Green Metrics, Clean Metrics

Food, Clothing and Shelter - Carbon Footprinting the Essentials

I typically don't use this blog for marketing messages, but I want to take a little space here just to point out some important things that are in the CleanMetrics pipeline. We are taking our life-cycle assessment methodology, software modules and data, and creating a series of highly customized industry-specific carbon footprinting tools. All are hosted software solutions that can be accessed through the web and will be available by annual subscription.

• The first of these is BuildingScope, which is being released in the next week or two. BuildingScope will address life-cycle GHG emissions and carbon storage in all phases of a building's life cycle, including construction, operation (including energy and water consumption), land use, landscaping, waste disposal, etc.
• Next in line is FoodCarbonScope, which is due around end of June. FoodCarbonScope will provide life-cycle carbon footprint analysis for food products, including agricultural production, processing, packaging, storage, transport, cooking, and waste disposal.
• Last in this list is ApparelScope, which will be ready in July/August. ApparelScope will target life-cycle carbon footprint analysis for clothing and accessories.

Kumar Venkat

Deep Carbon Footprinting (tm)

I believe that it is time to take product life-cycle carbon footprinting to the next level. Deep Carbon Footprinting^TM would look beyond static carbon footprinting, and explicitly consider the dimension of time in every part of a product's life cycle -- production, transportation, use, and disposal. It would also look at a broader range of biophysical phenomena (including some second-order effects) that could potentially impact a product's real carbon footprint. Deep carbon footprinting is needed to really understand the relative contributions of different stages in a product's life cycle, which is the first step in any attempt to reduce the product's footprint.

Here are a few examples of the types of analyses that would be included in deep carbon footprinting (I'll be offering numerical examples from selected industries/products in future posts):

• Consider the wood in a building or in a piece of furniture. The biogenic carbon in that wood is stored in the product as long as the product is in service. When the product (or a part of it) is disposed and landfilled, the wood might decompose aerobically or anaerobically (releasing its biogenic carbon atoms back into the atmosphere as either CO2 or methane) over a short or a long period of time, during which there is continuing but diminishing carbon storage in addition to the GHG emissions. A similar analysis can apply to a piece of cotton clothing, or any other product that sequesters and then releases biogenic carbon.
• Concrete in buildings and infrastructure continually absorbs CO2 from the atmosphere through a process called carbonation. At end of its service life, the concrete might be demolished and then either re-used as concrete aggregate or landfilled. Demolition/crushing increases the available surface area and potentially speeds up the carbonation. If we are looking at a 100-year assessment period, then the concrete would have to be credited with a certain amount of carbon sequestration, starting at 0 and ramping up over time. The carbon credit is not all the CO2 that is ultimately absorbed by the concrete in the 100 years, but a smaller amount that actually reflects the timing of all the absorption.
• On a related note, trees planted in a landscape project should not take credit for the total CO2 absorbed over the average growing period of 20 years or so. Any CO2 absorbed in the first year is a lot more valuable than any CO2 absorbed in the 20th year, so the time series of annual CO2 absorption amounts would have to be weighted appropriately based on the year of absorption and then summed together. (Since the current carbon offset market doesn't consider the time dimension in this manner -- as far as I know -- offset purchasers may well be getting considerably less climate-change-mitigation than what they are paying for!)
• Food waste is among the most easily decomposable materials in the waste stream. There is almost always some food waste before cooking and after cooking. Unless it is composted properly, most of the food waste will turn into methane under anaerobic decomposition over time (biogenic carbon released as CO2 very soon after production is climate neutral, but any biogenic carbon that is released as methane is decidedly not neutral unless it is recovered and used as fuel). Once again, the timing is important. We've seen that this effect can sometimes exceed the transportation impact as far as carbon footprint is concerned.

We are currently incorporating a Deep Carbon Footprinting^TM methodology into several new industry-specific carbon footprint tools that are in development. More on this in future posts.

Kumar Venkat

Dynamic Carbon Footprinting

The term "dynamic carbon footprinting" can be used in at least three different ways, as if we needed more confusion.

