Huang, R., Riddle, M. E., Graziano, D., Das, S., Nimbalkar, S., Cresko, J. and Masanet, E. (2017). “Environmental and Economic Implications of Distributed Additive Manufacturing: The Case of Injection Mold Tooling.” Journal of Industrial Ecology. doi:10.1111/jiec.12641 This article is open source.
Abstract: Additive manufacturing (AM) holds great potentials in enabling superior engineering functionality, streamlining supply chains, and reducing life cycle impacts compared to conventional manufacturing (CM). This study estimates the net changes in supply-chain lead time, life cycle primary energy consumption, greenhouse gas (GHG) emissions, and life cycle costs (LCC) associated with AM technologies for the case of injection molding, to shed light on the environmental and economic advantages of a shift from international or onshore CM to AM in the United States. A systems modeling framework is developed, with integrations of lead-time analysis, life cycle inventory analysis, LCC model, and scenarios considering design differences, supply-chain options, productions, maintenance, and AM technological developments. AM yields a reduction potential of 3% to 5% primary energy, 4% to 7% GHG emissions, 12% to 60% lead time, and 15% to 35% cost over 1 million cycles of the injection molding production depending on the AM technology advancement in future. The economic advantages indicate the significant role of AM technology in raising global manufacturing competitiveness of local producers, while the relatively small environmental benefits highlight the necessity of considering trade-offs and balance techniques between environmental and economic performances when AM is adopted in the tooling industry. The results also help pinpoint the technological innovations in AM that could lead to broader benefits in future.
Read the full story from NPR.
When it comes to climate change, we often think of the cars we drive and the energy we use in our homes and offices. They are, after all, some of the biggest contributors to greenhouse gas emissions. But what about the toast you ate for breakfast this morning?
A new study published Monday in Nature Plants breaks down the environmental cost of producing a loaf of bread, from wheat field to bakery. It finds that the bulk of the associated greenhouse gas emissions come from just one of the many steps that go into making that loaf: farming.
In 2009, the Oregon Department of Environmental Quality published a study that compared a wide range of environmental impacts (including greenhouse gas emissions) of drinking water from the tap, 5-gallon reusables, and single-use bottles. It also looked at the environmental impacts of tap water (“reduce”) against the impacts of bottled water (“recycle” and “dispose”). The study confirmed that while recycling bottles is environmentally preferable to disposing of them, buying bottled water and recycling the bottles is not the best environmental choice. Drinking water from the tap (waste prevention) typically has substantially lower impacts in most categories of environmental impact.
Other highlights of the study include the following:
- For water that is bottled and consumed within Oregon, the large majority of environmental impacts are typically from producing the plastic resin used to make the bottle.
- If the bottle comes from across the country or the world, most impacts increase by a factor of 3 or more.
- End-of-life (disposal) related impacts are very small, with the possible exception of biodegradable plastic bottles. If they decompose in a landfill, the resulting methane is a potent greenhouse gas. Even when landfills capture some of the gas to produce energy, the remaining gas escapes and contributes to climate change.
- If you choose to drink bottled water, recycling the bottle can have moderate environmental benefits. These benefits, however, are still overshadowed by the negative impacts of making and transporting the bottle in the first place.
- For tap water, the frequency of washing your container in a dishwasher influences the results more than any other factor.
- Life Cycle Assessment of Drinking Water Systems: Bottled Water, Tap Water, and Home/Office Delivery Water Final Report
- Supplemental Report: Comparing Prevention, Recycling, and Disposal
This supplemental report uses the results of the Life Cycle Assessment to compare the environmental impacts of prevention, recycling, and disposal.
Frequently Asked Questions
Kyle A. Thompson, Kyle K. Shimabuku, Joshua P. Kearns, Detlef R. U. Knappe, R. Scott Summers, and Sherri M. Cook. “Environmental Comparison of Biochar and Activated Carbon for Tertiary Wastewater Treatment.” Environmental Science & Technology 2016 50 (20), 11253-11262. DOI: 10.1021/acs.est.6b03239
Abstract: Micropollutants in wastewater present environmental and human health challenges. Powdered activated carbon (PAC) can effectively remove organic micropollutants, but PAC production is energy intensive and expensive. Biochar adsorbents can cost less and sequester carbon; however, net benefits depend on biochar production conditions and treatment capabilities. Here, life cycle assessment was used to compare 10 environmental impacts from the production and use of wood biochar, biosolids biochar, and coal-derived PAC to remove sulfamethoxazole from wastewater. Moderate capacity wood biochar had environmental benefits in four categories (smog, global warming, respiratory effects, noncarcinogenics) linked to energy recovery and carbon sequestration, and environmental impacts worse than PAC in two categories (eutrophication, carcinogenics). Low capacity wood biochar had even larger benefits for global warming, respiratory effects, and noncarcinogenics, but exhibited worse impacts than PAC in five categories due to larger biochar dose requirements to reach the treatment objective. Biosolids biochar had the worst relative environmental performance due to energy use for biosolids drying and the need for supplemental adsorbent. Overall, moderate capacity wood biochar is an environmentally superior alternative to coal-based PAC for micropollutant removal from wastewater, and its use can offset a wastewater facility’s carbon footprint.
Read the full story from Carnegie Mellon University.
Making plastics from plants is a growing trend. It’s renewable, but is it better?
A recent study by Carnegie Mellon University researchers examines the life cycle greenhouse gas emissions of three plant-based plastics at each stage of production compared with that of their common fossil fuel-based counterparts.
The study by Daniel Posen, Paulina Jaramillo and Michael Griffin in the Department of Engineering and Public Policy (EPP), was published in the Journal of Environmental Science and Technology.
The study is novel in the way it treats uncertainty and looks at emissions over the life cycle of plastics. The researchers used a technique called life cycle assessment that analyzes emissions at each stage in the life of a product: resource extraction to manufacturing, to use of the product and end of life.
Read the full story at Phys.org.
Policy makers currently examine the economic and social impacts of crime, but the environmental impacts have not, to date, been included. A new study, published in the Journal of Industrial Ecology, estimates the carbon footprint of crime. The study was conducted by a UK-based research team led by an engineering doctorate student, Helen Skudder, in the Centre for Environmental Strategy at the University of Surrey.
Read the full story at NPR.
A few days back, All Tech got a question from an NPR listener that got us curious.
Tim Callahan from Seattle wrote:
“A friend asked how texting – in all its forms (admittedly a squishy thing to corral) – is contributing to global warming? After saying, ‘minimally…’, I thought about how to answer that question. Putting aside the sunk contribution caused by the manufacture and transport of the device you text with, how much does the battery emit / generate while a person does a typical or somehow average text? … Can you help quantify?”
I tracked down someone who’d get us to the answer: greenhouse gas footprinting expert Mike Berners-Lee. Climate impact calculations are just the sort of thing he does for work at Small World Consulting at Lancaster University in the United Kingdom. And estimating the impact of a text message is exactly the thing he did for his 2010 book How Bad Are Bananas? The Carbon Footprint Of Everything.