Distribution level modeling or monitoring has not been of primary concerns of the utility companies so far, because traditionally the electric power is delivered unidirectional from distribution substations to the customers. Meanwhile, integrating Distributed Energy Resources (DER) into the distribution feeders and contribution of the customers in demand response and other aspects of the future smart grid is starting to push system planners, utility companies and researchers to build unabridged and detailed model of the distribution feeders even down to home appliances level. GridLAB-D™ and Open-DSS are both open source software tools, designed for modeling distribution level power systems. Design and development of multiple algorithms for peak shaving, arbitrage, load shifting and smoothing scenarios is of major concerns. We show that very promising results in terms of modeling future smart grid and various possibilities are expected.