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Is Off The Grid Living Feasible?

By Edited Aug 21, 2016 2 4

Five years ago, nobody had photovoltaic (PV) panels on their roof, today it is a common sight as more and more people live off the grid. I see daily on social media, like Facebook, many companies starting up in South Africa due to the country’s unreliable power supply. Suddenly the average person is able to identify what a DC to AC power inverter is and speak of deep cycle batteries along with the latest TV series they are watching. The country is currently in a power crisis with predictions that it will take two to three years to fully recover. Meanwhile as entire suburbs and towns are plunged into darkness, the middle-income citizens are cutting the cord and buying their freedom. Environmentally-friendly, clean, reliable, off grid power is rapidly being fitted into South African homes at an unprecedented rate due to South Africa’s power utility, Eskom, not providing a reliable electricity supply and hiking up the electricity prices by an approved 12.69% for 2015/16.[1]

Is Off The Grid Living Feasible?
Credit: Sudocream

New cabins at ‘The Travelling Tortoise’ being erected and fitted with an off the grid power system.

The Alternative - Off The Grid Living

The term ‘off the grid’ (OTG) refers to living in a self-sufficient manner without the reliance of one or more public utilities. Normally one will use the term specifically if a house is not connected to the national electrical grid and the home has a stand-alone power system however the term does apply to not being reliant on any traditional public utility services. A true off the grid house can function completely independent of municipal water, sewage, natural gas, electrical power or any other utility services.

The idea in recent years of off the grid homes has gained popularity with USA today reporting on 13 April 2006 that as many as “180,000 families were living off-grid”. Due to third world people not having the opportunity to connect and be on the grid, in 2013 it was currently estimated that 1.7 billion people live off the grid worldwide. These people must make use of alternative energy sources such as paraffin to provide light, heat water and cook food.[2]

Why Do People Choose To Live Off The Grid?

There are multiple reasons for why people are choosing off the grid living with the two main ones being long term financial savings and to lessen the impact one has on the environment – the green living, lower carbon footprint lifestyle. Other reasons could be that homes are built in rural areas where there is no infrastructure in place to connect to the grid. Normally, for most of us, these two main reasons alone do not justify creating an off grid home but here in South Africa, where I live, there is a very strong third reason prompting South Africans to go off the grid. South Africa’s state utility, Eskom, is battling to meet the country’s demand for power and has implemented an aggressive load shedding schedule to prevent the grid from collapse. Due to the unreliable power supply, where I have personally experienced power outages of 2-3 hours daily on most days of the week, South Africans are becoming increasingly self-sufficient. Off grid power systems are being built into existing homes and are being considered for new homes. In fact new homes being built today in South Africa use this as a selling feature.

Building An Off Grid Power System

Finding The Balance - Supply Versus Demand

Living off the grid is not such an easy thing to do and will definitely have an impact on your lifestyle. "You can't get off all of the grids all the time," says Nick Rosen, founder of the Off-Grid website. "It's a question of which grids you choose to get off of and in what way and for how long."[3] Before you go out looking for a new off grid power system, powered by the sun, you should probably be made aware that these systems are not cheap, especially in the short term. The main cost components, the photovoltaic (PV) panels and the deep cycle batteries are expensive and need to be seen as a long term investment. Sizing your off grid power system, one needs to look carefully at the home’s energy demand and supply the appropriate system to match.

Consider all your electrical requirement options. Going off the grid is no game, your energy consuming ways must change, and you have to be aware of energy consumption of all appliances. Whereas before you might have used electricity to heat your home, provide hot water and cook your food, these high energy consuming functions can be delivered by other energy systems. It is estimated that 43% of electricity usage is used for water heating. By installing a solar geyser to your home, the demand for electricity can be reduced drastically while the sun is shining. To complete your water heating requirements when there is no sun, the water heating system can be combined with a gas water heater. This setup is completely electricity free and can help scale back the size of your self-sustaining electrical power supply.

Wall insulation and roof foil for off the grid living

 

Following the above principle, the home’s space heating requirements can be taken care of by an indoor fireplace that burns chopped wood. Modern slow burning fireplaces can control the rate of combustion by choking the fire of air once the fire is going. A long stainless steel chimney flue gives extra heating capacity and is an effective means to warm your home. Roof and wall insulation is an essential must and an amazingly energy efficient product to keep your home both warm in winter and cool in summer.

