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 solar system 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.
A standalone solar 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 gird-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.
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
Posted in Miscellaneous
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 solar PV system will have a big impact on your ROI. A larger system will generally be cheaper on a per Watt basis and may provide greater savings over time. 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. It is, therefore, important to choose a system size that is appropriate for your energy needs 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 affect 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. 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 quality solar installer can assist with.
There are certain financing options available for solar PV systems in New Zealand, which can help to reduce the upfront cost and improve your ROI. These are predominantly low-interest loans from the banks. Unfortunately, there are generally not incentives in the form of subsidies or tax credits available for the installation of solar in New Zealand.
The performance and maintenance of your 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, and to perform regular maintenance tasks to keep your system running smoothly.
Installing a solar PV 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 solar PV 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 kWh of installed solar. There are also a number of American studies which support the increase in property values due to the installation of solar.
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.
Are you considering installing a solar PV system? One crucial component you’ll need to decide on is the type of inverter.
The basic function of an inverter is to convert the direct current (DC) electricity generated by your solar panels or drawn from your batteries into alternating current (AC) electricity, which is suitable for use in your home or business.
Let’s start with the clearest delineation – string inverters versus microinverters.
String inverters – receive DC output from multiple solar panels (often your whole solar array or at least a ‘string’ or two) and convert it to AC electricity. It is a single large(ish) component usually mounted near your distribution board (although certain systems will call for multiple string inverters).
Fronius Gen24 ‘string’ inverter
Enphase IQ8HC microinverter
The commonly held view has been that microinverters, when compared to string inverters, generally perform better, particularly if one or some of the panels are shaded, last longer and are safer. However, the latest string inverters, such as the Fronius Gen24 range, have very high performing maximum power point trackers (MPPT), which were found by a recent French study to perform as well as microinverters. These modern MPPTs even minimise the power loss across an array if there is shading on some of the panels to the extent that there is little to chose from between a microinverter system and a string inverter system.
The argument that they last longer is also generally discounted nowadays on the basis that they are both inverters and it really just comes down to the quality of the built by the manufacturer. Therefore, there is no particular reason string inverters from reputable manufacturers such as Fronius and Victron shouldn’t last as long as an Enphase microinverter. However, if a microinverter fails, it won’t take out the whole system, whereas a string inverter likely will. However, there is still a high likelihood it is simpler to get a string inverter repaired as it is usually at ground level, easily accessible and may only need a component replaced. With a microinverter, you will need to locate the problematic unit in the array, potentially requiring removing part of the array, and then install a new unit.
In New Zealand the warranties for Fronius string inverters (provided you register the inverter with Fronius) and Enphase microinverters (by far the most common microinverter brand) are both 10 years.
If the ability to expand your system is a key design requirement, microinverters are likely worth considering. As each panel effectively becomes its own little power station, feeding AC electricity, expandability can be more straightforward. However, as is usually the case, it depends on the situation. There can still compatibility issues with microinverter controllers and the like, and in many scenarios, especially with a bit of planning when the first phase of the installation is designed, it may be easier and cheaper to expand a system using a string inverter.
One notable upside to microinverters is that the electricity moving around is generally AC electricity, rather than DC electricity, which is safer. This is a consideration although modern string inverters do limit this risk through systems like Fronius’ Arc Fault Circuit Interruption (AFCI). There are also regulations in place to make sure the cables carrying DC cable are well protected and this part of the installation is a focus of the independent electrical inspector, who is required to inspect all solar installations.
Another advantage of microinverters is that the panels do not all need to be aligned the same way. A single MPPT requires all panels to be in the same alignment (both angle and pointing in the same direction). The likes of a Fronius inverter only has two MPPTs built into it so you can only arrays in two different alignments feeding it. Other manufacturers such as Victron, while they use string inverters, do not generally build in the MPPTs, producing these separately so they can be sized for the number of panels in a given array/on a given aspect. However these can multiply up quickly and create a complex power wall. Microinverters incorporate individual MPPTs so are a great solution if a installation calls for small numbers of panels (say 1 to 4) on lots of different aspects (three or more).
Victron Multiplus-II inverter. This inverter does not include a MPPT, instead it requires a standalone MPPT ‘solar controller’ such as the one below, to be incorporated in a solar installation.
