Green Bits

We've spent the last posting discussing supply chains from a manufacturing and green aspect. Following on these discussions, I wanted to mention an upcoming webinar on "Supply Chain Carbon Mapping in Four Industries" to be presented by Climate Earth on  Tuesday, April 20th, at 11 am PDT/ 2 pm EDT (1 hour). There is no cost for the seminar and you can register at https://www1.gotomeeting.com/register/346073969 or go to http://www.climateearth.com/. There is an archived webinar on "Carbon Efficient Supply Chains" at http://www.climateearth.com/webinar_2009_11_18.shtml. The four industries covered are food processing, packaged goods, manufacturing, and services

A recent survey by McKinsey on "How companies manage sustainability" caught my eye. You need to register to download the full report (but it is free) at http://www.mckinseyquarterly.com/How_companies_manage_sustainability_McKinsey_Global_Survey_results__2558. The survey was done in February 2010 covering almost 2000 executives in a wide range of industries and locations. Among the results shown is a table showing how companies keep track of the "value created by sustainability programs." Although no detail is given on the programs the results support some of our earlier musings on why green (or sustainable) matters.

The items tracked are:
- reputation building (over half agree this is a key metric)
- growth opportunities
- cost savings
- risk avoidance
- employee attraction, retention and productivity
- customer loyalty

The study also identified "proactive" executives (surprisingly only about 6% say "sustainability is a top-three priority" in their agendas with the associated actions associated with it.) These executives tend to be much more proactive in seeking ways to enhance the sustainability of their organizations. They list the following statistic - "84 percent of respondents at engaged companies are aware of whether or not their companies measure their carbon footprint" and, more importantly,  these engaged companies are more likely, with respect to their supply chain and customers,  to be keeping track of "relevant sustainability indicators such as waste, energy and water use, and labor standards."

Now to some green technology wedges!

I participated in and spoke at a conference earlier this month in Nashville sponsored by AMT and NCMS - two organizations well engaged with the manufacturing industry in the US. It was called the 2010 AMT/NCMS Manufacturing Technology Forum and the focus was on green manufacturing. You can see some details at http://www.amtonline.org/article_display.cfm?article_id=160249&section_id=268.

I presented an overview of issues and opportunities in green manufacturing (many of them discussed in these postings) and spoke again about the concepts of the technology wedges. I first introduced these in the September 15, 2009 blog (see http://green-manufacturing.blogspot.com/2009/09/green-manufacturing-technology-wedges.html). I related this concept to specific approaches to reducing energy consumption in manufacturing with examples from machine tool design and operation.

One of the other speakers, Scott Hibbard, Vice President of Technology at Bosch Rexroth in Illinois. Besides being a very sharp engineer in the drive and controller business we both have roots in Wisconsin. He discussed drive & control technology to increase energy efficiency and spoke of many bits of enabling technology for some of the exact applications I have been thinking about in the past. Things such as energy recovery from machines during changeover or down cycles, reduction in "tare" energy for machines, reduction (or increase in efficiency) of process related energy, etc.

He showed the required "what percentage of US consumption my particular area is responsible for" slide derived from Department of Energy data but this time reflecting motors and drives. Turns out about 70% of industrial energy consumption falls in this category. He further broke that category down to specific applications of these motors and drives to include pumps (hydraulic and others) 27%, compressed air systems 18% material movement (also known as motion control - this is used in machine tools, robots, conveyors, etc.) 30%, for example.

Just to make sure we are all on the same page let's define a few terms. Drives (often adjustable speed) is usually a combination of hardware and software that powering and adjusting the operating speed of a mechanical load. This is often an electric motor and a speed controller or power controller. The "drive" often refers to just the controller. In machine tools these motors can be synchronous or induction, AC, DC (brushed or brushless), or step motors and can be rotary or linear motion providers. Try our old friend Wikipedia for a quick source of info. The combination of a motor and drive with some higher level control hardware/software makes up one axis of motion of a modern numerically controlled machine tool as we've discussed them before.

Scott identified 4 major areas for energy savings and, incidentally, increasing productivity:

- Efficient components (use products and systems with optimized efficiencies)
- Energy on demand (only use energy when needed; recall our tare vs process energy discussion a few blogs back)
- energy recovery (store and reuse or sell back excess energy; and we had referred to energy recovery from the spindle of a machine tool also)
- Energy conscious system design (include energy consumption and efficiency in the design of the machine or system from the start)

One of his examples showed 20% regenerative power from "machinery braking" and the return of that power to the electricity utility. "Energy exchange" between motor and generator drive modes is also a possibility with 15% recovery.

One neat example relied on storing of excessive energy not required during short-time operation and intermittent operation by means of hydraulic accumulators and accumulator charging circuits. Without getting into the details, accumulators in hydraulic systems are pressure storage reservoirs containing a hydraulic fluid (considered to be incompressible - meaning doesn't compress under load - most liquids are like this) that is held under pressure by an external source such as a spring, compressed gas (gases do compress under load!), weights or other mechanisms. Using an accumulator, the pump on the hydraulic system need not be as large to accommodate the load variations and, they can store energy! Combine this with a variable speed pump which can use up to 65% less energy  thanks to utilization of stand-by mode when idle-running and speed reduction with slower motions.