Finally when it comes to cooking, a gas stove and gas hob is by far the most popular and preferred means to prepare food as well as being energy efficient. All these alternative energy systems can lower your home’s demand for power.

Curbing Energy Consumption

Some of the worst energy hogs to look at are the washing machine and the refrigerator, two appliances that most people cannot avoid to be without. Washing machine usage must be used sparingly and preferably performed when the batteries are topped up. By doing cold wash cycles the washing machine’s heating element is not used which can be a great energy saving. If you really must wash clothes with hot water, you could plumb the hot water from your gas geyser directly to the washing machine.

Consider scaling back on the size of your refrigerator; it can make quite a difference. Place the refrigerator in the coolest place in your home and out of direct sunlight. Not everything needs to be kept in the fridge. The lifestyle lends itself to healthy living with very few perishable items needing to be kept cold. A small AAA energy rated bar fridge can have amazingly low energy consumption of 146kW/year, with a conservative duty cycle (compressor running) of 30% equating to roughly a demand of 60W on the power system!

3W LED down lighting
Modern technology has made massive ground when it comes to lighting. Fluorescent tubes were great on saving power but LED technology is now affordable to everyone and has truly made lighting your home environmentally friendly. The efficiency of LED downlights is staggering with current LED lights consuming a mere 3W of power compared to a 50W halogen downlighter. Both lights emit the same amount of lumens yet the LED downlight does the job for 94% less power. And just to put the cherry on top, LED downlights will last around 50,000 hours, that means you will only be changing them every 20 years. On the subject of LED technology, an average 32” LED TV will use about 75% less energy than an identical sized CRT TV. So there are no questions as to why the new flat screen LED TV needs to be mounted on the wall of your home.   

Case Study: Off The Grid Cabins In De Rust, South Africa

Where the sun shines 330 days per year, De Rust, a small village in the semi-arid desert of the Karoo, has an almost perfect weather for generating solar power. I personally know the owner of the ‘The Travelling Tortoise’ (TTT), who is currently building and installing off the grid cabins. His vision is to create an almost self-sustaining eco–friendly holiday experience which is off the grid. The cabins are built on the hillsides which have spectacular views of the mountains. The cabins are built from rustic planking, with a corrugated sheeted roof. The cabins are supported on 40 concrete sunk poles deep into the ground.

The cabins are fitted with four 280W Photovoltaic (PV) panels mounted on the sun facing fixed pitch roof which supply the cabin’s electrical power requirements. The panels supply 24V DC to a Charge Controller which is installed inside the cabin. The Charge Controller regulates the incoming power and is able to give vital information to the charge levels of the deep cycle batteries, the current output voltage of the batteries and the temperature of the solar panels.

Photovoltaic (PV) panels on cabin roof at 'The Travelling Tortoise'
From the Charge Controller, six 12 V, 102Ah Excis deep cycle batteries are paired back to back and wired in parallel to store the energy for use. A TES regulator protects the deep cycle batteries from overcharging and excessive discharge. The charging rate of these batteries should be roughly 0.1 times their rated capacity in Ah for a maximum of 15 hours. Therefore these batteries with a capacity of 102Ah should be charged at 10.2A. In this situation, with the rated power of the PV panels being 280W, the charging amps are at best 11.66A on a day of perfect sunshine.  It is very important to use the right size PV panel to match the storage capacity. The batteries can be cycled down to 20% charge however the best lifespan versus cost method is to keep the average cycle at about 45% discharge.[5] The manufacturer of this particular battery specifies a performance of around 500 cycles at 40% ‘depth of discharge’ (DOD) at 25 degrees °C.
12 V - 102Ah Excis Deep Cycle Batteries used for Off Grid Living

The beauty of this set up is that the power system can be upgraded by adding additional PV panels and/or adding more batteries in parallel to the existing battery bank for extra storage capacity. Since the cabin is generally to be used for a short getaway, probably just a weekend, the power requirements are expected to be low. The battery bank’s capacity is well oversized and can comfortably provide enough power during a few cloudy days. In fact a discharge from full to 50% discharge on this power system, drawing 10A continuously, would take around 30 hours.

A 2500W pure sine wave inverter converts the 24V DC power supply from the battery bank to a 220V AC supply which can be used by standard 220V household appliances.

