Adding a battery to a solar system lets you use more of your own power and gives you some protection during outages. BYD batteries are widely reviewed across Australia, Europe, and New Zealand, and have built a solid reputation for reliability, safety, and long service life.
BYD (Build Your Dreams) is a global clean-energy leader founded in 1995 and headquartered in Shenzhen, China. Known for innovation in electric vehicles, energy storage, and solar technology, BYD manufactures everything in-house — from battery cells to final systems — ensuring total quality control. It has now grown to an international group with 180,000 employees.
The BYD Battery-Box range uses Lithium Iron Phosphate (LFP) chemistry, which is commonly recognised for its stability, safety, and long cycle life. Because of this, many reviewers and installers consider BYD to be a solid option for residential and commercial (as well as agricultural) storage.
A point raised often in independent reviews is that BYD makes its own cells and assembles its own battery modules rather than outsourcing. This approach gives more control over quality and consistency.
The process includes:
These steps are often highlighted in third-party reviews because they contribute to the Battery-Box reputation for consistency and safety. BYD has shared footage of its production lines, which provides insight into how these units are built.
The BYD Battery-Box is a modular lithium iron phosphate energy-storage system that can be used to store excess solar power for later use, or other situations where the functionality provided by battery storage is required. Each “box” contains stackable battery modules with a built-in Battery Management System (BMS), allowing capacity to grow as your energy needs increase. BYD’s design is fully scalable — from a few kilowatt-hours for a home to nearly a megawatt for commercial and agricultural operations.
Current Generation installs the following BYD models:
These units work with inverter brands such as Fronius and Victron, which Current Generation also supplies.
The LVL is BYD’s larger 48V option. Reviewers usually highlight its size, weight, and capacity, noting that it suits commercial or high-demand sites rather than smaller homes.
BYD LVL
The LVS is widely regarded as the most flexible model. It is commonly listed on “recommended battery” lists because it is simple to install and easy to expand in 4 kWh steps.
BYD LVS
The HVS and HVM are high-voltage versions designed for hybrid systems. Review sites often discuss these in relation to the Fronius GEN24 inverter, as the combination is common and well supported.
BYD HVS
BYD HVM
Choosing the right model depends on load size, inverter type, and how much storage is needed.
For larger systems or sites with unusual loads, getting the system designed is recommended.
One thing reviewers often highlight is the strong integration between BYD’s high-voltage batteries and the Fronius GEN24 inverter range. This pairing is DC-coupled, which means power goes straight from panels to the battery without extra conversions. This usually improves efficiency and reduces energy losses.
AC-coupled batteries (such as Tesla Powerwall or GivEnergy) work well too, but do involve more conversion steps.
BYD batteries have built a reputation for reliability, strong safety performance, and flexible system design. They suit a wide variety of homes, farms, and commercial sites, and work well with modern hybrid inverters such as Fronius GEN24.
If you’re considering battery storage or upgrading an existing setup, the Current Generation team can provide system design and installation across the South Island.
Or, talk to our team about the right BYD system for your property.
Posted in Miscellaneous
Major power cuts can arrive suddenly, particularly following storms, earthquakes, infrastructure failures, even the inadvertent removal of a few too many bolts in a critical pylon. When the lights go out, businesses face immediate disruption: production lines halt, cooling systems shut down, tills go dark, and, critically, your ability to communicate with and update your customers and suppliers and access your data can all but disappear.
Here are some practical ways you can keep your business’s critical functions running when the grid goes down.
For most businesses, power is something that’s easy to take for granted—until it isn’t there. An unexpected outage doesn’t just mean lost time; it can lead to costly spoilage, unfulfilled orders, and, ultimately, disappointed customers. Backup power systems ensure that even when the grid fails, your critical operations continue without missing a beat.
Battery backup systems are becoming more popular because they’re effective, quiet, and can also provide other financial benefits when the grid is up, particularly if coupled with solar. Unlike generators, they don’t rely on fuel, making them clean and quiet to run. Here’s why batteries might work well for your business:
The best way to determine if a battery system is right for you is to look at your business’s energy needs. A backup battery can be sized to support critical systems although if you have very high-power needs in an outage, a generator is likely to be required to supplement the battery. Battery is often coupled with solar as this gives you free charging and allows you to reap other financial benefits of having power storage onsite.
While battery systems are a great fit for certain needs, generators offer reliable, heavy-duty power and are often a good choice for businesses that need to keep heavier equipment running. Diesel generators are particularly popular because they’re robust, fuel-efficient, and dependable during long outages.
Putting backup power in place doesn’t have to be complicated, and it can make all the difference when it matters most. Here’s what you need to know about getting started:
Nobody likes to imagine worst-case scenarios, but having a solid plan in place provides peace of mind. A dependable backup power solution is an investment in your business’s resilience, helping you weather power cuts and keep serving your community. Whether you’re leaning toward a quiet battery system or a traditional generator, taking steps now ensures your business stays prepared, come what may.
A grid-tie solar system is an alternative power system designed for homes and commercial buildings that are connected to the electricity grid. It allows you to produce your own power, thereby reducing your electricity bill by needing to import less power from the electricity grid. Any excess power is fed back into the electricity grid with the system switching seamlessly between exporting and importing power to and from the grid depending on what is needed.
Grid-tie solar systems are a popular and efficient solution for homeowners in New Zealand looking to harness the power of the sun and reduce their reliance on traditional energy sources. In the following article, we will dive into the details to help you understand the workings of grid-tie solar systems, their benefits, and what you need to know before installing this type of solar system in your home.
A grid-tie solar system, also known as an on-grid or grid-connected solar system, is a type of photovoltaic solar setup that is directly connected to the electricity grid. The key components of a grid-tie solar system include:
When sunlight hits the solar panels, they generate DC electricity. This is transmitted to the inverter which converts this DC electricity into AC electricity. The AC electricity is then fed into your home’s switchboard. Any excess electricity generated by your solar system is sent back to the electricity grid with the electricity meter measuring it so it can be credited against your power bill.
During times when your solar system is not producing enough electricity to meet your household’s needs, such as at night or on cloudy days, your home automatically draws electricity from the electricity grid to make up the difference.
Grid-tie solar systems offer numerous advantages for New Zealand homeowners:
Installing a grid-tie solar system involves several steps:
Once installed, grid-tie solar systems require minimal maintenance. It is recommended that you clean the solar panels annually.
