CarGHG WebApp current version is 0.8.3

CarGHG WebApp Quickstart

Slider Definitions

Reference Battery System Cost [$/kWh] A change in the unit cost of the battery pack changes the cost to build a vehicle, and thus the owner's TCO. This slider shows the sensitivity of each vehicle’s TCO (total cost of ownership) to changes in battery pack costs. 

Reference Motor System Cost [$/kW] A change in the unit cost of a motor changes the cost to build a vehicle, and thus the owner's TCO. This slider shows the sensitivity of each vehicle’s TCO to changes in motor costs. 

Fraction of Maximum Incentives [%] CarGHG  estimates the financial value of all federal and state incentives for vehicles operating in 2021 in California, USA.  These include non-financial incentives, such as access to High Occupancy Vehicle (HOV). The value of incentives assigned to any specific vehicle are detailed in the original  CarGHG  tool.  A value of 0% removes all incentives from TCO consideration. 

Electricity Price [Cents/kWh] shows the sensitivity of each vehicle’s TCO to changes in residential electricity costs.  As a simplifying assumption, all vehicle charging is assumed to be done at home, at this (constant) rate.   More complex pricing has been considered but will likely come first to the original  CarGHG .

Gasoline Price [$/gal] shows the sensitivity of each vehicle’s TCO to changes in gasoline prices.  As a simplifying assumption, it is assumed that this price remains constant for all of the years of vehicle ownership.

Well-to-Battery Electricity GHG [g-CO2/kWh] shows the sensitivity of each vehicle’s well-to-wheels GHG to changes in the well-to-wheels GHG of the electricity it uses.  Any efficiency losses from battery to wheel are already modeled in each vehicle model.

Minimum Time Window for Daytime Charging [hr] defines the charging behavior assumed.  Today, both charging behavior and the availability of charging infrastructure are uncertain, so we developed a model to consider the impacts of daytime charging on the expected GHG produced in any given trip or travel-day.  A description of this model of charging events can be found in Section 2.2 of Optimizing the electric range of plug-in vehicles via fuel economy simulations of real-world driving in California [https://doi.org/10.1016/j.trd.2019.05.013]
Essentially, we assume that any time the vehicle is not driven for the specified time window or longer, we assume the vehicle is charging, at Level 2 for PHEVs, and at Level 3 for BEVs. 
We tend to focus on these three choices: ❴12 hrs, 4 hrs, 0.5 hrs❵.  Setting this slider at 12 hours roughly represents overnight charging only.  Choosing 4 hours represents primarily charging at work/school, plus overnight charging.  Choosing 0.5 hours represents the idealized “chargers everywhere” scenario.
Note 1: The main CarGHG  tool includes additional modeling options for charging behavior, including Fraction of PHEVs not charging.
Note 2: We are very open to user’s suggestions on how best to model the current charging behavior, especially as clearer data becomes available.

Number of Years of Vehicle Ownership [year] Vehicles are modeled to be brand new at the start of the analysis period, and Number of years Ownership is used to estimate the depreciation of the vehicle at the end of the analysis period. 
Note 1: Manufacturing GHG is not a function of the Number of Years of Vehicle Ownership, as the per-mile manufacturing GHG is spread over the whole life of the car, regardless of the length of ownership of the first user. 
Note 2: No major expense, e.g. the replacement of the vehicles engine or traction battery, is included in our TCO calculation.  Instead, a fixed annual maintenance cost is included in the TCO.  In the future, with clearer data, this may change.

FAQ

Q: Where can I find further documentation?
A: The above information in the Quick Start and Slider Definitions is currently the primary documentation for the web app CarGHG WebApp. CarGHG WebApp is primarily intended to give users a high-level appreciation of what CarGHG can do, without requiring download or installation.

Q: OK, so how can I get documentation for CarGHG?
The CarGHG download includes a brief User Guide, which is also separately accessible from www.carghg.org. In addition, CarGHGis open source, with all code available for public review and commentary. That said, we know that CarGHG would greatly benefit from a detailed user’s manual.  While this remains high on our list for future work, in the interim, please ask us detailed questions.  The best way to contact us is to email info@carghg.org.  We intend to answer all queries quickly.  Depending on the complexity of the question and answer, we may suggest switching to a different communication method.  We are also considering other channels of support.
  In addition, many of the key features and methods of CarGHGare explained in one or more of our published papers. Below, you will find a list of references that explains how certain parts of CarGHGare modeled.  We plan to continually add to this list.

