Offtake (million Nm3/d)
Figure 7‑1 Relationship between daily mean temperature and total natural
gas offtake in Denmark
Daily mean temperature (º C) 0 0.5 1.0 1.5 2.0 2.5 -15 -10 -5 0 5 10 15 20
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M/R station
Expected offtake during peak day
(-13° C)
Expected offtake during average
peak hour (-13° C) inlet pressureCalculated setpointAgreed
M/R station Calculated capacity (-13° C) Distribution companies’ expected capacity requirements Measured peak hour 2010-05-01 to 2011-04-30
1,000 Nm3/d Nm3/year Barg Barg Nm3/year Nm3/year Nm3/year
Amagerfælled 44 2,901 53.3 16.6 14,178 5,700 4,083 Billesbølle 93 4,343 60.9 17.1 9,291 5,500 5,103 Brande 91 4,449 64.9 35.4 10,789 6,000 4,950 Brøndby 1,696 67,549 54.4 33.9 127,160 90,000 79,648 Dragør 200 8,606 53.5 16.6 23,039 12,000 9,753 Egtved 1,029 45,012 64.2 35.4 61,507 65,000 56,788 Ellidshøj 193 8,617 68.0 35.4 10,793 12,000 9,607 Frøslev 690 28,809 61.5 35.4 40,021 43,000 39,968 Haverslev 298 14,471 69.3 35.4 26,327 34,000 21,158 Helle 13 628 65.1 16.0 8,543 600 407 Herning 2,002 84,230 65.4 47.6 153,419 120,000 97,600 Højby 465 22,249 59.3 18.3 126,985 34,000 31,829 Karlslunde 448 24,863 55.7 17.9 87,864 30,000 33,968 Karup 286 12,559 66.9 35.4 17,502 18,000 14,815 Koelbjerg 453 21,502 60.6 18.3 39,709 38,000 36,024 Køge 571 25,113 56.0 17.9 38,088 40,000 26,230 Lilballe 0 0 63.0 3.6 8,911 2,500 2,163 Lille Selskær 464 19,444 71.5 35.4 40,525 30,000 24,096 Lille Torup MR 60 2,685 62.9 35.4 8,806 5,000 3,284 Lynge 1,523 63,728 53.1 32.7 136,246 90,000 75,824 Middelfart 59 2,623 61.9 17.1 9,440 3,800 6,171 Måløv 1,852 54,568 53.5 17.9 106,000 70,000 64,640 Nyborg 47 2,195 58.5 17.1 8,928 4,000 2,970 Nybro 53 2,361 65.9 17.1 4,026 3,000 2,562 Nørskov 316 13,945 64.5 35.4 24,416 19,000 16,511 Pottehuse 197 9,029 63.5 35.4 31,795 12,000 8,296 Ringsted 681 29,909 56.6 25.0 38,309 39,000 31,432 Slagelse 298 13,646 57.9 16.7 27,757 21,000 16,469 Sorø 0 0 57.3 17.9 38,542 0 12,745 St.Andst 427 18,268 63.7 35.4 40,772 26,000 21,912 Stenlille MR 589 25,995 61.7 17.7 37,788 40,000 28,752 Sydhavnen 18 795 53.2 3.6 5,792 3,000 1,745 Taulov 69 3,758 62.3 35.4 33,201 7,000 5,362 Terkelsbøl 333 13,769 61.9 35.4 23,309 19,000 17,584 Torslunde 180 10,441 55.5 17.9 30,419 20,000 13,030 Ullerslev 132 5,914 58.9 17.1 8,985 7,500 6,090 Vallensbæk 122 18,641 54.7 17.9 31,113 25,000 23,290 Varde 174 8,476 65.5 35.4 40,061 15,000 14,980 Viborg 1,488 63,491 68.4 35.3 93,914 100,000 69,996 Aalborg 1,432 63,870 67.0 44.3 155,699 90,000 75,592
Gas in Denmark - Energinet.dk
Table 7‑1 Expected offtake, calculated inlet and outlet pressure and capacities of M/R stations in the transmission system in normal supply situations
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7.1.2 Adjusting capacity
requirements
For several M/R stations, the distribution companies expect that the offtake will be higher than the maximum capacity under the conditions calculated. Energinet.dk’s expectation and the realised peak hour are significantly lower than the calculated peak hours. The assessment is therefore that there is no need to change the capacity. In col- laboration with the distribution companies, Energinet.dk checks on an ongoing basis that the M/R stations have sufficient capacity. Generally, Danish gas consumption has experienced a weak decline for a number of years. This gives cause for reassessing the M/R stations’ capacity. Some stations have an overdimensioned capacity which is unsuitable for daily operation. This is inexpedient as there is a risk of operational disturbances, high fuel-gas consumption and metering inaccuracies.
