Global Climate Change Issue
Climate change is a serious global issue that threatens the future of our planet, and all plants and animals that inhabit it. Greenhouse gas emissions are trending upwards, and if they continue to grow at current pace or higher, this could “result in a wide range of adverse impacts and potentially trigger large-scale, irreversible, and catastrophic changes that will exceed the adaptive capacity of natural and social systems.”[IPCC] In order to prevent this future, a goal of limiting emissions to 450ppm and 20C increase in global temperatures by 2050 is required to give us a 50% shot of stabilizing the climate change onset by increased GHG emissions[IPCC]. At our current business as usual projections, we will achieve an atmospheric GHG concentration of 685ppm by 2050. The largest contributor to global GHG emissions is the power generation industry. The Global Demand for energy will continue to grow for decades to come as the developing world strives to improve its standard of living to first world status. As population increases worldwide, so does the rate of electrification and urbanization. The unfortunate consequence of global improvement in living standards, is the environmental costs associated with this rapid growth. According to the World Energy Council, global demand for electricity could increase by 50% by 2050, and 80% of this increase is expected to come from the Developing World [WEC]. As a result the globe can expect equivalent increases in GHG emissions. It is imperative, in order to ensure a sustainable future, that we are able to adapt our current energy portfolio moving forward, in order to mitigate the pending climate change that will come hand and hand with these alarming future emission projections.
According to the EPA, 77% of the GHG emissions from electricity generation comes from the use of coal [EPA]. Coal has proven it’s superiority as a cheap and energy intensive solution to power supply problem worldwide. One of the biggest downsides to coal is its environmental cost. In every evaluation of its current or future technology, Coal will continue to be the largest GHG contributor in electricity generation industry. The primary energy demand in both India and China is expected to double and increase by 150% respectively by 2035[WEC]. As the developing world continues to strive to reach First World Status, their electricity demand will continue to be met by environmentally harmful coal. Based on our data, the best way for the world to meet the IPCC’s emissions goals, is to influence the developing world to diversify their electricity generation portfolio, and transition to cleaner burning and more efficient natural gas for their electricity generation. This supply of natural gas should be supplied through LNG.
Environmental Analysis
An accurate and efficient environmental analysis of a coal and natural gas fired electricity generation systems is a complex task due to the various processes that occur prior to and during electricity generation. Instead of getting bogged down in all the small details of the supply chain, our drive was to rather address the issue from a holistic view using Life-Cycle Analysis, LCA. We used both the PACE and NETL life-cycle analysis, LCA, for the basis of our findings.
Coal vs LNG LCA (Life-Cycle Analysis) Findings
According to the LCA performed by both CLNG and NETL, existing domestic coal power plants produce two and a half times more emissions on a lifecycle basis than LNG [NETL] [CLNG]. Even the cleanest coal technologies were found to produce over 70% more emissions in all cases. In the case of both coal and LNG, most GHG emissions come from the combustion of hydrocarbons. Both Coal and LNG release GHG into the atmosphere, and Coal releases almost double the amount CO2 as LNG, but LNG releases more methane than coal. This is important to note, because methane has a 25 times greater climate change impact over a 100-year timespan compared to Carbon Dioxide [EPA]. LNG also has higher transportation emissions than coal, but this is most likely attributed to the fact that the mode of transportation is different and longer standing for coal. LNG’s largest emission source next to combustion is processing. In the LNG processing stage, natural gas is refined to remove the other GHG, impurities, and is then liquefied for ease of transportation. For more information on the processing of LNG, please view our process Tab. The environmental benefit to processing the natural gas before combustion is the reduction other more harmful GHG’s, in particular the complete removal of NOX, SOX, particulates, impurities, and mercury. Figure 1 below shows how each of the above compounds contain even higher Global Warming Potentials than both CO2 and Methane, CH4. Coal does not go through any refinement prior to combustion; therefore, the higher intensity GHG are emitted during its combustion. There are current technologies and processes used to remove these compounds after combustion, but they are not as successful as LNG. Coals largest emissions contribution besides combustion is in its production. According to the IPCC, even under the cleanest coal scenario, coal will release 73% more GHGs than LNG. Please See Figure 2 below for the LCA emissions results for the study.
LNG Impacts
Following the conclusions drawn from the LCA, and assuming that LNG will be implemented to provide the developing world with a more environmentally friendly alternative to Coal for power generation, a discussion of the environmental impacts throughout the supply chain must be had. The following paragraphs address the local, national, and global environmental impacts of this alternative energy source.
From a Local perspective we want to address the local impacts on the exporting country. It is important to note the local environmental concerns that arise when you build any processing facility, including an LNG liquefaction facility. There will undoubtedly be an impact on the natural environment from the physical plant itself. When you clear land to build a processing facility there will be an undoubtedly an effect on the local wild life and plant life. While the facility is being constructed, there is an increased environmental affect from the diesel combustion engines used to power equipment. There is additional deforestation caused by roads leading to and from the facility and from clearing land for natural gas pipelines feeding the facility. There is also increased CO2 emissions from vehicles driving back and forth to the plant. Assuming the plant is located near a waterway for LNG Vessel Loading, there will be an impact on local marine life as well. Once the plant is up and running, there is also the concern of the impact of GHG emissions, especially methane, on the local atmosphere, and the concern of the pollution being absorbed into local soils, groundwaters, and agriculture. There are also concerns of unnatural smells, low visibility from smog, and health related breathing issues. The local impacts from the LNG facility on the local environment might seem extreme, but in reality they are comparable to the environmental risks of other processing facilities [Exxon].
