There are three main types of PV solar installations that are possible:
GRID TIED:This systems main components comprise of the solar panels and inverter. It is designed to reduce your consumption from the grid, however should the main electricity grid fail it will switch off irrespective of whether the solar panels are producing voltage or not. This is the most cost effective method of reducing your monthly electricity account.
HYBRID:This systems main components are the solar panels, inverter and batteries. This is the system to use when wanting some autonomy in the event of the main electricity grid failing. Dependant on which inverter is used; this system will also continue to produce power from the solar panels during the day if the main electricity grid fails. In order to do this correctly you must either install a inverter that can run all loads on the premises constantly and then only supply to critical loads during a main grid failure or a smaller inverter can be installed that supplies certain circuits and these circuits will remain on when a power failure occurs. Either one of these options does require some work to be done on the distribution board in the premises. Due to the fact that batteries are used in this type of installation the cost of installation does increase.
OFF-GRID:This system is based on the same configuration as the hybrid system, however normally requires more solar panels and batteries so as to enable you not to have to rely on the main grid supply at all. We often find that for places like game lodges it is sometimes more cost effective to run a inverter with batteries for powering fridges and other small appliances, whilst running a regulator with MPPT and batteries to run 12V L.E.D lightning.
GENERATOR VERSUS SOLARGENERATOR VERSUS SOLAR Whilst a generator is a quick fix solution to having no power for a couple of hours, and may be cheaper to install, they require periodic maintenance and testing, and are noisy and create pollutants. Keeping this in mind, there are some high consumption electricity users that have no choice but to use a generator as installing a solar system with batteries to allow even a few hours autonomy would bankrupt them. There is however a solution to this, you install both. By installing a solar system with no batteries, whilst having a generator input on the inverter, you get to reduce your grid consumption during the day and have the generator on standby for those times when the grid is not available. This reduces the overall cost of the solar system and allows for lower electricity accounts to your service provider.
WHAT WILL SOLAR SAVE MEWhilst there will be a significant outlay on a solar system once installed it does start to pay for itself. Depending on your current consumption, how much you want to reduce grid consumption by and whether you want batteries it can begin to pay for itself from year 7 (consumption and offset dependant). You can reduce your consumption even further by installing energy saving devices like L.E.D globes in place of your current globes which will also allow you to install a smaller inverter, saving even more on initial costs. Let’s do a rough savings analysis. We all know prices on goods and services go up every year so let’s work on the assumption that your electricity provider will increase the cost of supplying you power by 10 percent each year and your solar system will save you 40 percent as you have installed a system purely to try reduce costs. You will learn to use your appliances during the day when you are getting solar power and run the basics at night when you are paying for power. We do know that a quality solar panel can only produce to their peak for about 20 years and then they will start to degrade, however they should last at least 25 years and continue to produce power even if a bit lower than when they were installed. We will start with a base figure of R 1000 per month or R 12000 per year that you pay to your electricity supplier
COST OF POWER PER YEAR
SAVINGS PER YEAR
TOTAL COST OF POWER OVER 10 YEARS WITHOUT SOLAR: R 191237
TOTAL SAVINGS WITH SOLAR: R 76419
So as you can see it does make a difference. If you consume more than the R 1000 per month as we have used in this exercise then the returns may even be sooner than expected.