1. As opposed to static carbon footprinting, I think of dynamic carbon footprinting as a method that takes into account the time dimension. When certain emissions are generated is as important as the quantity of those emissions. The timing is critical in analyzing a whole range of carbon emission and sequestration processes: CO2 gradually absorbed over time by newly planted trees, natural systems (such as soil) and products (such as wooden furniture or building components) that sequester CO2 for limited periods, emissions generated throughout a long use-phase for a durable product (especially in comparison to the production emissions generated at the beginning), etc. [More on this in previous posts: 1 2 3]

2. Businesses operating in a carbon-constrained world may evaluate each other's carbon footprints in a continuous attempt to minimize overall carbon emissions in their value chains. For example, this could involve comparing the footprints of similar products made in different parts of the world while choosing global suppliers [1]. The competitive dynamics involved in these emission reduction efforts have led to the term "dynamic carbon footprinting". [More]

3. The least interesting and unduly complicated use of the term has to do with displaying "dynamic carbon labels" for RFID tagged goods using NFC enabled mobile phones. The idea is that each "instance" of a product has a different footprint, because of differences in transport and storage emissions. A consumer could check the carbon footprint of a product on the store shelf using a mobile phone and get a number that is good for just that store. [More]

Kumar Venkat

Do food miles matter?

Do food miles matter? The short answer: Not much, from a carbon footprint perspective -- with some exceptions such as fresh foods that are air freighted.

By way of illustration, here is a pie chart that shows the life-cycle greenhouse gas emissions of cooked potatoes broken down into key life-cycle stages. In this particular example, potatoes are grown conventionally in California. The raw potatoes are then transported 1500 miles in a refrigerated semi-trailer truck. Cooking steps include baking or frying in commercial kitchen equipment, followed by a steam table. Of the cooked potatoes, 20% are wasted and landfilled. The landfill is located in a temperate/wet zone, 50% of the landfill gas is methane, and 25% of methane is recovered and combusted as fuel. Transport contributes about 9% of the total life-cycle greenhouse gas emissions in this example.

   

These results shouldn't be surprising. A 2006 study from New Zealand (Saunders, et al) showed that it was important to look at the full life cycle of food products in order to optimize carbon footprints. That study found that several food products (milk, lamb, apples, onions) produced in New Zealand and transported to the UK produced fewer total GHG emissions than similar products produced locally in the UK.

In addition, we've seen cases where locally produced food is distributed inefficiently using small vehicles that transport the products hundreds of miles to farmers markets and other outlets. So replacing the long-distance supplier with a local supplier in the above example wouldn't significantly reduce the (already small) transport impact.

So is there any value to emphasizing locally produced food?  There may well be benefits: taste, freshness, possibly lower risk of disruption/contamination, supporting local businesses, etc. But lower carbon footprint is generally not one of the automatic benefits.

Kumar Venkat

Managing Food Waste

Landfilled food waste can generate significant amounts of methane through anerobic decomposition. In a wet boreal/temperate climate zone, typical methane emissions are about 1.4 Kg CO2e per Kg of wet food waste (based on IPCC guidelines and 100-year assessment period). To put this in context, most fruits and vegetables have embodied carbon emissions of less than 0.7 Kg of CO2e per Kg of product at the farm gate (with some exceptions such as greenhouse production). Thus, landfilling has at least twice the impact as the original production. If we produce 1 Kg of some fruit/vegetable at this carbon emission rate and then throw away 20% of that into a landfill without methane capture, we are essentially increasing the carbon footprint of the product by 40%. On the other hand, composting generates little or no methane (less than 1% to a few percent of the initial carbon content is released as methane), and the biogenic CO2 from composting is not counted toward global warming.

Landfills are the largest methane source in the US (see EPA). Among degradable organic matter in landfills, food waste decomposes faster than anything else with more of the methane emissions occurring earlier in the 100-year period, which means higher global warming potential. The EPA estimates that food waste diverted from landfills decreases GHG emissions by 0.82 tonnes of CO2e per tonne of food waste -- presumably accounting for some average percentage of methane capture in landfills (per this report).

Kumar Venkat

Green Transportation

Following up on greening the auto fleet, there was an interesting news item yesterday that suggested the Obama administration is open to considering a tax on miles driven rather than fuel used -- but, unfortunately, this was quickly shot down by their spokesman.

In addition to increasing the average fuel economy of the auto fleet (through replacing enough clunkers with greener vehicles), we are going to need incentives to preserve the benefits of higher efficiency vehicles -- so that the fuel and cost savings are not used up in additional driving. One measure of this is the actual GHG emissions from the transportation sector. Beyond GHG emissions, there are other real costs to driving -- including wear and tear on the roads and other infrastructure, and the constant need to repave and widen the roads.

