SEANZ Solar Optimiser
The SEANZ Solar Optimiser has been independently created to help you understand more about solar electricity and how you can maximise your savings. The Optimiser takes you step-by-step through important questions specific to your household or business. These will help you optimise a system for your requirements and to understand the main factors that impact the savings you can make.
If you have a recent powerbill handy then grab it now before you start - if not then don't worry, we'll add some averages based on where you live.
The results obtained from the this tool should be regarded as an estimation only. A quote specific to your home or business from a SEANZ member is the only way to know the potential savings and benefits a new solar energy system can bring to you.

Your location and sunshine hours can determine how much electricity you generate.
This solar generation is defined in kilowatt hours (kWh). Every kWh you generate and use is one less you have to buy from
the grid.
The price paid for electricity from the grid varies from region to region. The more you pay (c/kWh or c/unit) the more you
will save per kWh you produce, from solar.
Click on your region to move to the next step...
Info On Selecting Region
Selecting your region will lock two important variables into the Optimiser as part of the calculation:
- The average sunshine hours for your region
- The average electricity price (c/kWh or c/unit) for your region based on government (MBIE) survey data (You can change this later if you know your actual electricity price)
How Solar Works For You
The electricity produced by solar can be used in any of the following three ways:

Used by household appliances and heating water - this is called self-consumption. The more solar electricity you consume, the better your return.

Sent to a battery bank or used to charge an Electric Vehicle (EV). Battery costs continue to fall so ask a SEANZ Professional.

Sent or exported to the grid, where the solar electricity is purchased for a low price by some retailers. It is also now possible to sell any excess electricity you generate to a neighbour or friend via a Peer to Peer provider.
Any or all of these can be applied depending on your needs
The Price You Pay For Electricity
If you have your electricity bill then enter your daytime electricity price (cents/unit or cents/kWh). If not, then leave the default which is the average cost for your region.
The Amount You Sell Electricity For
If you know the price you can sell electricity to your retailer (your export rate) enter it here (cents/unit or cents/kWh). If you don’t know leave the default rate which is the national average price.
Installing The Right Size Solar System
The size of the solar system (measured in kWp) you install should be determined by two factors:

1. The size of your household/premises.

2. The percentage of electricity generated that you can consume (self-consumption).
Select the best description of your household electricity consumption.
Or if you have your power bill you can compare your daily power consumption to one of the following selections (remembering that using your power bill as a measurement does not allow for optimising self-consumption).
1-3 people using 10-15 kWh's/day
3-5 people using 15-25 kWh's/day
4+ people using 25+ kWh's/day

Self-consumption
Self-consumption refers to using the electricity produced by your solar PV system as it is generated. Maximising this use, is where you save money. Limiting the excess electricity exported to the grid and purchased by a retailer for a lower price than you purchase energy from them for works best. The typical additional saving being around 20c/kWh. Running appliances during the day rather than in the evenings contributes significantly to your existing savings.
Consuming And Storing Electricity
Whether you are home or not, there are many ways you can maximise self-consumption of the electricity you generate during the day.

1. Change the time when you use power-hungry appliances

2. Use simple timers placed on appliances set to operate during the day when solar is generating

3. Use automated internet enabled in-home technologies with smart phone app access

4. Consider a Home Energy Management System that automatically controls appliances, diverts solar electricity to heat your water, and charges home batteries or an electric vehicle.
Your Results

$...
Savings First Year

Years To Pay Off

$...
Total System Cost

...c
Cost To Produce Electricity (c/kwh or unit)
vs

...c
Cost To Buy Electricity (c/kwh or unit)
How did we arrive at these results?
Your Results
Your results are based on the folowing assumptions:
- System Sizing: Low= 2 kWp, average = 3.5 kWp, high = 5 kWp
- PV Installed cost per kWp inc GST $ 2,820
- Discount rate (Opportunity cost) 3.0%
- Power price increase (year on year) 1.5%
- Maintainance + inverter replacement costs added to 25 year calc year on year 0.85%
Self Consumption
Move the slider below to simulate the amount (%) of electricity you may use during the day. Your results and savings will alter accordingly. Greater self-consumption of electricty as it is generated during the day = greater savings.
Low home energy use during the day means more is exported, lengthening your the time to pay off your system Producing a low yet positive return, this is typical of a household where occupants are not home during the day or have a larger than required solar system Producing a modest return this is typical of a household which runs night rate electric hot water heating from the grid and runs appliances during the day from solar Producing a strong return this is typical of a household which has anytime electric hot water heating and runs appliances during the day from solar Producing an excellent return this is typical of a household which heats hot water during the day using a solar diverter, and consumes high amounts of daytime electricity running appliances, charging an EV, or stored in batteries
Why Solar?
People choose solar for many reasons:
- energy freedom and independence from the electricity industry
- some love energy democratisation
- to save money
- to cap power bills into the future
- to lower their carbon footprint
- some are against non-renewable generation and want to do their bit
- some don’t want more hydro dams or geothermal plants built given their negative impacts
- some really like the idea of generating their own electricity from a free resource
These are all valid reasons, and only you know the true value of this investment. What is that reason worth to you?
Become a Solar Supporter
New Zealand’s energy system transformation is underway but we still have a lot of work to do. Net zero emissions, resilience through increasingly adverse weather events, and the electrification of our transport fleet all require immediate action to ensure existing technologies and business models are equally available to everyone. We also need a long-term plan with broad political support to drive us into our sustainable energy future.
If you want to be part of the energy revolution then sign-up to become a Solar Supporter. SEANZ is an independent not-for-profit organisation - so no spam, no sales pitches, and we won't share your details with anyone - just occasional news, info, and opportunities to help create this new era of energy.