TODAY’S STUDY: BRIDGING TROUBLE WITH NOT SO CLEAN NATURAL GAS

Many - the great environmentalist Robert F. Kennedy, Jr., is one - believe that natural gas will be a bridge to a New Energy future. They believe, and Mr. Kennedy has said so in the presence of NewEnergyNews, that ways will be found to adequately regulate the natural gas industry.

Given how aggressively the newly produced supplies of cheap, abundant shale gas are taking power generation market share away from other sources, this would convenient indeed.

It would be wonderful if Mr. Kennedy is right and he very well may be. But the Gulf of Mexico BP oil spill, West Virginia's Upper Big Branch coal mine cave-in ane and the Fukushima nuclear plant meltdown are all tributes to regulatory inadequacy.

There is only one alternative to effective regulation: Choosing a safer resource.

Though it may seem appealing to some, the human species is not about to retire to yurts. Until Paris and Shanghai and Brasilia go off-grid, demand for electricity will keep rising.

Do what they will to reduce, reuse and recycle, the global urban population - which is now half the world's people and is growing - will not be satisfied with what the New Energies can provide in the short term.

But energy infrastructure does not get built, or rebuilt, in the short term.

Old Energy advocates today insist New Energy is inadequate to power society. What they fail to mention is that if they had not made that very argument so effectively in the 1970s, there WOULD be adequate New Energy capacity today to shoulder a major part of the power generation burden.

Undoubtedly, New Energy advocates must this time stay focused like a drone's targeting device on building capacity so that by 2030, when urban population is 60 percent or more of the world's people, 20 to 30 percent of society's electricity will come from wind, 10 to 20 percent will come from sun and there will expanding geothermal abd hydrokinetic infrastructures under construction.

In the interim, one could reasonably conclude - as Mr. Kennedy has - that because natural gas is a theoretically cleaner and safer alternative than coal or nuclear, it should for now be given the go-ahead.

To date, the natural gas industry's biggest impediment has been its own hydrofracturing (aka hydrofracking or fracking). Fracking is a method of accessing previously inaccessible shale reserves of natural gas. Shale reserves turned what had previously been a dwindling resource into an abundant one and created a boom in the stagnant gas production industry. But many argue fracking makes gas not a safer resource than coal or nuclear but an ecological disaster, a threat to drinking water supplies wherever it is done.

Now, as the paper highlighted below shows, some studies are showing that natural gas may not be cleaner than coal but, over its lifetime, may generate spew just as severe.

Ironically, its failure to be either cleaner or safer may make natural gas the ideal bridge to a New Energy economy.

Ted Turner last year told Charlie Rose what the public now knows only too clearly: "Nuclear MIGHT kill you, but coal WILL kill you."

So here's the plan: The mega-money of the oil & gas industry gets in the arena with Big Coal and Big Nuclear and takes electricity market share away.

Meanwhile, environmentalists work at the margins, continuing the hugely successful fight to stop the building of new coal and nuclear infrastructure that has kept any coal plant from breaking ground in the U.S. since 2008 and any new nuclear plant from being completed for 4 decades.

The New Energies must go on fighting to do just one thing: Build infrastructure.

In 2030, the public will find itself with outdated, inadequate sources of coal and nuclear, fire in its drinking water and a costly dependence on dwindling, expensive, emissions-spewing natural gas.

And a potent generation capacity in its growing, clean, safe, prosperous New Energy economy.

All it takes is the right bridge.

Methane and the greenhouse-gas footprint of natural gas from shale formations; A letter
Robert W. Howarth, Renee Santoro and Anthony Ingraffea, 13 March 2011(Climate Change/Springer Verlag)

Abstract

We evaluate the greenhouse gas footprint of natural gas obtained by high volume hydraulic fracturing from shale formations, focusing on methane emissions. Natural gas is composed largely of methane, and 3.6% to 7.9% of the methane from shale-gas production escapes to the atmosphere in venting and leaks over the lifetime of a well. These methane emissions are at least 30% more than and perhaps more than twice as great as those from conventional gas. The higher emissions from shale gas occur at the time wells are hydraulically fractured—as methane escapes from flow-back return fluids—and during drill out following the fracturing. Methane is a powerful greenhouse gas, with a global warming potential that is far greater than that of carbon dioxide, particularly over the time horizon of the first few decades following emission. Methane contributes substantially to the greenhouse gas footprint of shale gas on shorter time scales, dominating it on a 20-year time horizon. The footprint for shale gas is greater than that for conventional gas or oil when viewed on any time horizon, but particularly so over 20 years. Compared to coal, the footprint of shale gas is at least 20% greater and perhaps more than twice as great on the 20-year horizon and is comparable when compared over 100 years.