Many New Zealand homeowners have already made the switch to grid-tie solar and are reaping the benefits. For example, a family of four in Nelson installed a 6kW grid-tie solar system on their home in January 2025. While they also have a solar hot water system, they have seen their energy bills decrease markedly. They are currently expecting to have power bills which average just $13 per month over the first year based on performance to date. They also enjoy the peace of mind knowing that they are contributing to a cleaner, more sustainable future for their children.
Another Tahunanui family with a 5kW grid-tie solar system have seen 53% of the output of the system self-consumed through their own usage. This has equated to 48% of their total power usage while still exporting 3,900kWh to the grid for a credit over the last 12 months.
The size of the grid-connected solar system you install is only constrained by your budget and the space available for mounting panels, whether that be on your roof or a ‘ground mount’. In saying that, there will be an optimum size of system depending on how much power you use and when.
Systems are often talked about as being XkW in size. This can refer to one of two things; the ‘peak’ output of the solar panels installed (denoted kWp) or the power rating of your inverter (generally measured in kW). Most systems are designed to have more potential peak solar output from the panels than inverter capacity (e.g. a system could have 12kWp of PV solar panels with a 10kW inverter). This is usually the most efficient and effective arrangement when considered from a return on investment as while some of the panels generating potential could be ‘clipped’ by the inverter in the middle of a summer’s day, the majority of the time the panels will be producing below peak and having higher overall generation in the darker months of the year and either end of the day results in better overall performance.
Typically, homeowners will install a system with an initial capacity of between 5kW and 15kW. Small businesses might be looking at 10 to 25kW. For larger commercial or industrial property owners, bigger systems that could be anything up to 1 MW could be the best fit. System can be single, two or three-phase, with the number of phases usually set by the number of supply phases to the property.
Often, owners choose to install a larger system as they are believe there is a likelihood of their power needs increasing in the near future (heat pumps, EVs, pool or spas being the usual suspects). Looking for an inverter that has ‘hybrid’ capability, the ability to integrate battery at a later date, is also high on the list for most people. The cost of the system is dependent on system generating capacity and ease of installation.
At Current Generation we are a one-stop shop, supplying a complete range of quality components, consulting with you, designing, and installing your grid-tie system. We will also liaise with the network company and electricity retailer. This makes the whole process easier for you. Ask us about designing and installing your system today!
Grid-tie solar systems offer a compelling solution for New Zealand homeowners looking for a great return on a financial investment, to minimise their environmental impact, and to increase the value of their homes. By understanding how these systems work, their benefits, and the installation process, you can make an informed decision about whether a grid-tie solar system is right for you.
To learn more about grid-tie solar systems and how they can benefit your home, come and talk to us at Current Generation for a consultation and personalised assessment of a solution that fits your situation.
At Current Generation, our approach is to empower you with the knowledge to make informed decisions about solar energy. As solar photovoltaic (PV) technology becomes more affordable and accessible, understanding the financial aspects—including buy-back rates—is crucial for anyone considering solar installations in 2025.
Buy-back rates (sometimes called export rates) are the prices electricity retailers pay for the excess electricity your solar PV system generates and feeds back into the grid. Feed-in tariffs (FITs) are similar but are often set by government policy to encourage renewable energy by guaranteeing a fixed, attractive price for exported electricity over a certain period.
In New Zealand, there isn’t a government-mandated feed-in tariff scheme for solar power. Instead, electricity retailers set their own buy-back rates, which are generally lower than the retail rates consumers pay for electricity.
Here is an overview of the buy-back rates offered as of June 2025 by some major electricity retailers (source: www.powerswitch.org.nz/solar-rates):
Please note that these rates can change, so we recommend checking with the retailers directly for the most current information.
The difference between the higher retail electricity prices (approximately 30 cents per kWh) and the lower buy-back rates means that the financial return on your solar PV system will be impacted by how much of the generated electricity you can use yourself.
For example, a 3 kW solar PV system might produce around 4,500 kWh annually. If you consume 70% of this energy, you avoid purchasing 3,150 kWh from the grid, saving about $945 per year. The remaining 1,350 kWh exported to the grid would earn you approximately $169 if your buy-back rate is 12.5 cents per kWh. This results in a total annual benefit of around $1,114.
The Energy Competition Task Force (jointly established by the Electricity Authority and the Commerce Commission) is investigating ways to improve the performance of the New Zealand electricity market.
This is relevant to people with solar and battery energy storage systems (BESS) as they have specifically been looking at, and consulting on, ways to encourage more ‘fairness’ for those consumers who are helping to ease the strain on the infrastructure and the market as a whole.
At present, two specific initiatives are being looked which directly support solar and BESS
There is no doubt in our mind that a more distributed power generation and storage market, predominantly underpinned by the adoption of solar and BESS by consumers (both residential and commercial), is critical to helping to solve the near-to-medium term challenges in New Zealand; namely its lack of security around its centralised generation capacity and transmission network.
Our reliance on hydroelectric power makes us vulnerable to dry years and changing climate patterns. Distributed solar generation can help mitigate these risks and contribute to energy security. It also helps reduce the need to fire up the hugely polluting coal power stations such as Huntly which currently act as the backstop to our power needs.
While there are challenges, the future of solar energy in New Zealand is promising:
At Current Generation, we’re committed to helping you navigate the solar energy landscape. Investing in a solar PV system can be financially beneficial, especially when you maximise your self-consumption. By making informed decisions, you can contribute to New Zealand’s renewable energy goals and enjoy personal financial rewards.
By taking these steps, you not only enhance the return on your investment but also play a part in creating a sustainable, secure energy future for all of New Zealand.
Have you noticed more solar panels popping up on roofs around Nelson? Maybe you’ve been considering them yourself. But there’s often a question that comes up: “What about when the sun’s not shining?”
It’s a fair point. After all, we still need power at night and on cloudy days. That’s where battery backup systems come in, and they’re becoming an increasingly common sight in homes across New Zealand.
We’ve been installing solar systems since 2006, and we’ve seen a lot of changes in that time. One of the biggest has been in battery technology. These systems used to be bulky, expensive, and a bit of a hassle. But that’s not the case anymore.
If you’re curious about how modern battery systems might fit into your home or business, you’ve come to the right place. We’ll walk you through the basics, explain who can benefit, and give you the information you need to decide if it’s right for you. No fuss, no exaggeration – just straight talk about powering your property.
