4、er some awareness may be created by TSOs that will enter this stage.3Market liberalizationSince liberalization of the gas market has been introduced, several changes have taken place:a.The incumbent integrated company is split into an independent Transmission System Operator and a Gas Trading Compan

5、y. This has several consequences for the TSO, amongst others for its network planning process and its investment process. The network planning process is further elaborated in chapters 4, the investment process which requires an adequate network planning process, is further explained in chapter 5.Ne

6、xt to the newly founded Gas Trading Company, several new trading companies entered the market all fighting for market share: liberalization started strong competition. The part that impacts the TSO most is that these companies, all fighting for a part of the market, also need infrastructure contract

7、s in order to compete. This is not only transmission but also storage.We observe a certain “hunger for infrastructure”, further explained in chapter 6. This sets the investment process and thus the network planning process - of the TSO under pressure.b.4Consequences for the network planning process

8、of the independent TSO (trading is no longer part of the control room)In the old world, in an integrated company, gas trade is considered to be the core business. This is where the profits are made. Gas transport is only there to execute the trade (commodity) contracts. Gas transport is only seen as

9、 cost. And of course, costs need to be as low as possible. If commodity contracts would show room to manoeuvre to save transport costs, this would be used to reduce transport investments.In fact, daily gas trade (not as much price driven in the past before liberalization as it is today) was part of

10、the control room. If the purchase of gas entering the grid at entry point A would cause a transport bottleneck, then simply the purchase of gas at entry point B, avoiding a transport bottleneck, would be chosen.Decisions about purchase of gas were taken bearing in mind transport limitations as long

11、as daily and annual contracted quantities were realized.Today, in an independent TSO, daily gas trade is no longer part of the control room. Instead, the independent TSO has to carry out the transport contracts with many (50) shippers. These shippers, large and small, of which one of them is the for

12、mer trading arm of the integrated company, all take their decisions only bearing in mind their own trade portfolio (which is much more price driven than in the past with long-term contracts). The TSO does not determine which entry points the shippers1should use in order to avoid bottlenecks.Next to

13、that, the behaviour of the flows has become far less predictable than it used to be.This is illustrated in the following graphs.Growing unpredictability of entry- and exitflows.The entry point Emden, where Norwegian gas is imported, shows a fairly predictable entry flow. The majority of the underlyi

14、ng commodity contracts are long term contracts that have little variations in daily contracted quantities DCQs. The utilization is in the seventies.Figure 1. Flow at entry point EmdenThis is an example of the flow at an entry point which is still quite predictable.The graph below however shows a dif

15、ferent behaviour. This is one of the cross-border points with Germany in the Oude Statenzijl Bunde area. This cross-border point has been made physically bidirectional which can clearly be seen at the left part of the graph. Clearly, the predictability of the flow at this cross-border point has decr

16、eased dramatically. There is no summer-winter pattern.Figure 2. Flow at a cross-border point that has been made bidirectionalAnother point with unpredictable behaviour is at a cross-border point with Belgium. The point Zelzate connects the Dutch TTF with the Zeebrugge hub in Belgium. Transmission co

17、ntracts are not used for long term commodity contracts but for short term trade. The result is as follows.2OSZ bidirectional point150,000100,000 50,000 013672 7343 11014 14685 18356 22027 25698 29369-50,000 -100,000 -150,000 -200,000Emden 20062,000,0001,800,0001,600,0001,400,0001,200,0001,000,000800

18、,000600,000400,000200,00001 666 1331 1996 2661 3326 3991 4656 5321 5986 6651 7316 7981 8646Figure 3. Flow at cross-border point ZelzateUtilization is very low (below 30%), and there is no summer-winter pattern.Another type of entry point that will become of interest is an LNG-terminal. Although ther

19、e is no experience yet in the Netherlands with this type of entry in a liberalized market, there is some experience in the UK. The graph below shows the behaviour at the Isle of Grain LNG terminal in the UK. The utilization is even lower (less than 20%).Figure 4. Flow at UK LNG terminalSource: Websi

20、te National GridAgain no summer-winter pattern but the flow is influenced by the emerging global LNG-market.It should be stressed that decisions made by traders do no longer take into account transport considerations. This is the area of the TSO. The impact depends on the way that these transport se

21、rvices are offered to the market.Point-to-point versus decoupled entry-exit systemThere are many ways to offer transport services to the market, varying from point to point to a completely decoupled entry exit system.The point to point system offers little flexibility for shippers and is mainly suit

