M-DEV0390: Contractual requirement to enable a fuel switch to a primary fuel other than natural gas during the gas supply interruption situation or emergency situation

AM0029 ver. 3: Baseline Methodology for Grid Connected Electricity Generation Plants using Natural Gas

The applicability criterion, which is referred to by this request for deviation, is as follows:

The project activity is the construction and operation of a new natural gas fired grid-connected
electricity generation plant;1
with
1 Natural gas should be the primary fuel. Small amounts of other start-up or auxiliary fuels can be used, but can comprise no more than 1% of total fuel use, on energy basis.

This footnote is the reason for this request for deviation when discussing the compliance of the project activity, which is the construction and operation of a new natural gas fired grid-connected electricity generation plant. But, as this plant plays a major role in the expansion plan of the relatively small grid of Sabah (East Malaysia, Borneo), and will receive high ranking in the dispatch order and is therefore considered as a base-load plant, the operator’s contract includes the obligation to set-up the plant in a manner that allows the immediate switch to another fuel independent from the gas pipeline (single-line-system) even in case of long-term interruptions. Thus it has been decided to install as secondary fuel supply system based on distillate fuel oil, which will be used during maintenance periods or emergency situations of the supplying pipeline. There is a tank farm for distillate fuel oil installed at the project operation which enables the continuous operation for seven days.
When the plant is fuelled by natural gas, the compliance with the 1% threshold for start-up and auxiliary usage can be ensured by existing evidences (design and records from similar plants), but in theory the primary fuel ight be different from natural gas for limited periods under the regular maintenance scheme of the gas supply system or even undefined periods in the case of emergencies. The duration of such periods is not under control of the project participants, as it would only become relevant when there is an interruption of the gas supply by the gas supplier or emergency situation. Due to the purchase and delivery contract the gas supplier has to provide documented information in case he intends or is urged to interrupt the gas supply. According to the special arrangements as used for such independent power utilities, the operator would have financially neither losses nor benefits, when switching the fuel type. In conclusion a registration as CDM project would even form a strong incentive for remaining at natural gas as preferred fuel.
The experience from the adjacent Ranhill 1 power plant is that by regular maintenance, the distillate fuel oil consumption will be much less than 1% of the gas consumption on energy basis, on the other hand this threshold is applicable for parallel usage and not for alternative usage. By applying the given formulae for the auxiliary or start-up usage of other fossil fuel, the project emissions can be calculated also for the period of alternative usage. This approach is suggested by the underlying PDD, but it deviates from the methodology as it does not only address auxiliary but alternate liquid fossil fuel, too. There is no risk that this situation would lead to an overestimation of emission reduction. Even more, the CDM registration would form a further incentive to minimize such periods as far as possible (by pushing the contracted gas supplier).

TÜV Nord therefore recommends accepting this request for deviation.

The given constellation is considered rather unique and therefore a request for deviation is more applicable than a request for revision. The situation that such a base-load plant is supplied by a single-line pipeline connected to a single off-shore gas field is also considered as unusual. This constellation creates the need for alternative solutions during maintenance periods or emergencies of the pipeline system. Hence TÜV Nord does not consider it necessary revising the methodology.

As written above there will be no impact with regard of determining the emissions reductions as the use of distillate fuel oil as primary fuel for short periods could be dealt with in the same manner and by the same formulae as for the use of the purpose of start-up or auxiliary fuel. As the baseline plant is a coal fired plant also the use of distillate fuel oil will lead to some (but less) emissions reductions compared to this baseline, which is outside the original intention of AM0029, which itself is considered being applicable for switching from more carbon intensive fuels to natural gas.

Hence TÜV Nord recommends giving advice in a manner that allows distillate fuel oil as primary fuel for limited periods only, when it can be clearly demonstrated that there was either a maintenance work done at the pipeline system or an emergency situation resulting in its disconnection.