Due to the intermittent character of renewable electricity sources and increasing decentralized electricity production, grid operators are facing challenges in balancing electricity- demand and supply within grid operations. These characteristics make it challenging for operators to forecast in- and outflowing electricity in the grid. This often leads to disadvantageous frequency-, voltage-, and electricity fluctuations in the grid. The implementation of smart grid technologies allows the easier integration of sustainable electricity sources and to increase the grid’s reliability. Additionally, more components can be integrated in the grid system that can provide grid regulating services. In the context of sustainability, it’s interesting to stress the potential of grid services delivered by parked electric vehicles. The principle of a Car as Power Plant (CaPP), where vehicles can provide electricity back to the grid via Vehicle-To-Grid (V2G) technology, can potentially solve challenges that grid operators are currently facing. This can be designed in such a way that the operation becomes beneficial for all parties involved. This research implies a techno-economic assessment of a power manager device; which is a multifunctional device that includes an energy management system (EMS), allows for vehicles to charge and discharge and functions as a converter (from direct current to alternating current). The power manager enables electric vehicles to deliver ancillary services when operating in V2G mode. This research stresses the economic- and environmental benefits of a power manager; once it’s integrated in grid-connected commercial- and residential buildings. Emphasis is put on buildings in future energy systems, which are equipped with DC loads and contain features that make the building operate in a more sustainable manner than today. For this purpose, several cases have been modeled to address the cost benefits of a power manager within a buildings’ electrical system. The cost optimization is conducted by means of the HOMER optimization software. Environmental- and financial benefits could be achieved in a behind-the-meter operation, in case electricity flows are managed smartly and ancillary services are delivered to the grid. Price arbitrage and peak shaving were among the most emphasized ancillary services. By integrating electric vehicles by means of a power manager, the batteries of parked electric vehicles could get an extra function, besides being primarily used for driving purposes. Several cases have been optimized by applying a dispatch strategy, considering different components in the microgrid (solar panels, DC electrical loads, battery electric vehicles). These dispatch algorithms were embedded in the power manager’s energy management system.This research has shown that, once the vehicles’ battery capacity was aggregated for grid facilitating purposes in a behind-the-meter operation, parties could achieve financial- and environmental benefits. This could be realized by integrating permanently parked vehicles within commercial- and residential buildings’ electrical systems by means of a power manager. When a power manager was added to a building’s system without integrated solar panels, annual cost savings of € 35 and € 60 could be achieved respectively for residential- and commercial buildings by accounting for price arbitrage services. Once a power manager device was added to a building’s electrical system with integrated solar panels, the renewable energy fraction of the system increased from 53.9 to 57.4 for a residential building and from 68.0 to 70.8 in a commercial building. Altogether, price arbitrage practices primarily caused financial benefits, while peak shaving services resulted in an increase in the system’s renewability. It’s presumed that a power manager’s economic- and environmental benefits could increase once a larger battery capacity is obtained by aggregating BEVs in a ‘before-the-meter’ operation. Favorable regulations and privacy matters need to be established and discussed to make a power manager device run at its full potential. Additionally, it’s important to determine what party will be fulfilling the aggregating role, and therewith, takes the responsibility for demand response operations. For this, a potential business case is established for the implementation of a power manager in the Dutch market.