A battery backup system is a smart addition to your grid-tie solar setup. It’s like having a big rechargeable battery for your whole property. During the day, when your solar panels are working hard, this system stores up extra energy. Then, when the sun goes down, it releases that stored power, keeping your lights on and your fridge running.
Here’s why our customers love their battery backups:
Now, you might think these systems are just for folks with solar panels, but that’s not the case. We’ve installed them for:
Whether you’re in sunny Nelson, coastal Marlborough, or tucked away in Golden Bay, a battery backup can make a real difference.
Choosing the right size isn’t too tricky, but there are a few things to consider:
A well-designed system won’t drain your batteries too much, which means they’ll last longer. Pop in for a chat, and we’ll help you figure out what’s best for your place.
Battery technology has come a long way in recent years, and we’ve kept pace with these changes. At Current Generation, we’re always looking for the best solutions for our customers across the Top of the South.
Lithium batteries: The new standard
Lead-acid batteries: Still an option
Why we choose BYD batteries We’ve done our homework, and that’s why we exclusively stock BYD batteries. You might know BYD as the world’s largest EV maker, but their energy storage solutions are top-notch too.
Here’s why we trust BYD:
Absolutely. The systems we install have some nifty monitoring tools:
Whether you’re at home in Nelson or Blenheim, or away in the Marlborough Sounds, you’ll always know how your system’s performing.
Good question. Batteries have some advantages over generators:
Let me show you some data from a system we installed in Richmond:
Here are some screenshots of the monitoring from a GTBB (Grid Tie Battery Back-up):
Battery SOC (State of Charge): The batteries were fully charged about lunchtime and were discharged by about 20% overnight.
Battery Performance: The battery voltage (blue) climbed during the morning (the dips are when the sun is behind a cloud, or when a large load is drawn). During the afternoon it stayed steady (float charge). At sunset, the bank is no longer being charged and the battery bank’s voltage drops and goes down slowly overnight. The ‘blips’ overnight will be the fridge compressor turning on and off.
Consumption: During the day, the house is running mainly from solar with minimal draw from the batteries or grid. Only ¼ of a kWh was taken from the grid for the whole 24 hour period ($0.07 worth).
Solar Yield: This shows how energy is sent to the batteries until they’re full and then exported to the grid after that. During the winter months, there would be far less energy exported. Ideally, the grid is only really used for back-up and most of the energy used is produced on-site.
Live Feed: This is the live feed from the same system the following morning. The energy being yielded is not being exported to the grid – it gets sent straight to the batteries and the home until the batteries are full. When this snapshot was taken, 223W was being sent to the batteries.
With these advancements in battery technology, there’s never been a better time to consider adding storage to your solar setup. Here’s why our customers across the Top of the South are making the switch:
Look, we know it’s an investment. But with battery prices coming down and technology improving, many of our customers find it’s worth every penny.
We’ve been in this game since 2006, and we’ve seen the industry grow and change. Our focus has always been on providing top-notch solutions for the Top of the South Te Tau Ihu region – from the West Coast to Golden Bay, Nelson to the Marlborough Sounds, and over to sunny Blenheim. But we’ve got experience all over New Zealand too.
We’re not just about selling you a system – we’re about finding the right solution for your needs. Our designs are customised to your site, maximising your resources and giving you the best value for money (which isn’t always the cheapest option!). We make sure it works first time and looks great to boot.
If you’re curious about how these new batteries might work for your place, why not give us a call or stop by our shop? We’ve been helping folks around the Top of the South with their power needs for years now, and we’d be happy to share our local knowledge and experience with you.
Always straight talking, we’ll give you the facts, tools and support to understand the solutions we think are appropriate for you, allowing you to make an informed decision about how you power your future!
Original article:
During the day, the house is running mainly from solar with minimal draw from the batteries or grid. Only ¼ of a kWh was taken from the grid for the whole 24 hour period ($0.07 worth).
This is the live feed from the same system the following morning. The energy being yielded is not being exported to the grid – it gets sent straight to the batteries and the home until the batteries are full. When this snapshot was taken, 223W was being sent to the batteries.
So, the system works very well and adds multiple layers of functionality to a grid-tie system. As very few units are being imported (bought from the retailer), the money saved offsets the cost of the batteries over time. In the event of a power cut, the system remains active. It might be necessary (depending on the power use at your property) to have certain circuits switch off during a power cut to prevent over-discharge of the batteries, but this is fairly easy to automate. It can also be done manually of course. A generator can also be added if you need to be able to run large loads during extended power cuts. The battery bank needs to be sized based on one’s consumption and PV yield. If a battery bank that is too small is used, the voltage will drop too much when large loads turn on, causing importing of energy from the grid. This can also shorten the battery life. Furthermore, if a large load is switched off while in ‘off-grid mode’, a sudden in-rush of current from the PV to the batteries can happen, which is not ideal. A large battery bank is better for the batteries, but a balance needs to be struck between the service life of the batteries, their performance, and the capital investment.
In my opinion, a battery back-up system is the best way to add value to a grid-tie solar system. It will cost more up-front, but this will even out over time, all the while giving you added functionality.
Solar energy is a renewable power source that harnesses the sun’s radiation (often called irradiance) and converts it into usable electricity. In recent years, solar technology has become increasingly popular and viable in New Zealand, thanks to improving technology and falling costs. This clean energy solution is helping Kiwis reduce their power bills while contributing to a greener future.
New Zealand is blessed with ample sunshine, making it an ideal location for solar energy generation. While Nelson boasts the highest average sunshine hours nationally (around 2,400 annually), many other regions are not far behind. Marlborough, Canterbury, Otago, and most of the North Island also bask in high levels of sunshine. Even areas with less direct sunlight can still benefit significantly from solar installations as modern panels efficiently capture the available irradiance across a wide range of light conditions.
Solar PV systems are at the heart of the renewable technology revolution. These clever systems use solar cells to directly convert sunlight into electricity through a process known as the photovoltaic effect. The term “photovoltaic” itself combines “photo” (light) and “volt” (electricity), perfectly describing how these systems operate.
A solar panel has silicon semiconductor layers that absorb solar radiation. When sunlight hits these layers, an electric current is generated that can be harnessed for power. It’s a simple yet ingenious process that’s helping to reshape New Zealand’s energy landscape.
