scholarly journals The role of concrete in life cycle greenhouse gas emissions of US buildings and pavements

2021 ◽  
Vol 118 (37) ◽  
pp. e2021936118
Author(s):  
Jeremy Gregory ◽  
Hessam AzariJafari ◽  
Ehsan Vahidi ◽  
Fengdi Guo ◽  
Franz-Josef Ulm ◽  
...  

Concrete is a critical component of deep decarbonization efforts because of both the scale of the industry and because of how its use impacts the building, transportation, and industrial sectors. We use a bottom-up model of current and future building and pavement stocks and construction in the United States to contextualize the role of concrete in greenhouse gas (GHG) reductions strategies under projected and ambitious scenarios, including embodied and use phases of the structures’ life cycle. We show that projected improvements in the building sector result in a reduction of 49% of GHG emissions in 2050 relative to 2016 levels, whereas ambitious improvements result in a 57% reduction in 2050, which is 22.5 Gt cumulative saving. The pavements sector shows a larger difference between the two scenarios with a 14% reduction of GHG emissions for projected improvements and a 65% reduction under the ambitious scenario, which is ∼1.35 Gt. This reduction occurs despite the fact that concrete usage in 2050 in the ambitious scenario is over three times that of the projected scenario because of the ways in which concrete lowers use phase emissions. Over 70% of future emissions from new construction are from the use phase.

2020 ◽  
Author(s):  
Jeremy Gregory ◽  
Hessam Azarijafari ◽  
Ehsan Vahidi ◽  
Fengdi Guo ◽  
Franz Ulm ◽  
...  

Concrete is a critical component of deep decarbonization efforts because it impacts the building, transportation, and industrial sectors. We use a bottom-up model of current and future building and pavement stocks and construction in the US to contextualize the role of concrete in greenhouse gas (GHG) reductions strategies under projected and ambitious scenarios, including embodied and use phases of the structures’ life cycle. We show that projected improvements in the building sector result in a reduction of 47% of GHG emissions in 2050 relative to 2016 levels, whereas ambitious improvements result in a 56% reduction in 2050, which is 22 Gt cumulative saving. The pavements sector shows a larger difference between the two scenarios with a 20% reduction of GHG emissions for projected improvements and a 68% reduction under the ambitious scenario, which is approximately 1.7 Gt. Over 70% of future emissions from new construction are from the use phase.


Author(s):  
Ching-Shin Norman Shiau ◽  
Scott B. Peterson ◽  
Jeremy J. Michalek

Plug-in hybrid electric vehicle (PHEV) technology has the potential to help address economic, environmental, and national security concerns in the United States by reducing operating cost, greenhouse gas (GHG) emissions and petroleum consumption from the transportation sector. However, the net effects of PHEVs depend critically on vehicle design, battery technology, and charging frequency. To examine these implications, we develop an integrated optimization model utilizing vehicle physics simulation, battery degradation data, and U.S. driving data to determine optimal vehicle design and allocation of vehicles to drivers for minimum life cycle cost, GHG emissions, and petroleum consumption. We find that, while PHEVs with large battery capacity minimize petroleum consumption, a mix of PHEVs sized for 25–40 miles of electric travel produces the greatest reduction in lifecycle GHG emissions. At today’s average US energy prices, battery pack cost must fall below $460/kWh (below $300/kWh for a 10% discount rate) for PHEVs to be cost competitive with ordinary hybrid electric vehicles (HEVs). Carbon allowance prices have marginal impact on optimal design or allocation of PHEVs even at $100/tonne. We find that the maximum battery swing should be utilized to achieve minimum life cycle cost, GHGs, and petroleum consumption. Increased swing enables greater all-electric range (AER) to be achieved with smaller battery packs, improving cost competitiveness of PHEVs. Hence, existing policies that subsidize battery cost for PHEVs would likely be better tied to AER, rather than total battery capacity.


Biomedicine ◽  
2021 ◽  
Vol 41 (4) ◽  
pp. 692-693
Author(s):  
Manjula Shantaram

