Excerpts on Steel and Concrete LCA

The following excerpts provide comparison between steel and concrete industry-sponsored LCA studies.

From Modern Steel Construction (Weisenberger 2010):

“In all but one category, the structural steel building outperformed the concrete-framed building; the comparisons, expressed as percentages, are as follows:

• Global warming potential: 9% less equivalent CO2 per sq. ft

• Acidification potential : 8% less mol H+ equivalents per sq. ft

• Eutrophication potential: 9% less kg N equivalent per sq. ft

• Smog potential: 14% less kg NO equivalent per sq. ft

• Non-renewable energy primary demand: 1% more MJ per sq. ft

The only category in which steel lagged concrete was energy demand, and only by one percentage point.”

The author goes on to acknowledge:

“While the study did conclude that the steel-framed building had a lower environmental impact in four of the five categories, it should be noted that the differences in these categories did not reach a confidence threshold of a 15% difference to conclusively recommend one material over the other.”

Similarly, from a recent PCA-sponsored study (Masanet 2012) the author concludes:

“Total life-cycle GHG emissions in the baseline scenario are estimated at 14,350 Mg CO2e for the steel framed building and 14,080 Mg CO2e for the concrete framed building.”

The author later states:

 “.. for some climate zones the superior option switched between scenarios, which suggests that the technology options might play a key role in determining which option has lower life-cycle GHG emissions in practice. For such instances, improved understanding and modeling of regional and technological variations in materials pathways is of particular importance for credible materials comparisons.”

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Comparing LCA Results with Biogenic Carbon

One study from New Zealand (Fernandez 2008) demonstrates the varying carbon emission results by comparing LCAs of the same building designed using four different primary building materials and two different LCI data sources.  Embodied carbon emissions factors in Figure 2 sourced from the a New Zealand dataset (Alcorn 2003) included biogenic carbon (negative indicating carbon sequestration) while the factors in Figure 3 from the GaBi inventory did not. 

Figure 1, Embodied CO2 for Four Buildings, Alcorn Database

Because the treatment of biogenic carbon in an LCA can result in significantly different conclusions, the World Resource Institute/World Business Council for Sustainable Development Greenhouse Gas Protocol (World Resources Institute 2011) recommends that biogenic carbon absorption and emissions be reported as a separate inventory item.  LCAs that report biogenic carbon in this manner are most transparent.  The LCI data for U.S. wood processes and products reported in the National Renewable Energy Laboratory’s LCI database and in CORRIM Reports does not include biogenic carbon, however, the carbon sequestered in a piece of lumber can be estimated based on wood chemistry.   

Figure 2, Embodied CO2 for Four Building Types, GaBi Database

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Where's the Money

I recently attended a presentation sponsored by the Chicago branch of the US Green Building Council entitled, “Where’s the Money – Building Energy Retrofits.”  A series of presenters, with intimate knowledge of the energy retrofit business, explained how companies and individuals can get support for improving energy efficiency in their homes and businesses.  The monies come from a variety of sources including: utility companies, finance companies, and government backed loans.

My electricity is provided by ComEd.  I was surprised to learn that a legislative act ordered the utility to promote energy efficiency.  Now ComEd offers many incentives.  For example, replacing your old inefficient fridge could warrant a $35 rebate.  Businesses can get $20 per exit sign.  In all ComEd estimates that lighting incentives can reduce annual costs by 75% and cover the initial investment in 2 years.

The American Reinvestment and Recovery Act also known as “the stimulus bill” provided states with funds for improving energy efficiency.  Many cities and states applied that money directly to upgrades of government facilities, like police and fire departments and government buildings.

Illinois, Cook County and Chicago teamed together to leverage those funds for greater impact.  Several organizations have sprung up to access these funds. The Chicago Region Initiative for Better Buildings and the Chicago Metropolitan Agency for Planning are two such organizations.  Through their work, several loan programs are available to local institutions and businesses, such as: employer assisted housing retrofits, energy saver loan loss reserves, multi-unit retrofits, residential retrofits, and more.

Navigating all of these available incentives can be a daunting task.  For businesses with other priorities, professional consultants can take charge of an energy retrofit.  Johnson Controls will even guarantee energy cost savings.  They’ll also help arrange 3^rd party financing and some incredibly complex contract structuring to help companies fund an upgrade.

I tend to think of achieving energy efficiency as a technical challenge.  However, the speakers stressed that the financial hurdles have the greatest influence on building owners and developers.  Fortunately, a maturing financing industry and government support is helping more buildings go green.

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House Bill takes on the EPA ruling process. What's best for Fly Ash?

Most of you will recall the EPA is considering whether CCRs that are not designated for beneficial reuse (such as fly ash in concrete) should be regulated as a Hazardous Waste or Household Garbage.  There are nuances to the ruling but that is the crux and either way beneficial reuse would still be allowed.  One of the raging debates is whether a hazardous designation will hamper or encourage higher recycling and reuse rates.   Now the House of Representatives has introduced a bill that would undermine the EPA ruling and comment process and their authority to regulate or not regulate based on considered analysis of science, economics, public comments and existing law.
The following link to a short article provides an interesting and concise update (and I’ve pasted some excerpts as a teaser):
http://www.wtrf.com/story.cfm?func=viewstory&storyid=98061
“ “During my 10 years working for the hazardous waste disposal industry, I noticed that hazardous waste disposal companies lost market share over time to recyclers and beneficial users,” according to Scott Slesinger, now legislative director for the Natural Resources Defense Council. “Market economics made this obvious — the higher cost of disposal led to finding cheaper alternatives.”
H.R. 1391, the “Recycling Coal Combustion Residuals Accessibility Act of 2011,” would prevent the U.S. Environmental Protection Agency from regulating coal combustion residuals, abbreviated as CCRs and often called “coal ash,” under the hazardous waste subtitle of the Resource Conservation and Recovery Act.
That would leave only one of two approaches the agency proposed in June 2010: regulating CCRs in the same manner as household garbage.….
….In an April 14 House of Representatives Energy and Commerce Committee hearing prompted by McKinley’s bill, Mathy Stanislaus, Assistant Administrator for the EPA’s Office of Solid Waste and Emergency Response, expressed the agency’s concern about the bill.
“We want to make an informed ruling,” Stanislaus said. “This would remove that one option and not allow us to make our decision based on all the data and the 450,000 comments.” ”

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