Embracing solar energy offers a multitude of benefits for Kiwi homes and businesses.
Nowadays the number one reason we see people moving to solar is financial. Gone are the days where solar was solely the domain of those prepared to (at least partially) ignore the economics for the sustainability benefits and/or the opportunity to use cutting edge technology to power their house. Now for most it is all about the 10-15% return on investment (6-9 year payoff) we are typically seeing for new grid tie systems; and this return will rise if power costs rise more quickly than the model predicts (we use 3% pa) or you can make changes to your power usage patterns to maximise the use of solar.
In addition, solar power is clean and renewable, producing no emissions during operation, thereby helping to reduce your carbon footprint.
Solar, particularly when coupled with a battery, also offers a degree of energy independence, reducing reliance on the grid and power companies. This can be particularly appealing in remote areas or for those looking to have more control over their energy supply.
From a practical standpoint, solar PV systems are remarkably low maintenance. With no moving parts, they require minimal upkeep, making them a relatively hassle-free addition to your property. We typically recommend you clean your panels every 12-18 months but that is it. Moreover, quality solar panels have a long lifespan with an expected lifetime of 30 years or more, providing excellent value for money.
An often-overlooked advantage is the potential increase in property value. As more Kiwis recognise the benefits of solar, homes equipped with these systems are becoming increasingly attractive to buyers.
When considering solar power for your property, you’ll encounter three main types of systems: off-grid, grid-tie (or grid-connected) and hybrid systems.
The financial aspect of going solar has become increasingly attractive in recent years. The cost of solar PV systems has decreased significantly, making them more accessible to a wider range of Kiwi households and businesses. Adding to the financial argument for solar, the price of power has been increasing meaning that each unit of power you produce on your roof is worth more to you. The combination of these factors now mean that many residential systems are projected to provide returns of 10-15%, equating to payoff periods of 6-9 years. Commercial systems can see much higher returns, up to 30% pa, due to the very high alignment between the timing of the power consumption by the business and the generation of power from the solar on the roof.
Residential systems typically range from $8,000 to $22,000 NZD, depending on size and complexity. Commercial systems, which can range from 10kW to 1MW, vary based on the project scope. While these figures might seem substantial, it’s important to consider the long-term savings and benefits.
Given that quality systems can last 30 years or more, this represents a significant period of ‘free’ electricity once the initial investment is recouped (although it would be prudent to factor in a change of inverter in that time period).
The outlook for solar energy in New Zealand is bright. Experts predict that solar PV could make up 6% of New Zealand’s electricity supply by 2035, marking a significant increase from current levels. This growth is expected to be supported by continued technological improvements, which should further reduce costs and increase efficiency.
The integration of solar power with other technologies, such as battery storage and electric vehicles, is set to enhance its value proposition even further. As grid electricity prices continue to rise and solar costs decline, the economic case for solar power in New Zealand is only getting stronger.
For Kiwis looking to reduce their carbon footprint, gain more control over their energy costs, and invest in a sustainable future, solar energy presents an exciting opportunity. As technology advances and adoption increases, solar power is poised to play an increasingly important role in New Zealand’s energy landscape.
Solar energy is a renewable power source that’s becoming increasingly popular among New Zealand homeowners. By harnessing the sun’s energy, you can reduce your electricity bills and lower your carbon footprint. However, the world of solar energy comes with its own set of terms and concepts that might seem daunting at first. This guide aims to demystify some of the most common solar terminology, helping you make informed decisions about adopting solar power for your home.
The conversion of sunlight directly into electricity using semiconducting material. Solar panels use the photovoltaic process to generate power.
A panel designed to absorb the sun’s rays and convert that into a useful source of energy, generally either electricity or heating; PV, or photovoltaic, solar is often used to refer to a system where the panels produce electricity.
A device that converts the direct current (DC) electricity produced by solar panels or discharged from batteries into alternating current (AC) electricity used in homes. Some inverters can also convert AC to DC to allow the charging of batteries from an AC source such as a generator or the grid, these are called inverter chargers.
A flow of electrical energy (technically usually electrons). Electrons need a conducting material or space through which to travel.
A device through which electrical current can move freely only in one direction.
A subatomic particle having a negative charge.
A crystalline substance having electrical conductivity somewhere between a conductor and an insulator. Silicon is a commonly used semiconductor in solar cells.
A non-metallic element often used as a semiconductor in solar cells.
A grid-tied solar system is connected to the local electricity grid. It allows you to draw power from the grid when needed and (usually) feed excess power back into it.
Off-grid, or grid-free solar is a standalone system not connected to the electricity grid. It requires battery storage to provide power when the sun isn’t shining and usually has a ‘back-up’ power source, such as a generator.
A grid-tied system that incorporates energy storage system (99% of the time, a battery) allowing the use of PV solar generated power when the sun isn’t shining and also provides back-up power during a grid outage, offering greater independence and energy security.
A collection of multiple solar panels working together to generate electricity.
A device that stores excess energy produced by your solar panels for use when the sun isn’t shining or during power outages. Batteries come with different ‘chemistries’. You’ll often hear about the likes of lead acid, lead carbon or deep cycle batteries (a particular lead acid battery construction). Now, lithium-ion batteries are generally considered the best solution for home or commercial battery storage with the two common chemistries being lithium iron phosphate (LiFePO4) and lithium nickel manganese cobalt oxide (LiNiMnCoO2 or NMC).
A device that optimises the output of the solar panels using a maximum power point tracker (MPPT) to vary the voltage and current from the panels to optimise the output of the panels. The solar charge controller then regulates the voltage and current going to the battery (or inverter), preventing overcharging and protecting the battery from damage.
Solar panels consist of a group of PV cells electrically connected and packaged in one frame.
Solar power is used to refer to the process of harnessing usable energy from the sun such that it can be used to as a utility. Solar panels are made up of photovoltaic (PV) cells, typically composed of silicon. When sunlight hits the silicon, it causes electrons to break free from their orbit around the nuclei of the silicon atoms. This creates a flow of electrons, or an electrical current.
The electric field surrounding the solar cells acts as a diode, allowing electrons to flow in a certain direction. By using metal contacts on the top and bottom of the cells, it is directed that current for use outside of the panel.
