Off-Grid: What Does This Really Mean?

Going truly “off-grid” can be an expensive exercise, as you need to cater for the worst-case scenarios of weather and energy consumption. Even if budget isn’t a constraint, your aspirations may be tempered by available roof space – a meaningful off-grid solar system requires significant rooftop real estate.

Becoming “grid neutral”, where you rely on Eskom for peak usage and periods of bad weather, is much easier to achieve. This would often be achieved through a phased approach, first ensuring that you have made your home as energy-efficient as possible by replacing outdated, energy-hungry power appliances and equipment with the most efficient alternatives, and then building your power system, either in one go or in steps as budget allows or circumstances dictate. For example, one may opt to invest in a battery backup system if power security is a pressing issue, and add solar panels at a later stage. It is of absolute importance though, that the end goal is understood, to ensure that the right components are installed from the beginning.

Solar panels have now become very affordable, and the cost of a good inverter also won’t break the bank. The key to becoming substantially grid-independent for residential homes is battery storage, as we use most of our electricity in the early morning, and evening, and not while our solar systems are producing most of their energy.
Until recently, this was not economically viable. Cheaper “deep cycle” lead acid batteries have very short lives when cycled deeply or frequently, and the best lead acid batteries (e.g. Hoppecke’s OPzS batteries) are prohibitively expensive, require maintenance and a lot of space in a secure, ventilated room.

 

Much of this has changed as Lithium Ion battery technology – and particularly LiFePO4 – has become much more affordable.
These batteries offer very long lives (more than 3000 cycles / 10 years, with warranties to match), very deep discharge, small footprint and very high round-trip charge-discharge efficiency, and the ability to scale the battery over time.
A further exciting development is the (limited) availability of “2nd Life” LiFePO4 batteries (see other articles on this page explaining the 2nd Life concept), which enhances the Lithium battery value proposition even further.

“The key to becoming substantially grid-independent for residential homes is battery storage, as we use most of our electricity in the early morning, and evening, and not while our solar systems are producing most of their energy.”

So, where does this leave us? Well, becoming largely grid-independent is no longer a pipe dream,- my own home is good example of this:
I have a medium/large (~400sqm) family home with pool, koi pond, air conditioning and the usual goodies. My wife runs her business from home, and my daughter is a student, so there are various computers, printers, etc in use. My grid electricity consumption for February 2019, thanks to a full week of rain, was 50kWh. Under most conditions, I “buy” less than 1kWh of grid electricity per day.

The house makes use of solar water heating, with a 7kWp solar system providing for the electric requirement. I use a 10kWh 2nd Life Lithium battery for storage, which is just enough for the summer part of the year, but which will be left a little wanting as we move into the longer winter nights.

Watch this space for a write-up on Balance of System costs, and why it’s important not to cut corners on system spec.

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Reinhardt Nel
Reinhardt Nel
2024-05-07
Professional service, great installation team, awesome aftersales service
Mark FORTUNE
Mark FORTUNE
2024-04-25
Greenhouse lives up to its promise of excellence.From the first phone call to look at their services we were treated with the utmost professionalism.All steps of instalation were communicated on a daily basis and Patrick our consultant was available on call anytime we had any queries. Greenhouse comes with a five star rating from us.Thank you to the whole team !
Megan D'Arcy
Megan D'Arcy
2024-04-19
Everything about Greenhouse Solar is amazing. The initial consultation, design of the system (set up for scaling up in the future), and after sales service is exceptional. The 24/7 helpline is handy to have for troubleshooting, although, due to the high-end components used (Victron, FreedomWon, JA panels), issues have been non-existent since I had the system been installed. The annual maintenance call-out is a great value-add, too. With solar becoming an essential option for many, it's critical to get the right advice and have the installation done to code. I highly recommend Greenhouse.
Horst Frenzel
Horst Frenzel
2024-03-13
Super fast response to the damage caused by a lightning strike, followed up by quality repairs and excellent workmanship. Thanks for the excellent service!
Irene Cowley
Irene Cowley
2024-03-01
Excellent service. The guys are very knowledgeable. They can help you work out the best ways forward to meet your budget and your needs. The installation teams are excellent. Work professionally and efficiently. We have been most impressed over many years now.
Sergio Coelho
Sergio Coelho
2024-02-26
The folks at GreenHouse did a sterling job installing an upgrade to my home solar system. They knew that it would be challenging to sort out the comms between the Victron equipment and the SMA inverter but in the end their team made it look easy.
Hennie Meeding
Hennie Meeding
2024-02-24
Absolutely satisfied with the service received from GreenHouse. From quote by Ethanne to installation by Mike and his team all were done professionally and efficiently. I highly recommend GreenHouse to walk the solar journey with you… After a year of absolutely no issues we recently had a lightning strike and GreenHouse had to assist to get us up and going again. It turned out that the only item that needed replavement was the controller - and this was replaced in no time…. Yes I would say Greenhouse is “fast and knowledgeable” in this new market segment where it is difficult to choose a supplier!.
lisa skinner
lisa skinner
2024-01-23
Notes: Feedback. From when I had my first engagement with Patrick to investigate alternative energy solutions for my house, through the quoting process, the installation itself and after installation follow up meeting I have been so impressed by the professionalism of Patrick and the full team. It was such a wonderful experience and completely painless from a customer point of view. The remi ders of what I needed to do, the scheduling and generally the full experience I had with Greenhouse was exceptional. I am so glad I went with yourselves. What a great and professional team. Rgs Lisa