Solar Citizens blog


Are High Voltages in the Grid Caused by too Much Input From Domestic Solar Systems?

Written by Solar Citizens volunteer Peter Youll. 

You may have been hearing reports that solar PV installations are causing dangerously high voltages in the distribution network, particularly in the middle of the day when solar generation is high and electricity demand is low. This effect is being hyped by those who want to maintain the status quo (electricity distributors) as an excuse to restrict grid connected solar installations. There can be no doubt grid voltages are increased by connected solar systems, however there is a readily available solution to this problem.

For decades until 2000, the nominal voltage to be supplied to domestic customers by Australian electricity systems was either 230v or 240v, depending on the state. In that year Standards Australia issued AS60038 and adopted a 20 year plan to change the nominal voltage for all states to 230v, to align with European Standard IEC38. The standard specified a minimum of 216v and a maximum of 253v – 230v -6% to +10%. Subsequently AS61000.3.100 was issued which specified acceptable voltages based on time distribution (voltage to be between 225v and 244v 50% of the time, 216v to 253v 98% of the time) with the intention that it be applied Australia wide. However compliance with this standard varies, depending on the distributor.

Solar systems will cause the voltage in the distribution system to rise. In order to export excess energy to the grid, the system inverter must increase the output voltage to slightly higher levels than present on the grid. As more distributed energy sources are connected, the grid voltage will continue to increase, raising it toward the limit that could cause damage to devices, and possibly causing solar systems to disconnect from the grid in order to protect themselves. At my solar equipped home I have regularly seen grid voltages up to 252v on sunny days, however I have never seen voltages drop lower than 239v at night when there is no solar generation. Obviously one major reason for high voltage in the grid on sunny days is that the grid voltage is already at a high level, way higher than the Australian standard of 230v.

This problem can be solved. In 2017, the Queensland government directed the state owned distributors (Ergon and Energex) to adopt the Australian standard and reduce grid voltage for several reasons, the main one being in order that connection of solar systems would not be unreasonably restricted! The distributors were given a year to get the job done, and as far as I can find out, the task has been largely completed. It is time for the other distributors to stop bleating about high grid voltages caused by solar installations, and reduce the nominal grid voltage to comply with the current Australian standard. I am advised by my favoured solar installer that this adjustment is done at the local area transformer, which could explain why the distributors are reluctant to get on with making the change – there are thousands of transformers requiring adjustment!

Five Solar Innovations

Written by Pauline Tan, Solar Citizens intern.

We have been harnessing the sun’s energy to power our homes for over 50 years. Not only revolutionising the energy sector, but with innovative thinking, we are using the sun’s energy in new and exciting ways. Here are some top solar innovations repowering different industries – the future is looking sunny and smart!

1. Waste

Clean power and clean streets! Solar Bins are already found in numerous communities; this bin is specially powered by the sun to compress 5 times the amount of waste in a 120L bin. It reduces the occurrence of overflowing waste, frequency of bin collection and ultimately, waste management costs.

2. Water

The sun is turning on the tap! Special solar panels are being used to capture drinkable water straight from the air. In a process similar to condensation, the sunlight is used to generate heat in special panels of material, which in turn allows it to absorb moisture from the air.

The panels are currently being trialled in Australia to see if it can help alleviate the dependency on plastic water bottles, as well as to provide fresh water to communities facing water scarcity. Even in arid climates with humidity levels well below 10%, this solar innovation can still extract at least 2L of water from the air.

3. Concrete

Forget external solar panel systems! A new method of concrete-laying includes a layer of photovoltaic cells allowing for the concrete to generate solar electricity. This makes the solar panel system ‘invisible’ and less bulky. Maybe soon the concrete under your feet could be generating solar electricity too!

4. Fashion

A new twist on being fashion forward! Shirts have been invented with 120 thin solar cells embedded into the fabric. Producing approximately 1W of electricity, these shirts produce enough to charge your portable devices. A hidden battery pack is located in the front pocket, allowing electricity to be stored for when your phone needs some extra juice.

