Solar power in its various forms can certainly be confusing if you’re new to the world of renewable energy. Below are answers to common questions we see asked about solar power in relation to residential grid connect systems.
What is PV?
PV is short for photovoltaic (photo=light, voltaic=electricity). PV is a semiconductor-based technology used to convert light energy into direct current (DC) electricity, using no moving parts, consuming no conventional fuels, and creating no pollution.
What is the National Electricity Grid?
The National Electricity Grid is the network that delivers electricity from generators to homes and businesses. When you install a solar PV system you become a generator of electricity, which can be fed into the grid. As this electricity is generated from the sun it is clean renewable energy.
How does a solar PV system work?
When sunlight hits a solar PV panel, direct current (DC) electricity is produced and the inverter changes the current from DC to 240V alternating current (AC). This electricity can be used immediately within the home or fed into the National Electricity Grid (grid).
What is a solar photovoltaic (or PV) system?
A solar photovoltaic (PV) system is made up of solar PV panels, an inverter, racking and wiring. Solar PV systems work very simply to provide a household or commercial structure with usable, renewable, clean, green energy. Flat solar PV panels are mounted to a roof and convert energy from sunlight into direct current (DC) electricity. A device called an inverter then changes the DC into 240V alternating current (AC) electricity, which can be used for a household’s electrical needs such as lighting and operation appliances.
What are the different types of solar PV panels?
There are many different types of solar PV panels currently in the Australian market. The three main types are monocrystalline, polycrystalline and thin film panels.
What is the difference between a solar hot water system and solar PV system?
A solar hot water system uses the sun’s warmth to directly heat water.
A solar PV system converts sunlight into electricity for use in the home or to be fed into the electricity grid. The heat output of the sun is not important for solar PV systems, but the amount of sunlight available is.
How long has PV been around?
The photovoltaic effect was first recognized by Edmund Bacquerel, in France, in 1839. Scientists made solar cells of selenium in the 1880s. And, modern PV technologies were developed at Bell Labs and RCA Labs in the mid 1950s.
Will solar panels heat my hot water?
No – these solar panels provide electricity. If you are interested in a thermal solar system to heat water, you’ll need a special type of collector unit – for more information, try our solar hot water section.
How does electricity get stored for use after sun goes down?
Generally, grid-connect systems direct excess electricity produced during the day back into the local electricity grid; so there is no on-site storage as such. You then receive credit for any power that you put back into the grid. At night time, you automatically use electricity straight from the grid. Off-grid systems store energy produced during the day in deep cycle batteries for use as required.
What happens on a cloudy day?
On sunny days your solar system will obtain the best possible electricity collection, however on cloudy days the panels will not collect the same amount. You can expect the panels to gather around half the output that would be achieved on a sunny day. If the electricity for a cloudy day is not enough to cover the household requirements, the system will use power directly from the grid. The performance of the solar PV system is affected by cloud cover. When there is not enough light to produce electricity, you will use electricity from the grid.
What happens with grid connect systems during a blackout?
The grid connect inverter will automatically shut itself off within a few milliseconds of a blackout, to avoid the potential of a dangerous “brown-out” in your home and to prevent back feeding the grid; which can pose a threat to workers rectifying a blackout. For safety reasons, in the event of a blackout, your solar PV system will stop producing electricity. This safety measure is mandatory and has been put in place to protect anyone working on the blacked-out grid system. As soon as the grid is back online, your solar PV system’s ability to generate will be restored.
With grid connect systems, what can I do to keep power during a blackout?
You will need battery back up.
Can you retro-fit battery backup into a grid connect system?
Yes, battery backup systems require additional components such as, solar regulator, batteries, and inverter.
What sized system will I need?
Any size grid connect solar system will help slash your power bills. To determine how large a system you’ll need to gain the savings you wish.
Will I need to re-roof my house?
In most situations, the PV panels can be easily removed and reinstalled, with minimal, if any, changes to your roof.
How much weight will the solar system put on my roof?
Think solar systems are light weight but with very strong Aluminium mounting frames, while distributing a total weight of just 10 to 12 kg per sq mts.
Will it affect my property resale value?
When you purchase a solar PV system, all of its benefits, including the warranties and electricity savings, are linked to the property. Even if you move, all warranties will remain with the system, meaning that the new owner will receive the benefits.