If one has a passion for the planet, then this is the right time to drastically lower the carbon emissions. A carbon footprint is the total amount of greenhouse gases (including carbon dioxide and methane) that are generated by our actions. The average carbon footprint for a person in the United States is 16 tons, one of the highest rates in the world. Some carbon emissions will probably never be eradicated entirely from certain industries, such as air travel or construction. When emissions cannot be further reduced, carbon offsetting is the next best thing, says Winters (1). Offsetting emissions is paying for or investing in organisations that can extract carbon from the atmosphere to help others reduce their footprint. It could include investing in reforestation projects or new technologies that suck carbon out of the atmosphere and sequester it underground permanently, technologies to replace jet fuel with alternative green fuels, or switching fossil-fuel-powered facilities with hydrogen-powered facilities.    Unless the global economy meets the aims of the Paris Agreement, keeping climate change well below 2°C, the world is expected to suffer extreme weather conditions leading to mass migration and global catastrophe. The argument for global companies to reduce their greenhouse gas (GHG) emissions is clearer than it has ever been. Business operations around the world are now subject to greater climate and transition risks. Consumers are insisting for eco-friendly products and responsible corporate behaviours. Investors are increasingly embracing capital-allocation strategies that take environmental, social, and governance (ESG) issues into account. Policy makers and government organizations are exploring the potential regulation of carbon emissions. The more aggressive the targets, the better the results.   In COP26 climate summit in Glasgow held in November 2021, it was made clear that the current climate crisis has been precipitated by unsustainable lifestyles and wasteful consumption patterns mainly in the developed countries. The world needs to awaken to this reality. Globally, the building and construction sectors account for nearly 40% of global energy-related carbon dioxide emissions in constructing and operating buildings (2). Current building codes address operating energy but do not typically address the impacts of embodied carbon in building materials and products. However, more than half of all GHG emissions is related to materials management (including material extraction and manufacturing) when aggregated across industrial sectors (3).   In order to reduce our carbon footprint, we can start an eco-friendlier life. In winter, instead of heating, insulate the loft and walls which will make sure our home retains heat during the winter and stays cool in summer. By switching to a company that provides electricity from solar, wind, or hydroelectric energy, we can reduce our household emissions. Buy energy efficient electrical appliances. Additionally, make sure to turn off and unplug anything we are not using. It takes energy and resources to process and deliver water to our homes. So, by using less water, we can help the environment and lower our carbon footprint. The food we eat can have a significant impact on the environment. For example, meat and dairy products require a lot of land, water and energy to produce. They also create a lot of methane, a greenhouse gas. Moreover, food shipped from overseas uses a lot more resources than local produce. By eating fewer animal products, especially red meat, (or choosing a plant-based diet) and shopping for locally sourced food, we can make a big difference.  Why not support our local farmers’ market?   Powering empty rooms and office space is a huge energy drain. By making sure we turn off lights and appliances when they are not in use, we can make sure we are not wasting power. we can also request to install automatic, movement-sensing lights and energy-saving LED bulbs to address the issue. It has never been easier to collaborate with others online. Whether through sharing documents using cloud storage or video conferencing instead of travelling, we can reduce our waste and emissions. Try moving away from printed documents where possible, and encourage others to work on their digital skills for the workplace. Cycling and walking are two of the most environmentally friendly ways to travel. And, not only are they good for the planet, but they are also good for our health. If we can, choose to cycle or walk to work where possible. ‘Reduce, reuse, recycle’ is a popular slogan. Companies of all sizes use a host of different products in their day-to-day running. Whether it has things like paper, electronic devices, packaging, or water, it all has a carbon footprint. By reducing the amount of waste, we generate, reusing IT equipment, and recycling waste, we can make a real difference. Single use plastics may be convenient, yet they are fairly dreadful for the environment. Not only do they pollute our waterways and oceans, but they also require energy to produce and recycle. We can stop using things like disposable coffee cups and cutlery to reduce our company’s carbon footprint. Instead of preaching, let us practise and bring a change.


Author(s):  
Fan Yang ◽  
Chris Yuan ◽  
Xiang Zhao

The use of electric vehicle (EV) has been widely recognized as an effective way to reduce greenhouse gas (GHG) emissions from transportation sector. However, the geographic difference of GHG emission reduction from EV deployment is seldom explored. This paper presents a study on the total GHG emissions generated from the life cycle of an EV (represented by Nissan Leaf) and an internal combustion vehicle (ICV) (represented by Toyota Corolla) for benchmarking on the potential emission reductions in the United States. The differences of electricity mix and driving style in each state are considered in the analysis. The results indicate a 43% GHG emissions reduction from ICV with the deployment of EV under the current average United States’ electricity generation scheme and transportation style. But the life cycle GHG emission reductions vary significantly from state to state in the U.S. Some states such as Indiana, Wyoming and West Virginia can only get 7237, 9501 and 9860 kg CO2 equivalent reduced, while some states such as Vermont, New Jersey and Idaho can get 57915, 57206 and 49039 kg CO2 equivalent GHG emissions reduced. This study can be useful in supporting future decision-making and strategy development for EV deployment in the U.S.


BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 3899-3914
Author(s):  
Kristen E. Tomberlin ◽  
Richard Venditti ◽  
Yuan Yao

Greenhouse gas (GHG) emission levels are causing concern as climate change risks are growing, emphasizing the importance of GHG research for better understanding of emission sources. Previous studies on GHG emissions for the pulp and paper industry have ranged in scope from global to regional to site-specific. This study addresses the present knowledge gap of how GHG emissions vary among paper grades in the US. A cradle-to-gate life cycle carbon analysis for 252 mills in the US was performed by integrating large datasets at the production line level. The results indicated that one metric ton of paper product created a production weighted average of 942 kg of carbon dioxide equivalent (kg CO2eq) of GHG emissions. Greenhouse gas emissions varied by pulp and paper grade, from 608 kg CO2eq per metric ton of product to 1978 kg CO2eq per metric ton of product. Overall, fuels were the greatest contributor to the GHG emissions and should be the focus of emission reduction strategies across pulp and paper grades.


2016 ◽  
Vol 113 (48) ◽  
pp. E7672-E7680 ◽  
Author(s):  
Ian J. Laurenzi ◽  
Joule A. Bergerson ◽  
Kavan Motazedi

In recent years, hydraulic fracturing and horizontal drilling have been applied to extract crude oil from tight reservoirs, including the Bakken formation. There is growing interest in understanding the greenhouse gas (GHG) emissions associated with the development of tight oil. We conducted a life cycle assessment of Bakken crude using data from operations throughout the supply chain, including drilling and completion, refining, and use of refined products. If associated gas is gathered throughout the Bakken well life cycle, then the well to wheel GHG emissions are estimated to be 89 g CO2eq/MJ (80% CI, 87–94) of Bakken-derived gasoline and 90 g CO2eq/MJ (80% CI, 88–94) of diesel. If associated gas is flared for the first 12 mo of production, then life cycle GHG emissions increase by 5% on average. Regardless of the level of flaring, the Bakken life cycle GHG emissions are comparable to those of other crudes refined in the United States because flaring GHG emissions are largely offset at the refinery due to the physical properties of this tight oil. We also assessed the life cycle freshwater consumptions of Bakken-derived gasoline and diesel to be 1.14 (80% CI, 0.67–2.15) and 1.22 barrel/barrel (80% CI, 0.71–2.29), respectively, 13% of which is associated with hydraulic fracturing.


2008 ◽  
Vol 57 (11) ◽  
pp. 1683-1692 ◽  
Author(s):  
Andrea Tilche ◽  
Michele Galatola

Anaerobic digestion is a well known process that (while still capable of showing new features) has experienced several waves of technological development. It was “born” as a wastewater treatment system, in the 1970s showed promise as an alternative energy source (in particular from animal waste), in the 1980s and later it became a standard for treating organic-matter-rich industrial wastewater, and more recently returned to the market for its energy recovery potential, making use of different biomasses, including energy crops. With the growing concern around global warming, this paper looks at the potential of anaerobic digestion in terms of reduction of greenhouse gas (GHG) emissions. The potential contribution of anaerobic digestion to GHG reduction has been computed for the 27 EU countries on the basis of their 2005 Kyoto declarations and using life cycle data. The theoretical potential contribution of anaerobic digestion to Kyoto and EU post-Kyoto targets has been calculated. Two different possible biogas applications have been considered: electricity production from manure waste, and upgraded methane production for light goods vehicles (from landfill biogas and municipal and industrial wastewater treatment sludges). The useful heat that can be produced as by-product from biogas conversion into electricity has not been taken into consideration, as its real exploitation depends on local conditions. Moreover the amount of biogas already produced via dedicated anaerobic digestion processes has also not been included in the calculations. Therefore the overall gains achievable would be even higher than those reported here. This exercise shows that biogas may considerably contribute to GHG emission reductions in particular if used as a biofuel. Results also show that its use as a biofuel may allow for true negative GHG emissions, showing a net advantage with respect to other biofuels. Considering also energy crops that will become available in the next few years as a result of Common Agricultural Policy (CAP) reform, this study shows that biogas has the potential of covering almost 50% of the 2020 biofuel target of 10% of all automotive transport fuels, without implying a change in land use. Moreover, considering the achievable GHG reductions, a very large carbon emission trading “value” could support the investment needs. However, those results were obtained through a “qualitative” assessment. In order to produce robust data for decision makers, a quantitative sustainability assessment should be carried out, integrating different methodologies within a life cycle framework. The identification of the most appropriate policy for promoting the best set of options is then discussed.


2019 ◽  
Vol 230 ◽  
pp. 1156-1164 ◽  
Author(s):  
Xin Xu ◽  
Mehdi Akbarian ◽  
Jeremy Gregory ◽  
Randolph Kirchain

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