A solar power system often requires an energy storage unit called a battery to use the energy obtained throughout the day. The charge controller ensures that the batteries are not overcharged during the day or drained too much at night. To protect the battery from damage, the controller will not allow more current to be drained once the battery has been depleted to a certain level.
A kilo is “one thousand”, as in kilometre.
A measure of power equal to a Joule (J) per second (s) (1W = 1J/s). A Joule is a measure of energy, defined by James Prescott Joule as the energy used to accelerate a body with a mass of one kilogram using one newton of force over a distance of one meter.
The measure of time you know well.
So kW is 1000 Watts, a measure of power.
The size of a solar system is defined by its peak power, often denoted as kWp (the p standing for ‘peak’), e.g. a 1 kWp system can produce 1 kW of power per hour when operating in line with the ‘standard test conditions’.
kWh stands for kilowatt-hour; a kWh is a measure of energy (not power). This is what your power retailer charges you for in your power bill as it is the amount of energy you have used in the month.
If your solar panels (for example) continuously output 1kW of power for 60 minutes, they will have produced 1 kWh of energy.
The amount of electricity you use (or generate) is defined in kWhs. e.g. “My solar system produced 4 kWh of electricity today!”
So at the highest level: kW measures power, and kWh measures energy.
The average number of hours per day when solar irradiance reaches an average of 1,000 watts of electricity per square metre.
The policy that allows small-scale electricity generation, like rooftop solar, to be connected to the national grid.
The rate at which your electricity retailer buys back excess electricity generated by your solar system.
New Zealand’s goal to generate 100% of its electricity from renewable sources by 2030.
Understanding solar terminology is crucial for making informed decisions about adopting solar energy for your home. As solar technology continues to advance and become more affordable, it’s an increasingly attractive option for New Zealand homeowners looking to reduce their energy costs and environmental impact.
We encourage you to continue exploring solar energy options and contact your local solar providers to determine the best solution for your home. Remember, investing in solar power is not just about immediate savings—it’s a long-term commitment to sustainable living and energy independence.
—
This article was first published in 2018
COMMON TERMS
One of the key considerations for most people considering a home solar system is the potential return on their investment (ROI). While the upfront cost of installing a solar system can be significant, the long-term savings on electricity bills and other benefits can make it a smart financial decision in many cases. The solar experts at Current Generation break down the factors that impact your ROI and help you make an informed choice for your home or business.
These are some key factors that can affect the ROI of a solar PV (photovoltaic) system:
The size and cost of your PV solar system will have an impact on your ROI. A larger system will generally be cheaper on a per Watt basis and may provide greater savings over time resulting in a higher ROI. However, it will also have a higher upfront cost and, once your self-consumption needs are largely met, there becomes a point where the ROI likely starts to diminish because the additional power produced is never being self-consumed, it is all being exported. While current export rates offered by many power companies are making exporting power and the related ROI significantly more appealing, it is still important to choose a system size that is appropriate for your energy goals and budget.
The amount of electricity your home or business uses, the time of day it is used and the rates you pay for that electricity, will have the biggest effect on your ROI. If you have high electricity usage, use a lot of your electricity during the day and/or have high electricity tariffs, you will likely see greater relative savings from your solar PV system. It is important to review your electricity bills and usage patterns to estimate your potential savings, and to consider any likely changes in your energy needs or tariffs over time. This is something a reputable, experienced solar installer can assist with.
There are currently some great financing options available for solar in New Zealand, which can help to reduce the upfront cost. These are predominantly low-interest loans from the banks. With the right financing, you may even see an improved ROI.
Unfortunately, there are generally no incentives in the form of subsidies or tax credits available for the installation of solar in New Zealand.
The performance and maintenance of your PV solar system will also affect your ROI. A well-designed and properly maintained system will generally produce more energy and last longer, providing greater savings over time. It is important to choose high-quality components and work with a reputable installer to ensure optimal system performance. While the maintenance requirements shouldn’t be onerous, reasonably regular cleaning of your panels, particularly if you live in an area with a lot of dust, pollen or salt in the air, will help with ongoing performance and, therefore, improved ROI.
Installing a PV solar system can also increase the value of your property, which can provide an additional financial benefit beyond energy savings. Studies have shown that homes with PV solar systems can sell for a premium compared to similar homes without solar, and that this premium, in some cases, can be significantly more than the initial system cost. A study by homes.co.nz in 2020 showed that a 3kW solar installation could increase the sale price of a house by as much as $35,000 when compared to similar houses. An Australian study also suggested increases in property prices attributable to solar of $6,500 per kW of installed solar. There are also a number of American studies which support the increase in property values due to the installation of solar. As power generation and prices become more challenging in New Zealand, the value placed on PV solar by prospective buyers is only likely to increase.
While every situation is different, here are some general estimates based on current market conditions:
Of course, these are just rough estimates, and your actual ROI will depend on your specific circumstances and system design. It’s important to work with a reputable installer who can help develop a detailed ROI analysis for your solar PV system, taking into account all of the relevant factors and assumptions. By doing your research and making informed decisions, you can maximise the financial and environmental benefits of going solar, and enjoy a strong return on your investment for years to come.
Solar panels are where it all begins for any solar energy system, responsible for converting sunlight into usable electricity. Also known as photovoltaic (PV) modules, solar panels are made up of a series of interconnected PV cells that use semiconductor materials to generate an electrical current (direct current or DC electricity) when exposed to light.
The most common type of panel for residential/home solar systems is the crystalline silicon panel, which comes in two main forms – monocrystalline and polycrystalline. Monocrystalline panels are made from a single continuous crystal of silicon, giving them a characteristic black colour and the highest efficiency ratings. Polycrystalline panels are made from multiple silicon crystals melted together, resulting in a blue speckled appearance and generally lower efficiencies but often a lower price point.
As solar technology continues to advance, new types of panels are emerging, such as thin-film modules, bifacial panels, and building-integrated PV (BIPV). However, crystalline silicon panels remain the workhorse of the industry, offering a proven, reliable, and cost-effective solution for most applications.
You may also hear about N-Type or P-Type panels. This refers to technical differences in the type of crystalline silicon wafers which make up the so-called ‘bulk’ and ‘emitter’ regions. Generally, N-Type panels are slightly more efficient than P-Type panels.
