What is Solar PV?

Solar power, solar electricity, solar PV, solar Photovoltaics are all ways to describe making electricity from the sun by using solar panels on your roof.

Why choose solar power?

NZ has an abundance of sunshine hours compared to many other countries so it makes sense to utilise this free source of energy to help minimise your monthly power bills. Investing on solar power will also help reduce the impact of increasing power prices, improve the value of your home/business and protect the future of our environment. Once you have paid for the initial instalment of your solar PV system, the energy that is generated is absolutely free.

Are solar PV systems good value to money?

The cost of solar systems have reduced significantly in recent years making it more affordable. The payback period is generally between 6-9 years, after which, the power your system generates is free, without factoring in the added value to your home or business. Commercial installations often provide a quicker return on investment due to the ability to claim back GST and depreciation on the panels.

What is solar power self-consumption?

The concept of solar power self-consumption applies to grid connected solar power systems.  When your solar panels are producing power you will either be exporting the power to the grid or you will be using the power for electrical appliances within your home or business.  Self-consumption is when you use solar power directly for your own use. Why should you aim for solar power self-consumption? Off-setting your electricity bill with solar power is more valuable than exporting your power to the grid, and this is why self-consumption is ideal. By using solar power directly you are eliminating the need to buy power from the grid, which is approximately 30¢ per kWh. If you were to export that power to the grid energy companies will only get paid around 4-8¢/kWh for your power, which is not as valuable as using the power yourself.

What size solar system do I need?

Renewable Solutions customise solar PV systems to suit your unique requirements to help you maximise your self-consumption. Off-setting your electricity bill with solar power is more valuable than exporting your power to the grid, and this is why self-consumption is more economical. If you want to install a larger system and then store any excess power we can also advise and provide battery storage options. We are happy to carry out a free assessment of your power usage and your goals and recommend a system size accordingly.

How do solar PV panels work?

Solar panels are fixed to your roof, ideally in a north facing direction so they capture as much of the sun’s rays as possible.

The PV cells in the solar panel convert the sunlight into Direct Current (DC) electricity. The DC power then needs to pass through an Inverter which converts the DC electricity into Alternating Current (AC) electricity. The AC electricity can then be used to power lights and appliances in your home / business. On cloudy days you will still be generating electricity though not as much as on sunny days. During cloudy days and at night, you can draw electricity from the grid.

You can choose to size a system in line with your daytime usage, if there is any power that you don’t use, this can be sold back to your electricity company. You would need to ask your power company to install and import/export meter so that this can happen, most power companies do this for free. Typically, power companies will then buy the power for between 4-8 cents per kWh.

Storing power

Self-consumption of the solar energy you generate is ideal so should you choose to invest in a larger PV system that generates more power than you are likely to use during the day then we recommend that you store any excess power that you don’t use into batteries. This will allow you to use the stored power in the evenings when it’s dark when the panels aren’t generating electricity.

If you choose not to store excess power in batteries then, in the evening, when it is dark, your home/business will simply switch back to using power from the grid.

Which solar panels are the best?

At first glance, it is difficult to tell the difference between solar panels.  That's why the inner values, like the quality of the materials used, specifications, manufacturing processes and reliability of the manufacturer are important.

Internationally, solar panel manufacturers are rated as Tier 1, 2 or 3. Tier 1 being the most reliable and from the most reputable and financially secure companies and Tier 3 being potentially the least reliable. A Tier 1 company invests heavily in Research and Development, uses automated manufacturing, is vertically integrated, (makes the PV cells, not just an assembler), and has been manufacturing for more than 5 years.  Less than 2% of manufacturers are Tier 1.

We recommend Kyocera panels, who in our view, are one of the best Tier 1 manufacturers.  Kyocera is one of the world's largest vertically-integrated producers and suppliers of solar energy panels. Since 1975, they have manufactured and installed over 5 gigawatts of solar collection equipment, setting the industry standard for innovative solar power solutions with dependable, affordable best-in-class technology.

