Off-Grid
WHAT IS AN OFF GRID SYSTEM?
Pure off grid system means that there is no possibility to access the national grid or you are willing to live off the grid by disconnecting your connection with the grid operator. The concept of living without the grid is to rely on energy sources (solar, wind, hydro…) at small scale to charge a battery bank. Via power electronic, the energy stored in batteries is used to power electrical appliances.
APPLICATION
In some cases, it’s impossible to be grid connected because of high cost to build a power line,
remote location such as mountain refuge, island without connection to main land. The use of a generator diesel in such conditions should be limited only to back up (stand-by) otherwise the cost of diesel and logistics to bring hundreds of liters is very high.
REMOTE AREAS
Security and comfort (lighting, heating, household appliances, leisure electronics, telecoms…) can now be provided by autonomous energy systems; when far away from any electrical grid, either by choice or reason.
These systems consist firstly of an energy source; normally a genset, a solar generator, a wind turbine or a combination of these. Secondly of a battery storage, and then thirdly of devices (inverter-charger, battery charger) able to charge the battery from this energy source and to supply users with AC voltage (inverter, inverter-charger).
EQUIPMENT
In pure off-grid system, it’s important to maximize various energy source to be able to
produce as much as possible in summer, winter, day and night. Recommended equipments:
- Solar panel generating DC voltage with solar charge controller to provide 48V dc to battery bus bar.
- Small wind turbine generating variable frequency AC with wind charge controller to rectified to 48V dc for battery charging and additional dumpload that create a load diversion when batteries are 100% in order not to overload batteries
- Batteries bank ideally 48 Vdc but could be 24 or 12 Vdc for smaller systems. With recent technology improvement and cost per kWh, lithium batteries are the best choice for off grid systems.
- DC/AC inverter so voltage and frequency can be used by electrical appliances. A single phase system will require the Next1 from Studer or the Next3 if 3 phases are needed. The 48Vdc from batteries is then converted to 230Vac/50 Hz or 380Vac/50Hz
- Optionally, it is adviced to have a generator as backup which is connected to the AC input/AC source of the inverter.
HYBRID SYSTEM / RETROFIT AC SYSTEM
Hybrid is a word that can have different meanings depending on the system you refer to. In the case below, hybrid means a mix of DC (battery side) and AC (after inverter). Off grid equipment can be also introduce in a more classic configuration where you have already
installed on grid solar and a wind inverter. The grid connection remains optional, there it is called AC coupling. Batteries are not connected to a solar hybrid inverter but rather they are connected to the power electronic, offering an alternative to grid connection.
We can offer the right
off-grid system for you.
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