Energinet.dk has therefore launched a study, which also involves the distribu- tion companies, the purpose of which is to ensure better adjustment of M/R station capacity. Where stations are ring- connected, the possibilities of transferring
capacity from one station to another are investigated. This ensures better operation of stations whose capacity is overdimen- sioned and makes it possible to close down some stations, with corresponding savings in the operating expenses as a result. This is only possible if the associated distribution networks have the necessary extra capacity at their disposal.
7.1.3 Gas from Germany
Gas imports from Germany on interruptible conditions became possible from 1 October 2010. The market wanted to import gas from Germany for most of the winter of 2010/11, and this request has now been granted. The minimum pressure of German gas is 68 barg at Ellund. The import of gas from Germany did not and will not lead to any restrictions in M/R station capac- ity in proportion to the expected capacity requirement.
7.1.4 Dimensioning of
distribution network
In connection with the preparation of the 2008 Plan for the Security of Natural Gas Supply, detailed analyses were made of the
relationship between temperature and natu- ral gas consumption for each M/R station in the transmission system. The purpose was to uncover any congestion in the system. These analyses are deemed to also cover Gas in Denmark.
When assessing consumption especially at very low daily mean temperatures, it is important to consider the simultaneity of various types of consumption to ensure that the capacity requirements for the M/R stations stay realistic. The assessment of offtake at very low temperatures is ham- pered by the fact that no relevant metered data are available for daily mean tempera- tures lower than approximately -7° C. Furthermore, ring connections make the assessment of the individual M/R stations difficult.
7.2 Special security of supply
issues in the individual
distribution areas
7.2.1 Naturgas Fyn
Distribution
The M/R stations supplying Naturgas Fyn Distribution A/S are assessed to have
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Gas in Denmark - Energinet.dk
sufficient capacity to meet the supply re- quirement for the winter 2011-2012. At Energinet.dk’s request, Naturgas Fyn Distribution A/S has calculated the pos- sibility of perhaps closing down Højby M/R station due to excess capacity, but the com- pany does not believe that it is possible to maintain supply if this came to pass. Instead, Naturgas Fyn Distribution A/S has suggested to Energinet.dk the possibility of downscaling Højby M/R station so that station capacity is brought more in line with the supply require- ment. Similarly, Naturgas Fyn Distribution A/S has, at Energinet.dk’s request, calculated the possibility of downscaling Middelfart M/R station, which is considered unproblem- atic from a supply perspective.
As regards the distribution companies’ ex- pected capacity requirement as shown in Table 7-1, the figure stated for Naturgas Fyn Distribution A/S is based on empirical figures and by examining the customers’ capacities. Furthermore, the figures have been adjusted taking account of the simultaneity of various types of consumption.
7.2.2 DONG Gas Distribution
Overall, Energinet.dk’s M/R stations are as- sessed to have sufficient capacity to meet DONG Energy’s requirements in the coming winter 2011-2012. Where the Egtved, Frøslev, Terkelsbøl and Stenlille M/R stations are concerned, the relationship between ca- pacity limits and peak hour expectation is, however, of such a nature that it calls for the planning of a capacity increase. The expected introduction of gas with a lower calorific value renders such an increase even more necessary.
