Solar panels, batteries and grids – what’s the difference?
How do solar panels work?
Solar photovoltaic (PV) panels absorb energy from sunlight and convert it into direct current (DC) electricity that you can use in your home, or sell back to the grid.
Each solar panel is made up of many individual solar cells, which in turn are made from thin wafers of silicon sandwiched together. Sunlight hitting these silicon cells provides the energy for electrons to move between the silicon layers and this flow of electrons is the electricity the panels produce.
How many solar panels do I need?
This depends on available roof space and household usage. A typical solar system would be about 15 to 20 panels.
How long do solar panels last?
Provided households invest in quality components, a solar system can last several decades. Solar panel manufacturers typically offer warranties of 15-25 years.
So, you can safely assume that the average life of a quality panel is around 25-30 years; however, this can vary depending on a range of factors.
Typically, grid connected inverters have a lifespan of 10-25 years. You should expect most high quality units to last 10 years minimum.
Solar inverters have warranties ranging from 5-25 years, with an increasing number of manufacturers offering pay for service warranty extensions.
What is the role of the solar inverter?
Solar panels generate electricity in the DC form. The solar inverter converts the DC electricity to the Alternative Current (AC) form, which can be used to power your home.
Can you install solar panels on all roof materials?
RACV installs panels on tin, cement and terracotta roofs, but not slate. If your roof is made of a different material, speak to one of our solar experts.
My house isn’t north-facing. Does this matter?
In Australia, the best position for solar panels to face is north – but don’t stress if they can’t. It’s all about positioning them where they’ll get the maximum daily sun exposure. (This is one of the solar myths, debunked.)
Which are the best solar panels?
There are many good brands, but many more average and poor ones. Good solar panels should have a product warranty of 12 years or longer, with an efficiency higher than 310W. RACV uses only premium products and currently installs Winaico and LG panels.
What is the grid?
The ‘grid’ refers to the network that transports power from generators (coal plants, solar and wind farms, hydro projects, etc), through the high-voltage transmission network (HV powerlines), then the low-voltage distribution network (street power poles) and to consumers (homes and businesses).
Can I disconnect from the grid?
While it is possible to go completely off-grid, it is not the best solution for most homes. In periods of cloudy or rainy days, it is possible to deplete your energy supplies and you may find that you need to reconnect to the grid to sustain power to your home. Alternatively, you would need to invest in a very large solar-and-battery system that would be under-utilised most of the time, producing significantly lower savings than what it would cost to install.
How does battery storage work?
Batteries allow you to store excess electricity generated when the sun is shining and use it at other times when you need it. It stores excess energy to be consumed after dark, increasing a household’s independence from the grid, ultimately saving more money. A battery may also offer a household limited back-up power in the event of an outage.
Because the value of excess electricity that you sell back to the power grid (feed-in tariff) is generally lower than what you are charged when you consume electricity, it is more efficient to store your own energy for later use.
Do I need a battery?
Batteries provide several benefits, mainly around maximising the amount of solar power that can be used in the home, and most can provide protection from blackouts. Whether or not these benefits are worth the cost of battery installation is a case-by-case question for households. The price of batteries is likely to come down as they become more common, but for now, most households install solar panels without a battery.
Will my battery cover me in a blackout?
Many home batteries have blackout protection, but not all. In the case of a blackout, power to the home will be cut for around 30 seconds while the system recognises the blackout and switches to blackout mode. Back-up systems fall broadly into two categories:
- Whole-of-home backup: where everything in the house can be powered in a backup. The risk is that this will drain the battery quickly if the household continues to use large loads, such as air-conditioners.
- Essential-load backup: when installing the battery, the electrician can isolate only certain circuits in the home to be protected in the blackout, to ensure things such as lighting and fridges can keep operating. This means the battery powers only these loads in a blackout to maintain charge for much longer.
How long could a battery power my home?
Battery power varies depending on the type of unit and the amount of power you expect to draw from it.
As a guide, a typical $10,000 battery being sold today will hold about 50 to 75 per cent of an average home’s daily electricity usage.