Following COP26, many countries are embarking on decarbonization strategies for the power sector that may include inter alia storage, hydrogen and carbon capture (and storage). There is also significant increase in load that may come in the form of electric vehicles (EV) charging and hydrogen requirement for decarbonization of other sectors. While there is a growing literature around long-term decarbonization strategies, there is still ample room for a practical methodology to rigorously test capacity plans to include a range of options inter alia re-optimization of the mix of renewable technologies, better coordination of the (EV) load from a system perspective, or augmenting the plan with battery energy storage (BESS) and hydrogen. This paper presents our research on EV load and green hydrogen modeling including how they can be integrated into long-term electricity models. We present a methodology that allows planners to undertake a rigorous assessment that can be readily implemented using the World Bank Electricity Planning Model (EPM). The application of the model is illustrated through a case study for Turkey (Türkiye) for 2050. The case study shows how an incumbent policy-driven capacity plan for 2050 that included 33% contribution from variable renewable energy (VRE) may be prone to unserved energy risk during winter months due to seasonal variability of VRE. The analysis goes on to demonstrate how the plan can be reinforced with additional peaking gas turbines, re-optimization of wind and solar, BESS and hydrogen. Coordinated charging of EVs is also shown to bring significant relief to investment requirements.