Biogas
Together with Fredericia Central Wastewater Treatment Plant and Fredericia Municipality, DONG Energy has established Denmark’s first plant for injecting bio natural gas into the natural gas distribution system. The plant, which is constructed at Fredericia sew- age plant, was inaugurated on 15 September 2011.
DONG Energy receives the raw bio natural gas from the sewage plant and upgrades it in a facility supplied by Greenlane Biogas AB. The facility has a capacity of 300 Nm3 of raw
biogas, which corresponds to approximately 180 Nm3 of bio natural gas per hour. The bio
natural gas is supplied by the upgrading plant at a pressure of approximately 8 bar to an M/R station supplied by Dansk Analyse A/S. Here, odorant is added, the gas is meas- ured and analysed, and the pressure is ad- justed down to approximately 3.6 bar. The M/R station is connected to an existing distribution pipeline via a new 70 m long plastic pipeline. The distribution pipeline has been out of operation for a while, but is now being reused as a 4-bar distribution pipeline. The bio natural gas travels 3.5 km through this pipeline to DONG Energy’s Hejse M/R station, where the pipeline is connected to the existing 4-bar network. To ensure the offtake of bio natural gas in the summer, a new plastic pipeline has been established connecting the Hejse network to the Taulov network. Consumption in the network exceeds the production of bio natural gas, and Hejse M/R station supplies the missing volume.
The calorific value of the bio natural gas is approximately 10% lower than the calorific value of Danish natural gas, and it is there- fore necessary to calculate the actual calo- rific value of the mixture at Hejse M/R sta- tion. In order to make the calculation, there
77
Gas in Denmark - Energinet.dkcan be only one infeed point in the network (at Hejse M/R station). DONG Energy’s other M/R station, Taulov M/R station, has there- fore been placed on standby.
7.2.3 HNG Distribution
and Naturgas Midt-Nord
Distribution
Generally, the M/R stations in the transmis- sion system and the distribution systems in HNG’s and Naturgas Midt-Nord’s licence areas are assessed to have sufficient capacity for the coming winter 2011-2012.
Due to the import of German gas and for settlement purposes, HMN’s eastern dis- tribution area was split up into new areas (determined by the calorific value) in 2011. This changes somewhat the offtake from the M/R stations in the transmission system in 2011-2012 as opposed to previous years. The capacities stated in Table 7-1 indicate the enterprise’s forecast for 2011-2012. However, there is some uncertainty associated with the forecasts.
The development in gas consumption and the consequences of changes in the gas quality
are analysed on an ongoing basis. Any facili- ties required to reinforce the network will be established on the basis of the analyses.
7.2.4 Gas supply
in Copenhagen
In connection with converting produc- tion from using city gas to using city gas based on natural gas/air in November 2007, Københavns Energi has looked into whether it would be possible to have the linepack in Energinet.dk’s 80 bar network made avail- able in the event of supplies to Copenhagen being interrupted. In connection with the conversion, the old production facilities, pump stations and gas containers have been closed down. Therefore, the city gas supply no longer includes a gas storage facility. Københavns Energi’s city gas network is a ring-connected network which must always be kept pressurised as a total pressure failure could potentially cause air to penetrate large parts of the network, thus cutting off gas supply in Copenhagen. It is therefore vitally important that the supply of gas raw mate- rial is always maintained at a pressure of a least 15 bar at the Strandvænget and Kløver- marken gasworks.
Inadequate gas supply to Københavns Ener gi’s city gas network could have serious econo- mic consequences. In addition to reserving linepack in the 80 bar network, a manual bypass was established in 2010 at Mørkhøj 37/19 bar pressure regulation station in HNG’s network so that Strandvænget gas- works can quickly receive supplies from Sten- lille gas storage facility. Energinet.dk has also established a new remote-controlled valve at Torslunde M/R station so that gas from Sten- lille can be sent direct into the Lynge pipeline if the main transmission pipeline between Torslunde og Dragør breaks down. All these measures have substantially improved secu- rity of supply towards Copenhagen.
Tonne Kjærsvej 65 DK-7000 Fredericia Tel.: +45 70 10 22 44 [email protected] www.energinet.dk