Scott showed this technology applied to a hydraulic press. These presses are used for forming large sheets of metal as in automotive components like fender, hoods, etc as well as a variety of formed metal products. Think of a giant hydraulic cylinder with a forming tool set (punch and die) and sheets of metal.

The figure below, from Scott's presentation, shows a typical energy use cycle for a hydraulic press. The top figure shows the press cycle with a rapid down motion, the press forming section,

decompression and return of the cylinder (and top die) to top position. The bottom portion compares the energy used over time with the conventional and variable speed pump drive with regeneration. There is a dramatic savings. In addition, since motors generate heat, etc. there will be a reduced building environmental load as well.

We've gotten a little heavy on the tech talk this time. But, it is an excellent example of the potential in operation of our manufacturing machinery to apply wedges that, in combination with a lot of other machine improvements, make big differences. A typical automotive manufacturing press shop will have dozens of these presses operating 24/7 (when production is good of course) and the savings realized on one machine multiplied by all adds up.

More tech stuff next time!

And, for youtube fans, we've posted two videos on our lab website from a recent open house called "Cal Day": one is on how we calculate the carbon footprint of our laboratory and another on a recent experiment showing side by side energy consumption and a milling experiment in the lab. Both are accessible at http://lmas.berkeley.edu/public/?p=1266. Enjoy!

Greening the supply chain, Part 4

Last of a series

I ended the last supply chain discussion remarking that keeping track of the bits and pieces of a supply chain (resources, impacts, locations, suppliers, transit routes, etc.) is not trivial but that, as we become better at tracking these, the metrics, software tools, analytical methodologies and, even, simple rules of thumb, can be developed and used to get a better picture of where we are and what progress we are making.

I know from a number of advertisements and tech magazine articles that the major players (think SAP, Oracle and ERP and PLM applications - I am sure there are many more) are already well established in the "bean counting" and can provide much of the data needed to get us started at the enterprise level and supply chain at some level.

In an earlier example in this series, we focused on a fictitious auto production  operation with stamping, assembly and sales in different parts of the workd. We saw the sensitivity to energy source impact variations in different locations. Last time we dug a bit deeper into these variations and what they mean in supply chain impact determination.

In this posting, I'd like to present a more practical example based on real data from work done in our lab. And, I'll admit, it's tax time and I have to work on my contribution to the State of California and the Federal Government so this saves me a little time!

This example is based on a paper titled “Development of the Supply Chain Optimization and Planning for the Environment (SCOPE) Tool - Applied to Solar Energy,” which was presented at the IEEE International Symposium on Electronics and the Environment in 2008 in San Francisco. Copies of the full paper are available for download at http://escholarship.org/uc/item/9tq5x8fb.

The paper addresses the need for supply chain optimization and planning with the environment in mind, using reasonable metrics as part of the decision making process. The proposal is for a tool (called SCOPE as defined in the paper title) and the example applies the tool to solar panel manufacturing.

Renewable energy systems are being developed to satisfy three main goals: (1) provide reasonably priced energy (2) mitigate climate change (3) provide energy independence.  The life-cycle environmental impact of energy supply can be reduced through research on materials, product design, manufacturing, and the supply chain; the focus here is on the supply chain because environmental tradeoffs at this level are generally not considered in new energy development.

The supply chain is defined as the set of suppliers required for a complete and successful final product, and the interconnecting network of these suppliers around the globe as detailed in previous postings in this series. The supply chain has been found to impact up to 25% of manufacturing costs in typical products, and preliminary studies indicate that environmental impacts may be similarly distributed. In this study we worked with SolFocus, Inc. (see http://www.solfocus.com/en/) a manufacturer of concentrator photovoltaic systems.

An initial assessment of SolFocus Inc. concentrator photovoltaic systems found transportation to be 10-20% of the lifecycle energy demand when panel transportation to installation site and glass transportation to assembly were included. Additionally, our research has shown that the strategy to minimize greenhouse gas emissions depends both on the electricity mix at the customer and transportation distances.

To do this correctly, environmental supply chain considerations can and should be incorporated early in the design process to ensure the greatest possible reduction in impact. Previous solar energy assessments, while thorough in their execution, have not focused on the climate change mitigation potential of a re-organized supply chain or installation location variables.

The SCOPE tool is a hybrid LCA tool and incorporates the following:

1. Electricity mix and resource differences throughout the supply chain since parts may originate from all over the globe, such as China, India, the U.S.A, and elsewhere. This approach parallels today's economic assessment for production, where manufacturing location decisions are influenced by economic decisions such as labor costs, energy costs, local regulations, resource availability, flexibility, and lead times. (But, the tool does not include these latter elements - yet.)

2. Transportation emissions and energy demand.

3. Electricity distribution and circularity.  When determining the electricity that is offset by a new solar installation the "circularity" or distribution losses of electricity supply are usually not considered. Demand for electricity requires extra production to account for electricity that is lost in transport to consumers (distribution losses) or internally demanded by the energy sector (circularity).

The proposed SCOPE tool's basic architecture and underlying hybrid LCA methodology are presented in the paper and energy and greenhouse gas metrics are used by the tool to assess alternatives so check the paper for details. A case study of preliminary results for SolFocus Inc. is presented to establish the feasibility, applicability, and usefulness of SCOPE.

The metrics used are:

- energy payback time (EPBT) which indicates the number of years a technology must produce electricity, thus offsetting the use of primary energy from another electricity source, to offset the total energy required over its lifetime (including manufacturing, transport, installation, etc.)

