ASSESS EMBODIED CARBON

The beginning of the first sentence is describing cradle-to-gate (A1-A3) embodied carbon, not upfront embodied carbon.  The second part of the sentence is then correctly clarifying that this represents the bulk of upfront and overall life-cycle embodied carbon emissions. Please clarify.

Table 1 – Because the table is incomplete, the source of the benchmark data and what it represents (in terms of percentile of a certain date of available data) must be disclosed so that other benchmarks for materials not listed can be formed in a consistent manner.  There may also be questions regarding at what “level” (and date of data) to set the benchmark once that information is disclosed.

Table 1 – The Board and Foam Insulation category is far too broad to have any meaning and also to avoid grouping together materials that are not comparable on a functional basis beyond just the narrowly focused basis of the functional units used.  These functional units for GWP do not ensure an equivalent comparison between insulation materials (board, foam, or otherwise) because insulation materials are not single function products, like concrete, steel, and aluminum for example. They often have multi-functional properties and uses or in some way impact functional material and design considerations of other parts of the assembly or building they are used in.  To avoid this problem (in the current framework proposed by LEEDv5 for Table 1 and related credits for reducing embodied carbon), the category needs to be broken down into specific insulation materials types and within those types different sub-types (such as the different ranges of foam plastic insulation boards necessary for specific building application requirements – see discussion in general points above).   Again, segregation of the insulation type is critical as this is how they are specified for each specific project.  Alternatively, to this necessary expansion of benchmarking, data-sourcing, etc. an approach like that described under “possible solutions concepts” could be adopted (as an alternative to the current LEEDv5 structure or at least an option).  But, if the current LEEDv5 approach is maintained, the benchmarking in Table 1 is significantly over-simplified to avoid non-equivalent comparisons or groupings (on a functional basis) within each listed category and this would seem to apply to nearly all of the categories in the table. The data intensity of the table and precision of categories needs to be significantly expanded to avoid unintended consequences to building design, performance, optimization of total carbon, etc.

REDUCE EMBODIED CARBON    

Option 1: Whole Building Life-Cycle Assessment -- As noted earlier in general comments, Option 1 Whole Building Life-Cycle Assessment must be changed to include operational energy when considering the embodied carbon of insulation materials.  Their primary function is to offset and reduce energy use and GHG emissions over the life of the building and as current data shows, the payback period for all modern US insulations is generally 1 year or less and the life cycle payback is 100:1.  Employing the various functional attributes (beyond just R-value) of the various insulation materials and variations with the types of insulation materials for specific building application conditions is crucial to energy efficiency. And, energy efficiency is crucial to maximizing the investment in and utility of a transitioning energy supply. 

Option 2: Procurement of Low-Embodied Carbon Construction Materials  -- See comments below regarding an alternative basis for procurement that incentivizes investment in lowering GWP of various materials types while avoiding arbitrary baselines that are too broad to avoid unequal comparisons and unintended performance or functional trade-offs, change over time, and also vary based on region/availability creating potential supply chain issues.

Option 3/Table 3: EPD Analysis – See comments below regarding an alternative solution/approach as noted also above for Option 2. However, if the current references for Table 3 GWP Limit Thresholds for Product Categories is maintained, then links to dated sources indicated in the table should be made directly available in the table for transparent inspection and described sufficiently in basis to be replicable.  Also, explanation is needed to justify the difference in treatment of “non-wood products” vs. “structural wood products”.  Many of the structural wood products used today (engineered wood) would not be products and would not work without plastic adhesive technology.  They are effectively “hybrid” materials.  But, it appears upfront emissions associated with these wood products are ignored with regard to benchmarking (instead only requiring reporting for facility specific EPDs). The GWP Limit thresholds state “better than EC3 achievable”. It is unclear what products were used to build this category.  The EC3 tool needs to allow for insulation products to be sorted by their application location on the structure and their type as not all insulations are the same.  Is the intent of EC3 to update this “achievable” category on a regular basis in order to pull in the latest insulation products?  Who controls what products are pulled into the EC3 tool? A recommendation would be to include a static table of insulation products, separated by product category and type, be included as the GWP reference tables so that current manufacturers of those products could review them for accuracy.

