What’s a ‘Grid Support Solar Hybrid ‘?

When building or renovating a home the electrical network may not have capacity to provide enough ‘peak power’ for your planned appliances.  Network upgrades could then end up costing 10’s or 100’s of thousands in high voltage lines or transformers, and the user will pay for it but the network owns the asset.  

In this case the builder or Lvl 1 electrician might recommend an ‘Off Grid Solar’ system, and in some cases that might be economical, however it will require a petrol or diesel generator to top up the batteries during cloudy weather. Also consider a future of electric vehicle charging and this is less than ideal.

Not to be confused with a standard Solar Hybrid system as those are a popular option for homes with a sufficient grid connection, but 90% of those models are built for the cheapest price point and have limits to power output, switching mechanisms, and software.

A Grid Support Solar Hybrid utilises a powerful off grid inverter with a significant battery, this has a ‘reserve level’ maintained by Solar and the weak grid connection and it allows the system to carry intermittent high-power loads and then be recharged. The Solar panels supply 85% of the energy needs and keep the electricity bills close to zero.

The key here is to professionally ‘load profile’ your appliances for surge power across all the seasons of the year. 

To ensure that your Solar & Battery consultant (not the company) has a design accreditation with the Clean Energy Council then check by surname or location @ CECfindaninstaller

Geoff Tosio – Better Volt Solar + Batteries: Dorrigo

0422 544 555

Is Solar to blame for high grid voltage?

Yes in some cases, with a big impact for the electrical network.

Solar systems can play a positive or negative role in our electrical grid’s stability, so as long as a Solar system designer stays within the rules then a balanced, cheap, and renewables + storage dominated grid can be built for the future.

The Solar industry is governed by the Clean Energy Council and Australian Electrical Standards however, a large proportion of Solar system designers do not train for any CEC qualifications and instead defer the electrical design responsibilities onto the installation crew.

Grid connected Solar systems are entitled to a set level of ‘grid export’ for leftover Solar power that the building does not use, and this varies due to 3 different factors. The starting point for any design should be the Voltage Rise Calculation or ‘VRC’. (AS/NZS 4777.2 2020). By placing an unrestrained Solar inverter on long and/or thin wires traveling back to the transformer the grid shared voltage can be raised up high, and this risks the Solar inverter performing poorly, shutting down, or in the worst cases it can damage your buildings appliances.

We recently dealt with a client in the Thora valley who was quoted by another company and they had apparently “lodged an Essential Energy grid application” and were “approved for 5kW of export”, but the Solar designer had ignored the VRC (or the cabling was inspected correctly) because we calculated the correct limit to be 3.7kW and installed the system accordingly.

Shortly after installation the inverter signalled (through its online monitoring) that the voltage was getting too high, so the high voltage network was already at the upper limits before the Solar was even installed and the client’s water pressure pump was damaged.

The key to this story is that because we had kept within the ‘VRC’ rules we were able to lodge a complaint on behalf of the client with Essential Energy to rectify the grid voltage (re-tapping the transformer), and the pump was repaired at no cost. Had the higher export level been implemented then the voltage issue would have been blamed on the Solar system with no chance of fixing the issue.

To ensure that your Solar & Battery consultant (not the company) has a design accreditation with the Clean Energy Council then check by surname or location @ CECfindaninstaller

Geoff Tosio – Better Volt Solar + Batteries, based in Dorrigo.

0422 544 555

Designing a Solar + Battery Hybrid

Many people are buying a battery for their home or business, so beware of cheap and unreliable products. 

Battery and Inverter combinations that seem too cheap – simply are, they may not work effectively, rapidly degrade their battery capacity, give no blackout protection, cause a fire, and or cease being supported in Australia before they reach their claimed lifespan.

A high-quality Solar and battery hybrid system will pay for itself within the warranty period but only just, and that’s with the Solar panels doing most of the financial ‘heavy lifting’. So if you’re doing your homework then you’ll probably want a few more reasons to make it worthwhile.

Blackout protection is the most common secondary feature, with fires, storms and floods increasingly causing concerns to home or small business owners, but a lot of products may be too weak to run a realistic number of appliances when the grid goes down, so please do some online research and have an accredited designer go through their design process with you when they come to site, and never purchase only over the internet or phone.

Some companies and energy retailers are spruiking the idea of being part of a Virtual Power Plant program, but they may have variable pricing and daily caps of kWhrs that are allowed to be exported. Remember that you are cycling your battery which is draining your assets value at around 20c per round trip ‘cycle’ so these financial contracts usually don’t stack up. The Australian market operator is talking about changing the rules on the National Electricity Market to allow for more value to flow back to your retailer for dispatchable energy, so this may increase the benefits and competition in coming years. 

The aspects that we consider if we are recommending a battery include:

  • Is the inverter and battery capable of running all of the appliances that we expect to be running during a blackout?  
  • Does the system automatically drop out ‘non-essential’ circuits when the grid blacks out? This makes the battery last effectively.
  • Does the inverter have an ability to set a ‘reserve’ battery level for blackouts? Meaning that even after a cloudy day the battery will have a certain percentage left over. Also consider this when sizing the battery.
  • Does the building have single, dual or three phase power connections, and are there any plans for new high-power appliances? Consider the future of fast charging for electric vehicles.
  • Will the inverter continue to produce Solar energy during a blackout?
  • Most Solar & Battery hybrid systems run at around a 80-85% cycle efficiency, a world award for the best efficiency rating was 92.2% and this was achieved with a Fronius & BYD combination.

There are plenty of battery specifications to consider:

  • The manufacturers length of time in Australia, their warranty, and record of after sales support
  • The price – per kilowatt hour, per cycle life, including the degradation over lifespan.
  • Has there been any Independent testing of the battery’s speed of degradation?
  • Temperature effects – both the upper and lower limits
  • Maximum power input and output ratings – in relation to the above temperature limits
  • Weight / Size / Shape 
  • Components that can wear out or fail – such as a pumps on flow batteries
  • Battery location limitations – where you can store it: Standard AS/NZS 5139:2019
  • Water resistance of the enclosure: the IP rating
  • Recyclability and toxicity of the materials
  • Conflict Minerals used in the battery cells manufacture (Cobalt being the most concerning)
  • Ability to expand the battery capacity with more cells
  • Fire safety – the ability for a battery cells chemistry to sustain a flame. 

Lithium Nickel Manganese Cobalt (LNMC) is a type of serious concern, therefore we recommend and sell Lithium Iron Phosphate (LiFePO4) cells – they last a little longer and are therefore relatively the same price per cycle. Have to look at the 2021 Victorian big battery fire as a prime example, it could not be extinguished for 3 days as the LNMC cells produce their own oxygen – we never want to be responsible for a situation like that.

To ensure that your Solar & Battery consultant (not the company) has a design accreditation with the Clean Energy Council then check by surname or location @ CECfindaninstaller

Geoff Tosio – Better Volt Solar + Batteries: Dorrigo

0422 544 555