stand-alone system

A stand-alone system is a system that operates independently of, or is not connected to, an electric transmission and distribution network. This is in contrast to a grid-connected system.


Powering homes or small businesses using small renewable energy systems that can function separately from the electricity grid can have both economic and environmental advantages. In addition to purchasing photovoltaic panels (also known as solar panels or solar modules), a wind turbine, or a small hydropower system, you will need to invest in some additional equipment called balance-of-system to condition and safely transmit the electricity to the load that will use it.


The amount of equipment you will need to buy depends on what you want your system to do. In the simplest systems, the current generated by, for example, your wind turbine is connected directly to the load. However, if you want to store power for use when your turbine isn't producing electricity, you will want to purchase batteries and a charge controller. Depending on your needs, balance-of-system equipment could account for half of your total system costs. Your system supplier will be able to tell you exactly what equipment you will need for your situation.


Major balance-of-system equipment for a stand-alone system includes:


  • Batteries
  • Charge controller
  • Power conditioning equipment
  • Safety equipment
  • Meters and instrumentation

    For more information on stand-alone systems, see:


       • small stand-alone solar electric systems
       • wind power in stand-alone systems