- energy return on investment (EROI) calculated as the lifetime of the product divided by the EPBT  EROI indicates how many MJ of primary energy are saved from consumption for every MJ of primary energy consumed.

- greenhouse gas payback time (GPBT), an analog of energy payback time for green house gas emission, and

- greenhouse gas return on investment (GROI). Similar to  EROI, GROI indicates the GHG emissions prevented for every unit of GHG emitted encouraging the fastest route to reducing energy related greenhouse gas emissions.

To illustrate this approach an example is presented. In this collaborative project, we looked at a particular  utility scale concentrator photovoltaic system SolFocus was developing. It is comprised of a solar panel, a "tracker" support structure that moves the panel to maintain incident solar exposure during the day, controller in the tracker, etc. Although the design and manufacture were still under development,  available cost estimates and preliminary manufacturing data were available. A mockup of choices for producing a solar panel is shown in the figure below. The double boxes indicate one possible supply chain.

To illustrate the variability in energy and GHG metrics, four scenarios are considered: (1) no transportation over the life of the supply chain (2) transportation of goods across the SolFocus supply chain using the most efficient methods possible (truck, rail, water freight) (3) transportation using only air freight as a worst case scenario (4) same as 3 except installation in France rather than Phoenix with a DNI of 5.3 kWh/m2/day. DNI refers to "direct normal irradiance" and gives a measure of the direct solar energy available at a location. Not surprisingly, locations in sunnier locations (as in closer to the equator) are better for solar energy. Phoenix is considered a good site while France is considered marginal; DNI values can be even higher in Africa, Australia and other parts of the southwest United States. If you want to see what the DNI is for your location (in the US) see http://www.solarpanelsplus.com/solar-calculator/, for example.

For this assessment, installation is assumed to occur in Arizona, USA with a DNI of 6.9 kWh/m2/day. The panels are assembled in India, and most components come from China, India, Spain, or the U.S. The installation is utility scale and assumed to replace rather than supplement the local electricity mix; therefore production, circularity, and distribution of the current electricity mix are offset.

Although the SCOPE tool is still under development in LMAS, the application of the SCOPE methodology to this particular solar system, given available data, results in the supply chain tree shown in the figure below. Note that in the figure transportation is not yet included for every component.

The results of the analysis are shown in the table below and indicate the influence of transportation

in energy and GHG metrics. In reading the table, smaller values of payback time and impact of GHG/kWh are better! The GPBT shows the largest sensitivity to installation variations because it is directly proportional to the conversion factor for GHG per unit of electricity (recall last posting) and the circularity. Each metric is also sensitive to the type of transit used throughout the life-cycle as seen between scenarios 2 and 3. These results indicate the potential for supply chain and installation optimization using the SCOPE tool. The impact of variations in electricity mix at each supplier site on these metrics have not yet been explored.

Preliminary results for SolFocus concentrator systems across the range of scenarios tested indicate that the EPBT of SolFocus Panels can vary from 0.6 to 5 years depending on installation and manufacturing locations. The GPBT can vary from 1.1 to 49 years depending on the same factors, and is seen to be more greatly sensitive to location factors than an energy-based metric.

But, there is much to be done to complete such tools - specially for alternate energy applications. Energy use and greenhouse gas emission metrics are discussed here because energy use is relevant to the efficiency of solar technology and greenhouse gas emissions are relevant to climate change; however an additional key concern of climate change is water scarcity. Solar has the distinct advantage of not requiring water during its use-phase; therefore, the installation of solar to replace thermal power plants (which consume nontrivial amounts of water per kWh generated) in water scarce regions of the world could prevent water use and thermal pollution of waterways. Tradeoffs then emerge between EROI, GROI, and water scarcity that will require further investigation and understanding to design minimal impact manufacturing supply chains. Also, additional environmental metrics could be added as well, such as toxicity and acidification potential.

The tool does not currently account for travel by engineers, managers, and executives to work collaboratively, ensure quality control, and provide feedback. Also, estimation of error will be an important final step to an analysis using SCOPE. As inputs on costs, weights, distances, and more are entered into the tool, confidence intervals could be included that would result in a confidence interval on the final solution.

Finally, it is important to note that while SCOPE provides decision makers the ability to understand environmental tradeoffs between supplier location and transportation, decision makers must also consider lead times, flexibility, and quality of suppliers before making a decision; cost and operations considerations must eventually be included in SCOPE for it to be a viable and useful tool for decision makers (or, conversely, the tool must be integrated with existing software for estimating these elements as part of an integrated package.)

Although this example is more complex than the automotive example, there are obviously, still many layers to be considered. But, in this realistic example, the potential for assessing and optimizing (or at least choosing among several alternatives) the manufacturing supply chain for a real product is illustrated.

I hope you found this series interesting and that it gave some insight into green supply chains from a manufacturing perspective. For sure there will be more reference to green manufacturing supply chains in the future. It is one of the critical elements in green manufacturing.

Now ... back to my taxes!