2500W Pure Sine Wave Power Inverter For Off The Grid Living
A basic calculation shows that the maximum amperes that can be delivered by the system is 11.36A. If the demand is greater than this maximum rated current, the voltage will dip and the household appliances will likely not work properly. To keep this from occurring the distribution board is simply fitted with a standard earth leakage breaker and a 10A circuit breaker. The whole independent power system was installed by a qualified electrician, which will provide an electrical certificate once completed.

The cost components of this mini off the grid system can be broken down as follows and does not include the standard items found in a regular electrical reticular system. The table is simply the additional cost incurred by having an independent stand-alone power supply for one cabin.

 

Equipment

Number

Unit price

Total

24V Photovoltaic (PV) Panels280W

4

R 4200

R 16 800

20A 12/24Volt Ecco solar controller

1

R 400

R 400

12V Excis Deep Cycle Batteries 102Ah

6

R 1800

R 10 800

0 to 60A TES Regulator

1

R 730

R 730

2500W Pure Sine Wave Inverter

1

R 7300

R 7300

Y plugs for PV panels

4

R 85

R 340

Male solar panel plugs

6

R 18

R 108

Female solar panel plugs

6

R 18

R 108

Roof Clamp

1

R 1 900

R 19 00

 

 

TOTAL

R 38 486

@12.36ZAR to 1USD =

 

 

USD 3113

Problems Faced In The Future

Maintaining an off the grid power system requires a lot of capital initially for the key items but once it is installed the running costs are basically zero. Most salesmen will have you believe that the power system will last a lifetime but unfortunately the photovoltaic (PV) panels will start to degrade through aging. The PV panels are normally sold with a performance guarantee for 20 to 25 years however by the 25th year the panel will be delivering around 75% of its original power output. This is not a massive loss in potential power production but one should consider replacing the panels when the batteries do not become fully charged anymore.[4]

The lead-acid deep cycle batteries have a typical efficiency of 85-95% and only a small power loss is expected when charging up the batteries. The lifespan of a deep cycle battery is very dependent on how they are used, maintained and charged. Even the temperature affects the battery’s lifespan. Deep cycle batteries used in conjunction with PV panels are expected to last anywhere from 4 to 10 years. Replacement of the deep cycle battery bank is an inevitable future cost that the owner of an off grid power system must face.

Is It Feasible?

Living off the grid in terms of having a self-sufficient electrical supply is not easy and it will require a lifestyle change due to not having ample power. You will become acutely aware of the weather patterns and become grateful the sun is shining today. Power management will be continuously in the back of your mind when switching on any appliance. These things are not bad, just something one must deal with in order to prevent the utility bills arriving in the post! In South African there are currently no regulations in the solar industry and the quality of the equipment varies wildly. Most of the PV panels are coming out of China! You really must do your homework and see the solar supplier’s equipment working elsewhere before making a commitment to live off the grid. There have been reported cases where the PV panels melted in the hot Karoo sun.

I took what could be easily be seen as the most minimalistic off the grid power system, in an extremely sunny environment and found that it is feasible to live off the grid for the most part. However, when it rains for a week, having a backup generator or power utility connection to fall back on might not be a bad idea.

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Comments

Aug 10, 2015 11:19pm
HonestAbe
Great article! It never occurred to me that with new lighting setups less energy is used and combining that with higher efficiency solar panels gives great results. I was aware of both but combining these advancements will make better off the grid living! Thanks!
Aug 11, 2015 3:11am
benjaminellis
Thanks, the LED lights are super energy efficient and last a very long time, it would be ridicules not to take advantage of their energy savings - especially in an off the grid setup.
Sep 17, 2015 4:09am
ormseobangalore
nice one
Sep 18, 2015 12:01am
benjaminellis
Thanks for reading, glad you enjoyed it!
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Bibliography

  1. "Latest news on the 2015/16 tariff submission." Eskom. 13/07/2015 <Web >
  2. "Off-the-grid." Wikipedia. 13/07/2015 <Web >
  3. John Platt " Going off the grid: Why more people are choosing to live life unplugged ." MNN.com. 14/11/2012. 13/07/2015 <Web >
  4. Charlie Fripp "Loadshedding strikes again: is it time to go off-grid?." HTXT Africa. 9/01/2015. 13/07/2015 <Web >
  5. "Deep cycle battery." Wikipedia. 13/07/2015 <Web >

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