Each version of the VISION model consists of two workbooks. (We use the VISION 2008 version as an example in the following, but the instructions apply to all versions.) The two workbooks in the VISION 2008 version are called "VISION 2008 AEO Base Case Expanded" and "File to be copied to all runs of VISION 2008 Expanded."

Open ONLY the "File to be copied…" When opening the file, answer "No" when you are asked whether you would like to update all linked information. (Beginning with the 2009 version, this link to the Base Case file is removed.)
Immediately save it under a different file name. The new file name should reflect the underlying assumptions of the specific run.
Do NOT change the VISION 2008 AEO Base Case Expanded file.

The File to be copied... and the copy you save contain the results from the VISION 2008 AEO Base Case Expanded file. When inputs are made to "Model Input" worksheet on the copied file, the results of the run are compared directly to the AEO Base Case in the “Model Results” worksheet (as well as several other worksheets). Please note that the VMT elasticity is applied only in the "File to be Copied."

The "Model Input" worksheet allows you to input various assumptions about the future of vehicle technology and vehicle use, such as market penetration of various light- and heavy-vehicle advanced technologies, vehicle energy efficiency, alternative fuel use, VMT, and auto vs. light truck share of total light-duty vehicle sales. All items highlighted in yellow on the worksheet can be modified. The assumptions are generally input in 10-year increments: 2000, 2010, 2020, 2030, 2040, 2050, 2060, 2070, 2080, 2090, and 2100. However, the model is set up to accept other starting dates for vehicle technology and fuel shares.

The model calculates energy use, oil use, and carbon emission results for all years between 2000 and 2100 but displays only the results at ten year intervals on the "Model Results" worksheet. If results for intervening years are needed, they can be found in various worksheets.

The model calculates average new car and light truck fuel economy for the year ending in zero for each decade beginning 2000 on the "Light Vehicle MPG (gge)" worksheet. It does not compute the results for intervening years, though these values for each technology can be found on each technology's individual worksheet. Three results summary worksheets: (i) “Hydrogen Results,” (ii) “Feedstock Energy Results,” and (iii) “Fuel Energy Results” have been added beginning with the 2010 version. The “Hydrogen Results” worksheet summarizes hydrogen production by 11 fuel and pathway combinations. The “Feedstock Energy Results” worksheet summarizes energy used in feedstock production for each fuel consumed by vehicles (and summarized in the “Model Results” worksheet). The “Fuel Energy Results” worksheet summarizes energy used in production of each fuel consumed by vehicles (and summarized in the “Model Results” worksheet).

As stated in item 4, assumptions are generally input in 10-year increments, though starting dates may differ. The model uses linear interpolation to estimate market shares and fuel economy improvements for the years NOT specifically input on the "Model Input" worksheet. If you want to input specific vehicle fuel economy or market penetration in specific years not listed on the "Model Input" worksheet, you will have to hard-wire those inputs in the model's vehicle technology worksheets.

You need only input data to the "Model Input" worksheet and review the run results in the "Model Results" worksheet. However, there are many more worksheets in this model (a total of 43 in the expanded version and 47 beginning in 2010). Most are self-explanatory. One in particular needs to be commented on: "Lt Veh Incremental Cost Summary." The "Model Input" worksheet permits you to input vehicle cost ratios for the various light vehicle technologies. These ratios in turn generate the results shown in the "Lt Veh Incremental Cost Summary." However, we have not evaluated the cost ratios in the model and thus have not presented the cost summaries in any of our presentations of the model.

For further explanation about how to use VISION, see the VISION User's Guide (633kb pdf).

October 22, 2010