On a National scale, it is important to address the production of natural gas, and its transportation to a Liquefaction facility. Using the United States as a model, it is easy to see that the source of the supply of natural gas to a liquefaction facility is just as important as the facilities themselves from an environmental perspective. The United States supply of natural gas has skyrocketed by 20% in the past decade due to increasing proved reserves from unconventional extraction techniques [WEC]. These unconventional techniques like tight gas, shale gas, and coal bed methane are more environmentally intense than the conventional sources of natural gas. It is also important to note that LNG is the most environmentally unfriendly natural gas technology in terms of production and transportation to a Power Plant, but coal is still at least double as environmentally hazardous [NETL]. Nationally it is also important to address the location and source of the production of the Natural Gas and its proximity to the LNG Liquefaction Facility. There is a direct correlation for increased methane emissions and distance from production to the processing facility due to leaks in the transportation pipeline.
On a global scale it is important to address the concerns of the importing countries environmental concerns. The local concerns of the regasification facilities is similar to that of the local concerns of the liquefaction facilities. The main issues fall with protecting the local ecology and wildlife. Limiting damage to groundwater, soils, and local marine life is also important to address. Nationally in the importing country, like in the exporting country, there needs to be a concern with increasing methane emissions through pipeline transportation. The shortest distance from regasification facility to power plant is suggested. This is important to note because in the developing world, the natural gas pipeline infrastructure is in its infancy. In this case LNG provides another viable option to transport Natural Gas via rail or truck directly from the offloading facility directly to the power plants. Inevitably, the biggest environmental concern for the importing country, comes from the pure combustion of natural gas for power. As we mentioned above, under a LCA, Natural Gas 161% more clean than coal, but in retrospect the combustion of hydrocarbons is still occurring.
Plans for Improvement
Even though LNG is much cleaner than Coal, it can still make significant adaptions and improve its GHG emissions by making a few simple changes to the process stream. According to PEMBINA, there are four major categories for process improvement in the LNG facility, Combustion, Venting, Fugitive Gas, and Flaring.
In the combustion category, LNG plants could have their electricity supplied by renewable sources of energy. One of the largest sources of GHG emissions in an LNG facility come from compressors. Most current industry compressors run on diesel fuel. By replacing this fuel with a renewable source of electricity, not only would they decrease fuel consumption, but also CO2 emissions from the combustion of diesel. Another problem with compressors are the gas leakage that occurs from improper seals being installed on the pumps. This issue not only causes pump degradation, but it also one of the leading causes of methane emissions in the entire LNG supply chain. By ensuring the seals are properly maintained, large amounts of potential methane emissions could be prevented.
Venting applications throughout the facility are also huge environmental emitters with the ability to improve. It is common industry practice to vent the CO2 that is produced with natural gas and the CO2 separated from Natural Gas during processing directly to the atmosphere. By putting a stop to this practice and utilizing the CO2 in some other way all LNG facilities could expect significant changes in their emissions data. The second largest cause of emissions issues in an LNG plant come from methane venting as a result of pneumatic controllers. These emissions could be mitigated by using low bleed devices, devices that run on compressed air instead of natural gas, or even switching to electrical activated valves with the electricity supplied by a renewable source of energy.
Another huge source of emissions come from fugitive emissions. Most of these emissions are direct causes of poor maintenance plans. Most of the emissions are sources of leaking valves and fittings along the process chain. By implementing a quarterly leak testing plan, the operating company would be able to identify and correct any problem area. This way they could not only verify the integrity of their piping, but also help reduce their emissions at a low cost.
The final area that the LNG process chain can make improvements is in Flaring. During both production and refinement, it is common industry practice to flare natural gas. By enforcing a more reduced emission completion, reduced emission well test, and limiting flaring during liquefaction and regasification, LNG LCA emissions would decrease dramatically.
By implementing the above process adaption suggestions, the LNG industry as a whole can expect drastic decreases in emissions. It is important to note, that these changes would not only make LNG a more impressive alternative energy option, but it would increase the environmental gap between LNG and Coal. Please see Figure 3 Below for a Summary of Reduction Opportunities and their proposed reduction capabilities.
Conclusion
Based on our research, in order to reach the IPCC’s goal of limiting emissions and temperature rise to 450ppm and 20C respectively, a transition from coal fired power plants to the cleaner and more efficient Natural Gas is required. This source of natural gas should be supplied in the form of LNG. As both of our LCA illustrate, in every case, LNG is cleaner than coal for power generation. According to CLNG, a one to one replacement of a coal fired plant with an LNG fueled plant would equate to removing over 250,000 cars off the road in a year [Figure 4].
While LNG might not be the most environmentally friendly natural gas option, it provides the opportunity to transport LNG without the need for long pipelines. It also provides a cleaner burning option to natural gas due to the refinement aspect of the process. Based on our research, the proposed adaptions are made to the LNG supply chain, there is no doubt that LNG can make a significant impact in GHG emissions worldwide.
