Residential/Domestic Solar Energy & Battery Storage Solutions

Household electricity consumption in Queensland averages 22 kWh/day under Tariff 11 and about 8 kWh/day under off-peak tariffs 31 and 33. A suitable sized solar photovoltaic (PV) of 6.6 kW together with a 5 kW inverter will generate on average 25 kWh per day during daylight hours.

The electricity generated by PV costs as little as 5 cents/kWh and therefore it’s advantageous to utilise this energy to supply domestic loads while the sun is shining.

Excess Energy

Excess energy from the photovoltaic array is exported to the power grid with a credit received. In many cases the electricity bills can reach zero or receive credit when exported energy during the day pays for energy used at night and on cloudy days. In most cases the payback period on a residential solar system is less than 3 years.

Battery Storage

In situations where most electricity consumption happens at night a battery bank can be used to store energy from PV to be used at night. The size of the residential system’s battery range from 12 to 25 kWh. The energy stored can also be used as an emergency supply during power outage. The added cost of the battery translates to a longer payback period – usually 7 years.

Off Grid Photovoltaic System

‘Off grid’ solar systems for electricity generation employ a PV array, a storage battery and a stand alone inverter. A maximum power point tracker is used to optimally charge the battery bank. The ‘off grid’ system usually incorporates a backup diesel or petrol generator.

During the day energy can be used to supply the day load and the excess energy is stored for use by the night load. Either lead acid or lithium batteries are used at a D.C. voltage of 24 V or 48 V depending on the inverter capacity. Higher D.C. voltage is preferred if the connected load exceeds 3 kW to reduce internal resistance losses.

A choice of 3 kW or 5 kW inverter and 5-6 kW PV with 15 kWh of battery storage will be most suitable for households with no grid power.

Detailed Modelling & Projections

SEBSS will prepare a comprehensive financial projection and modelling and a proposal on the recommended system’s impact. This covers considerations such as:

  • Capital outlay;
  • Projected electricity cost savings;
  • Rate of return on investment over the system’s lifetime;
  • Your projected payback period; and…
  • The net present value (NPV) of the recommended system.
On-Site Assessment

With an on-site assessment SEBSS can provide you with the photovoltaic array, inverter and battery storage specifications best suited to meeting your domestic energy needs, reducing your electricity bills, and maximising your return on investment. Contact SEBSS today on 0414 636 099