5. Printing

This is a cool method being developed that allows solar cells to be more portable and flexible. Solar cells can now be printed onto flexible plastic films – a process similar to how banknotes are made. This allows the generation of solar electricity to be more flexible and portable. Printing could be a new method that could fast forward the development of other innovations such as solar fashion.

Race for a Renewable Energy Future

Written by Hyacinthe Uwizera, Solar Citizens intern.

I find it disappointing that the Federal Government is dragging its feet when it comes to repowering Australia with clean, cheap renewable power, especially considering recent survey results that show that 84% of people back renewables over coal-fired power generation.

My name is Hyacinthe Uwizera and I’m an intern at Solar Citizens. I am here through a program from my school, the University of Pennsylvania, and I am Rwandan. I care about the decisions that are made here in Australia because, with so much sun and wind potential, Australia could show the world how it’s possible to transition to clean power.

The Federal Government’s energy policy, the National Energy Guarantee (NEG), is an anti-renewable plan that will be negotiated at the next COAG Energy Council meeting on August 9-10 in Sydney. The policy will directly affect the future of renewables across the country, which is why a range of groups in the Repower collaboration held an action outside of Parliament House in Canberra called the Race for a Renewable Energy Future.

To support renewables and a brighter future, I got up at 4am on a cold winter morning to set off from Sydney to make it to the action. At 8:30am, as the action was about to begin, there were people who dressed up as Malcolm Turnbull and Tony Abbott, coal to represent fossil fuels, and solar to represent renewable energy.

In the stunt, solar and coal were racing. In the beginning of the race solar was ahead, but after some time, solar got trapped in Malcolm Turnbull’s red-tape net. Coal continued but fell down after some seconds. Tony Abbott then injected a $16 billion adrenaline injection into coal. Coal then limped towards the finish line and won the race. The scene was surrounded by a crowd of renewable supporters, like me, and was watched by some politicians too.

The action was highlighting that renewables with storage are the cheaper and better option for Australia, but under the NEG they will be held back with a very low national renewable target. We were there to get our voice heard, and speak for other Australians, asking for a safe environment for the future generations.

As a young person, I care about the environment and my future. We should all care about our environment. We either choose a clean, efficient and cheaper source of energy or the opposite. We should care about our health and the health of the generations to come.

Solar just makes sense. We could power the entire world by harnessing just 1% of the solar energy we get from the Sahara desert. A national plan that holds renewables back is bad for power bills and the planet.


Time-of-use Electricity Rates More Attractive with Ausgrid Change

Written by Solar Citizens volunteer Peter Youll.

If you have a smart meter in NSW and are on a standard, flat electricity rate, it might be time to look at changing to time-of-use rates.

Time-of-use rates mean you pay less for the electricity you use during off-peak and shoulder times and more for it during the peak periods.  

From the 1 July 2018 Ausgrid, the distributor serving metropolitan Sydney and the Hunter Valley, has changed the hours that peak, shoulder and off-peak charges apply for electricity use. The biggest change is that the hours actually reflect when peak consumption hours occur—amazing— and will vary with the seasons.

For households on the Ausgrid network, there will be no peak hours during autumn (April and May) and spring (September and October), and the winter peak hour will be shorter and apply later than before.

With Ausgrid’s change, it means the higher peak rates won’t be charged by retailers at all for a third of the year.

Is this for you? First up you need to have a smart meter. Secondly, you need to be able to adjust your electricity consumption habits to avoid using lots of power during the peak periods. If you’re home during the day or able to run your appliances on the weekend, it will be easier for you to do things like putting on the dishwasher or washing machine in the middle of the day when you know your solar panels are producing power and not in the evening.

Have a look at the Ausgrid explanation, then check how much power you use and when to work out the changes you should make. Some retailers (Powershop, Origin and AGL) make this easy by providing detailed consumption numbers from your smart meter on demand via their website.