There is not yet enough data to accurately predict the effect of a solar energy system installation on property prices.
Building suitability for Solar System?
Several aspects will need to be evaluated to determine if your home is a good solar site, such as orientation, space available, shadows on the space available and your current electricity usage. The best site will be one with adequate unshaded northerly facing roofing. Variations on that will cut into the productivity of the system.
What is the cost of a solar power system?
Please contact Energis Team.
Can solar panels work in the shade?
The output of any panel will be reduced or cut off if shaded. However, some solar panels do work better than others in the shade.
All solar panels sold by Energis have “bypass diodes”, which send output from the remaining cells around that dead cell.
Dirt, dust, leaves, bird droppings, shadows from trees, vent pipes, etc can all cause reduced output due to shading. Wash panels down occasionally, especially if mounted flat on a roof, eg. caravan installations. A quick wash with a soapy brush or mop and then rinse. However, some tree waste may need to be cleaned off with a solvent such as turpentine.
Does the orientation of the roof affect whether or not a home can successfully install a solar product?
Although it is optimal to install solar products on the north-facing side of a roof, it is also possible to install a solar PV system on the east or west facing side of a roof, as long as there is sufficient space. However, this will not produce the same results as a north–facing installation.
Is mains electricity still needed?
Because solar PV systems only produce electricity when they are exposed to sunlight, at other times another source, such as mains electricity or a generator, will be required. When there is no sunlight, no electricity is produced, so you will need to draw electricity from another source such as the grid.
Are batteries needed for a solar PV grid connected system?
No. Grid–connected solar systems do not store electricity – instead, any electricity you do not use in your home is ‘exported’ to or fed into the electricity grid.
Is it possible to increase the size of a solar PV system in the future?
This depends on your roof space and the size of the inverter. If you have sufficient roof space and additional capacity in the inverter you could increase the size of your system. Or you could add a second system to your roof.
What happens at night?
As solar PV systems only produce electricity when they are exposed to sunlight, they do not produce electricity at night. At night you will need another source, such as electricity from the grid.
Where do residential solar PV panels get placed?
Your installer should determine the optimal position for your solar PV system.
There are many factors to take into consideration when planning the placement – from orientation to the sun, to the area available and the distance to the meter. In an ideal situation, the panels would be oriented as close to north–facing as possible, in an area with no shading.
Is it true that solar electricity systems are more efficient inland rather than on the coast?
There are many factors affecting efficiency. Inland regions generally have fewer cloudy days than the coast. Conversely, high temperatures, smog and dirt are more prevalent inland and can also affect performance.
How much electricity does a solar PV system produce?
There are a number of factors that will affect how much electricity a system will produce. The orientation of the panels, where you live in Australia, any shading of your panels and the amount of sunlight on a given day will all affect how much energy the solar PV system produces. You should refer to the product specifications of the solar power system you are considering, or talk to your installer.
What are Small-scale Technology Certificates (STCs)?
STCs are created under the government’s Small Scale Renewable Energy Scheme. SRES is part of the government’s Renewable Energy Target initiative which create a financial incentive for investment in renewable energy sources through the creation and sale of certificates. Each STC represents 1 MWh (Megawatt hour) of energy able to be produced.
STCs are created when you purchase qualifying solar hot water, wind power systems or residential solar PV systems.
SRES and the associated creation and sale of STCs was devised to encourage Australians to take action to help meet the government’s 20% renewable energy target by 2020.
How much are STCs worth?
The value of the STCs you are eligible for varies depending on your location and zone rating, the size of the system you install and the market value for STCs. Website’s such as the Government’s Office of Renewable Energy Regulator site have solar STC calculators, providing a guide to the number of STCs your system could be worth.
Do I have to sell my STCs as part of installing a solar power system bought?
Generally when purchasing a solar PV system and having it installed by Energis, you will be asked to assign your STCs to Energis. The value of STCs is usually applied as a discount, reducing the upfront costs of the solar PV system. Customers should consult Energis for confirmation on the process.
What is a feed-in tariff?
A feed–in tariff is the rate paid for any electricity your solar PV system feeds into the grid. The rate, which is paid, varies depending on your state and whether you are eligible for a government feed–in tariff or not.