Going off the grid with Solar

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Going off the grid is the buzz word in the industry at the moment. Most of my customers start their conversation with that phrase, a smile on their face and a budget of R50 000. Expecting the process to be quick, efficient, not have any limitations and not cost them too much. Normally by the end of the conversation they’re a little more sombre about the solar prospect.

Going off the Grid with both electricity and water is a great idea. It really is something that I strongly advocate for. Energy Independence and water independence can really make a huge difference to your monthly bills as well as your lifestyle when the inevitable power cut, load shedding, maintenance or El Niño phenomenon hits.

Today I am specifically going to talk about solar power. Education on this topic is very limited, in general people don’t understand electricity very well and their consumption of it even less.

These are the steps you should take to prepare your home for solar power.

  1. Do a mini audit of your energy consumption: You don’t need anything fancy. Set-up a basic spreadsheet, or download one from the internet. There are plenty of them available. (Make sure it’s 230V if you’re in South Africa). Take the time to write down the information off all your electrical appliances. Then record how many hours per day you’re planning on using that appliance. There are 2 important things to remember when making this list.
    • Electricity over time: Find out how much power you need by making the list and the hours (Alternatively you can use your electricity bill – take an average over a few months, including winter and summer).
    • Peak Electricity demand: You need to determine peak load. Not only do you need make sure you have enough power for your home, you also need to make sure you have enough when you turn everything on you want to.
  2. Start making the small changes first: The most common misconception about solar is that you can just put it on your roof with some batteries and you’ll run your house. You have to reduce the electricity demand. This is absolutely necessary before you even consider putting in Solar. If you have made your mini-audit as mentioned above, you’ll see that you’re probably using a lot of power.
    • Change your light bulbs to LED: This is the cheapest step on your journey to power independence. There are so many LED options available now and the price is always coming down. A standard bulb can use 100w per hour, whereas an LED equivalent may use 5w. So the power you use in 1 night might be enough to power them for a whole month if you change all the bulbs. Yes, LED is more expensive, but the price is currently anything from R50 – R100 for a down-lighter bulb. They’ll have paid for themselves within months due to the MASSIVE energy saving.- 100w bulb run for 4 hours per night = 400w p/day = 12 000w p/month (12 kWh) = +/- R 20 p/month.
      – 5w bulb run for 4 hours per night = 20w p/day = 600w p/month (0.6kWh) = +/- R1 p/month.As you can see, simple maths shows how quickly you’ll pay off the new bulbs.
    • Change your Geyser: This is one of the most power hungry things in your home. You need to change this to solar or gas. Traditional geysers can use 2 – 3kW when in use. While they’re becoming more efficient they still use loads of power. Solar is a good option, but the best in my opinion is gas. It is instant heat. It is only used when needed and doesn’t go cold, or need to top up with an element.
    • Cooking: much like geysers, ovens and stoves use loads of power. It’s important to change this to gas. In South Africa this is a 2 birds with 1 stone situation. You’re going to reduce the amount of solar (in terms of storage) & Eskom you need, but you’ll also be able to cook if there is a power outage.
    • Air-Conditioners: This is a tough one. You get different types of heating and cooling devices, but air-cons are the dominant, and they use lots of power. If you are going to use air conditioners, make sure that they’re the inverter type. They use about a 3rd of the electricity of a conventional air conditioner.
    • Pumps: Pumps also use lots of power… I know the list is getting quite long. Pool and pond pumps are the main culprits here as they run for so many hours per day. Solar pumps are the answer here, take them off the grid, save money on your current electricity bill and substantial savings when you put in your household solar system.

Household Solar System

I am only going to discuss what you need for your solar system based on a Hybrid System. This is my personal preference, what I have installed in my house.

Why Hybrid? A hybrid solar system gives you the best of both worlds. You’ll use as much solar as possible and it will be supplemented if needed by mains electricity or a generator.

What you need?

  1. Hybrid inverter
    • Built in MPPT charger (Charges the batteries optimally – Multi power point tracking).
    • Inverts the power from DC (battery power) to AC power (230v like you use in your home)
  2. Solar Panels
  3. Solar Panel mounting system
  4. Cable from panels to hybrid inverter
  5. Deep Cycle Batteries (Preferably AGM, Gel or Lithium)
    Battery technology varies a great deal and so do the prices. Having used a number of lead acid products, I don’t believe they’re ideal for a solar system due to their short number of cycles at higher depths of discharge (DOD). Below is a list of batteries in order of their expense and cycles. (Sorry if I’ve missed any!)

    1. Lead Acid (cheapest)
    2. AGM
    3. Gel
    4. Lithium (most expensive)
  6. Battery Stand
  7. Installation
    Installation can vary in price depending on the installer and the cable used. Keep in mind that Direct Current (DC) requires a lot thicker cable and hence is more expensive. This applies to both the cabling to the panels and to the batteries.

At the time of writing this (Jan 2018) you’re looking at a price of +/- R 120 000 incl VAT for a fully installed hybrid system that will be suitable for most standard 3 bedroom homes, provided you’ve taken into account the above mentioned energy saving tips.

So what’s the pay-off on a system like this? Well, that’s difficult to say as you have to factor in the rand savings, the convenience of having power even during an outage and what tariff increases will be approved for Eskom each year. On a very basic level, a system such as this will save you R 1 200 per month currently. Taking into account tariff increases at 10% per annum, you’re looking at a +/- 6 year pay off period. Keeping in mind that you’ll also be able to sell your house for more and you’ll always have power. It is a long term project, but one of the most satisfying.