Q: What is the difference between CarGHG and CarGHG WebApp?
A: CarGHG is the original implementation of the current analysis tool.  It requires downloading and installing the program from www.carghg.org. The functionality of CarGHG WebApp is the subset of two of the modules in CarGHG, with the CarGHG version having many more sliders and configurations available.  In addition, CarGHG provides links that explain our validated vehicle models.  CarGHG additionally has a module that shows full distribution curves of the GHG analysis.  CarGHG WebApp is a web application that allows users to generally understand what CarGHG is, without needing to first download and install anything.

Q: How can I be assured that these results are valid and accurate?
A: The web app, CarGHG WebApp, is designed to closely reflect the results of our primary analysis tool, CarGHG, downloadable at www.carghg.org. That tool is built from open-source code, available from the associated Github site, and open to review by all.  Further, each vehicle model based on an existing vehicle has gone through a validation process, as described in our papers (see above).  Many of the other key steps of the tool’s analysis are described in public, peer-reviewed articles.  We feel this represents a transparent, good-faith effort to predict how vehicles perform on the roads. Of course, we are fallible human beings.  If you find something that looks wrong, please let us know.  As was state elsewhere: We make no guarantees about the tool, except that we very much want to fix any issues or bugs you may find.

Q: Why do I see differences between the web app CarGHG WebApp and the CarGHG program?
A: The original, downloadable application CarGHG remains the primary analysis tool.  It has more features and flexibility, including the ability to save, recreate, and export results. Users can also use the original CarGHG to create their own analysis (e.g. analysis with their own trip files).  There may be times when the downloadable application has recent code updates that have not yet been ported to the web app.  That said, it is our goal to keep the web app CarGHG WebApp in sync with the primary CarGHG as much as possible.

Q: What is the difference between CarGHG WebApp and CarbonCounter
A: Functionally, both of these web apps have many similarities. 
We are fans of CarbonCounter and its creators, the MIT Trancik Lab.  It has been around as a web application for longer than CarGHG WebApp and has developed a great interface. 
To the best of our recollection, the CarGHG team had already sketched out the basic contours of CarGHG (including a planned web app) before discovering CarbonCounter. We are happy to learn that our two groups (apparently independently) share a similar vision of how to think about these topics.
We think the largest differences between the two tools are their respective sources of data.  CarbonCounter uses the US EPA label values to calculate the use-phase GHG of each vehicle, while CarGHG uses its own simulation results of each vehicle performing real-world driving.  This means that CarGHG can also calculate, and visualize, the performance of hypothetical vehicles. 
Similarly, CarbonCounter uses the Manufacture Suggested Retail Price (MSRP) as an input into the Total Cost of Ownership (TCO) model.  CarGHG uses the MSRP for actual vehicles (which have official MSRPs) but can additionally use its own (published and open-source) cost model as an input to its TCO estimates.  This allows CarGHG to estimate costs of imagined vehicles, which do not have a MSRP.  In addition,CarGHG can also predict the cost sensitivity of real vehicles if the costs of components change.  For example, CarGHG can predict what a discontinued vehicle would now cost to build, assuming today’s lower battery costs, or even a future cost if batteries become cheaper still.
However, CarbonCounter models far more vehicles than CarGHG, as we have found the creation and validation of each CarGHG vehicle model to take a fair amount of effort.
Stated succinctly, CarbonCounter compares performances of many vehicles currently (or recently) available for purchase in the US (which all have an EPA rating and an MSRP). CarGHG can do the same, but can also include hypothetical vehicles in its evaluations.

Q: Who are the people that produced this tool?
A: The web application (WebApp) was built by Nicholas Makharinets. Nicholas worked closely with the architect and creator of CarGHG, Karim Hamza.  Ken Laberteaux and Jean Chu provided additional support.  This work was done while Karim, Ken, and Jean worked at Toyota Motor North America-R&D in Ann Arbor, MI.

Q: Can we site the results of CarGHG WebApp in our papers, presentations, and reports?
A: Absolutely!  When doing so, we suggest the following citation:
Open-source tool for estimation of cost and greenhouse gas emissions of light-duty vehicles: CarGHG WebApp, v X.XX (webapp.carghg.org)
where X.XX denotes the version of CarGHG WebApp used, shown at the top of this page.

ChangeLog

0.8.3 Fix for the bug where cost bars did not multiply certain annual costs insurance by the number of years of vehicle ownership (20 Nov 2023)

0.8.2 Set default incentive=0 until new incentive structure is coded (01 Feb 2023)

0.8.1 Minor Fixes (01 Feb 2023)

0.8.0 Added Total Cost of Ownership module to Web App (01 Feb 2023)

0.7.1 Added About link and page, providing a Quick Start, Slider Definitions, and FAQ (07 Jun 2022)

0.7.0 Public beta release at app.carghg.org (17 Apr 2022)

0.6.0 Soft launch of beta (23 Feb 2022)