Greening the supply chain, Part 3

Part of a series

Our supply chain discussion started with some basic definitions of what is included in a supply chain from a manufacturing perspective, and then added what would be green elements for consideration.  Last time I referred to Interface Carpets as a leader in sustainable business development because they have a corporate mission held from top to bottom, they have a set of measures to indicate where they are and what progress they are making toward eliminating waste, excess energy and materials use and intense recycling and reuse - and they track all this diligently. Continuous energy per unit of product reduction - the key ingredient in the equation for reducing impact. As you can tell, I think this company is "walking the walk" and not just "talking the talk."

Last time I also presented an example to illustrate the impact of supply chains and, in particular, energy mix and transportation related to a simple vehicle manufacturing global supply chain. One of the important determinants in the impact of that was that the CO2 emission will be different at each facility in the supply chain due to the different energy mixes associated with the electricity supplier in that location.

This is a serious consideration. Around the world, the energy mix by location can be dramatically different. We had discussed this in an earlier posting but let's look into this in more detail. The figure below with data from a number

Conversion factors for CO2 generated per kWh of electricity around the world

of sources shows the variation in the energy conversion factors from a number of countries around the world. The units in the table indicate the carbon intensity of electricity production (gCO2 per kWh of electricity (or 0.001 MTon/MWh). Smaller numbers indicate a lower impact per unit of energy. France is lowest due to the preponderance of nuclear power. Countries with a preponderance of coal-based electricity (such as China or India) will have a larger impact. As seen in the figure, the difference can be as high as 10 to 1 (if comparing India to France). (Data from: Source: MacKay, D., Sustainable Energy - without the hot air, UIT, Cambridge, 2009, pp. 335; China/India: http://www.ghgprotocol.org/calculation-tools/all-tools; accessed 7/9/09)

Now, if we consider the manufacture of, say, an automobile (to continue in the same vein as the last example), an estimate of the "embodied energy" of a new automobile is about 76,000 kWh (Source: Treloar, G., et al, “Hybrid life-cycle inventory for road construction and use,” J. Const. Engrg. and Mgmt., 130, 1, 2004, 43-49.  (Values vary depending on recycling, etc.)). So, if we manufacture this automobile different places the impact, in terms of CO2, will differ according to the conversion factors. Same car, same manufacturing process and this is before any use effects are considered - big difference in impact.

Let's consider a few manufacturing locations:
- France = 6.30 MTons CO2 (76 MWH x .083 MTon/MWh = 6.30 MTon)
- Japan = 36.70 MTons CO2
- USA = 46.60 MTons CO2
- India = 71.76 Mtons CO2

Same car … same process steps … big difference in impact! That's what was a big differentiator in the supply chain example of last time. If this impact/product at the manufacturing stage must at some future time be accounted for then where you make something will be even more important from the impact aspect and not just labor rates.

Now, these conversion factors are the weighted average for the country. Obviously, specially for large countries with variation in energy supply technology, these can differ within a country as well. Let's look at a prime example of this - the US. The figure below (click on it for detail) is a map of the United States

Conversion factors for CO2 generated per kWh of electricity in different regions of the US

with the conversion factors superimposed over regions of the country (and here, the conversion factors are 1/100th of the factors in the first figure; US average here is .606 (or would be 606 from the first figure) due to the source of the data). And, the source of the data in this figure is  EIA, US DOE, “Updated State-Level Greenhouse Gas Emission Coefficients for Electricity Generation 1990-2000,” April 2002; and map: http://wordpress.org/support/topic/255876, accessed 6/27/09.

The US average CO2 impact to build the car was 46.6 MTons CO2. But, looking at building the same car in different parts of the country we see, again, tremendous differences:

- Washington (0.111) = 8.44 MTons CO2
- California (0.275) = 20.90 MTons CO2
- North Dakota (1.017) = 77.30 MTons CO2
- Kentucky (0.911) = 69.00 MTons CO2

Building our auto in areas with a heavy dependence on coal fired power plants for electricity gives the auto a large carbon footprint. The difference is as large as 3 or 4 to one (California vs North Dakota) or almost 10 to 1 (Washington vs North Dakota.) Of course, we don't build cars in Washington state or North Dakota. But we build them in Kentucky (Prius, for example) and used to build them in California at NUMMI in Fremont. So a comparison of the California vs Kentucky impact is rational - over 3 to 1 difference. So, if you buy an auto made in Kentucky and ship it to California for sale you might be looking at a substantial "impact penalty" compared to making and selling the auto in California.

As they say in the real estate business - location, location, location. Maybe the same advice applies (or will apply) for manufacturing and the supply chain!

If we would do the same sort of analysis, as we did in the example from last time, and consider more of the sustainability elements - social, environmental and economic impacts - the dominance of supply chain and the need to green that chain comes into perspective. We've put together a figure that captures
some of these impacts as shown below.

                                     Global green supply chain considerations

Companies today get resources from many different places, convert that material in others, acquire and convert the materials from yet other places and, finally, assemble the products from components made them selves in one or more locations along with components from others from other places in the world.

I've tried to capture some of this complexity in the figure below (again, click on it for detail) which attempts to show, relative to many impacts and resources, the developing

Accumulation of product life cycle impacts 

embodied material, water, energy and green house gas impact "profile" over the life cycle. This, to me, shows the real supply chain and includes more than just one element. Where ever one is in this diagram - you can look backward in your process rearview mirror and see what "consumption and impact baggage" you are responsible for even before you start your processing. And, looking forward, you can see how the impact and consumption of your stage of the life cycle will ripple through the system.