22、able for long-distance pipeline systems.On the other side, a decoupled entry exit system offers much flexibility to shippers.Let me explain how a decoupled entry exit system works.Transport in a decoupled entry exit system is contracted by just contracting capacity on entry- en exit points. No contr

23、acts on (internal) pipeline segments are required. The entry- and exit contracts can be concluded separately. The amounts can differ, the time of concluding contracts can differ and3daily utilization01-Jan-0818-Jan-0804-Feb-0821-Feb-0809-Mar-0826-Mar-0812-Apr-0829-Apr-0816-May-0802-Jun-0819-Jun-0806

24、-Jul-0823-Jul-0809-Aug-0826-Aug-0812-Sep-0829-Sep-0816-Oct-0802-Nov-0819-Nov-0806-Dec-0823-Dec-08Isle of Grain, January 2008 - December 2008120%100%80%60%40%20%0%Zelzate 2008500,000450,000400,000350,000300,000250,000200,000150,000100,00050,0000also the shipper can differ.In short, an entry contract

25、gives a shipper the right to supply gas into the network, an exit contract gives a shipper the right to take out gas from the network. The network can thus be seen as a large “box” (no buffer) where shippers can contract entry and exit.When using the contracts there is a further condition: the amoun

26、t taken out of the network must equal the amount supplied to the network (within ranges where of course balancing and network integrity comes in).This system offers the opportunity to introduce title transfer. Gas once in the network can be sold (transferred) to another shipper. This means that a sh

27、ipper in itself doesnt need to be in balance on its entry- and exit points as long as the difference is made-up on the TTF (title transfer facility).A network planning methodology is always focusing on situations where the network load is at its maximum. In a “simple” pipeline system where transport

28、 is sold “point-to-point”, the maximum load occurs at the contracted level. In a more complicated network where entry-exit capacity is sold decoupled, the maximum load on certain pipeline segments can occur at low utilization of contracts at entry exit points.This may be illustrated by the following

29、 example.Let us imagine a simple gas transmission network with a layout in the shape of the letter H. The network has two entry points, A and B, and also two exit points, also labelled A and B. All have a contracted capacity of 100 units. The pipeline from entry A to exit A has a capacity of 100 uni

30、ts and the pipeline from entry B to exit B also has a capacity of 100 units. The connecting pipeline has a capacity of 50 units.In the first utilization scenario, all contracts are fully utilized. There are no bottlenecks in the system.Figure 5. Scenario with full utilization of entries and exitsIn

31、the second utilization scenario, exit B is not used and the shipper has chosen not to use entry A. This means that exit A has to be supplied with gas coming from entry B. The interconnecting pipeline however only has a capacity of 50. A bottleneck appears.4Utilization scenario 1 : both entry and exi

32、t contracts fully utilized, no bottlenecks in systemCapacityCapacityCapacity10050100CapacityCapacity100100Exit AExit B100100Entry B100Entry A100Figure 6. Scenario with lower utilization of entries an exitsIn the past, in the time of the integrated company, this bottleneck could easily be avoided by

33、using entry A for at least 50 units. But an independent TSO is not in control about the utilization of transport contracts. The system bottleneck has to be solved in another way.Figure 7. How a low utilization scenario would have been solved in the pastThe only way the system bottleneck can be solve

34、d permanently, without limiting the entry- and exit contracts of the shippers in this decoupled entry exit system, is to expand the capacity of the interconnecting pipeline.5In the past this could be solved by shifting suppliesfrom entry B to entry A but this is no longer under control of the TSOCap

35、acityCapacityCapacity10050100CapacityCapacity100100Exit B100Exit A100Entry B50Entry A50Utilization scenario 2 : Entry B and exit A contracts fully utilizedbut entry A and exit B contracts not used, a system bottleneck appearsCapacityCapacityCapacity10050100CapacityCapacity100100Exit AExit B 100100En

36、try B100Entry A100Figure 8. How a low utilization scenario can be solvedThis example makes clear that the network planning methodology must not only look at high utilization of contracts but also at low utilization : the TSO must “imagine” how the shipper will use its contracts. This is becoming par

37、ticularly difficult at entry- and exitpoints that show a capricious pattern.A number of utilization scenarios (likely entry exit combinations) must be defined that are challenging for the network (there are of course also a lot of scenarios that can be even more likely but are not challenging). Thes

38、e scenarios must be used to check whether new contracts can be accommodated and if not, which network expansions are required before they can be accommodated.This approach differs from the one used before in a sense that the amount of utilization scenarios that are used to check the network is incre