Victron MPPT SmartSolar 250/100 Solar Charge Controller. This is a standalone MPPT that works with the likes of a Victron Multiplus-II string inverter.
The major advantage of string inverters is price and simplicity. The reality is that for the vast majority of installations undertaken in New Zealand, the advantages of microinverters are very limited when compared to modern string inverters (and MPPTs) and do not justify the additional cost which can result in the system costing as much as 50% more.
A basic inverter function is to simply convert a particular voltage of DC electricity (usually 12V, 24V or 48V) to AC electricity (230V for regular NZ usage). It does not have a MPPT and therefore needs a separate solar charge controller, such as the Victron SmartSolar Solar Charge Controller above, to manage the ‘raw’ output of the PV solar. It will then take the DC output of the solar charge controller or the battery and convert it to AC for use in your household or business. It only has an AC output, not an AC input, and therefore cannot charge a battery from an AC power source such as the grid or a generator.
An example of this type of inverter is the Victron Phoenix range of inverters.
An inverter charger is similar to the basic inverter above in that it doesn’t have an in-built solar charge controller, but it will have at least one AC input. This allows it to take power from an AC source such as a generator or the grid and charge the battery. This is a requirement in most off-grid systems with a back-up generator and in grid-tied peak shaver systems that charge the batteries from the grid to provide back-up capability from battery, shift import of power to times with cheaper tariffs or provide additional capacity to a system for high demand periods (i.e. if power demands at certain times are higher than the the supply current, in NZ most single phase residential systems have a supply limit of 63A).
Examples of inverter chargers are the Victron Multiplus, Mulitplus-II and Quattro ranges.
A hybrid inverter is a string inverter (i.e. an inverter that has the MPPT to allow it to manage the PV solar) that can also integrate with a battery. Hybrid inverters are often quite particular about the batteries they will integrate with but, for many people, it gives a great, streamlined system.
A hybrid inverter will also synchronise with the grid and meets the regulations to be compliant to be connected to the national power grid – the relevant regulation for whether you can have an inverter connected to the grid in New Zealand is AS/NZS 4777.2.
Examples of hybrid inverters are the Fronius Gen24 Plus inverters and the Victron EasySolar range.
Ultimately, the best inverter for your solar installation depends on your specific needs and situation. For the majority of grid-tie installations, a string inverter or hybrid inverter will be the best, most cost-effective solution but there is definitely a place for microinverters and inverter chargers in certain systems. In off-grid systems, inverter chargers come into their own, but there are significant loads while the PV solar is producing (e.g. a spa pool or EV charging), including an efficient string inverter such as a Fronius Gen24 inverter in the system may still make sense.
By carefully weighing the factors and consulting with a professional solar installer, you can choose the inverter(s) that best meets your requirements and optimises the performance, cost-effectiveness, and longevity of your solar system.
Investing in solar is a significant decision, and selecting the right inverter is crucial to ensuring that your system performs at its best.
New Zealand is a windy place and any systems out there at the mercy of the elements, wind or solar, must be capable of coping with our harsh environmental conditions. Current Generation supply Pinnacle wind generators. If you’re thinking of investing in a small wind turbine to generate electricity, here are some answers to some of the most asked questions.
Wind turbines are a clean and efficient method of turning raw kinetic wind power into electric power.
Wind turbines can be connected directly to machinery for mechanical energy, or they can be connected to power generators and can create electricity. These three bladed structures, mounted on high poles or towers, are typically pointed into the wind using computers and sensors.
The wind turbine itself is made up of a rotor mounted to a wind turbine generator which is mounted to a frame and then a tail is mounted on the opposing side of the rotor.
If the wind turbine does not have a sensor-based system pushing it into the wind, the tail will adjust it manually. Higher towers and broader rotors will generate more energy overall, so if you are considering the investment, understand that it is long term outlay and that the relatively low additional cost for a higher tower or larger rotor on your wind turbine will help offset the overall cost more quickly.
As you consider your investment in a wind turbine generator, consider a hybrid power system using solar electric panels as well. Depending on where you live the seasonality of wind speed and the amount of sunshine produced in the warm summer months, you may find that you’ll reap more benefits from using all of your natural resources to power your home rather than just one or the other.