This is not at all trivial to keep track of these impacts let alone the source of all of these little bits and pieces. How this is done is still being developed and is of interest by a large number of multinational corporations.

But, to know the challenge is the first step. Then the metrics, software tools, analytical methodologies and, even, simple rules of thumb, can be developed and used to get a better picture of where we are and what progress we are making.

Greening the Manufacturing Supply Chain, Part 2

Part of a series

We started a discussion about supply chains with respect to environmental impacts related to the various actors in the chain. We'll continue here with an example.

But, first, a story from the trenches.

I've mentioned Interface Carpets before as an example of a company dedicated to green manufacturing and on a path to sustainable business practice. An AutomationWorld article recently on "Sustainability Leads To Next-generation Manufacturing" (by Gary Mintchell, March 10th, 2010; download the article at http://www.automationworld.com/print.php?id=6671) gives some statistics on how Interface has done in the words of its founder and retired CEO Ray Anderson. Anderson talks about the 12 year process starting from the Kyoto Protocol in 1997 which he says "was widely derided by his fellow CEOs that sought to reduce greenhouse gas (GHG) emissions by about 7 percent in the United States by 2010. Others were afraid that meeting that goal would drive them out of business."

His statistics show the opposite is quite true if pursued consistently and with metrics to measure where you are and where you are going. Anderson states "Interface’s performance by 2008 revealed a reduction of 71 percent in absolute tons of GHG emissions while sales increased by two-thirds and earnings doubled. Interface consumption of fossil fuels per square yard of carpet was down 60 percent, and waste reduction measures put a cumulative $405 million of avoided costs directly into the bottom line."

Energy per unit of product reduced by 60%! Recall the "master equation"? It defined impact as a product of three terms: population, per capita GDP, and impact per unit of GDP. I noted that the only "knob" we can twist on this equation is impact/GDP. And 60% reduction as realized by Interface is on track to meet the reductions needed that we spoke about several postings ago.

Anderson goes on to enumerate the tangible benefits of following this path - strong competitive position, growth in sales, higher profits (since costs are down) and adding to employee satisfaction being part of such an organization.

Back to supply chains (although if you are a builder of commercial space then Interface is probably in your supply chain!). A recent article in Environmental Leader (Feb 1, 2010, see http://www.environmentalleader.com/2010/02/01/survey-56-of-cdp-members-may-cut-out-suppliers-who-dont-manage-carbon/ for the full article) discussed a survey of the Carbon Disclosure Project (CDP) regarding their attitudes towards suppliers (supply chain) that do not manage their carbon. These are real companies in the survey (like PepsiCo, Dell, Google, IBM, Kellogg, HP and Unilever.)

The results are enlightening. Over 1000 suppliers to these companies were surveyed. Survey reported that 38% of the supply chain respondents have some type of carbon reduction targets in place. Of these respondents, almost two thirds report Scope 1 and Scope 2 emission. Scope 3 emissions are reported by 8%. Strikingly, 56% of the CDP members (remember the big companies listed above?) say that they may eliminate suppliers who don't manage carbon.

You can get the full CDP report (download the pdf) online at https://www.cdproject.net/reports.asp.

Now, let's look at an example of the impact of supply chains and, in particular, energy mix and transportation.

This example comes from one of my PhD students, Corinne Reich-Weiser, who is studying decision-making methodologies as applied to reducing the greenhouse gas emissions of manufacturing.

In this example,  the effect of minimizing global emissions on a supply chain is considered by looking at a simple vehicle manufacturing global supply chain with four candidate facility locations for assembly and stamping. We assume that the company serves the US market and wants to decide (1) where it should open facilities and (2) how to ship from the stamping facility to the assembly facility, and from the assembly facility to the market. The manufacturing technology, and the product produced, is the same regardless of location.

That is, the energy consumption for stamping and assembly is the same at each facility. But, the CO2 emission will be different at each facility due to the different energy mixes associated with the electricity supplier in that location (recall our discussion about conversion factors for kilowatt-hours to carbon dioxide for different regions of the world and US - this was in one of the earliest postings, see http://green-manufacturing.blogspot.com/2009/07/why-green-manufacturing-part-2.html.) There is only one supplier in this example (the stamping facility), one component (the stamped metal sheets),
and one manufacturer (the assembly facility.) We assume that the rest of the components needed for vehicle assembly are produced in local facilities. Also, the location and transportation mode are determined independently.

For this example, we assume that a typical vehicle weighs about 1,500kg and the total stamped sheet metal weighs about 1,000kg. The cost for stamping and assembly of one vehicle are $700 and $100, respectively.

The table below shows the estimated CO2 emission levels associated with vehicle stamping and assembly the different areas we are manufacturing in this example derived from EIO-LCA data.

You can see from the table (and apologies for the clarity of the table and figure below) the candidate locations for our stamping and assembly and, eventually, market example.

If a facility is outside the US, then components have to be sent to a port and then shipped internationally. We assume that air transportation is not an option here. There is only one way to ship products internationally, but one can choose either truck or train to deliver the product domestically. Further, emission characteristics will differ depending on the type of vehicle used. Because the carbon emission factor of trains (0.022 kg-CO2/tonne-km) is less than trucks (0.033 kg-CO2/tonne-km) according to Mike Ashby's data, it is always optimal to select trains over trucks if we only consider carbon emission.

