A recent International Energy Agency (IEA) report, “CO2 Emissions from Fuel Combustion Highlights,” estimates the energy sector is responsible for more than 40 percent of global carbon dioxide (CO2) emissions. Gas flaring is one of the primary contributors to industrial emissions from the sector, and while gas is often flared for safety reasons, a large proportion is still flared as the main method of disposal for facilities that do not have the infrastructure to capture, transport and monetize it. Flaring is a wasteful process — producing more than 300 million tons of CO2 emissions every year — and a significant contributor to global warming.
Now or never
In September 2016, Hawaii’s Mauna Loa Observatory — the primary global site for atmospheric CO2 monitoring — recorded an atmospheric CO2 concentration of 400 parts per million (ppm), a threshold first reached during the winter of 2013. In winter, atmospheric concentrations are usually higher than in the summer months when plants absorb CO2 during photosynthesis.
Despite a higher CO2 concentration in recent winters, during the summer levels have always fallen below 400 ppm again. A reading of 400 ppm in September 2016 — the month CO2 levels are at their lowest — suggests the global atmospheric concentration of CO2 may never fall below it again. The increasing level of atmospheric CO2 is causing global temperatures to rise.
In a recent interview with Fluenta, World Bank Global Gas Flaring Reduction (GGFR) Partnership Program Manager Bjorn Hamso explained one of the tangible impacts gas flaring is having on the environment: “Scientists estimate that 40 percent or more of the black carbon (soot) that is deposited on the Arctic snow and ice cap comes from flaring inside or near the Arctic Circle. This accelerates an already deeply troublesome melting of snow and ice near the North Pole.”
Equipment must be maintained and calibrated to ensure accurate measurements.
A combined effort
Support is growing for initiatives such as the World Bank’s Zero Routine Flaring (ZRF) to reduce the sector’s routine carbon emissions. Launched in April 2015 with 25 endorsers, the ZRF initiative brings governments, oil companies and development institutions together to work toward eliminating routine gas flaring by 2030. The initiative now has 62 endorsers. Many governments and regulators are taking the initiative seriously and are increasing the pressure on companies to accurately measure and report flaring as well as to implement new ways of reducing flare gas volumes.
It is likely that during the next few years there will be an increase in new and improved regulations governing flaring, measurement accuracy and gas capture requirements. Signatories to ZRF have committed to publicly reporting flaring volumes on an annual basis, eliminating flaring within existing operations and ensuring new sites incorporate gas utilization solutions that avoid routine gas flaring or venting.
A trend reversal
Despite the issue gaining more recognition globally, new data released in December 2016 by the World Bank’s GGFR Partnership shows an increase in global gas flaring over the last five years.
The flaring report is based on satellite data and shows 147 billion cubic meters (bcm) of natural gas was flared globally in 2015. This is an increase from 145 bcm in 2014 and 141 bcm in 2013. The largest flaring country is Russia, which flared 21 bcm of natural gas, followed by Iraq at 16 bcm and Iran and the U.S. at 12 bcm.
The GGFR attributes the increase in global flaring volumes to the growth in oil production in Iraq and the U.S. Flaring in the U.S. has continued to increase despite widespread drives for reduction.
The increase in U.S. flaring has been linked to the shale gas revolution; However, new statistics from the U.S. Energy Information Administration have shown its potential to reduce CO2 emissions. A report issued on Oct. 12, 2016, found that CO2 emissions fell to 2,530 million metric tons in the first half of 2016. Levels are projected to fall to 5,179 million metric tons by the end of 2017. This level has not been recorded since 1992 and is most likely explained by the impact hydraulic fracturing has had on emissions from burning coal. Coal burning generates significantly more carbon emissions than natural gas, and volumes fell 18 percent compared to the first six months of 2015. This suggests that a continued focus on reducing routine gas flaring during oil and natural gas production has the potential to achieve significant CO2 reductions for the sector overall.
Flare gas meters enable businesses to measure and limit CO2 emissions.