For a detailed explanation about smart meters, have a look at this article from Choice. 

Not in Sydney or Newcastle? While Ausgrid are the only distributor who have introduced different peak times for each season, going on to time-of-use rates might still be worth it for your house, have a look at the rates and distribution times.

10 Things To Know About Batteries

Written by Abby Bower, Solar Citizens intern.

The storage revolution is here!

And it’s coming to homes across Australia. Home battery storage is looking better than ever - in fact, nearly 21,000 Australian households installed a solar battery in 2017. Both the cost and size of batteries are shrinking, and the variety of makes and models is increasing. It is predicted that Australian households will install 1 million batteries by 2020.

So whether you’re considering installing home battery storage, already have it or you’re wondering what all the fuss is about, here are 10 things you should know about batteries and the storage revolution:

1. Home batteries allow solar owners to store energy generated by their solar PV system during the day

The big appeal of home battery storage is that it makes solar energy available when the sun isn’t shining. Batteries store excess energy produced by a solar PV system during the day, which can then be used at night or at peak times when buying electricity from the grid is more expensive.

This flexibility means battery owners can save money on their energy bills, maintain some independence from the grid and increase their energy efficiency. Plus, with a few add-ons, a battery may also offer protection against blackouts and power outages. Remember, for a solar and storage system to work during blackouts, you need a hybrid system that isolates the installation from the main grid.

2. Home battery prices are dropping

In 2018, the average cost of home battery storage in Australia was around $650 to $2400 per kWh capacity, plus installation. For context, residential batteries usually have a capacity of 3-12kWh, though smaller units are becoming more popular.

Prices are falling, and they're falling quickly. Consumers are already seeing the benefits of these plummeting prices; battery enthusiasts were thrilled when Tesla’s Powerwall 2 stayed the same price as its predecessor while doubling in capacity

What prices are out there? This table gives 2017 prices for a some popular battery products in a variety of sizes.  


3. It’s all about the payback period

With prices dropping, batteries are on the cusp of becoming cost-effective for more and more Australians. In fact, the Alternative Technology Association (ATA) predicted that they would be economically attractive by 2020. 

You can determine whether or not installing a home battery makes economic sense for you by looking at its payback period – the amount of time it takes for the savings created by battery storage to equal or exceed the installation cost of the system. Generally speaking, a battery will save you money if its payback period is shorter than its warranty.

Battery warranties are a bit tricky to compare because they’re not standardised yet. While there are a few resources that help you compare warranties in detail, a rough baseline for home battery warranties is three to 10 years. The most common type of new batteries, lithium ion batteries, last about 10 years on average.

Under the right circumstances, payback periods will be shorter than the 10 year average warranty. A variety of factors influence the length of a payback period, including the location of the battery owner, the amount of energy you’re using and when you plan to use it. It’s a good idea to have a think about all of these before you decide on your storage system.

Of course, payback periods aren’t everyone’s top priority. If you’re less worried about the savings and more focused on the other advantages of battery storage, you might want to consider the battery technology that best suits your needs, whether your battery can be wall mounted and how much independence you’d like from the grid.

4. Some cities are more battery friendly than others

Location, location, location! Due to differences in feed-in tariffs, weather and solar PV prices, certain cities are currently more economically favourable for battery storage than others. Australia’s best city for battery storage at the moment is Perth, followed by Brisbane, Adelaide and Sydney. It’s worth doing some research on your town before deciding if battery storage is right for you.

5. Knowing how much energy you use and when you use it will help you get the most out of a battery storage system

In general, batteries make the most economic sense for homes that consume a large amount of electricity. Using Sunwiz’s PVSell software, Solar Choice calculated that households that consume 30kWh of energy per day consistently see better returns and shorter payback periods for batteries than those that consume 20kWh daily. The average Australian household uses about 18kWh per day. You can install a device to monitor how much energy you're using and when, so you can make an informed choice about what battery system is right for you.  