Solar Panel Fine Tuning Process
Solar panel performance is typically measured in watts (W), indicating the maximum power output under standard test conditions. Residential solar panels usually range from 250W to 450W each, with 60 to 108 PV cells (or half-cut cells) per panel. The efficiency of a panel refers to how much of the sun’s energy it can convert into usable electricity, with most modern panels averaging greater than 20% efficiency with the best panels now greater than 22%.
When designing a solar power system, the number and wattage of panels needed will depend on factors like the property’s energy consumption, available roof space, shading, and local climate. Panels are mounted on the roof or ground using flush racking, tilt racking, or tracking systems that follow the sun’s movement.
They are then wired together in series to form ‘strings’. In turn, these strings can be connected in parallel before being fed into a MPPT (maximum power point tracking) solar controller (often called a charge controller). Solar controllers are sometimes standalone units which vary the direct current (DC) electricity from the panel into DC electricity that meets the input requirements of either a battery or inverter downstream of it.
Solar controllers can be built directly into inverters. The inverter’s fundamental purpose is to convert DC electricity to AC (alternating current) electricity that we use in our daily lives, but some inverters can also charge a battery, either by passing the DC electricity from the panels straight through to the battery (at a specific voltage that is required for charging the particular battery) or by converting AC electricity into DC electricity (batteries only charge and discharge DC electricity). An inverter that has solar controller functionality, converts DC to AC, charges a battery and is grid compatible is called a ‘hybrid’ inverter.
The lifespan and durability of solar panels are key considerations, as they are exposed to the elements year-round. Most quality panels come with performance warranties of 25 years or more which mean they will still be producing somewhere between 80 and 90% of their rated power (depending on the warranty) at the end of this warranty period. The panels are designed to withstand hail (typically up to 25mm hailstones), snow, wind, and temperature extremes. Reasonably regular cleaning and inspection should help maintain panel performance over time.
Most modern solar panels will work well in New Zealand. Here are some key factors to look for in solar panels for the conditions here:
Naturally efficiency is important. However, while a high efficiency panel is definitely desirable, there is a premium for the absolute state of the art panels which doesn’t stack up for most people on a watts per dollar basis. Most NZ installers currently install panels providing between 400W and 440W of peak output, this being the sweet spot between high efficiency and value. Efficiency and, therefore, panel ratings are also improving all the time as the technology advances.
The temperature coefficient of a panel is the measure of how much the performance degrades with each degree warmer the panel is (the standard test condition is 25 degrees, panels often get warmer than this even if the ambient temperature is lower). Panels with a low temperature coefficient are better able to maintain their performance in hot weather. Look for panels with a temperature coefficient of -0.35%/°C or better.
NZ’s weather can also be harsh on solar panels, with high winds and hail. While snow is rare in the Nelson, Marlborough and Tasman regions, it is an important consideration elsewhere in the country – especially off-grid, high-country installations. Choosing panels with robust construction and high wind and snow load ratings can help ensure they withstand the elements over their 25+ year lifespan. Look for panels with a wind load rating of at least 2400Pa and a snow load rating of at least 5400Pa, especially if your installation is in an area prone to heavy snow.
While the top of the South Island is one of the sunniest places in NZ, there can still be cloudy and overcast days. Panels with advanced cell technologies like PERC (passivated emitter rear contact), bifacial design, and half-cut cells can help maintain output even in low light conditions. For those lucky enough to be in the Nelson/Marlborough region, low-light performance may be less of a priority compared to other factors like efficiency and durability.
Given the long-term nature of a solar investment, it’s important to choose panels from reputable manufacturers with strong warranties and quality control. Look for panels with a product warranty of at least 12 years and a performance warranty of at least 25 years, guaranteeing a minimum output level over time.
Solar panels are the heart of any solar energy system, transforming sunlight into clean electricity. Whether you choose traditional crystalline panels or cutting-edge thin-film designs, it’s crucial to consider efficiency, durability, low-light performance, and warranty when selecting panels for New Zealand’s diverse climate. But a successful solar system goes beyond just panels – effective design that accounts for your unique energy needs, space, shading, and local weather is key to maximising performance and returns. By partnering with experienced solar professionals to create a tailored solution, you can fully harness the power of solar.
As technology advances and more people recognise the environmental and financial benefits of solar, New Zealand’s renewable energy future looks bright. By embracing solar power, Kiwis can reduce reliance on fossil fuels, cut emissions, and build a more resilient energy framework. With the right panels, design, and support, solar energy has the potential to revolutionise how we power our homes, paving the way for a greener, more prosperous future for all.
In recent years, solar power has emerged as an increasingly popular and viable option for homes and businesses across Aotearoa New Zealand. As the costs of solar technology continue to fall and awareness of the environmental and economic benefits grows, more and more Kiwis are turning to the sun to power their lives.
However, with several different types of solar systems available, each with its own advantages and considerations, it can be challenging to determine which option is best suited for a particular property or energy goal. This comprehensive guide aims to demystify the key solar power systems commonly installed in New Zealand – off-grid, grid-tie, and hybrid/grid-tie with energy storage (ESS) – the energy storage system is almost always battery. By understanding the components, operation, benefits, and limitations of each system type, readers will be better equipped to make informed decisions about their own solar journey.
Whether you’re a homeowner looking to reduce your power bills, a business seeking to boost your sustainability credentials, or a remote property owner aiming for energy independence, this guide offers valuable insights into the evolving landscape of solar power in New Zealand. So let’s dive in and explore the exciting possibilities of harnessing the power of the sun.
There are several types of solar power systems commonly installed across New Zealand. Each caters to different energy needs, budgets, user preferences and property types.
The three broad categories frequently installed are:
The choice of type of system depends on factors like location, energy usage patterns, budget, and desire for independence from the grid. Generally, grid-tie systems are most popular for their balance of cost-effectiveness, economic return and convenience. However, off-grid systems are becoming more viable as battery technology improves, costs decline and grid related charges such as connection fees balloon. Hybrid systems are quickly gaining popularity for the security they provide against grid outages, while still being significantly cheaper than a typical off-grid system.
Regardless of type, most solar systems in NZ are designed to prioritise self-consumption of solar power over exporting to the grid. This is because NZ power companies offer relatively low buy-back rates for solar exports and also often limit the amount you can export. This means it is generally more economical to directly use as much self-generated power as possible. As a result, it’s important to size a solar system based on a property’s actual power usage.