One must include some production costs in the analysis as these will vary substantially with location. We can estimate the variable production cost in different areas by considering labor cost, utility cost, and facility rental costs in different countries.

The summary carbon footprint using three different distribution options (minimal economic cost, local manufacturing, and optimal carbon emission) is illustrated in the figure below.

The figure shows the contribution of transportation (hatched), stamping (black) and assembly (white) for each of the scenarios.

The lowest cost option is to stamp and assemble in China and then ship to the US. The minimal cost option  emits more than twice as much CO2 as the minimal CO2 option. The minimum carbon emission is achieved when the stamping is done in Germany with  assembly in the US. This is because the energy mix in Germany is half the impact of that of the US. The transportation emission is also smaller compared to other countries except the US because of the relatively short distance between our assumed location for stamping (Stuttgart) and the port. Because local manufacturing (i.e. in the US) saves on dramatically on transportation costs and emissions, it ends up in the middle in this example (due to energy mix issues again.)

This example shows that supply chain designs change when environmental impact is considered. This was arguably a very simple example with only a few options for organizing the supply chain. But, as seen in the lower figure comparing the results, there is a tremendous difference in these three scenarios. The optimal chain is less than one half as impactful as the "minimum cost" chain.

So, specially if you are a supplier to any of the CDP companies, it might make sense to look at all your supply chain options!

Greening the Manufacturing Supply Chain

First in a series

The last couple of postings covered some examples of the dramatic changes in production and materials processing that are going to be required to meet the goals for green house gas reduction set by various entities. These will go well beyond efficiency "tweaks" and involve substantial new technology wedges. We reviewed a couple of examples. We'll get back to this again I'm sure.

If you Google "green supply chain" you get over 12 million results. If you search the same term on Environmental Leader you get quite a list of related articles. This is now one of the hot topics and, as with most of things green, there is a wide variety of interpretation of what, exactly, the term means.

So, here is my interpretation!

First of all, I am not a supply chain expert. I have come to realize over the past few years that there are companies that make almost everything themselves (fewer and fewer but they still exist) and rely on some outside suppliers and there are companies that make almost nothing themselves and rely on an extensive network of suppliers. And, most important, I've come to know some supply chain experts here at Berkeley (particularly Professor Max Shen in Industrial Engineering and Operations Research) so I am emboldened to charge ahead!

Let's start with some definitions. Remember the Ricoh Comet Circle? (Use the search function on the blog page to find this if you need a refresh!) That shows the path of a product to the consumer and the fate of the product after it leaves the consumer. The consumer can be you or me, a company using a machine (product) or consumable, etc. This diagram visualizes the forward and reverse supply chain.

A supply chain can be defined as the "network of retailers, distributors, transporters, storage facilities and suppliers that participate in the sale, delivery and production of a particular product" (source: http://www.investorwords.com/4823/supply_chain.html). These are usually stratified into first tier, second tier and, sometimes, third tier suppliers depending on where they are in the "food chain" so to speak.

The image below, from otl.curtin.edu.au/tlf/tlf2001/ee.html, shows the inter-relationship among these suppliers and manufacturing, etc. including material and information flows.

And, one could add 3rd tier suppliers to this as well. All the components of the Comet Circle are represented. The locations of these elements in the figure can be anywhere in the world (and usually are) that the company feels the best value can be obtained. The time, cost, and now, environmental impact of all these flows is of major importance.

Remember the discussion of the UK's goal of CO2 reduction and the comparison of the actual vs "apparent" reduction we spoke of a few postings ago? (See http://green-manufacturing.blogspot.com/2010/03/digging-deeper.html for details.) The actual, if you included "outsourced CO2," was moving in the opposite direction of the target reduction. The figure above tells you how that happens - make sure the heavy CO2 contributing elements are outside the UK. Bad for the accounting and, incidentally, for domestic manufacturing!

These supply chains can be impressively complicated for sophisticated products, for example the laptop computer I'm writing this on. This is due to the large number of different parts and elements, the large number of suppliers (at all tiers) of these parts and, importantly, their location and the transport means for getting all this together to result in my laptop.

Our concern here is with these material flows and the embodied energy, water, resources, for all aspects of the manufacture, including transportation and storage/distribution associated with those.

Depending on how much a company relies on its supply chain will determine to what extent that company can affect the impact of its product. Wal-Mart's sustainability initiative is a major example of this new trend. It is estimated that, for Wal-Mart, as much as 90% of a product's associated carbon emissions (transportation, manufacturing, farming, etc.) are from the suppliers. So for a company like Wal-Mart, if they want to reducing their emissions overall, they need to find a way to affect their supply chain.

Recall that a  firm's environmental performance is usually evaluated in terms of energy consumption and carbon footprint. Most companies focus on direct emission (Scope 1) and indirect emission from purchased energy (Scope 2) (recall our discussion of these scopes, see the December 25th posting at http://green-manufacturing.blogspot.com/2009/12/green-new-year.html.) Direct emission from company owned or controlled activities and indirect emission from purchased energy make up only a small percentage of the total supply chain emission, excluding emission from the use phase.

The supply chain emissions will vary with the product and industry. For example, the figure below, derived from the CEDA database from Professor Sangwon Suh at the University of Minnesota, shows the carbon emission in the supply chains in several selected manufacturing industries.