Many view natural gas as a transitional fuel, allowing continued dependence on fossil fuels yet reducing greenhouse gas (GHG) emissions compared to oil or coal over coming decades (Pacala and Socolow 2004). Development of “unconventional” gas dispersed in shale is part of this vision, as the potential resource may be large, and in many regions conventional reserves are becoming depleted (Wood et al. 2011). Domestic production in the U.S. was predominantly from conventional reservoirs through the 1990s, but by 2009 U.S. unconventional production exceeded that of conventional gas. The Department of Energy predicts that by 2035 total domestic production will grow by 20%, with unconventional gas providing 75% of the total (EIA 2010a). The greatest growth is predicted for shale gas, increasing from 16% of total production in 2009 to an expected 45% in 2035.

Although natural gas is promoted as a bridge fuel over the coming few decades, in part because of its presumed benefit for global warming compared to other fossil fuels, very little is known about the GHG footprint of unconventional gas. Here, we define the GHG footprint as the total GHG emissions from developing and using the gas, expressed as equivalents of carbon dioxide, per unit of energy obtained during combustion. The GHG footprint of shale gas has received little study or scrutiny, although many have voiced concern. The National Research Council (2009) noted emissions from shale-gas extraction may be greater than from conventional gas. The Council of Scientific Society Presidents (2010) wrote to President Obama, warning that some potential energy bridges such as shale gas have received insufficient analysis and may aggravate rather thanmitigate global warming.And in late 2010, the U.S. Environmental Protection Agency issued a report concluding that fugitive emissions of methane from unconventional gas may be far greater than for conventional gas (EPA 2010).

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Fugitive emissions of methane are of particular concern. Methane is the major component of natural gas and a powerful greenhouse gas.As such, small leakages are important. Recent modeling indicates methane has an even greater global warming potential than previously believed, when the indirect effects of methane on atmospheric aerosols are considered (Shindell et al. 2009). The global methane budget is poorly constrained, with multiple sources and sinks all having large uncertainties. The radiocarbon content of atmospheric methane suggests fossil fuels may be a far larger source of atmospheric methane than generally thought (Lassey et al. 2007).

The GHG footprint of shale gas consists of the direct emissions of CO2 from end use consumption, indirect emissions of CO2 from fossil fuels used to extract, develop, and transport the gas, and methane fugitive emissions and venting. Despite the high level of industrial activity involved in developing shale gas, the indirect emissions of CO2 are relatively small compared to those from the direct combustion of the fuel: 1 to 1.5 g C MJ-1 (Santoro et al. 2011) vs 15 g C MJ-1 for direct emissions (Hayhoe et al. 2002). Indirect emissions from shale gas are estimated to be only 0.04 to 0.45 g C MJ-1 greater than those for conventional gas (Wood et al. 2011). Thus, for both conventional and shale gas, the GHG footprint is dominated by the direct CO2 emissions and fugitive methane emissions. Here we present estimates for methane emissions as contributors to the GHG footprint of shale gas compared to conventional gas.

Our analysis uses the most recently available data, relying particularly on a technical background document on GHG emissions from the oil and gas industry (EPA 2010) and materials discussed in that report, and a report on natural gas losses on federal lands from the General Accountability Office (GAO 2010). The EPA (2010) report is the first update on emission factors by the agency since 1996 (Harrison et al. 1996). The earlier report served as the basis for the national GHG inventory for the past decade. However, that study was not based on random sampling or a comprehensive assessment of actual industry practices, but rather only analyzed facilities of companies that voluntarily participated (Kirchgessner et al. 1997). The new EPA (2010) report notes that the 1996 “study was conducted at a time when methane emissions were not a significant concern in the discussion about GHG emissions” and that emission factors from the 1996 report “are outdated and potentially understated for some emissions sources.” Indeed, emission factors presented in EPA (2010) are much higher, by orders of magnitude for some sources.

…[1] Fugitive methane emissions during well completion…[2] Routine venting and equipment leaks…[3] Processing losses…[4] Transport, storage, and distribution losses…[5] Contribution of methane emissions to the GHG footprints of shale gas and conventional gas…

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6 Shale gas versus other fossil fuels

Considering the 20-year horizon, the GHG footprint for shale gas is at least 20% greater than and perhaps more than twice as great as that for coal when expressed per quantity of energy available during combustion (Fig. 1a; see Electronic Supplemental Materials for derivation of the estimates for diesel oil and coal). Over the 100-year frame, the GHG footprint is comparable to that for coal: the low-end shale-gas emissions are 18% lower than deep-mined coal, and the high-end shale-gas emissions are 15% greater than surface-mined coal emissions (Fig. 1b). For the 20 year horizon, the GHG footprint of shale gas is at least 50% greater than for oil, and perhaps 2.5-times greater. At the 100-year time scale, the footprint for shale gas is similar to or 35% greater than for oil.

