How To Take A Factory Off-Grid With Solar And Storage

SolarQuotes founder Finn Peacock chats with Glen Morris from SolarQuip about an interesting project involving taking a small factory off-grid with solar and storage using a very clever approach.

SolarQuip has been involved in a few “grid defector” projects over the past 4-5 years. Mr. Morris says people who leave the grid are often doing it for ideological reasons, but never for economic ones.

The commercial property job evolved out of SolarQuip upgrading a residential system. That customer left the grid and liked it so much he thought he’d do the same with his small factory.

It isn’t heavy industry by any means – daily consumption at the factory is around 96 kilowatt-hours a day and SolarQuip has sized a system to take it off-grid based on the factory’s very reliable load. However, there is still a safety net – the customer is  not turning off his mains supply completely and there is a changeover switch.

The Rectifier Workaround

The project has an option for installation of generator backup, but also using the legacy grid via rectifiers that could be utilised to recharge the batteries in a worst-case scenario.

“Was it hard to convince the grid [operator] that it wouldn’t be interactive – that it wouldn’t feed power back into the grid, and to treat you differently?” asked Finn regarding the use of rectifiers.

It seems it’s a non-issue.

“Frankly, we don’t even have to ask them,” said Glen. “If you install a new air conditioner in your office, you don’t have to ask the grid operator is it OK for me to put in an air conditioner. Well, a rectifier is a load.”

“Death Spiral Accelerator”

The term “death spiral” was coined in relation to grid defection leading to a point where utilities discover price increases to be ineffective in raising sufficient revenue to cover their total costs.

Mr. Morris quips this type of system is a “death spiral accelerator”.

“It makes it possible to start to move away from the grid and use it more and more as a legacy [system].”

This type of arrangement can also be valuable where energy security is a significant concern – not just in terms of relying on renewables, but also the potential of grid events interrupting supply.

The batteries used for the system are a sealed lead acid (SLA) GCS model from China, a brand Glen professes to know little about as they were supplied by the customer and are not covered under warranty related to the work.

Asked if he would recommend sealed lead acid for the application, Glen said probably not. He would prefer lithium-ion because of its characteristics, such as being more tolerant to partial state of charge cycling.

Further details of the system are mentioned in the video.

Partial Grid Defection To Gain Popularity

Glen says he is seeing more interest from home owners unable to install more solar power capacity due to Distributed Network Service Provider (DNSP) restrictions who are looking for options – and a legal workaround is the addition of a non-grid interactive system.

This and much more was further discussed – it’s well worth the 18-minute time investment to view the whole video.

About Michael Bloch

Michael caught the solar power bug after purchasing components to cobble together a small off-grid PV system in 2008. He's been reporting on Australian and international solar energy news ever since.


  1. Just bought a Tesla battery Can you use a rectifyer for my reverse heating system to give me more Power access
    Had the system for a week still can’t full the battery due to using the heater

    • Ronald Brakels says

      Hi Jim

      I’m guessing you want to install solar panels for your reverse cycle heating system and use a rectifier so you won’t have to worry about DNSP limits. This definitely can be done and the panels could provide energy for cooling in summer. Getting this system installed would still be a little expensive. It would be the cost of a small solar system plus a rectifier. It won’t be able to send electricity into the grid for a feed-in tariff, but it will increase the amount of energy your existing solar system can send into the grid. As costs come down this kind of set up may be common in the future.

    • I have the same problem, I bought 9 Tesla’s yesterday for my kids and they hate them! I was hoping you could find Michael Bloch for me, and get him to tell them how nice and lucky they are to have such cars.

      Thx, Elon Musk

  2. Lawrence Coomber says

    Finn: Commercial / Industrial /Factory Standalone Off Grid PV system designs are certainly happening and will become very popular going forward.

    Adding a Standalone Off Grid PV System to a factory or commercial premises s a straight forward process and can be done most cost effectively using a DC Coupled PV + Storage design and a Standalone Off Grid PV Inverter (or multiple depending on the requirement).

    There are several approved Standalone Off Grid PV Inverters on the CEC/CER approved inverter list both 1 phase and 3 phase from 20 KW up to 100 KW designed to accommodate the above scenario cost effectively and reliably.

    A common scenario often found in (day time) commercial factory type operations, relates to the daily duty cycle requirements of specific equipment (loads) at the premises. These type of operations may even have their power requirements fully satisfied by the Standalone Off Grid PV system alone, and not require any other power source such as batteries to meet their power needs.

    For managing small demand overnight loads at factories, a small DC coupled PV/Battery Storage System can be easily added to manage loads such as security lighting and any other overnight use equipment such as fridges etc.

    A typical example of a larger Standalone Off Grid Specific Load Circuit would be a Golf Course that includes a large irrigation pump (or several). This scenario is perfect for adding a separate Standalone Off Grid System for the customer to service these specific loads only, and no batteries are required in this sort of scenario. It is easy to extrapolate this concept to any other equipment (loads) as well.

    There have been virtually no commercial or industrial premises that I have come across that cannot benefit substantially by installing a Standalone Off Grid PV – Specific Loads system (with or without battery storage – depending on the premises load circumstances).

    Lawrence Coomber

  3. Lawrence Coomber says

    Further to my earlier comment:

    I will point out that system designers / installers entering this space must be CEC endorsed for bothe Standalone Off Grid Design and Install as well as Storage, and also be up to speed with how to properly manage dual power system at a single premises in accordance with AS3000 and other applicable standards.

    Most important.

    Lawrence Coomber

  4. What’s all this talk of rectifiers?

    That sounds like people who don’t really know what they re doing.

    DC coupled? Seriously?

    Sunny island’s with AC coupled Sunny Boy units is so much more elegant than the rats nest of Sp Pro’s etc etc.

    CEC accreditted? yeah right…add the rebate to the price to scam the poor mums and dads…fit breakers that burn houses down….etc etc

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