Off-grid solar systems are standalone electricity generation and storage systems that operate independently from the public power grid. These systems typically harness energy from the sun using photovoltaic (PV) panels generating DC (‘direct current’) electricity. This can then be converted to AC (‘alternating current’) electricity by passing it through an inverter. AC electricity is what almost all electrical devices are designed to use. Excess electricity is stored in a battery for later use (batteries charge and discharge using DC power so the power still needs to run through an inverter when you come to use it).
An off-grid system must be carefully designed to meet 100% of a property’s energy needs year-round, even during periods of low sunlight. This typically requires a larger array of solar panels and higher-capacity battery storage compared to grid-connected systems. A back-up power source, typically a generator, is usually incorporated into an off-grid system for periods of unusually high power demand or extended poor weather.
The key components of an off-grid solar system are:
While off-grid systems are generally more complex and expensive than their grid-tied counterparts, they offer unparalleled energy independence and can be the only option for properties too far from existing power grid infrastructure. Sometimes the costs of a grid connection to a site as little as 200 metres from a grid transformer/connection will be so high that an off-grid system is more economical, and there are no ongoing power bills!
Historically popular with remote homesteads, DOC huts, and mobile homes, off-grid solar is becoming increasingly viable for a wider range of rural and semi-rural properties with the fall in equipment costs and improvements in performance.
An example of a real-time off-grid system as viewed in Victron’s VRM monitoring tool. You can see the solar producing 3059W, 2694W being immediately consumed through the AC loads in the home and the remainder charging the battery (101W). The generator is currently in stand-by mode.
There are several compelling reasons why a household or business might choose to go off-grid with solar:
Of course, off-grid solar isn’t without its challenges. Higher upfront costs, complexity of design, and the occasional need for maintenance are all important considerations. But for those seeking true energy freedom and willing to make the investment, the benefits of going off-grid can be transformative.
Some key considerations for off-grid home solar include:
To maximise the efficiency and lifespan of an off-grid home system, energy conservation and smart power management are key. This can involve using energy-efficient appliances, scheduling power-hungry tasks for sunny periods and monitoring usage with a solar tracking app. Many modern off-grid inverters also have built-in load management features to automatically optimise power consumption.
With careful planning and the right setup, off-grid solar can be a reliable, cost-effective, and eco-friendly way to power a Kiwi home for decades to come.
Off-grid solar is not just for remote homes – with improvements in reliability, it’s also an increasingly viable option for businesses looking to reduce operating costs, improve energy security, and boost their sustainability credentials. Rural farms, eco-lodges or even industrial facilities can often feasibly power their operations with off-grid solar.
The benefits of off-grid solar for businesses are similar to those for homes, but on a larger scale. By generating their own electricity, businesses can significantly reduce or eliminate their reliance on the grid, leading to substantial long-term savings on power bills. The daily power usage profile of a business often also aligns very well with the production of solar PV electricity, allowing relatively more of the power to be consumed immediately and thereby allowing a smaller battery requirement when compared to the solar array – battery still typically being the most expensive component within an off-grid system.
Off-grid solar also provides businesses with a level of energy security, efficiency and independence that can be critical for continuity of operations. With a reliable on-site power supply, businesses are protected from grid outages, brownouts, or other disruptions that can impact productivity and profitability.
Furthermore, making the switch to renewable energy can be a powerful way for businesses to demonstrate their commitment to sustainability and attract eco-conscious customers and investors. With growing public awareness of climate change, many consumers are actively seeking out businesses that prioritise environmental responsibility. An off-grid solar system can be a visible and tangible symbol of a company’s green values.
Specific design is absolutely critical with a commercial application with the system needing to meet the unique energy needs and circumstances of each operation. A large dairy farm, for example, will have very different power requirements than a remote luxury lodge. However, the key components – solar panels, batteries, inverters, and backup generators – remain the same.
Some important factors for businesses considering off-grid solar include:
Grid-tie solar systems, also known as on-grid or grid-connected systems, are the most common type of solar setup in New Zealand. These systems are directly connected to the public electricity grid, allowing them to export excess solar power and import grid power as needed. This two-way flow of electricity provides the benefits of solar while maintaining the convenience of the grid. It also makes it easier to size your system to your budget as smaller systems will just result in the need for more importation from the grid, not a lack of power.
Similarly to off-grid systems, a grid-tie system consists of solar panels mounted on the roof or ground which generate DC electricity. This is then converted to AC electricity by an inverter and used to power the home or business. Any excess solar power not used on-site is automatically exported to the grid, earning the owner a credit on their power bill. Conversely, when the solar system is not generating enough power to meet demand (e.g. at night or on cloudy days), electricity is seamlessly imported from the grid as usual.
The key components of a grid-tie solar system are:
Grid-tie systems are generally simpler and more affordable than off-grid systems as they don’t require large battery storage or backup generators. They are also more flexible, as they can be sized based on available roof space and budget rather than having to meet 100% of a property’s energy needs.
However, grid-tie systems do have some limitations.
Firstly, they typically shut down during a grid power outage for safety reasons, meaning they can’t provide backup power during emergencies. However, some inverters, most notably the Fronius Gen24 inverters, can now be fitted with a so-called ‘PV Point’. This is a power socket which will supply limited power in an outage, provided the PV panels are producing. However, you will need to plug directly into this, it won’t power your household circuits, and it won’t work at night!
Secondly, while this has improved significantly, the economics of exporting electricity to the grid doesn’t always stack up that well. NZ power retailers typically offer buy-back rates between 8c and 17c per kWh for solar exports. As a result, you generally want to size a grid-tie system to maximise self-consumption of solar power rather than large-scale export. Just view the export component as a bonus.
Despite these limitations, grid-tie solar remains a popular and accessible way for Kiwi homes and businesses to enjoy the benefits of solar power while maintaining a connection to the public grid. With a well-designed system and smart energy management, grid-tie solar can significantly reduce electricity bills and carbon footprint without sacrificing reliability or convenience.
Grid-tie solar systems offer a range of compelling benefits for NZ homes and businesses:
Of course, grid-tie solar is not without its considerations. The upfront installation cost can still be a barrier for some, although prices have dropped significantly in recent years and sustainable loans with interest rates 0% or 1% are available through all of the major banks. There’s also the limitations in a grid outage to consider, at best you’ll have power from a power socket by the inverter while the sun is shining. This may be a concern for those in remote or blackout-prone areas.
