Annex 4 analytical methods

model description

general description

acronym
CO2MPAS
name
CO2 Model for PAssenger and commercial vehicles Simulation
main purpose
CO2MPAS is a vehicle simulation model for the calculation of CO2 emissions, energy, and fuel consumption from passenger cars and light commercial vehicles. It uses experimental data, retrieved from chassis dyno or on-road tests, to simulate the operation of vehicles under different operating conditions.
homepage
https://co2mpas.readthedocs.io/en/stable/

Developer and its nature

ownership
EU ownership (European Commission)
ownership additional info
The model is being developed and maintained by the JRC.C.4 Unit who entirely owns the intellectual property of the tool.
is the model code open-source?
YES - It is a JRC developed open-source software. All sources are available online.

Model structure and approach with any key assumptions, limitations and simplifications

details on model structure and approach

CO2MPAS is coded in PYTHON v3.4 computer language. It is based on vehicle longitudinal dynamics and has a modular architecture. It includes a series of predefined algorithms for simulating the operation of various components. It has the capacity to self-calibrate based on given experimental data.

model inputs

The primary use foreseen for the model is to correlate type approval CO2 emissions determined for light duty vehicles in accordance with the new WLTP test procedure set out in Commission Regulation 2017/1151 with the CO2 emissions determined pursuant to the old NEDC test procedure set out in Commission Regulation (EC) No 692/2008. The CO2MPAS model calculates CO2 emissions of light duty vehicles on the NEDC test procedure using as input data retrieved during the vehicle type-approval carried in accordance with the WLTP test procedure (Commission Implementing Regulations (EU) 2017/1152 and 2017/1153, hereinafter ‘Correlation Regulations’)). The correlation procedure and the model allows the transition from the NEDC to  the WLTP without affecting the CO2 targets defined in Regulations 443/2009 and 510/2011 (replaced since 1 January 2020 by Regulation (EU) 2019/631). The model requires an extensive list of inputs, as set out in Table 1 of Annex I to the respective Correlation Regulations, in order to ensure the required level of accuracy in the correlation of the CO2 emission values. The inputs include in brief:

  • type of fuel
  • engine/powertrain characteristics
  • gear-box characteristics
  • electric components
  • vehicle characteristics
  • specific technologies of the vehicle
  • the results of the vehicle tested under WLTP conditions.

A number of default input values are defined for vehicle classes for the model to be used for other purposes. For example it might be used to carry out scenario analyses on the effect on global CO2 emissions due to the introduction of specific vehicle technologies in the vehicle fleet, or to assess the effect of modifying some aspects of the vehicle type-approval test. In this case achieving high accuracy on the single estimation is not important and the default values can allow its use to derive aggregated statistics.

model outputs

CO2MPAS is able to provide fuel consumption, energy consumption and CO2 emissions for a vehicle following a predefined trajectory. Default simulation conditions are the NEDC and WLTP test procedures, for which it has been designed. 

Intended field of application

policy role

CO2MPAS is used to analyse the correlation between the CO2 emissions from the Worldwide harmonized light vehicles test procedure (WLTP) and the New European Driving Cycle (NEDC) test procedures. The WLTP is a new test procedure developed at the UN/ECE level that the Commission has introduced (in the place of the NEDC) for the type-approval of passenger cars and light commercial vehicles starting on September 1st, 2017 (EU Regulation 1151/2017).  The CO2MPAS model is used by vehicle manufacturers and type-approval authorities during the WLTP phase-in (2017-2020), to calculate the equivalent NEDC CO2 emissions for vehicles tested on the WLTP. In this way, the CO2 emission targets set by Regulation (EU) 2019/631 can remain unchanged in spite of the introduction of the new procedure.

Commission Implementing  Regulations 2017/1152 and 2017/1153 provide for the use of CO2MPAS during the vehicle type-approval process.

An extended version of CO2MPAS has been used in the Impact Assessment for the “Review of Regulations setting emission performance standards to establish post-2020 targets for cars and vans" (see [1]) in order to calculate the baseline 2015 CO2 emissions from the European fleet of new passenger cars under WLTP conditions.

CO2MPAS to the Commission Roadmap:

  • Primary:
    • CO2MPAS can also be used to provide “Data, analysis and intelligence for the Energy Union: initiative pooling and making easily accessible all relevant knowledge in the Commission and Member States”
  • Secondary:
    • CO2MPAS can be used in the “Master Plan for the deployment of Cooperative Intelligent Transport Systems”. In particular CO2MPAS can serve as a reference simulation platform, for testing optimization of transport and logistics system in specific cases [2].

The model has been already presented to several international conferences and the results from its use published in different scientific journals and JRC reports.

 

References: 

 

[1] Tsiakmakis, S., Fontaras, G., Cubito, C., Anagnostopoulos, K., Ciuffo, B., 2017. From NEDC to WLTP: effect on the type-approval CO2 emissions of light-duty vehicles (Science for Policy Report No. EUR 28724 EN). https://doi.org/10.2760/93419

[2] Makridis, M., Mattas, K., Mogno, C., Ciuffo, B., Fontaras, G., 2020. The impact of automation and connectivity on traffic flow and CO2 emissions. A detailed microsimulation study. Atmospheric Environment 226, 117399. https://doi.org/10.1016/j.atmosenv.2020.117399

policy areas
  • Climate action 
  • Institutional affairs 
  • Energy 
  • Transport 

Model transparency and quality assurance

Are uncertainties accounted for in your simulations?
YES - The model is regulated and its calibration is based on experimental data that are generated during the official vehicle certification test. Each new model version is released with a validation report that is available on the CO2MPAS Reports site.
Has the model undergone sensitivity analysis?
YES - By the JRC the results were presented to the technical working group overlooking CO2MPAS development (see next point).
Has the model been published in peer review articles?
YES - An ad-hoc technical working group was established by DG CLIMA during the development phase (comprised of industrial and independent stakeholders). Additional external validations are carried out on a yearly basis.
Has the model formally undergone scientific review by a panel of international experts?
NO
Has model validation been done? Have model predictions been confronted with observed data (ex-post)?
YES - The model is used on a daily basis by type approval authorities across Europe. JRC receives continuous feedback on its operation. In addition to this a dedicated validation based on 50 light duty vehicles has taken place.
To what extent do input data come from publicly available sources?
Based on both publicly available and restricted-access sources
Is the full model database as such available to external users?
NO - There is no underlying database. Input data to use the tool are technical vehicle information.
Have model results been presented in publicly available reports?
YES
Have output datasets been made publicly available?
NO - This is s part of the vehicle certification process.
Is there any user friendly interface presenting model results that is accessible to the public?
NO
Has the model been documented in a publicly available dedicated report or a manual?
YES

Intellectual property rights

Licence type
Free Software licence

application to the impact assessment

Please note that in the annex 4 of the impact assessment report, the general description of the model (available in MIDAS) has to be complemented with the specific information on how the model has been applied in the impact assessment.

See Better Regulation Toolbox, tool #11 Format of the impact assessment report).