39、ased and also the process of arriving at these scenarios is continuously monitored. Crucial input for these scenarios is our imagination how shippers will utilize their contracts. This can be done by looking at actual behaviour of shippers and of flows in order to get a better understanding of the m

40、arket. This is an evolving process.5Consequences for the investment planning process of the independent TSO (not commodity contracts but transmission contracts are core business)As mentioned above, in an integrated company gas trade is core business. Moving from an integrated company in the past to

41、an independent TSO in the future, the way decisions on investments are made will greatly differ. There are a few factors that are significant.First, decisions on transport investments were made as part of decisions of trade contracts (of just one shipper=integrated company). The money was made with

42、commodity contracts and transport was just cost.This has now changed into the situation that it is the transport contracts where the money is made.In the new environment, decisions on transport investments must be made on transport contracts only (many shippers with many small contracts).Important c

43、ondition is that there must be an investment climate for the TSO (such as an adequate tariff system) that allows investments.Second, there must be developed a way to bundle and to aggregate the many new small transport contracts into a single package of additional capacity. Each of the separate smal

44、l transport requirements will often not result in an economic network expansion project. The size is simply too small. Aggregation will lead to more cost-efficient measures.So an investment process must be developed to bundle separate contract requests. A so-called Open Season process is suitable to

45、 do just that.From a screening of the market it is determined whether there is a need for more transport capacity, and if so, where and when. This determines the scope of the Open Season.Shippers that want to participate are requested to sign unilateral binding contracts before a fixed date. This de

46、fines the “bundle”, the package of contracts. From this, the TSO determines the required investments and makes an investment decision. The time in between needs to be as short as possible since the shipper is exposed to the risk that the TSO cannot reach an investment decision. After a6Solution will

47、 be to increase transmission capacity from 50 to 100 : system bottleneck disappearsEntry AEntry B100100CapacityCapacityexpansionCapacity100from 50 to 100100CapacityCapacity100100Exit AExit B 100100positive investment decision, the unilaterally signed contracts are also signed off by the TSO.During t

48、his procedure, the TSO has many stakeholders to satisfy: shareholder (return on investments), shippers (capacity delivered in time, decision making process in time), neighbouring network operators (align capacity expansion with neighbouring networks), regulators (need, necessity and efficiency of in

49、vestments).6Consequences for market parties (shippers/traders) and their infrastructure needsThe transmission capacity of a network is determined by the entry capacity at the wellhead, the exit capacity at the burnertip and the required loadfactor conversion (fit for the market) in between.Figure 9.

50、 Transmission capacity in the “old” worldIn a market structure with a limited amount of players and long term contracts, the available transport capacity will have been made “fit for purpose” to carry out this task, schematically shown in figure 9 above.Introducing competition on the commodity marke

51、t means that market parties will compete for market share. Price is very important. Consumers want to buy their gas from the producer offering the lowest price and producers want to reach the markets where they get the best (highest) price. Both want sufficient infrastructure so as not to miss oppor

52、tunities. It should be noted that transmission costs are low compared to cost of commodity. See Figure 10 below.Figure 10. Transmission costs as part of the energy bill for households in the Netherlands Source: Crossing Borders in European Gas networks : the Missing Links. Clingendael Energy Paper (

53、to be published)Since the cost of infrastructure is low compared with commodity shippers are willing to contract additional capacity in order not to miss opportunities.Note that the utilization of the entry- and exitpoints of the whole chain will not change. See table 1. below7Distribution, Transmis

54、sion, 10.2%2.7%Ecotax, 12.9%VAT, 19.0%commodity,66.2%Transmission Capacity in the “old” world, sized for long term contractsNetwork CapacityNetworkNetworkEntryExitCapacityCapacityLoadfactor Conversion by Storages close toPRODUCERthe MarketCONSUMERA limited number of producers selling to a limited nu

55、mber of customers under long- term contractsTable 1. Typical utilization per type of infrastructureSource: Aad Correlj, 30 april 2009, European University Institute, FlorenceThus, in the “new” world, the entry capacity at the wellhead and the exit capacity at the burner tip are not likely to change

56、but more interconnections are required to connect markets, facilitate commercial behaviour and opportunities for shippers.This typically leads to a situation that can best be described according to the graph below.Starting point is the network that is in place for the integrated company and that has been designed fit for purpose of this company (figure 9 above).New parties entering the market have other wishes which means that the network has to