Disruptive Technology Meets the Intractable Challenge of Fugitive Gas Emissions
Total Page：16
File Type：pdf, Size：1020Kb
Sustainability: Technical solutions, practical actions. Disruptive technology meets the intractable challenge of fugitive gas emissions www.advisian.com Sustainability: Technical solutions, practical actions. Author: Laith Amin Senior Vice President Digital Enterprise Houston 1 | Advisian Disruptive technology meets the intractable challenge of fugitive-gas emissions Optical gas imaging makes gas clouds visible In 2016, regulatory authorities in North America started taking seriously the fact that methane is a very powerful greenhouse gas in its raw, or unburnt, form. They also took note that recent advances in thermal imaging technology had lent credence to the assertion that fugitive emissions, or unintentional gas leaks, are happening on a much greater scale than ever before. Combined with an unprecedented expansion in U.S. onshore extraction and processing of natural gas, a basis for a perfect storm exists. An estimated $2 billion of natural gas is lost each year to leaks. The idea of natural gas as a clean fuel that can contribute to a reduction in urban pollution and greenhouse gas emissions is well-accepted both within the oil & gas industry and beyond. Even the most prominent voices advocating for non- fossil-fuel renewable technology, including Greenpeace, publicly have accepted the important role natural gas plays in acting as a clean fuel stepping stone from energy based on coal or oil toward energy less reliant on fossil fuels. This strategy of expanded exploitation of natural gas is working, and globally so. For example, on April 21, 2017 the UK enjoyed its first 24 hour power generation period completely free of coal since the year 1880. In the U.S., natural gas has surpassed coal as the nation’s leading power generating fuel source, with its growth rate surpassing any other energy source for power generation. Advisian | 2 Sustainability: Technical solutions, practical actions. Reasons for Methods of uncertainty measurement Climate change commitments have been made by many But why do these estimates vary so widely? To answer western, economically developed countries. Gas is a this question, it is essential to also examine the ‘method key weapon in the fight against CO2 emissions. In Asia, of measurement’ itself — and there are several different growing unease about air quality in post-industrial China methods used. has led to some impressive deals with natural gas supply One method to estimate leak emissions rates from countries such as Russia and Australia, but it is also this equipment items having the potential to leak in any plant very supply chain that sometimes calls into question the environment is simply to apply emissions factors and greenhouse gas reducing credentials of natural gas and its schedules provided by regulators. The emissions-per- categorization as a clean fuel. equipment item then can be aggregated to a plant total In the U.S., awareness of the raw methane emissions to produce a volume for undesirable leaks, or fugitive environment in the natural gas production and supply emissions. This method takes no account of the actual value chains has been growing. Emissions traces seen leak rates, or if in fact the equipment is leaking at all. from space mirror the concentrations of activity around The second, so-called incumbent, method is what is unconventional oil & gas production. referred to as EPA Method 21. A measurement instrument, Methane is a powerful greenhouse Raw methane is i.e., a flame ionization detector, is held near the stream of gas in its unburnt form. In fact, raw a suspected leak and measures the concentration of the methane is 86 times more potent fugitive gas in the atmosphere (typically on a parts-per- as a greenhouse gas than CO when million basis). 2 86xmore potent as a impact is considered over a 20-year greenhouse gas It is difficult to underestimate the impact of Method 21- period. Ultimately experts agree type emissions measurements on the oil & gas industry that if natural gas is to rival coal as a than CO2 over a in recent decades. This method verifies that there is in means of reducing greenhouse gas 20-year period fact a leak — vital information that can be passed on to emissions, then emissions of raw methane in the supply repair programs. In this way, significant greenhouse gas chain must be held to less than 1% of total production. reductions have been possible over the years, not to In the U.S., raw methane emissions estimates have mention the valuable gas retained in the supply chain for been ranging from a lower level estimate of 2% of end use. overall production to around 17%. Alarmingly, the U.S. However, the historic success of Method 21 testing Environmental Protection Agency (EPA) in recent years still does not explain the wide variances in estimates has increased its estimate of emissions in upstream gas for fugitive greenhouse gas emissions, nor adequately operations by 134%, bringing the overall total to 1.4% explain why, if the method is as effective as supposed, a of total production (which from time to time they flag methane emissions footprint is visible from satellites to as a possible underestimation), or 40% higher than the an extent that alerts regulators to a growing problem. target that must be met for gas to provide comparative These questions themselves illustrate our increasing advantage over coal. sophistication, in terms of technology and otherwise, in informing ourselves as to the nature of fugitive gas emissions. 