Gas capture for small sites
Nigeria, historically one of the highest flaring countries, has reduced flaring volumes by almost 20 percent since 2013. Nigeria loses an estimated $166,582 million every year to gas flaring, but efforts to capture natural gas are not only increasing revenues from natural gas sales, but production and sales of associated products such as fertilizer.
If the 147 bcm of gas flared globally every year were captured and used to generate power, it would provide around 750 billion kilowatts (kWh) of electricity. To put that into perspective, 750 billion kWh would be enough electricity to power more than the continent of Africa.
It is still a commonly held belief that small-scale gas utilization is not commercially viable. New gas utilization methods, however, are increasingly cost-effective. Companies that flare minimal volumes can also significantly reduce their tax bills through advanced measurement processes. In countries where many smaller flare sites are common, for example where fracking is popular, local utilization of flare gas can be a practical way of reducing CO2 emissions from flaring.
The World Bank flared gas utilization strategy outlines four methods companies can adopt to reduce routine gas flaring in smaller sites. These methods do not require significant infrastructure investment.
The suggestions are:
- Install power generators within the oil production site and use previously flared gas to power them. Power can then be used to run the site and the excess can be transmitted to the existing power grid.
- Install power generators within the oil production site, which can be used to power a previously nonelectrified local rural area.
- Implement power cooperation schemes with larger companies in the surrounding area. Associated gas can be supplied via short pipelines to larger corporate consumers, such as heat and power plants, as well as other industries.
- Produce liquefied petroleum gas to be used as fuel in heating appliances, cooking equipment and vehicles. This can be implemented either as a stand-alone measure or in combination with other gas utilization methods.
Critical accuracy
For small-scale gas capture to work, an operator needs access to reliable and accurate gas measurement data. It enables the whole process to be managed safely and effectively and helps operators ensure regulatory compliance. With advanced measurement techniques, operators who reduce routine flaring can achieve additional tax savings for the gas they do flare.
An optimized flaring process often enables an operator to capture almost all the gas previously flared. The remaining flare gas — even if only present during plant shutdown or emergency procedures — can be mixed with nitrogen to maintain pressure and velocity in the flare line.
Nitrogen does not burn or produce CO2 and operators are not taxed for releasing it. “Purging” with nitrogen is only cost-effective, however, if the operator can identify and report the difference between CO2 and nitrogen. If not, the operator will pay tax on the whole volume of gas released, rather than just the CO2.
Enhanced density monitoring
Enhanced density monitoring (EDM) is a flow measurement process that provides automatic subtraction of nitrogen from flared gas volumes. This enables businesses to accurately report CO2 emissions from flare gas while purging nitrogen.
Preprogrammed flow composition scenarios based on predicted flow velocity variations allow the EDM algorithm to differentiate between nitrogen and CO2 to report the difference.
The EDM algorithm measures sound velocity to determine if a difference exists between the measured and the expected value. A difference indicates a change in gas composition, suggesting the operator may be flaring an unexpected volume of CO2.
EDM does not need a stable flow velocity to work, which allows operators to use EDM across all flaring environments. The automated process means EDM could be used by an operator who only flares gas during emergencies or plant shutdowns. For operators who purge with nitrogen because gas utilization is in place and flare volumes are low, EDM provides a fast return on investment through more accurate emissions reporting and a reduction in taxation.
Conclusion
The speed of environmental changes associated with carbon emissions is putting more pressure on the energy industry to respond. While gas flaring has long been a controversial issue, many operators now see accurate measurement and emissions reduction as strategic metrics. The introduction of new technologies to help operators capture gas economically, even on smaller sites, means operators have access to the tools they need to maximize the value of the natural resources they produce. Many operators have begun to see that capturing previously flared gas can be profitable if the process is managed effectively. Emerging technologies such as EDM have the potential to help operators manage carbon tax obligations more effectively, while at the same time significantly reducing the sector’s impact on the environment.
Lana Ginns is marketing manager for Fluenta, a provider of ultrasonic flow measurement for the oil and gas and chemical industries. She is fluent in German, English, Spanish and French.
