Performance of a campus photovoltaic electric vehicle charging station in a temperate climate

A photovoltaic (PV) array can be combined with battery energy storage to satisfy the electrical demand of lightweight electric vehicles. Measured solar resource and vehicle energy consumption, together with locational, mechanical and electrical constraints were used to design a vehicle charging station comprised of a 63 m2 10.5 kW AC PV array, with a 9.6 kWh lithium-ion battery. PV output, battery charge and discharge, electricity flows were monitored over one year. Deviations between measured and calculated annual AC generation averaged to 14%. Average annual direct consumption, self-consumption and system self-sufficiency were 8.47%, 30.3% and 74.36% respectively

Battery Energy Storage System (BESS) Based Photovoltaic Charging Station (PV-CS) For A Green University Transportation

With the trends encouraged by governments and political parties to increase the adoption of Renewable Energy Sources (RES); solar energy, and in particular photovoltaics (PV), is poised as an excellent candidate to offset the energy requirements of charging stations (PV-CS) for Electric Vehicles (BEV). This work presents a 10.5 kW Transient System Simulation (TRNSYS) model of a university campus PV-CS to determine sizing as well to determine the best operating strategies for a Battery Energy Storage System (BESS). The economical optimization model is formulated via theoretical approach adopting the Simple Payback Period (SPP) indicator. The optimization takes into account the campus transportation load profile while BESS is used to attain the shortest SPP gain. The results, from both theoretical as well as simulation approach, reveal that leveraging the campus BEVs charging via BESS based PV-CS scheme has the potential to reduce the energy demand from the grid, and to maximize self-consumption efficiency

Modelling and Energy Management Optimisation of Battery Energy Storage System Based Photovoltaic Charging Station (PV-CS) for University Campus

As utilization of Photovoltaic Charging Stations (PV-CS) that generate clean electricity from the sun increase, Dublin Institute of Technology (DIT) adopts this application for accommodating the required charge of small campus Battery Electric Vehicles (BEVs). This paper presents the virtual simulation of the 10.5 kW Battery Energy Storage System (BESS) based PV-CS model. Transient System Simulation (TRNSYS) built-in climatic data and modular structure properties were adopted to replicate the experimentally proposed PV-CS, where special attention was paid to the electrical measurments and energy flow signals. The objective was set to model the PV-CS system, formulate an energy managment optimisation and justify the ideal value and or potential range of the equivalent battery size. The primary assessment for energy management of the charging infrastructure was performed through the formulation of analytical energy balancing optimization. The energy balancing approach adopted the Simple Payback Period (SPP) method in order to investigate the acquired positive gains (Gain-1 and Gain-2) by BESS unit. The key variables for tuning the BESS capacity were load profile and size of BESS. The resultant measurement signals from TRNSYS were monitored and compared to their analytical equivalents, where verification and conclusion on accuracy improvements for BESS capacity and reliable system performance were drawn

The Battery Energy Storage System (BESS) Design Option for On-Campus Photovoltaic Charging Station (PV-CS)

As the application of Light weight Electric Vehicles (LEVs) increase in communities, Dublin Institute of Technology (DIT) uses these small vehicles for short distance journeys around its 78 acre campus of “Grangegorman” located in inner Dublin city, Ireland. This paper presents an introduction to the campus Photovoltaic Charging Station (PV-CS) that generates clean electricity from the sun and charges the LEVs batteries which can lead to reduction of CO2 emissions, along with fulfillment of national and international green sustainability targets. Based on the evaluation of possible options for PV-CS design, the optimal design configuration was chosen as a "Battery Energy Storage System (BESS)”. The PV generated electricity that is stored in battery banks will serve as the primary source for charging the campus vehicles, with any surplus demand being met by the utility grid. Batteries have been included in the design due to intermittent nature of Irish sunshine and the charge time requirements of campus load. This paper concentrates on the detailed sizing of the BESS via two approaches: BESS with DC generation and BESS with LEV load demand. In the first approach the outputs were normalized and grouped into specified generation categories in MATLAB. To establish the accurate BESS capacity the load demand variations of the LEVs were monitored. Based on DC generation and demand profile, the optimal capacity of BESS was chosen to be in the range of 6-8 kWh, which can accommodate up to 6 LEVs