3 | Advisian Disruptive technology meets the intractable challenge of fugitive-gas emissions Seeing is believing One technology — which the EPA refers to as optical-gas imaging (OGI) — recently has been added to the list of regulator-allowable methods of measurement. It is essentially an infrared (IR) sensor capable of operating within the thermal spectrum. It generates an image of a gas leak that can be seen with the human eye. For the first time, users see what a gas concentration reading from a Method 21 test never could allow them to see: a gas cloud. For the first time, Millions of TV-news viewers were introduced to OGI when they saw EPA footage of the Aliso Canyon gas leak on October 23, 2015. It was reported to be the users see what a worst gas leak in U.S. history, with 97,100 tons of methane and 7,300 tons of gas concentration ethane released into the atmosphere. Comparisons have been made to the reading from a equivalent carbon footprint of 1.4m cars or six coal-fired power plants. Method 21 test The Aliso Canyon leak showed us the important role OGI can play in measuring a leak in terms of how much — something that Method 21 could not do. never could allow However, the more OGI is deployed the more practitioners realize that, contrary them to see: to what EPA schedules of leak estimates assume, a small number of very large leaks often are responsible for most of the emissions in a defined scope of a gas cloud. study. Further, many of the other equipment items are either not leaking at all or have such small emissions rates that they are not economically viable to fix. Compare this to the inability of the incumbent method of measurement, Method 21, to provide a mass leak rate. You could survey your entire plant and a) not know which leaks are large or small, and b) be unaware of a super-leak coming from a part of your plant not surveyed at all. This inability to provide data that supports insight into the impact of a leak-repair program, for example in terms of priority, is cause for serious concern. There is growing acceptance that the scenario has led to significant underestimations. Additionally, the idea that 80% of the emissions can be caused by 20% of the leaks has led to about reducing overall emissions totals — if those leaks are not detected and dealt with. Advisian | 4 Sustainability: Technical solutions, practical actions. Which way now? While OGI has been a massive leap forward and broadly welcomed by the industry, one fact remains: an IR sensor cannot provide quantitative information about a fugitive emission. It can only provide a qualitative image of a leak — and one that is periodically apt to either show false positives (e.g., of a moisture vapor cloud) or false negatives (e.g., because of range, focus, shadows or other issues). Every engineer knows that “you can’t improve what you can’t measure,” so Every engineer what is the way forward here? Energy companies have been incentivized to invest billions in the development of gas production and supply infrastructure. knows that “you Coal plants have been shuttered and emissions-reduction commitments have can’t improve been made on the strength of the important role that natural gas will play in the reduction of greenhouse-gas emissions. what you can’t Given that more credible technologies such as OGI are starting to be measure,” so recognized by regulators, what can be done to anticipate this emerging what is the way realization that a lack of fugitive emissions control in the production environment could be jeopardizing the agreed-upon environmental forward here? credentials of this clean burning fuel? It is difficult to prescribe a solution to this that will work for all industry, but one fact is clear: without the ability to quantify an emission from a leaking equipment item in a process, any leak-repair program will have to be based to some extent on something other than science. Indeed, if the logic follows that about 20% of a given plant-environment fugitive emissions are large leaks that are economically viable to fix, then a technology’s ability to quickly determine which 20% of leaks that is will be key.