Energy systems are changing worldwide, and particularly in Europe, where energy policies promote a more sustainable energy production. Variable Renewable Energy sources (VRE) such as wind or solar are benefiting from these policies, but the long term implications need to be anticipated, through energy scenarios. Long term energy models are used, and VRE integration challenges are a hot topic in energy modelling. An assessment of long term energy models is necessary to understand how they represent the specific constraints of VRE on the rest of the power system. Therefore a new typology is proposed for comparing both long term energy models and power sector models. This comparison shows that, despite all the recent modelling efforts, no long term energy model represents in detail the power sector, with all the impacts of VRE. For example, there is no real representation of the electricity storage operation. Therefore we develop a new power sector module for POLES (Prospective Outlook on Long-term Energy Systems), one of the most technology-detailed long term energy models. We present the first results of this new detailed electricity module.