Finally, grouping insulation materials into one broadly described category (and not separating it into various types of insulations and applications) for benchmarking purposes will result in unequal comparisons and trade-offs leading to potentially misinformed material selections or de-selection. Again, this can be avoided with some of the alternative solution concepts presented later below, while rewarding significant advancements in specific manufacturer/material GWP reductions as documented in EPD history.

Table 4: In this table and also in earlier Table 1, gypsum panel and sheathing products are missing from the tables or accounting.  Gypsum sheathing is second to only concrete in terms of total US GHG emissions associated with annual production and use of building materials.  This raises the concern with focusing effort or priorities where the greatest gains and least harms or unintended consequences may occur in addressing embodied carbon emissions.  Toward that end, here is a ranking of US building and construction materials annual GHG emissions in comparison to total global GHG emissions (which relates the emissions directly to global climate impact which is the intent of LEEDv5 and essentially all other GHG climate related policy goals):

U.S. Concrete                                                                    0.17% of total global annual GHG emissions

U.S. Gypsum Board & Panels                                      0.14%

U.S. Steel (structural)                                                     0.09%

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U.S. Bldg Insulation (all types)                                    0.01%  (with these emissions recouped within a year after building completion and subsequently resulting in a 100-fold or more emissions savings over the life of the building)

U.S. Flat Glass (glazing)                                                  0.008%

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All other U.S. bldg. & constr. mat’ls                          0.2%

                                                                                                ________

TOTAL ANNUAL U.S. Bldg&Constr Mat’ls               0.61%

SOURCE FOR DATA: ABTG Report (as referenced above, particularly Table A on page 8 of executive summary) – based on multiple international and US sources for GHG emissions data.

POSSIBLE SOLUTION CONCEPTS RELATED TO DECARBONIZATION & ENERGY EFFICIENCY

  1. Provide reward (credit) for manufacturers who demonstrate a history of reduction in GWP of their material – either for a product-specific or industry-wide EPD basis.  This will incentivize and sustain progress toward lower and lower GWP for a given product type and even variation in functional capabilities within a given product type that are important to a variety of building design and construction applications.  It will provide opportunity for all manufacturer’s to invest and receive reward for lowering GWP of their materials.  This will greatly expand impact and benefits for the climate, beyond the current bottom up or top down approaches to indirectly influence the market through inefficient and data intensive accounting processes (with the data constantly changing).
  2. For the current energy source situation for buildings, elevate the importance of insulations for building envelope/enclosure energy efficiency to capitalize on major paybacks for avoided future carbon emissions (i.e., 100 fold or more avoided emissions as noted above).  This will also address major energy supply issues, such as peak demand in a transitioning electric grid and make it more feasible to electrify heating for buildings.  It will also reduce the cost of energy infrastructure to meet a growing building population and energy demand (particularly if electricity eventually shifts to winter-time peaking).  The GWP improvements of insulation materials would still be captured and incentivized in #1 above.
  3. Provide for an integrated “total carbon” approach when doing WB-LCA as a means to optimize the balance of embodied carbon, operational GHG emissions, and other functional considerations that may impact building performance and durability.  Set goals for credits that are less prescriptive (picking arbitrary winners and losers) and instead focus on the intended performance such as (1) Bring the building to GHG emissions neutrality within, say, 3 years after construction (at which point operational GHG emissions savings exceed the initial GHG embodied investment of the insulation material).  Over the life of the building, provide an insulation package that provides at least, say, a 50:1 payback in total carbon savings (e.g, ratio of operational savings to upfront embodied carbon investment in the insulation package). 
    1. NOTE: An ultimate performance basis (related directly to climate risk and mitigation) would be to apply a realistic and scientific social cost of carbon (e.g., ~$200 / tCO2e) to the life-cycle analysis in terms of present value of GHG emissions associated with a project. But, that may be better as a future step toward a performance-based approach to LEEDv5 credit system and public policy evaluation in general. This would answer the question, what design decisions today would optimize mitigation of future climate risk in terms of costs and resources available today to achieve it (or accelerate it as a basis for increasing credits for the investment made and performance achieved).