As the average fuel economy of the auto fleet improves, a tax on miles driven would be the next logical step in reducing both emissions and infrastructure costs. The tax would depend on miles driven, roads used, weight/size of the vehicle, etc., to fully account for the wear and tear and congestion caused by driving a particular vehicle a certain number of miles on specific routes. This can be done using GPS technology and might be the best way to fund future transport options.

Kumar Venkat

Food Carbon Footprint Training

This article on the effects of food carbon footprint training on consumers just came out -- based on work we did in 2007. Our tools/databases have progressed significantly since this was done, but the results might still be useful in thinking about how consumers can incorporate carbon footprint info in their decision making.

 

Kumar Venkat

 

 

Greening the Auto Fleet

Economist Alan Blinder suggested last year a Cash for Clunkers program in which the government would pay a premium to buy inefficient clunkers and take them off the road and resell them as scrap. Targeted at cars and light trucks that are over 15 years old (there are 75 million of these in the US, about 30% of the vehicles in use), this would cost about $4 billion per million cars based on an average purchase price of $3500, according to Blinder. Since most clunkers are owned by low-income people, this would transfer some purchasing power to them which they are likely to use quickly. So the idea is that this would also be an effective economic stimulus while reducing pollution. But a big potential problem with this proposal is that the cash paid for the clunker may be too little to help purchase a replacement vehicle that is significantly greener.

Although automakers are being pressured to produce more fuel-efficient vehicles, and there is some funding in the stimulus package for battery development and tax incentives for plug-in hybrids, there hasn't been a systematic approach to greening the auto fleet. It is clear that we know how to make vehicles that are significantly more efficient, but the price tag for a new green vehicle ($20,000 and up) makes it a challenge to replace enough of the older vehicles to really reduce GHG emissions.

A workable plan needs to target not all clunkers, but only those that are driven more than X miles per year, and must provide enough of a subsidy to help purchase a replacement vehicle that delivers at least Y miles per gallon based on GHG reduction goals. Plus some way to discourage the higher fuel efficiency from being used up in additional driving, so that GHG reduction goals are actually achievable. I'll be coming back with a bit more analysis soon.

Kumar Venkat

Green Recovery

A September 2008 report from the Political Economy Research Institute (University of Massachusetts) lays out the case for a rapid green economic recovery program. The report estimates that a two-year government investment of $100 billion in green buildup would create 2 million jobs -- four times as many jobs as investing the same amount in the oil industry and 300,000 more jobs than similar government spending (such as tax rebates) directed at increasing household consumption. Nearly half the new jobs would be in construction and manufacturing. The unemployment rates used in the report are from July 2008 and obsolete now, but the general conclusions are still important.

The initial version of the House stimulus bill appears to have about $54 billion allocated for renewable energy and overall energy efficiencies, and the list matches several of the key investment areas assumed in the above study. This does look like a decent down payment on a much-needed investment. There is uncertainty in all such estimates, to be sure, but if the green stimulus can come close to creating jobs at a cost of $50K per job while building a launch pad for the next crucial steps in green buildup, then it is an absolute win-win. Why didn't we just do this years ago and why aren't we investing more today?

Kumar Venkat

Inside Carbon Foodprints

Energy use in agriculture and food production receives a lot of attention, but non-energy related greenhouse gas emissions play a significant role in the carbon footprints of many food commodities. The non-energy emissions are typically nitrous oxide and methane generated by enteric fermentation in ruminants, manure management practices, nitrogen fertilizer applications in soils, crop residues, anaerobic decomposition in flooded rice fields, etc. Based on our recent LCA calculations, here are some typical numbers for a selection of food commodities from various parts of the world.

Food commodity	% of non-energy GHG emissions (farm-level) in life-cycle carbon footprint @ farm gate
Beef	94.44
Lamb	94.04
Rice	78.92
Wheat	59.34
Barley	51.90
Spinach	50.76
Rape Seed	50.46
Rye	49.44
Oats	49.36
Sugar Beets	46.82
Corn	41.49
Cabbage	38.69
Potatoes	35.41
Broccoli	33.82
Brussels Sprouts	33.15
Red Beets	33.13
Onions	32.80
Cherries	28.92
Green Beans	28.32
Chicken	25.48
Apples	24.24
Tomatoes	24.19
Loose-leaf Lettuce	23.12
Oranges	22.10
Dry Beans	21.75
Table Grapes	7.70
Soybeans	7.30

Kumar Venkat