Solar Bonus Cost Savings

Note – Changes to the QLD Solar Bonus Scheme – only people who are already connected under the “old” QLD Solar Bonus Scheme can access the $0.44 /kWh Net feed in tariff, people connected to this tariff will lose eligibility if they upgrade inverter size, or change the electricity account holder’s name.

Thanks to the LNP government, any new applications for grid connected solar in QLD will only be eligible for around $0.06 / kWh feed in tariff (customers will need to negotiate a feed in rate with their electricity retailer);  Note – where you are using more electricity than your PV system is generating you will make cost savings at the same rate you pay for that electricity (e.g.  26 cents / kWh).  If you use less electricity than what you are generating (at any instant) excess electricity will feed in to the grid for which you will only be payed around $0.06 / kWh (depending on electricity retailer).

Cost Savings depend on your “daytime electricity usage” as well as the output of your PV generator.

For PV Only systems (without batteries) : Queensland has a NET feed in tariff,  so unless you know how much electricity you use during the daytime when the solar generator can potentially feed to the grid (approx 8am to 4pm), any cost saving advice is a guess using assumptions that may not reflect your actual electricity usage habits.

Simply looking at your power bill will not give any idea of your daytime usage because your power bill measures all usage including the night time when in many cases, the majority of power is used.

Guessing what proportion of power is fed to the grid might help other companies over-sell solar power systems, but I would be very hesitant to invest in an expensive asset such as solar power based on a guess.

 

We recommend to measure your actual “daytime electricity usage” between 8am & 4pm to provide a better estimate of realistic cost savings.

To do this, take the difference of two meter readings (of your general supply tariff kWh meter) – once in the morning around 8am and once in the afternoon on the same day around 4pm.  Typically you would do this on several days to get an average “daytime electricity usage” per day.

For information on reading kWh meters and reducing your energy demand, please see our FAQ page.

 

Non-Linear Load Profiles :  For some installations, where more accurate cost savings estimates are required, it may be necessary to measure the installation’s load profile using data-logging equipment, since early morning / late afternoon electricity consumption may be significantly higher than middle of the day electricity consumption;  couple this with a PV system that only makes a small amount of power during morning / afternoon, but generates most of it’s power between 10am to 2pm and the cost savings estimate becomes even further from the truth and the limitations of a PV system without battery becomes all too apparent.       This is where Hybrid battery systems come in……

Hybrid Battery systems will store the excess energy generated by your PV system in a battery, and use this energy in preference to grid supplied energy when your PV system is not generating as much electricity as you are using (e.g. when a heavy cloud reduces PV output, or at night time).

 

For Hybrid PV systems (with batteries) :  Firstly, you will only receive around 6c / kWh for excess energy that you feed to the grid, so feeding to the grid should be the lowest priority.

Looking at your electricity bill will be the fist step in deciding what size PV system will be required to reduce or in some cases zero your electricity bill.

However to size the batteries accordingly (to be able to use energy at night that is stored in the batteries) you will need to know what proportion of your electricity is consumed during the night,  this is equivalent to  your total energy consumed per day minus your “daytime electricity usage”.

A well designed Hybrid system will be able to minimise feeding to the grid, and maximise self consumption, the only downside to Hyrid systems is the high cost of quality batteries.

 

Simplified Net Feed in tariff Example (44c/kWh) PV only,  –

e.g. if your solar generator makes 10 kWh of electricity in a day and you only consume 4 kWh in that “daytime” period,

you will feed 6 kWH to the grid for which you’ll be credited $0.44/kWh for that 6 kWh,

and you will also make a cost saving at $0.27/kWh (your normal electricity cost) for the other 4 kWh that didn’t feed to the grid.

This means that the best cost savings are made when you have very little “daytime” electricity usage, since most of the generated PV energy will be fed to the grid at a rate which is significantly higher than the rate you pay for energy.

 

Simplified Net Feed in tariff Example (6c/kWh)  PV only  –

e.g. if your solar generator makes 10 kWh of electricity in a day and you only consume 4 kWh in that “daytime” period,

you will feed 6 kWH to the grid for which you’ll be credited $0.06/kWh for that 6 kWh,

and you will also make a cost saving at $0.27/kWh (your normal electricity cost) for the other 4 kWh that didn’t feed to the grid (which is equivalent to the amount of energy that you have not needed to use from the grid).

This means that the best cost savings are made when you have “daytime” electricity usage that is equal to the output of your PV generator, since most of the generated PV energy will be used in your own installation at the same rate that you pay for energy.

 

“Daytime Electricity Usage”

Not everyone uses electricity in the same way or at the same time of the day, some customers are quite unwilling to reduce their power consumption and think that a solar power system will fix it – its not until their “daytime electricity usage” (between 8am & 4pm) is measured that the realistic effect of a solar power system can be calculated.

Typical “Daytime electricity usage” for domestic situations varies from 1 kWh for some customers up to 14kWh for other customers that I have dealt with, yet all of them “don’t use much power”.

In general,  larger systems will provide greater annual cost savings and have faster payback times when your “daytime electricity usage” (between 8am & 4pm) increases beyond 11kWh per day, however under the new  $0.06/kWh feed in tariff  smaller systems will have a better payback period if your “daytime electricity usage (between 8am & 4pm) is between  3kWh and 11 kWh.

A Solar Power Generator is a long term budget consideration, which will help to reduce your electricity bills, however any renewable energy system is an asset that provides tangible value to your home or business and may increase its resale value.

Once you know your “daytime electricity usage” between 8am & 4pm, you can compare your own “daytime usage” with that in our Payback period charts to get a realistic idea of Pay back times and Cost Savings for each of our standard systems.

Note – the cost savings / payback times on the link below are for optimum orientation, unshaded systems – an accurate site survey is always required for your specific site in order to calculate the reduction in performance from shading and non optimum orientation.

 

View PV only (non battery)  Payback periods – Pay back periods Aug2014 REC$35 PV only