Back in the early days, the introduction of solar PV systems as a consumer good turned out to be an issue. To be of practical use for the typical household, solar energy uses photovoltaic panels to convert sunlight into electricity, and this has previously been an expensive technology.

 

The advantages of solar-powered homes and residential buildings are obvious: solar energy is infinite (at least for the next 5 billion years), provides clean energy without emitting greenhouse gases, and that it save households' money on their electricity bills.

 

The benefits of solar PV systems for households far outweigh costs. See benefits of going solar here.

 

But before you go out and install a solar PV roof system, there are factors to consider – and cost is just one of them. These factors are the so-called 'prefeasibility' factors before any financial benefit is gained.

 

Here in this article, we consider the most important issues that need to be addressed. The use of solar energy is a very “green” solution and a potentially worthwhile investment, but it is not as straight forward as getting energy from a conventional power grid.

 

Maintenance

Turning your home into a little power plant that requires more than using a conventional power grid.

 

Solar panels have no moving parts. They are a part of a complete fixed system. So, once they are installed, it is pretty much a 'set and forget' exercise - there aren’t many things that can go wrong. Almost the only one a house owner should do is to keep the panels clean. That’s important because too much dust and bird droppings, and even ice on the panels can reduce the amount of sunlight. Dust accumulation on the panels can reduce the amount of electricity produced by the system by as much as 10 %.

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Today, all inverters have a monitoring app to see solar generation. So you can easily see with your smartphone how your system is performing day in day out. Any future system fault, your installer should be able to come out, look into it and perform any service repairs.

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Surroundings and Landscape

The location of your house has a great impact on your solar energy efficiency. It’s an obvious problem – solar power depends on sunlight, so things like tree shadows and neighbours with two-storey to high building shadows will be a setback.

 

This is an even bigger issue than some people realise. Different types of panels differently react to shadows. Thus, to build a solar-powered house, it is necessary to make sure that there is no shade on the roof panel during the most sunshine hours in the day (usually from 10 a.m. to 2 p.m.) and preferably during all solar hours. The more hours the panels are exposed to full sunlight, the more efficient the production of free electricity will be.

 

Achieving the greatest efficiency can mean trimming or completely removing trees on your site, installing tilts to get the best angle and so on. And if your home is surrounded by high-rise buildings that block the sun, then that might be the 'deal-breaker' in whether you decide to proceed with solar installation.

 

Insolation

 

Insolation, is a measure of how much solar emission will fall to the ground in a given area over a given period of time. This is usually measured in kWh / m2 and it will show you how much sunlight will be available for your solar panels to turn into electricity. The higher the insolation value in your region, the more electricity each of your panels will be able to generate. A high insolation value means that you can get more energy from smaller panels. A low value means that you might end up spending more to achieve the same output power.

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So do you have solar panels predominantly facing north-west? If not quite, this simply means that you will probably need more panels to achieve the same output power.

 

See the Australian PV institute webiste to get an estimate on how much solar radiation you can get on your roof – via SunSPoT. The online system can be slow.

 

Coverage

Contrary to what most people think, the size of a rooftop solar system has nothing to do with the size of a house. Instead, only two parameters should be considered: insolation, as above; and the amount of energy you need (or consumption).

 

To get an estimate of how big the system you need, look at your electricity bill and find out how much kWh you use per day in the past calendar year. Just saving 30-50% of your electric bill may not be enough to warrant installation. But if it can save you much more, perhaps have no electric bills to pay for the next 5 years, then it really is a “no-brainer” to install solar PV for your home.

 

 

Meter Box

The meter box housing the current circuit plays an vital part in determining the size of your solar PV system. Here in NSW Australia, for residential property you either are connected to supply grids, Ausgrid or Endeavour. You either have a single phase or a three phase circuit. Three phase circuits allows more electricity supply to your home that accommodate the running of large power appliances like ducted AC and pool pumps.

 

Each supply grid have their limits to how much electricity supply going in and out of your home. In relation to solar export (together with feed-in tariff), it does mean you can't take full advantage of your solar export from these limitations.

 

E.g. Endeavour only allows 5kw per hour for each phase. The reason they limit export feed in, is to not overload the grid with excess power. They deem it too expensive to upgrade their power network to allow PV system owners to install systems beyond a certain size, as they put it, “the current network can’t cope”. One way around it is to limit your solar export via your inverter. Speak to your solar expert for more on this.

 

 

Costs

In the 1960s, solar panels cost about $300 per watt. Those days, the system could only be afforded by the wealthy.

 

Today, prices are more affordable than ever. In most areas, solar panels operate at around $1-3 per watt.

 

To get a better return on your investment, we always recommend, installing more than your average consumption. The reasoning behind this is because typically the average household energy consumption increases with inflation – so too are the energy retailer's cost rate of supplying electricity. Furthermore, the whole solar PV system output does diminish over time and loses its efficiency at a slow rate. See Is Solar Worth My Investment.

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Recycling

The service life of solar panels is approximately 30-50 years, the inverter – 15-20 years, batteries (depending on their type and usage), 4-10 years.

 

Although the issue of disposing solar panels remains open, only 30% of all manufacturers take them back for recycling. However, the demand for spent solar panels is growing every year. As extraction of rare metals becomes more and more expensive, and processing of the unwanted panels will lead to their reuse.

 

In summary, the above factors should be taken into account apart from financial costs before you decide on installing solar PV for your home. These factors will help determine if it is feasible to install solar before any financial benefits is gained.