Essentials for On-Campus Photovoltaic Charging Station(PV-CS): Grangegorman

As Light weight Electric Vehicles (LEVs) are gaining interest, Dublin Institute of Technology (DIT) realises the value and application of these vehicles for short distance commutes around its newly built campus of “Grangegorman” located in inner Dublin city. Introduction of the campus Photovoltaic Charging Station (PV-CS) that generates clean electricity from the sun and charges the LEV’s batteries can help achieving Ireland’s 2020 targets on both national and international levels. This paper highlights the design essentials of on-campus PV-CS, via assessments of: LEV load consumption, vehicle tracking and sizing of the storage unit. The pattern for LEVs charging and load consumption was studied on a daily basis utilising a designated energy meter while the typical journeys were tracked using a GPS device. The specified conceptual calculations resulted in appraisal of 5 possible design options. The components for each configuration are listed and the significance of each case discussed, where “coupled PV-grid with storage” option is chosen as the most viable choice of design. The potential size of storage batteries was projected with respect to average and peak demand variations. Battery density, weight and efficiency were identified as the main barriers, which will require future economic and technical investigations in this field

Energy Managment of Photovoltaic Charging Station (PV-CS) For Green University Campus Transportation

Battery Electric Vehicles (BEVs) have been recognised as the ideal solution for lowering the CO2 emissions in the transport sector and helping to achieve a sustainable future. When BEV technology is leveraged with a solar energy source such as a Photovoltaic Charging Station (PV-CS), the CO2 saving potential is extended to both generation and consumption points. Due to the intermittent nature of our solar resource, once the PV-CS is combined with a storage unit, energy production is achieved without risking the disruption to power supply reliability and quality. Dublin Institute of Technology (DIT) has recognised the viability of this dual design solution, with its recent deployment of a 10.5 kWp PV-CS. The charging point has the potential to accommodate the existing charge of two campus Light weight Electric Vehicles (LEVs). Depending on the vehicles charge time, the demand can be accommodated through an individual or combination of the following options: direct solar, PV stored energy of BESS unit and the grid, while the surplus generation is used to charge the BESS or spilled into the grid. This paper presents the AC coupling configuration of grid tied (GT) and Battery Based (BB) inverters in the campus charging point. In order to prioritise the optimal energy flow of the PV-CS, an Energy Manager (EM) device along with Battery Energy Manager (BEM) has been incorporated. The EM controller is set with an objective to maximise self-consumption and further reduce the energy dependency on the grid. The preliminary results obtained from the online portal illustrates the relationship between the captured outputs of: PV generation, BESS charge / discharge, direct / total consumption, grid feed in and external grid supply, and further speculates the incorporated control strategy of EM and ancillary control components

Electric Bike Photovoltaic Charging Station (PV-CS): Experimental Design for Electrical Fault Investigations

Electric Vehicles (EV) have gained interest over the past decade. Accordingly, to support EV technology installation of charging stations are required. A Photovoltaic Charging Station (PV_CS) can generate clean electricity from the sun for charging electric bikes but as can be exposed to harsh weather conditions and faults, which can result in deviations of system characteristics from their normal operating conditions. Reliability of these charging stations is extremely important for supplying adequate charge to EVs, and therefore it must be maintained at all times. This paper presents a systematic approach to electrical reliability issues for PV_CS, by establishing an experimental test bed, which will ultimately allow the examination of a number of electrical faults scenarios that can occur in PV_CS systems. The design and installation of the PV_CS system, as well as assembly of different measurement sensors are presented to distinguish the electrical and thermal characteristics of each signature fault. Through this work, PV_CS charging stations will have the embedded capability of specifying when a fault is occurring and where the fault is occurring, thus reducing maintenance costs and downtime of the PV charging system