off-grid solar electricity explained.

PowerSmart are experts in off grid solar electricity solutions. We have installed over 3MW of off-grid solar systems since 2007. These systems range in size from massive utility scale systems such as in Tuvalu and the Northern Cook Islands which are used to power whole communities, through to residential systems that power peoples homes and holiday cribs or baches. 


what is off-grid solar?

Off-grid solar electricity is for homes that do not have access to grid electricity - i.e the house cannot be or chooses not to be supplied electricity from a power company.  These systems offer complete autonomy and independence from the national grid and power companies, meaning you never have an electricity bill.


how does off-grid solar work?

Simply sun shines on solar PV panels on your roof or mounted near your house. These panels generate electricity which is used to power your home and charge your batteries. The batteries allow you to store electricity for use at night or times of low production like cloudy days. 

  1. Solar PV panels mounted on your roof or near your house capture energy from the sun and convert this energy into DC electricity
  2. A Solar Inverter converts this DC electricity into 230V AC electricity. 
  3. The main switchboard takes electricity from the solar inverter or battery inverter and sends it to power your home. 
  4. The battery inverter is two way and can take surplus electricity from the main switchboard and convert in into DC electricity to be stored in batteries or demand is their convert stored DC electricity from the batteries into AC electricity to power your house. 

understanding off-grid solar.

Off-grid solar electricity is complex and getting it wrong leads to expensive mistakes. What follows below is a simplified explanation for understanding how an off-grid solar power system works and the process we go through to design your system correctly. 

The more intense the sunlight that shines on your solar PV panels the more electricity that is produced, so when the sun is low in the sky less electricity is produced. Likewise on cloudy days and overcast days, less electricity is produced than on a bright sunny day. In the winter less electrical energy is produced than during the summer as the sun shines for less hours. the dotted line represents the increased electricity production on a summers day. 


How do we size your off-grid system?

We size all PowerSmart Off-Grid electricity systems based on winter production as this is when your system produces the least electricity and when most households have the highest demand for electricity.

Two families might live in similar sized homes but use very different amounts of energy. One family might have people at home during the day while the other family are all away at work during the day. For this reason every system PowerSmart designs is customised for each client.

Our first step with all our clients is a Full Energy Audit. When PowerSmart conducts the energy audit we take into account many factors including a families: lifestyle, lifestage, house design, their electrical appliances - when they use them, for how long and how often. 

The graph below shows how energy demand varies during the day depending on what appliances are used. Please note there is no allocation of energy for heating or cooking using electricity as we find for off-grid systems it is more efficient to use gas. 


Solar PV panels generate electricity during the day when the sun is shining, but households use electricity throughout the day. When PowerSmart designs an off-grid system we take into account how much energy you use and when, so we have enough solar PV panels to generate electricity and enough batteries to store the power for use at night. Households who use lots of energy at night will need more batteries than a household that uses most of their power during the day. 


In the diagram above you can see how surplus electricity produced during the day is used to charge batteries which in turn produce electricity to run the house in the evening. As a general rule we design our systems to have enough battery storage so a household can last without significant sunshine for 2-3 days.


How Much do Off-grid solar electricity systems cost?

Off grid systems are more expensive than grid connnected systems due to extra componentry required- such as batteries to store the power. PowerSmart off-grid systems start at about $29,000 ex GST, which is less than $1500 per year over 25+ years a system will last. We are so confident in our components and installation that we offer a 25 year performance warranty on our panels and a 5 year warranty on inverter parts and workmanship.


I want more information on Off-grid solar.


"We have never had a project go so smoothly, they finished two weeks ahead of schedule."

Dan Udy - Director: Udy Group