Photovoltaics Stand Alone
When planning stand-alone solar electricity systems the most important task is to balance the energy consumption with the supply. Solar energy is a limited and fluctuating supply. Therefore, the daily electrical consumption, radiation level and battery capacity must be correctly calculated and balanced with each other.
When the system is required to supply electricity throughout the year the design can become more difficult. The amount of radiation we receive in the summer is nine times greater than that received in the winter and the electricity demand will usually be greater in the winter.
If a Solar PV system is designed to provide electricity in the winter it can lead to a large surplus of energy in the summer. This makes the system uneconomic and unsatisfactory from an ecological point of view.
The optimum design to provide electricity throughout the year is a hybrid system. The hybrid system could consist of a Solar PV system and an auxiliary generator or a Solar PV system and a wind turbine. Combination with a wind turbine can be a good idea if there is a suitable site for a wind turbine (open location without buildings or trees). The solar and wind will complement each other.
The battery's task is to compensate for the mismatch between energy supply and consumption. There will be large fluctuations, therefore, the batteries should provide a reserve of at least 3 days for the summer months and 5 days for the winter months. There are different types of batteries available. The best type of battery to be used depends on the application. Please contact Ecofirst for more information.
The PV generator voltage must be matched to the batteries (accumulators). The usual system voltages are 12, 24 and 48V. The charge voltage must be higher than the battery voltage. To regulate this voltage a charge controller (regulator) is used.
Normally the electrical loads are realised using direct current. However, to use conventional appliances (230V ac) a stand-alone inverter will be required.
Ecofirst can design, supply and install PV stand-alone systems and hybrid systems. Please call 0845 257 5064 or email for a design or quote.
