Solar vs Generator: The Pros and Cons for Home Energy

Are you exploring sustainable energy choices for your home? We understand that deciding between solar vs generators involves more than just upfront costs. Our CEO, Svilen Voychev, emphasises that going ‘off the grid’ requires careful consideration of various factors.

While businesses and industries have adopted alternative power supplies out of necessity, homeowners may find themselves in a quandary, hesitant to invest tens or even hundreds of thousands of Rands for reliable electricity. The decision-making process involves weighing the pros and cons of two main options: solar energy and diesel/petrol-powered generators.

Let’s dive into the details and discover, with insights from Svilen, in terms of which option aligns with your priorities. Whether you’re leaning towards the eco-friendly allure of solar power or the reliability of a generator, both choices necessitate a shift in mindset regarding how we perceive and utilise electricity. 

Let’s explore the unique advantages and considerations of each, helping you make an informed decision that suits your needs.

GENERATORS

Pros

• Relatively lower upfront cost

• • Depending upon the power output required, a 7kVA petrol-powered generator costs approximately R12 000 and will suit the average 3-bedroomed home. Diesel power is more expensive and is usually available for larger outputs with a 20kVA costing up to R50 000 – which is still cheaper than solar. Smaller, less sophisticated ‘camper’ type units are available but a permanent installation is what is being discussed here.

• Easy installation
  • Providing you have space in your backyard or in a well-ventilated garage or outbuilding, generators don’t take up much space, and connection to the home distribution board is relatively easy although like solar, must be connected by a registered electrician.

• Portable
  • Generators up to about 20kVA output usually come on wheels and can be moved around.

• Instant power

• • Providing there is fuel in the tank, instant power up to the rated output is available immediately.

Cons

• Manual switch over
  • Although generators can be installed with an automatic start when an outage is detected, manual start may be more desirable for the homeowner, who may not want the generator to start in the middle of the night, for example, or during temporary or prolonged absence. This could mean the installation of a change-over switch on the DB board, which has to be initiated at the start of loadshedding, and switch back to grid power when loadshedding is over, coupled with manual start and shutdown.

• Pure sine wave output

• • Cheaper generators typically designed for site use by contractors do not have a ‘clean’ energy output. Modern hi-tech appliances require a pure sine wave electrical supply – such as smart TVs, modems, PCs, and modern kitchen appliances, such as dishwashers and washing machines, to ensure reliability, which means that when choosing a generator, the more costly inverter type is the preferred choice.

• High running costs
  • South Africa’s high and fluctuating cost of both petrol and diesel mean that monthly running costs will be high – for example: during Stage 2 loadshedding – using a 7kVA diesel generator that runs for 60h/month would cost more than R2 500/ month. At Stage 4, this jumps to more than R4 500 at current fuel prices.

• Regular maintenance required
  • Both petrol and diesel engine generators need regular maintenance to run reliably. An annual cost could be around R1 000.

• Finite life span
  • Just like any mechanical equipment, generators have a lifespan. A regularly maintained unit will probably last up to 10 years before replacement is required.

• Noise
  • Unless you buy an acoustic enclosure or the generator you choose has one as standard, the noise will be a constant issue, not only for yourself but also for neighbours. A further issue is that an enclosed generator must have adequate ventilation, which could be an additional complication and cost issue.

• Space requirement

• • Although relatively compact, generators especially with acoustic enclosures need a fair amount of accessible space. An outdoor, free-standing 7kVA unit with an enclosure needs at least 1m3; but don’t forget that now and then it will need maintenance – either by a travelling mechanic or by taking it to the local dealer. Generators are heavy, can you manhandle it into the back of a bakkie or will your SUV take the load?
• Pollution
  • Fumes for both petrol and diesel engines are toxic and can kill you! Will the prevailing wind drive the fumes into your living area or your neighbour’s yard?

SOLAR

Pros

• Automatic, seamless switchover during loadshedding.
• Inverter control system optimises grid electricity consumption saving thousands of Rands per year.
• Fit and forget with maintenance limited to periodic cleaning of the solar panels once a year, depending upon location.
• Nil battery maintenance
  • Lithium-ion batteries require no maintenance but some lead acid types do.

Cons

• Very high installation cost
  • There are several variables to take into consideration depending upon the desired output of the system such as the number of solar panels, the size of the inverter and the number and size of the batteries. The cost for a regular-sized three-bedroom house would have a starting cost of around R150 000 but would exclude connections to electrical geysers, cooking hob and ovens. Generally, any appliance or device that has a high consumption electrical heating element will be excluded from a solar installation except a kettle, toaster, microwave or air fryer as its use with other appliances can overload the system.

• Space requirements and installation
  • The inverter cabinet can be quite large – typically 0,6m x 0,8m x 1,4m high and must be located in a dry, well-ventilated place – usually a garage, and can be free-standing or wall mounted. Cabling from the solar panels into the inverter cabinet and out to the distribution board must comply with SABS standards of installation.

• Component replacement
  • Solar panels and particularly batteries don’t last forever and their replacement is expensive but batteries should last at least 10 years. Batteries can cost R30 000 or more depending upon size and number.

• Reputable installers
  • It is vital that a homeowner doesn’t choose a solar installation based on price alone but on the reputation of the installer. ‘Buyer beware’ is the watchword as there are still several ‘bakkie brigade’ or ‘Johnny come lately’ installers who aim to take advantage of the boom in solar to make a quick buck with shoddy workmanship and sub-standard equipment and components. 

• Discipline

• • Homeowners with solar installed have to become more savvy as to how the system works and its limitations. Knowing which appliances can be used together to prevent an overload is imperative. Knowing the output of your system and the rough consumption of your appliances will ensure that overloads don’t occur. Don’t put on the electric kettle, toaster, microwave and air fryer at the same time, if your inverter output is 5kWh.

At Valsa, we have been a reputable supplier of solar system components for the past 14 years and provide advice to homeowners and training and skills transfer to would-be-installers. We also carry a list of experienced installers, which is available to homeowners wanting to embark on solar power as a reliable supplement to an intermittent grid.