Understanding CDM Methodologies - SuSanA
Understanding CDM Methodologies - SuSanA
Understanding CDM Methodologies - SuSanA
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Monitoring of<br />
Flare Efficiency<br />
Project Developer<br />
proposed Default<br />
Values or Use of<br />
Proxies<br />
MP Rejection of<br />
Proposal<br />
Box 32: Measurement of the flare efficiency<br />
Another outstanding issue that influenced the development of ACM0001 relates<br />
to the requirement to measure the flare efficiency (i.e. the fraction of methane<br />
destroyed within the flare) throughout the project cycle.<br />
A request for revision 268 argued that the flare efficiency monitoring requirements<br />
stipulated in ACM0001 269 posed several limitations:<br />
1. Obtaining reliable and comparable measurements was problematic because<br />
sampling of the exhaust gas could hardly be repeated under similar conditions.<br />
2. Project participants generally face difficulties to regularly monitor the exhaust<br />
gas of the flare due to the hazardous nature of the operation, the specialized<br />
equipment required, the technical expertise needed, and the relatively<br />
high costs involved, which often require project participants to hire foreign<br />
consultants to perform the operation.<br />
3. Because flares are designed to completely destroy the methane they receive, it<br />
is unlikely that even highly precise equipment could detect remaining traces of<br />
methane in the flare. It argued that available equipment is primarily designed<br />
to detect traces of other exhaust gases (such as NO x<br />
, SO x<br />
, and VOCs) and<br />
therefore may not be precise enough to efficiently detect traces of methane in<br />
the exhaust gas.<br />
Thus, two alternative methods were proposed to assess flare efficiency:<br />
1. Use of default values: Pointing out that ACM0008 (for flares destroying coalmine<br />
methane) and AM0016 (for flares destroying animal waste methane) both<br />
permitted the use of default value to estimate flare efficiency (99% for enclosed<br />
flares, 50% for open flares), DNV argued that landfill activities flaring methane<br />
should be allowed to use the same default values as the processes involved are<br />
not technically different.<br />
2. Determination of flare efficiency using flame temperature and combustion<br />
time: The submission also argued that increasingly, industrialized countries<br />
allowed their methane-regulated industries to measure flare efficiency using flame<br />
temperature, pointing out recent peer-reviewed studies showing a correlation<br />
between flame temperature and methane destruction level. For instance, it<br />
was raised that the Dutch government required a minimum flame temperature<br />
of 900˚C to ensure an efficient combustion of methane, while other studies<br />
suggested a minimum flame temperature of 760˚C. It was therefore proposed<br />
that flare efficiency be determined using flame temperature, providing that a<br />
curve correlating a set of combustion temperature values to a set of efficiency<br />
values be made available to project proponents.<br />
Though it recognized the difficulties related to measuring efficiency of open<br />
flares, the MP rejected the request to allow project participants to use default<br />
values to assess flare efficiency, arguing that these did not provide the level of<br />
precision needed to accurately estimate the emission reductions. It added that<br />
the efficiency of enclosed flares could be easily monitored at a relatively low cost.<br />
However, the MP did not give any explanation as to why default values could be<br />
used under ACM0008 and AM0016 and not under ACM0001.<br />
Interestingly, the MP proposed a revision to ACM0001 – albeit unrelated to this<br />
request for clarification – allowing project participants to use a default flare<br />
efficiency value of 50% in cases where flare efficiency would deliberately not be<br />
monitored. This recommendation indirectly contributed to eliminating certain<br />
barriers faced by project participants operating an open flare system (as raised<br />
by DNV).<br />
234<br />
See AM_REV_0012<br />
235<br />
ACM0001’s guidelines to assess flare efficiency allows for two different monitoring options: (1) continuous<br />
monitoring of flare efficiency during operating hours; or (2) quarterly<br />
92