We know of no other estimates for the GHG footprint of shale gas in the peer reviewed literature. However, we can compare our estimates for conventional gas with three previous peer-reviewed studies on the GHG emissions of conventional natural gas and coal: Hayhoe et al. (2002), Lelieveld et al. (2005), and Jamarillo et al. (2007). All concluded that GHG emissions for conventional gas are less than for coal, when considering the contribution of methane over 100 years. In contrast, our analysis indicates that conventional gas has little or no advantage over coal even over the 100-year time period (Fig. 1b). Our estimates for conventional-gas methane emissions are in the range of those in Hayhoe et al. (2002) but are higher than those in Lelieveld et al. (2005) and Jamarillo et al. (2007) who used 1996 EPA emission factors now known to be too low (EPA 2010). To evaluate the effect of methane, all three of these studies also used global warming potentials now believed to be too low (Shindell et al. 2009). Still, Hayhoe et al. (2002) concluded that under many of the scenarios evaluated, a switch from coal to conventional natural gas could aggravate global warming on time scales of up to several decades. Even with the lower global warming potential value, Lelieveld et al. (2005) concluded that natural gas has a greater GHG footprint than oil if methane emissions exceeded 3.1% and worse than coal if the emissions exceeded 5.6% on the 20-year time scale. They used a methane global warming potential value for methane from IPCC (1995) that is only 57% of the new value from Shindell et al. (2009), suggesting that in fact methane emissions of only 2% to 3% make the GHG footprint of conventional gas worse than oil and coal. Our estimates for fugitive shale-gas emissions are 3.6 to 7.9%.

Our analysis does not consider the efficiency of final use. If fuels are used to generate electricity, natural gas gains some advantage over coal because of greater efficiencies of generation (see Electronic Supplemental Materials). However, this does not greatly affect our overall conclusion: the GHG footprint of shale gas approaches or exceeds coal even when used to generate electricity (Table in Electronic Supplemental Materials). Further, shale-gas is promoted for other uses, including as a heating and transportation fuel, where there is little evidence that efficiencies are superior to diesel oil.

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7 Can methane emissions be reduced?

The EPA estimates that ’green’ technologies can reduce gas-industry methane emissions by 40% (GAO 2010). For instance, liquid-unloading emissions can be greatly reduced with plunger lifts (EPA 2006; GAO 2010); industry reports a 99% venting reduction in the San Juan basin with the use of smart-automated plunger lifts (GAO 2010). Use of flash-tank separators or vapor recovery units can reduce dehydrator emissions by 90% (Fernandez et al. 2005). Note, however, that our lower range of estimates for 3 out of the 5 sources as shown in Table 2 already reflect the use of best technology: 0.3% lower-end estimate for routine venting and leaks at well sites (GAO 2010), 0% lower-end estimate for emissions during liquid unloading, and 0% during processing.

Methane emissions during the flow-back period in theory can be reduced by up to 90% through Reduced Emission Completions technologies, or REC (EPA 2010). However, REC technologies require that pipelines to the well are in place prior to completion, which is not always possible in emerging development areas. In any event, these technologies are currently not in wide use (EPA 2010).

If emissions during transmission, storage, and distribution are at the high end of our estimate (3.6%; Table 2), these could probably be reduced through use of better storage tanks and compressors and through improved monitoring for leaks. Industry has shown little interest in making the investments needed to reduce these emission sources, however (Percival 2010).

Better regulation can help push industry towards reduced emissions. In reconciling a wide range of emissions, the GAO (2010) noted that lower emissions in the Piceance basin in Colorado relative to the Uinta basin in Utah are largely due to a higher use of low-bleed pneumatics in the former due to stricter state regulations.

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8 Conclusions and implications

The GHG footprint of shale gas is significantly larger than that from conventional gas, due to methane emissions with flow-back fluids and from drill out of wells during well completion. Routine production and downstream methane emissions are also large, but are the same for conventional and shale gas. Our estimates for these routine and downstream methane emission sources are within the range of those reported by most other peer-reviewed publications inventories (Hayhoe et al. 2002; Lelieveld et al. 2005). Despite this broad agreement, the uncertainty in the magnitude of fugitive emissions is large. Given the importance of methane in global warming, these emissions deserve far greater study than has occurred in the past. We urge both more direct measurements and refined accounting to better quantify lost and unaccounted for gas.

The large GHG footprint of shale gas undercuts the logic of its use as a bridging fuel over coming decades, if the goal is to reduce global warming. We do not intend that our study be used to justify the continued use of either oil or coal, but rather to demonstrate that substituting shale gas for these other fossil fuels may not have the desired effect of mitigating climate warming.

Finally, we note that carbon-trading markets at present under-value the greenhouse warming consequences of methane, by focusing on a 100-year time horizon and by using out-of-date global warming potentials for methane. This should be corrected, and the full GHG footprint of unconventional gas should be used in planning for for alternative energy futures that adequately consider global climate change.