**EIOLCA 2002: ReadMe File for EIOLCA 2002 Model ZIP Archive**
**Disclaimer**: This is the Matlab version of the 2002 EIO-LCA model of the US economy. It is intended for users with an advanced

understanding of Economic Input-Output Life Cycle Assessment and, like the web version of the model (at

www.eiolca.net) it is provided as a service to the scientific community and is not supported. You will need to have Matlab and Microsoft Office installed on your computer to fully use this tool. For those of you familiar with the 1997 EIO-LCA matlab file, this will be very familiar. Matlab, Microsoft Excel, and the online version of the model all manage significant digits differently. This may lead to the same value being displayed in multiple ways. For example 4095.263 may also appear as 4095.26 or 4100. While these values may appear different, given the way digits are managed (and the uncertainty of data in LCA models) they are the same values. Also note that this Matlab file, unlike the 1997 Matlab model posted, does not contain the energy or GHG factors (see below). Please post any comments or questions about this model in the “2002 EIO-LCA Matlab Model” thread.

**Files included in this ZIP archive:**

• Output.txt – Sample text file that stores the results of the model. All values are semicolon delimited. It is recommended that the text be pasted into excel in order to make it more readable (see details below).

• EIOLCA02.m – Matlab Model code

• eio02.mat – Matlab storage file which stores all matrices used in the model, including the current Economic matrices and environmental matrix. Variables contained in eio02.mat include:

- A02ic – The 2002 industry by commodity direct requirements matrix (also known as the A matrix). Note that unlike previous model

versions, the default model used on the EIO-LCA website for the 2002 US economy is an industry by commodity matrix. In short, a commodity may be produced by multiple industries, and thus the economic and environmental results will be different (e.g., in the industry by industry models an input of $1 million into an industry sector always resulted in economic output from that industry sector of more than $1 million – but this is no longer always true since that commodity could be produced by multiple industry sectors totaling $1 million).

Several other A matrices also are present in this model such as A02ii and A02cc (i = industry, c = commodity).

- EIOsec –Input-Output sector codes

- EIOsecnames –Input-Output sector names

- envect02 – Variable that stores the labels for the 13 environmental impact categories present in the model.

- final – The final demand vector in 2002 million dollars. By default this vector contains $1 million in the oilseed farming. Users can

change this vector or create their own final demand vector for use in the model.

**WARNING**! - If using a modified “final” as the final demand vector, the user must save his or her workspace before running the model. If the workspace is not saved, EIO02.mat is loaded as a command in EIOLCA02.m which will cause the new “final” to be replaced by the original “final” vector. This is easily avoided by naming the final demand vector something other than “final”.

- L02ic – Industry by commodity Leontief matrix. Like the A matrices, several other L matrices are also present in the model.

- purchtransmat – matrix to split purchaser prices into producer price, wholesale margins, retail margins, and transportation margins

(created using data from BEA)

- trisect – 428x10 Matrix containing summary information after converting emissions of toxic releases through the IMPACT2002 impact assessment model factors (note that the underyling TRI emissions by chemical will be added to this matlab file soon and posted online)

- W – Make Table - matrix mapping 428 industries into 428 commodities

- water – 428x1 water use vector

Many other variables are created when the EIOLCA02.m file is run. For a further description of these variables and how the program executes, refer to the EIOLCA02.m file and it comments.

**Model Summary:**

This is a standalone, Matlab version of the 2002 EIO-LCA web model with more flexibility and options than currently available on the web. It is actually two different models, both implemented from the same underlying code: a producer-price, industry-based model similar to the model published on the website, and a purchaser (retail) price, commodity-based model of similar form. The model will replicate results shown on the web (with the exception of energy and greenhouse gas emissions which are only available via a licensing agreement) but allows for inputs of compound vectors. The purchaser model is designed to adjust for retail to producer prices, and thus model the delivery and retailing stages of the supply chain, as well as allowing modeling of commodities as opposed to industrial activity (e.g., a car instead of ‘automobile production’).

For a more in-depth understanding of how this model works, reading through the EIOLCA02.m code and all of its notes may be helpful.

**Model Use:**

Use of the model has been made as similar to the web model as possible. Inputs are made through the final demand vector, final.

Users also have the ability to create their own final demand vector as the final demand vector name is asked for while the model is being run. This is similar to choosing a sector and increment of demand on the “use the model” web page at eiolca.net. This method allows for a bit more flexibility than the online model, as users can input demand into multiple sectors simultaneously.

Once the final demand vector is set, the EIOLCA02.m file can be run. First make sure the current working directory in Matlab is the

directory in which EIOLCA02.m resides. The present working directory is shown in the upper left window. Type ‘EIOLCA02’ into Matlab and press enter. Several options are now given:

1. Select which model to use: 1 = producer price (industry basis), 2 = purchaser price (commodity basis)

2. Enter the name of the final demand vector. This entry must be the name of a previously created 428x1 double in the Matlab environment. See “final” variable described above.

3. Enter the name of the output text file name including the “.txt” portion of this file. A sample output text file has been included in

this model displaying the results for $1 million of producer price oilseed farming. This file is Output.txt. If Output.txt is entered

as the filename at this point, this file will be written over.

After pressing enter, the model will begin running and displays either the total production value for the producer price model or the split

between the production value, retail and wholesale markups, and transportation margins for delivery if the commodity retail model is

chosen. All the rest of the work is done internally and the results are then written to the output text file. Open the file to view model

results.

It is often helpful to import this output file into Microsoft Excel. Once imported into excel, the user will see an easy to read Excel

spreadsheet of the selected results.