It also matters when you use the most energy. Solar Choice also found that consumers who use energy late in the day with an evening peak - likely households with a home office - are the best candidates for batteries.


Source: Solar Choice, March 16, 2017

6. Battery technology isn’t one size fits all

Batteries store electrical energy and then release it through a chemical process, but not all batteries do this in the same way. There are a few different types of batteries on the market. The most common are lead acid and lithium ion (Li-on). A few less commonly used technologies are nickel-based, flow and sodium ion. 

In the past, lead acid batteries were the standard for home storage systems and electric vehicles, but they’re being surpassed in popularity by lithium ion batteries.

Lithium ion batteries are made of lithium and a mix of other chemicals that usually includes aluminum, cobalt, nickel or phosphate. They have a high energy density, so they are smaller and lighter than their lead acid counterparts. They are expected to dominate the storage market in coming years due to their versatility, potential for recycling and a projected drop in production costs.

Other technologies are rare in Australia right now, but they’re worth keeping an eye on since battery storage is evolving so quickly.

7. Battery inverters differ from traditional solar inverters

Solar systems change the direct current (DC) power generated by a solar panels into alternating current (AC) power for household use using an inverter.

When you add a battery into the mix, you have to add a battery inverter or upgrade to a solar and battery hybrid inverter. Unlike traditional solar inverters, battery inverters can convert DC power into AC and visa versa, which allows the battery to be charged from the solar sytem and discharged to power the load in your home.

It’s easy to add a battery inverter to many existing PV systems - so you might already be battery ready. If you’re adding a new system entirely, you might consider getting a hybrid inverter that can manage both.

8. A variety of battery brands and products are available in Australia

If you’re in the market for a home battery system, you’re spoilt for choice! More than 150 different products are offered in Australia and there are some great online tools to help you make sense of them all.

There are plenty of professionals who can help you out, too. The Clean Energy Council has a list of accredited installers who can answer your storage questions.

9. Regulations on batteries are being developed right now

Home storage batteries are widely considered to be safe - no riskier than keeping a car with a tank full of petrol in your garage. Batteries do, however, pose the same risks as any other electrical system. You can avoid risks of fire or leakage with regular maintenance and by keeping batteries in well-ventilated areas that are separate from living spaces in a household.

10. The benefits of batteries are still secondary to the benefits of solar itself

Batteries offer a great deal of potential, but they still act as an add-on to PV systems. If you’re not producing any solar power, it doesn’t matter how much storage you have! Batteries don’t generate power on their own, and studies show that batteries are most beneficial for those who are already using their solar systems effectively. 

Solar power is already an economic no-brainer in Australia. The standard warranty on a rooftop PV system is 25 years and most solar owners see a payback period of about three years. So if you want to get solar with batteries, you might as well get the panels now and install your storage later, when it makes economic sense for you. Find more info about going solar here and a free tool which estimates the economic feasibility of a solar-battery system here.

So, where does that leave you?

So if you’re already a part of the rooftop revolution, joining the storage revolution might be your next move. For those who aren’t yet ready to become early adopters of home storage, know your battery basics. And keep an eye out, because battery technology is charging ahead!    


Alternative Technology Association
Australian Battery Recycling Initiative
Australian Energy Market Operator
Australian Solar Council
Clean Energy Council
Solar Choice
Solar Quotes
Standards Australia
Australian Solar Quotes
One Step Off the Grid
Renew Economy
Gizmodo Australia Battery Guide


Keeping Solar FiT

Written by Pauline Tan, Solar Citizens volunteer.

After the Independent Pricing and Regulatory Tribunal (IPART) proposed to cut the benchmark solar feed-in tariff (FiT) in NSW from 11.9-15c/kWh to 7.5c/kWh, the Sydney Solar Citizens group sprung into action to get solar owners a fair go.

With IPART considering slashing the solar feed-in tariff, it’s clear that solar owners and supporters aren’t being listened to. Solar owners are tired of doing the legwork and not seeing any gains. Why should solar households be punished for lowering wholesale power prices a