A basic wind power system will consist of:
Wind turbine on top of a tower (1) that is wired down to a control box (2) that regulates the charging of a large deep cycle battery bank Inverter which draws electricity from the battery bank and converts to normal household electricity (AC) & feeds the appliances in the home with power as needed.
Various safety devices like fuses, breakers and lightning arrestors
Free energy for renewable energy installations comes mainly from the sun and the wind. Wind turbines are the ideal partners for solar panels because when the sun is not out during the day, the wind is usually blowing if you’ve got a good wind turbine site. At night there is no power from your solar panels, but it is often windy. Wind turbines are also cheaper than solar panels for the same power output, although the overall cost of the energy installation must be considered.
This depends on how much energy you need, and how much is available from the wind at your site.
Evaluating your energy requirements is not too hard – it focuses on the various electrical appliances you have, how much power they use, and how often you use them.
If your intended site for the wind turbine is up on a hill or a ridge and/or is exposed to high prevailing winds, then there is a good chance that much of your energy can be supplied from the wind turbine.
Renewable energy installations for homes often have a 1 kW wind turbine that has a rotor that can be anything from 2.1m to 3.6m in diameter.
If you have larger energy requirements and you have a good wind resource, then a turbine might suit.
A windy place on your property is the obvious choice, but carefully consider the options before deciding on the best spot.
For example, although the edge of a cliff on a coastal property might be windy, don’t put your wind turbine there because abrupt changes in the landscape makes the wind do strange things and can adversely affect your wind turbine’s performance.
In general terms, a site that has at least a half-acre of open land and average of 10 mph (16km/h) or higher winds is a good candidate for a wind turbine installation.
Pine trees can grow quickly, so don’t erect a turbine amongst young trees As a general rule, an exposed and elevated site with gentle surrounding contours (preferably flat) is the best.
Distance between your wind turbine and your house will vary from site to site, and there are ways of minimising the losses in your cable connecting the two, depending on the specifics of the machine you buy and your application.
Check with your local authorities for their requirements regards, height, distance from dwelling etc too!
Noise is an issue for some people, and not for others.
It is subjective. If you are intending siting your machine close to your home and are worried about the noise, then buy a machine that is designed to be quiet. In many cases you won’t be able to hear it no matter how noisy it is, because the wind itself creates noise around the house, trees and so on, or the machine is sited far enough away from your house. Don’t be tempted to attach the wind turbine directly to your house, no matter how easy it looks to do. The vibrations and resonance from the turbine will keep you awake at night.
When considering renewable energy options for your home or property, you may be wondering whether wind or solar power is the better choice. Both have their advantages and can work well together in a hybrid system.
Here’s a comparison of wind and solar energy to help you make an informed decision:
Both wind and solar power have their strengths and can be effective renewable energy sources. The best choice for your property will depend on factors such as your location, available space, budget, and energy requirements. A hybrid system that combines wind and solar can offer the benefits of both technologies, providing a more reliable and consistent power supply.
This article was originally published on Solar Quotes, the original post can be found here. So, what is a kW & a kWh?
And what is the difference between a kW and kWh?
An older style meter showing kWh
Let’s start with what each letter stands for:
So kW means kilowatt which is 1000 Watts, a measure of power.
Notice that, if you like to keep pedantic electrical engineers like me happy, the correct way to write it is always with a small k and a capital W.
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 testing parameters.
kWh stands for kilowatt-hour; a kWh is a measure of energy (not power).
If your solar panels (for example) continuously output 1kW of power for a whole 60 minutes, you will have produced 1 kWh of energy.
Why is the difference between Energy and Power important?
It is very common for people to mistakenly interchange the terms energy and power as if there is no difference. Most people do it all the time without noticing. It drives electrical geeks up the wall.
For example, if someone is talking about their electricity usage and says, “I used 8kW yesterday”, they probably mean that they used 8 units of electrical energy yesterday. In this case they should really say, “I used 8kWh yesterday”
Yeah, yeah I know what you are thinking: Who cares?
Well it is actually quite important if you are buying a solar system. If someone says they need a solar power system to produce 8kW, they might end up being quoted an 8kWp solar system. Which will cost about $24,990 + installation at today’s prices and produce about 32kWh per day.
If, what they actually meant was that they need one to cover an energy usage of 8kWh per day, then they really need a 2kW solar system which costs about $8,375.00 + installation at the time of writing!