The range is impressive. For some electronics only about 10% of the carbon emission is direct. The bulk of the emissions for computers, more than 80% in the figure, is from embodied emissions of the purchased parts. Ditto for motor vehicles. The lowest supply chain impact in this example, plastic materials and resins, is still showing that less than half of the carbon emission is due to direct emissions and electricity consumption - rest from the supply chain.

Some companies have started to look at overall supply chain carbon emissions. However, they often tend to ignore the interaction between different elements of their supply chains. This could be due to the complexity of tracking material flow through all the elements. These elements include all the components seen in the first figure above.

Ignoring interactions can have deleterious effects. For example, if one changes the shipping mode to a lower-carbon option such as rail, the carbon emission per product will decrease. However, delivery by train may result in a longer lead-time and, thus, necessitate a higher safety stock at the retailer or production facility. In turn, greater inventory at the retailer or plant will increase the energy consumption and carbon emissions of their storage facility and warehouses. At least it will likely require more floor space and the related impacts of that in energy, etc. Thus, the overall CO2 reduction may be smaller than expected or, perhaps, non-existent.

As another example, suppose there is a manufacturing process changeover that consumes more materials and resources. One may want to increase the batch size to reduce carbon emissions. However, larger batch sizes will require an increase in the system WIP, and thus increase inventory level carbon emissions.

We discussed some of the means to evaluate such trade-offs in an earlier posting on lean and green manufacturing since many of these concerns are also central to lean manufacturing analyses.

We'll continue this discussion with a more detailed example next time to show how we account for some of these interactions and weigh the impact of a particular supply chain.

Not Business as Usual

The challenge of keeping ahead of the curve on the reduction of consumption or impact was made clear in the last posting. We saw the expectations of the EU to achieve a 60% absolute cut in yearly carbon emissions by 2050 compared to 1990 levels. And we saw how they were doing.

The problem is that consumption keeps increasing (and impact with it) while we are trying to reduce this impact. Thus,  we need to accommodate both reduction in per unit impact (CO2 for example) as well as the increased production with increased demand. One of the key strategies to this is to fundamentally rethink how we process, and re-process materials. The example from Allwood cited last time showed the extent to which this needs to be done for steel. We need to be able to facilitate the loops closest to the consumer in the Ricoh comet cycle to make this work.

This will require a number of substantial technology wedges to pull off.

So, what are some examples? I'm going to start with a couple of examples given by Professor Allwood in the presentation slides I referred to last time. These deal with photocopy paper and aluminum.

Allwood compares existing methods of paper recycling from the office copy paper use with a new process. Traditional recycling collects paper from the user (large and small offices or homes), pulps the paper and adds chemicals to de-ink it (remove the ink from the fiber matrix usually in a foam or froth) and then insert the de-inked fiber back into the papermaking process. The result is new paper with some percentage of recycled paper.

An alternative process uses a novel toner removal technique right in the office. Think of a "reverse copy machine" that takes in used paper (paper with fused toner material on it) from the office and with some type of adhesive, solvent, abrasive,  or laser process (the latter two accompanied by a vacuum tube) removes the toner to yield paper for re-use. A paper by Allwood on these approaches titled, appropriately "Meeting the 2050 carbon target for paper by print removal," (the web link is too long - "google" Allwood and the paper title if you want to see the details!).

Another idea put forward in the Allwood presentation is on recycling aluminum by "cold bonding." Cold bonding is a process where by ductile materials, such as aluminum, are fused into homogeneous masses by pressure as in an extrusion or pinch rolling process. The traditional means for recycling aluminum is to collect, separate, sort and clean the metal from a variety of sources. The material is then melted and cast in a manner close to original production. The ingots of aluminum resulting are then converted into products much as before. This recycling method uses about 5% of the energy needed for production of virgin aluminum (not bad actually.)

But, the cold bonding process would be done on a smaller, more local, process with cleaned aluminum scrap. Deformation under high compression and extension yields a lower strength product but one which is produced in one stage from scrap to product with, according to Allwood, only 1% of the energy of the recycling methodology in the traditional means. So ... now you are down to 1% of 5% of virgin material production energy.

The two figures below show, on top, methods of compression and extension suitable for cold bonding and, on the bottom, a photo from Allwood of the resulting material (aluminum) stock.

Clearly, in these two examples one might question whether or not the resulting material is suitable for all applications. It won't be in some cases. But it will in a lot of cases and offer a substantial reduction in impact while still contributing to demand. And, specially in the paper recycling example, you'd need to consider the materials and impact embedded in the hardware for toner removal.

The last example is much closer to implementation (in fact is available today) and is from a company in San Francisco called Industrial Origami (see http://www.industrialorigami.com/home.cfm ). I ran into this company some years ago when they were getting started and requested some assistance in developing some applications of their novel, and patented, technology.

Industrial Origami (or IOI) has a technology of precision material folding "based on the creation of fold defining geometries which, when put into sheet metal, enable structure and innovative shapes never before possible with traditional technologies. These features called "smiles", control the folding and are responsible for the accurate folding properties." The smiles guarantee certain folded strength and precision of the edge. The pre-cut sheets (both shape and integral "smiles") essentially code the DNA of the final part. A sequence of folding yields a complex three dimensional box for appliances, electronics, automotive components, towers, structures, etc. And the folding process insures accurate dimensions without tooling or fixturing.

