PROS AND CONS SOLAR ENERGY
Solar is the more commonly used for home alternative energy generation at this point.
Advantages and Disadvantages Solar Energy: ADVANTAGES
Solar energy photovoltaic panels have no moving parts and so make no noise. Even those with tracking systems hardly make a peep. This is a distinct advantage over wind powered home generators in residential areas particularly.
Because of this your local authority may require a permit prior to installation of wind mills elec systems especially in residential areas – not needed with solar.
However some councils haven’t caught up with the current trend towards renewable energy and so haven’t yet got round to devising rules re the installation of wind turbines. So now is a good time to get one!
Wind turbine blade design and technology is such at the moment that the wind noise is now minimal compared with just 5 to 10 years ago.
But if you pick a noisy one close neighbours will no doubt complain and you may be forced to take it down. Added to the arguable visual effect, for residences with noisy wind turbines property values may be adversely affected.
• Reliable Resource
Just about anywhere in Australia there is ample daylight most times of the year to collect a useful amount of photovoltaic energy.
Apart from impairment by shading cast by trees or adjacent buildings, any north facing surface (south if you are in the northern hemisphere) is likely to be capable of harvesting sunlight. Even in winter the solar resource in Australia is significant.
In ideal conditions in Australia you can bank on your photovoltaics systems producing at between 17 and 23% of its maximum capability over the year. So a 1 KW system would produce up to 2000 kWh a year.
While wind turbines can operate night and day whenever the wind blows, the reliability of wind as a resource is much more variable than solar.
It not only depends on your local topography, but also on season.
Summer easterlies in Perth are by far the strongest winds of the year in the hills area, while winter storms deliver the strongest winds on the coast.
Wind turbines may average 20% to 30% of their energy generating capacity over the whole year depending on the efficiency of their design and the wind resource. For example, for a site with an average wind speed over the year of 7 m/s, a conventional (3-blade) 3 kW turbine could be expected to output about 6600 kwh in a year, which is 25% of its maximum energy generating capacity.
In Perth, Western Australia, good wind sites are likely on the coast and also at the foot of the Darling Range hills system. However, you need a clear pathway for the wind to your turbine to get the most out of it. Tall trees and buildings can create turbulence that makes for less efficient turbine operation.
It makes sense to monitor your local wind resource over a period of at least 12 months, or at least speak to some locals, before purchasing a wind turbine, as they come in small, medium and large capacity to suit your conditions.
To can access local wind resource data
(for free Australian data click here). You can also use Permaculture landscape design
You can also use Permaculture landscape designto create windbreaks and fodder shrub plantings that funnel wind towards your windmill, enhancing the local resource.
Solar panels need little maintenance, aside from being cleaned occasionally of dust, and the salt that may accrue in coastal areas.
The bearings of wind turbines may need to be checked every 5 years or so for maintenance. To overcome any potential difficulties, you should select a wind mill that has a tipping tower for ease of access to the turbine.
• Visual Impact
The visual impact of solar systems can be minimal, and is generally a lot less that wind turbines.
A wide range of photovoltaic designs provides you with choices too – from the usual solar panels to photovoltaic roofing material such as photovoltaic roof tiles and photovoltaic shingles that simply become part of your roof.
With the recent availability of thin film photovoltaics - which are flexible photovoltaic cells - you can use the roof of your car or caravan, windows - in fact anywhere facing the sun to collect solar energy.
• No Significant Bracing Required
In strong wind areas wind turbines may need considerable bracing. Solar panels have to be anchored securely too, but don’t need as significant bracing.
• No Danger to Birds or Bats!
Solar power poses no direct threat to flying animals. However, wind turbines do undoubtedly kill both birds and bats, though it’s poorly understood exactly why and how often these deaths occur.
Unlike the case at some large wind farms, the thousands of wind turbines on US farms are reported to be relatively safe for both raptors and songbirds. The exact reasons are a matter of debate.
Firstly, collisions seem far fewer when wind turbines are sited away from major flyways and give a wide berth to rich prey sites that attract eagles and attractive bird habitats such as wetlands.
Some researchers also speculate that newer turbines allow the same amount of electricity to be generated with far fewer blades, thereby reducing the risk to birds and bats. Vertical wind turbins are a new technology that may further cut the risk.
So you may be able to improve the situation by siting residential wind mills away from heavy bird traffic areas, and using those with a bird friendlier design.
Advantages and Disadvantages Solar Energy: DISADVANTAGES
• Cost Per Watt
The cost is relatively high for the amount of energy that you get from photovoltaics. For example, the retail on photovoltaic panels for sale is currently around $10 to $15 per watt compared to around $4 a watt for wind powered home generators.
And with wind generators, its not hard to
make your own for a fraction of the off-the-shelf price.
The photovoltaic efficiency of solar panels is constantly improving so that the output even on a cloudy day is considerably more than it was 5 or 10 years ago.
By comparison, if sited in a reasonable wind resource area, wind turbines can produce a lot more power than a standard photovoltaic system. One smallish wind turbine for instance could easily supply 500 W per hour (average) while it would take 5 to 10 solar panels to create the same amount of energy.
Solar panels come in modules of watts that need to be connected together to make up a large enough bank to create a reasonable amount of usable energy.
They are therefore more complicated and fiddly to install yourself than wind powered home generators, and you can’t install either yourself if you want an Australian Government rebate (unless you are an accredited installer that is!).
The voltage output of solar systems is low (12V to 24V) so they are a little safer to connect up yourself than wind turbines which typically have a high voltage output (75 to 240V)
SO WHICH SYSTEM IS BEST FOR ME?
Assuming you are permitted under local bylaws to use either system, you would need to make a decision based primarily on your local wind or solar resource and financial considerations.
Our preference would be a little of both if possible. We all go through 4 seasons a year – with variations in wind and sun. It is never a good idea to rely on only one sort of technology for your energy needs.
So instead of having 1000 watts of solar panels – for example - that would cost a large investment to buy and to install, consider having 500W solar and 500W wind turbine to get a better than average chance of having your batteries charged continuously.