The document discusses plans to update the ETSAP-TIAM energy-economic model through a collaborative process. It proposes organizing workshops with ETSAP-TIAM users to identify needed updates, revising model data and structures, recalibrating the model, and documenting results. The goals are to facilitate analysis of deep decarbonization scenarios and improve linking of ETSAP-TIAM with other models. A two-year, €100,000 budget is presented to fund updating energy balances and technologies, workshops, recalibration, documentation, and scenario development through biannual phases.