There are a number of "green" advantages to this. Complex 3-d shapes can be fabricated in the "flat" and shipped efficiently for local product fabrication. Minimum tooling to produce the final part means low embedded energy and resources in fabrication. Recycling and recovery is enhanced due to minimum fasteners and other attachments. And, in the "Chevy hood to Chevy hood" mode I mentioned last blog - you literally end up with a flat sheet of metal when the product is "deconstructed." It could, within some reason, go back into another product.

One of the applications IOI has been working on is low cost commercial production of light weight vehicle chasses using "using less material, simplified assembly processes, significantly reduced capital investment in a much shorter product development cycle." The image below from IOI's website (http://www.industrialorigami.com/solutions/transportation.cfm ) is an example.

The autobody has additional fasteners (spot welds, for example, to improve crash worthiness) but is basically a "folded" structure. This technology is right in line with the other examples offering "leap frog" advances in material utilization and production efficiency and leading to close to the consumer recovery of materials in line with the Comet circle.

This is getting interesting!

Next time we start talking about greening the supply chain.

Digging Deeper

The ongoing low hanging fruit discussion here was the preamble to the last posting about scratching the surface (or, as one of my grinding expert friends says ... when it comes to abrasive process research we've only just scratched the surface! Sorry... engineering humor).

It is necessary to understand the magnitude of the challenge and where to best concentrate our efforts. And, sometimes the easiest stuff doesn't do much to advance the cause, specially with respect to greening manufacturing.

Last time I presented some perspectives on what it really means to be sustainable and this referred back to the earlier discussions about "technology wedges." An analysis of some of the potential wedges was presented from the Vattenfall report. Many of those technology wedges were related to manufacturing as noted.

One can find similar data on what kinds of reductions in CO2 emissions (in terms of parts per million in the atmosphere) are needed to get the atmospheric concentration of CO2 at a "sustainable" level. Again, I point out that not everyone agrees with the data and I am not promoting any specific interpretation. But (and a significant but) agencies, states, countries and regions are making regulations based on these discussions, consumers are making choices based on products and companies that respond to this data and companies are changing business plans and strategies based on this. So, in keeping with the "Everett and Jones" philosophy... we'd better be at least watching this carefully (and if you don't recall what this is - search Everett and Jones on this blog page!)  If you check the pages of Environmental Leader (link at bottom) on any day you see a growing list of reports of companies responding.

Ok...we've got the motivation. Now, what will really work.

Last July in this blog referred to a presentation in 2005 by Professor Julian Allwood of Cambridge University on "What is Sustainable Manufacturing" as a good place to start this discussion (see http://green-manufacturing.blogspot.com/2009/08/dimensions-and-metrics-of-green.html for the blog and http://www.ifm.eng.cam.ac.uk/sustainability/seminar/documents/050216lo.pdf for a download of Allwood's slides).

Allwood discusses in detail strategies for reducing the carbon footprint and other impacts of manufacturing. He specially discusses these with reference to targets for reduction set by governmental agencies in the UK and elsewhere. For example, the figure below shows the reduction targets set by the UK and EU to allow surface temperature stabilization. The target is a 60% absolute cut in yearly carbon emissions by 2050 compared to 1990 levels. What is seen is the slope of reductions (in CO2 equivalent)

needed to meet this ambitious goal (in blue), the actual reductions observed over the first few years (and reference to the Kyoto target, in red) and, gulp, these actual reductions adjusted to "off shore" effects. That is, moving the production and associated CO2 generation out of the region of calculation (i.e. out of the UK and EU) in orange. That curve is moving in the wrong direction.

This is not a pretty picture and emphasizes the complexity and difficulty of the task. Smoke and mirrors are not going to get this done.

Since consumption increases annually with additional production of products to meet growing demand fueled by, at least, growing populations (and compounded by increasing expectations of quality of life - recall the "impact equation" we discussed some postings ago on the drivers of impact including impact/GDP) we need to accommodate both reduction in per unit impact (CO2 here) as well as the increased production with demand. A double whammy.

Allwood puts some numbers on this. He summarizes data from an EU project on reducing CO2 in steel production. If demand for steel doubles then stablizes, and every efficiency known is perfectly implemented, the carbon target requires that two thirds of all steel is re-used without re-smelting, and the energy of all forming processes is halved.

Think about this (and keep in mind the Ricoh comet cycle; see http://green-manufacturing.blogspot.com/2009/09/sustainability-angst.html). Two-thirds of all steel re-used without re-smelting! That cuts out a major part of the present strategy for recovery and recycling steel (and many other materials as well.) That means, effectively, if we are to meet this aggressive target (but the type of target many feel is absolutely needed and being discussed by other countries and regions in the world) we'll be taking the steel hood off of our Chevy and re-assembling it onto another with little additional processing! That is, we have to be able to facilitate the loops closest to the consumer to make this work.

Hopefully, this will spur research on and development of a whole host of imaginative re-processing technologies that can cut out the "dirty" part of recycling.

We'll look at some ideas about this next time.

Finally, Professor Allwood has just written a paper to be published in  Environmental Science and Technology Journal (ES&T) detailing some potential next steps. The article, titled "Options for Achieving a 50% cut in Industrial Carbon Emissions by 2050" introduces the idea of material efficiency with reduced primary production. We will delve into this more in the future.