So please don’t confuse kW and kWh. If you do you may end up with a solar system that is completely the wrong size! Top tip for filtering out the worst solar salesmen: Ask them to explain the difference between a kW and kWh. If they get this wrong how on earth are they gonna understand your requirements? A lot of cold calling door knockers will fail this test in my experience. The technical bit for those that are interested:
Is Your Roof Right for Solar Power?
Solar power is a fantastic way to reduce both your electricity bills and carbon footprint, particularly in regions like Nelson, Tasman and Marlborough which are known for their high sunshine hours – but not every roof is suitable for solar panel installation. If you’re thinking about adding solar to your home, here’s a guide to assessing if your roof is suitable for mounting solar panels.
The first thing to look at is the angle of your roof. The optimal angle for solar panels is generally equal to the latitude of your location to maximise sun exposure throughout the year. For example:
If your roof angle differs from these ideal conditions, don’t worry too much. A deviation of about 10° from the ideal angle typically results in less than a 5% decrease in power output. In New Zealand, typical roof angles are between 15° and 35°, which are generally sufficient for effective solar energy generation. If your roof is flat, consider installing tilt racking to position the panels optimally. Despite the additional cost, the additional output from mounting your panels at a more optimal angle with typically result in a short pay-off period.
The next thing you should consider is the direction that your roof is facing. In the Southern Hemisphere, a north-facing roof is perfect for solar installations. While north is ideal, technological advancements and reduced costs have made east or west-facing roofs increasingly viable. In New Zealand, where sunlight is abundant in many regions, an east or west orientation can still harness significant solar power. In fact, this may work well with your daily energy usage profile, providing good output earlier and later in the day when your demands are higher.
Previously panels needed relatively direct sunlight to produce a meaningful amount of energy, nowadays the technology has improved such that even south facing panels will provide reasonable production; similarly you’ll see production on overcast days. As an example, and this is not to suggest you mount your panels facing south(!), on a 15 degree southerly facing roof in Hobart, Tasmania (which at 42.9 degrees latitude, is south of Nelson) a panel will still provide 74% of what it would if mounted in the ideal direction over the year. However, it is worth noting the winter production will be fairly abysmal, generally only about 40% of their north-facing counterparts.
Today, the improvements in PV panel affordability also helps provide a solution. Where roof aspects are not ideal for all-day sun, it is often worth adding a couple of extra panels (so-called ‘over-panelling’) to get the most out of your system. This works very well where you have panels facing multiple directions (e.g. NW and NE) as it provides more consistent output throughout the day, as opposed to their being a large peak in the middle of the day.
The last one, the biggie… is shading. If any shade falls on your roof, then you must quantify whether that is going to be a problem – or how big of a problem it is going to be. Shading is a critical factor that significantly impacts the effectiveness of a solar installation. If trees, nearby buildings, or other obstructions cast shadows on your roof, it’s essential to conduct a detailed shade analysis. We generally work with 16 degrees being the angle above which we want to avoid any substantial objects that may shade the panels; this equates to the mid-winter sun angle at 10am.
Occasion shading of a small part of an array on a string inverter is not such an issue nowadays as it was in the past. Where in the past, microinverters were often used to manage potential shading by effectively individualising the management of the panels so shading on one panel wouldn’t effect the production of another, panel and solar controller technology has improved significantly meaning it will only limit the production from the shaded panels (and possibly only the shaded half). This improvement has meant there is generally less call for microinverters in installations than there once was.
Determining whether to install solar panels on your roof isn’t just about having the perfect conditions; it’s about making the best of what you’ve got. Most roofs, while not ideal, can be adapted to significantly boost their solar viability. This is where a skilled solar installer becomes invaluable. They won’t just look at your roof and see an angle or orientation; they’ll see potential.
By carefully assessing the specifics of your roof’s angle, direction, and shading, a seasoned installer can provide you with a detailed analysis of what to expect in terms of energy production. They’ll give you the hard numbers on potential power output losses and weigh them against the benefits of going solar. This means you won’t be going in blind; you’ll have all the facts you need to make an informed decision.
Remember, if your roof isn’t viable, there may well be the option of a ground mounted solar array, so all is not lost. One advantage of ground mounted arrays is that you can generally position them to face the ideal way, at the ideal angle and avoid any shading.