But for the majority of NZ homes and businesses, the benefits of grid-tie solar are clear and compelling. With the right system design and energy management approach, grid-tie solar can deliver significant financial and environmental returns for decades to come.
At the heart of a grid-tie solar system is a two-way connection between the on-site solar array and the public electricity grid. This requires a ‘grid-compliant’ inverter, an inverter approved for connection to the grid by the lines companies. A grid-compliant inverter includes critical electronic mechanisms to ensure power isn’t fed into the grid during a grid outage; this could put lines people working on the grid at serious risk by livening wires thought to be not live.
Here’s a step-by-step look at how a typical grid-tie system works:
It’s worth noting that the exact mechanisms and economics of grid-tie solar can vary depending on the tariff structure the retailer provides and the usage profile of the user.
Regardless of the specific arrangement, the basic principle of grid-tie solar remains the same – generating clean, renewable energy on-site to reduce reliance on the grid, while maintaining a reliable grid connection for backup and export. With a well-designed system and favourable utility policies, grid-tie solar can be a cost-effective and low-maintenance way for NZ homes and businesses to take control of their energy future.
Hybrid solar systems, also known as grid-tie with energy storage (ESS) or grid-tie battery backup systems, combine the best aspects of both grid-tie and off-grid solar. Like standard grid-tie systems, they are connected to the public electricity grid, allowing for the import and export of power. However, they also incorporate a battery bank, enabling them to store excess solar energy for later use, similar to off-grid systems.
This stored energy can be used to power the home or business during the evening, on cloudy days, or during a grid outage. As a result, hybrid systems provide an extra level of energy independence and resilience compared to grid-tie only systems, while still maintaining the convenience and reliability of the grid connection.
With the advent of variable export tariffs from retailers such as Octopus Energy, batteries can even be used to take advantage of more favourable export tariffs at certain times of day.
The key components of a hybrid/grid-tie ESS solar system are:
Hybrid systems operate on a “solar first” principle, where the energy generated by the PV panels is first used to power the immediate needs of the home or business, with any excess then used to charge the batteries. Once the batteries are full, additional excess is exported to the grid. When solar production is insufficient to meet demand, the batteries are discharged to make up the shortfall. If the batteries are depleted, power is imported from the grid as needed.
Other demands can also be included into this equation, such as EV chargers and hot water diverters. The user can decide whether, once the immediate household or business demands are met, whether the excess power is used first to heat the hot water, charge the car or charge the batteries.
A more complex grid-tie battery back-up system as seen real-time on Victron’s VRM monitoring tool. It is a 3-phase system which includes an EV charger and has both AC and DC coupled solar. The AC coupled solar provides a highly efficient AC output, particularly good for the EV charger and household loads, while the DC coupled solar provides efficient battery charging. This system is currently exporting 7.79kW to the grid as the battery is fully charged and the total consumption (AC Loads and Critical Loads are significantly less than the current solar production (8.09kW).
One of the key benefits of a hybrid system is the ability to time-shift solar energy from the daytime to the evening peak usage hours. By storing excess solar in the batteries during the day and discharging it in the evening, homeowners can reduce their reliance on the grid during the most expensive peak tariff periods. Some hybrid inverters even offer “peak shaving” and “load shifting” functions to automate this cost-saving process.
Hybrid systems can also provide backup power during grid outages. Most hybrid inverters automatically isolate the home or business from the grid during a blackout and continue to operate using solar and stored battery power. This can be a huge advantage for those in areas prone to extreme weather events or an unreliable grid. Typically a system will be set to maintain a certain level of battery charge in case of grid outage, e.g. the system might start using grid electricity when the batteries have 65% of their charge remaining so that if there is an outage, this stored power can be used.
Of course, the addition of batteries does increase the upfront cost and complexity of a hybrid system compared to grid-tie only. However, with the rapidly falling cost of lithium-ion batteries and the development of new energy storage technologies, hybrid systems are becoming an increasingly attractive and affordable option.
Ultimately, the choice between grid-tie and off-grid solar comes down to the individual circumstances and priorities of each project.
Factors like location, energy usage, budget, and desire for independence will all shape the decision – for NZ homeowners and businesses looking for a solar solution that combines the energy independence of off-grid with the convenience of grid-tie, a hybrid/grid-tie ESS system is well worth considering.
With the right system design and component selection, a hybrid solar setup can provide reliable, sustainable, and cost-effective power for years to come, while also future-proofing against rising electricity costs and grid disruptions.
Current Generation are distributors and integrators of the BYD are pleased to supply of batteries for Fronius inverter products,
Fronius, a premium inverter manufacturer which is well respected in the world, have chosen BYD as their battery partner, making BYD the only approved battery for use with the new Gen24 line of Fronius inverters. This move reaffirms the standing of the BYD products.
THE NEW STORAGE GENERATION WITH THREE-PHASE AND SINGLE PHASE GRID BACK-UP
The high voltage BYD Battery-Box Premium Line has two models, the smaller HVS, and the larger HVM. The HV Premium Line from BYD is compatible with GEN24 Plus inverters, both the single phase Primo range and three phase Symo range.
The storage capacities available are 5.1–10.2 kWh for HVS and 8.3-22.1 kWh for HVM.
The voltages of the HVS and HVM differ. The more powerful HVS modules have a nominal voltage of 102.4 V each. By contrast, the HVM modules have a nominal voltage of 51.2 V per module. These different voltages subsequently lead to different charging and discharging characteristics.
Fronius has achieved a true grid back-up solution, with the BYD Battery-Box Premium HVS/HVM, allowing even three-phase loads to be used in a grid failure situation.
Like its predecessors, the Battery-Box Premium HVS/HVM is based on lithium iron phosphate – one of the most reliable storage technologies. The battery has a modular structure and can be expanded in steps of 2.6 kWh (HVS) or 2.8 kWh (HVM). This means that there is nothing to prevent the storage being expanded at a later date.
Another advantage of the BYD HVS/HVM is there is the option for the parallel operation of up to three battery storage systems. This enables higher storage capacities for larger household needs or small commercial systems.
The floor mounting allows the installation and commissioning process to be carried out quickly and easily.
By combining the BYD Battery-Box Premium HVS/HVM with other sectors such as heat supply or e-mobility, it is possible to achieve very high self-consumption rates and self-sufficiency levels. This results in maximum independence in the home.
Talk to Current Generation about your options, Trade enquiries welcome.