For homeowners in New Zealand, considering these factors can help maximise the benefits of solar installations, allowing you to tap into the renewable energy market efficiently. This proactive approach not only supports the environment but also aligns with New Zealand’s goals for sustainable development and energy independence. By overcoming the usual hurdles associated with residential solar power systems, you not only contribute to a greener planet but also invest in long-term savings and energy security for your home.
Should you put your panels on tilt frames?
Tilt frames are used to get solar panels to the optimum angle and maximise power output.
Here is really common dilemma:
“I’ve got 3 quotes for solar: The first company says my roof is at the wrong pitch and wants to charge me hundreds of dollars extra to put my solar panels on tilt frames to optimize the amount of electricity I get. The second mob say it is fine to just put the panels flush on my roof and the third guy says that, yes, my roof isn’t at the perfect pitch, but the best solution is to mount them flush to the roof and simply add an extra solar panel to make up for any reduced power output.
Now I’m really confused! Help!”
The problem here is that there are two extremes of solar installers:
At one end of the spectrum, you have “The Solar Purist”.
They are only happy if the solar panel is positioned for the absolute optimum power output – they are a perfectionist, highly technical, and have been in the industry since the dawn of solar, when solar panels cost 10 times what they do today. They think a few hundred dollars is a small price to pay to squeeze a bit more power out of those precious solar panels. And please, never, ever suggest to them that they use a non-German inverter.
Then at the other end of the scale – you’ve got the “She’ll Be Right” Solar Installer.
They just want to get the install done. If you’ve got a roof, and it doesn’t face south, and it’s not completely shaded they’ll bang the panels on and move on to the next job.
We believe that the best installation for your home is somewhere in the middle.
The best solution to maximize return on your investment.
You need to consider the financial consequences for each option and then decide whether tilt frames are a good investment or not.
So, let’s look at a typical scenario where tilt frames would be an option and see which of our 3 original options makes the most sense from an economic perspective:
To Tilt or Not to Tilt – that is the question
How to work out if tilt frames make sense or not:
Imagine you have a house in Nelson and you want to install a solar system. The house has a North facing roof that has a very shallow slope of 10° and you want to install a 3kW system. The perfect tilt angle for solar panels is the same as the latitude of the install location. Nelson has a latitude of 41°.So therefore the panels should be of the Latitude.
So, if we follow those guidelines, we’d have to use tilt frames for all our solar panels, right?
Panels at the perfect Angle:
If we crunch the numbers, then we can quickly work out that 3kW of north facing solar panels at the perfect angle of 41° will produce 12.0kWh per day averaged over 1 year. If we value our electricity at 25c per kWh, then that earns us $1095 per year.
Panels at 10° If we crunch the numbers for 3kW of North facing solar panels at only 10° then we discover that we get 11.6kWh per day which makes us $1058.
How much do tilt frames cost?
Assuming our 3kW system uses 195W panels, the extra cost of tilting 16 x 195W panels should be around $450. So to make an extra $47 per year, we are going to be spending $450. About a 9-year payback.
Whether you think this is a good investment is completely up to you. But your solar installer should give you the numbers so you can make an informed decision!
I personally wouldn’t bother, mainly because, if you use tilt frames on your roof, you can fit fewer panels on that valuable roof space.
Why?
Because you need to leave extra space between the panels so that one row of panels doesn’t cast a shadow on the row behind it. I also think that tilt frames are not so aesthetic to look at. But perhaps that is just me.
What about adding an extra panel?
The third option you have – is to make up for any lost power by simply adding an extra solar panel. A few years ago, when panels were 5 x the price, this would have been an insane suggestion (and some old school solar installers still think it is a terrible waste!) but in 2012 it can make a lot of sense.
The cost of one extra 195W panel will be about $440. Installed flush to your roof, this 17-panel system will generate 13.0kWh per day and make us $1186 per year.
So, your extra $440 investment is returning you an extra $169 per year compared to the 16-panel system mounted on tilt-frames at 41°. I’d say that the extra panel is a much better investment that the racking.
The third installer was right! (Oh! That’s us!) Call Current Generation today for common sense solar facts.
Note: One thing that you don’t want is completely flat panels (angle = 0°). You want them to slope at least 10° so that the rain flows down the slope and helps the panels self clean.