To find out about Kyocera module certification click here

http://www.kyocerasolar.com.au/about-kyocera-solar/kyocera-solar/certifications.htm

and…

http://www.kyocerasolar.com.au/assets/pdfs/we_are_in_the_details.pdf

Can I use solar PV to heat my hot water cylinder?

The simple answer is “yes”. By integrating some simple control devices you can use any excess electricity generated to heat your hot water cylinder and switch on four other appliances. For example: Your dishwasher, washing machine, spa pool, garden irrigation. Often these devices offer a smart personal energy monitoring & management system that transmits information on the energy generation and household power consumption directly to your smart phone or tablet. Compatible with both Android and Apple devices, you can see the system working on your device by downloading an App.

What is an inverter?

An inverter is an electronic device used to change DC electricity into 230V AC electricity that you can use in your home. Inverter can be single phase or 3 phase, as required making them suitable for residential and commercial/industrial use. There are many manufacturers of inverters worldwide, including Enasolar from New Zealand and Enphase who have their R&D site in Christchurch.

What are the best inverters?

As the efficiency and reliability of the inverter is essential to every system, Renewable Solutions have heavily researched the products we offer. We will recommend a product that provides the best solution to suit your unique requirements.

What is a string inverter?

Most grid tied systems use a centralised "string inverter" for high performance, durability, simplicity and cost effectiveness.

What is a micro inverter?

A micro inverter is a small inverter dedicated to each solar module and can offer better performance when partial shading of the panels may be an issue or you want to add more panels to a system a later date.

What is a grid tied inverter?

Put simply, a grid tied invertor is used for properties still connected to the national grid. It converts the sun's energy via the panels on your roof, into useable electricity in your building or home. You don’t have to buy power from the grid (energy company) when your generation is equal or greater than the building /house demand. Any power that the panels produce that you don’t use is sent back to the electricity grid. A smart meter will measure how much electricity is drawn from or fed back to the grid, and any excess electricity generated can be credited back to your power account.

What is a battery inverter?

A battery inverter takes stored DC power from a battery bank and converts this into 230V AC that goes to your switchboard to power your home.

How do solar PV panels fix to the roof?

Your solar panels will generally be positioned on your roof, facing as close as possible to the north for maximum sunshine, hours and positioned at the optimum angle to capture the sun's energy as effectively as possible. Depending on the pitch of your roof, we generally ensure the panels are pitched up at a 35 degree angle from horizontal.

In most cases, a roof top provides the least shaded position, however, there are situations where a ground mounted panels are a more practical option and offers an optimum panel aspect for the greatest power yield.

All panels are secured to the roof of your building or ground structure to withstand our NZ weather extremes. Kyocera panels also have two backing rails per panels to provide extra mechanical strength in adverse weather conditions.

How much roof space is required for a solar PV system?

The amount of roof space required will depend on the size of the system you wish to install. For example, a 3kW system will require about 24m2 of roof space that is un-shaded and ideally, north facing.

How effective are solar systems in winter?

Solar PV Systems are not reliant on heat, simply sunlight and ultra-violet rays. While there may be fewer hours of sunlight in the winter months, the actual conversion of power will be unaffected by the change in season. Having the panels pitched at a 35 degree angle will help to optimise the amount of power generated during winter.

Do solar PV panels generate power on cloudy days?

Solar PV panels are made of silicon and only need the sun’s radiance to work, so even on a cloudy day they will still generate power – albeit with lower production than on clear days.

Can I add more panels to my solar PV system if my circumstances change?

Assuming you have extra suitable roof space to accommodate more panels then feasibly you can add to an existing system. If you think you might want to increase the size of your PV system in the future, micro inverters are always a good choice as these can be added to easily and can work out more cost effective. If you have installed a string invertor then it will depend on whether you have reached the maximum capacity of that string invertor, if you have reached that capacity you could look at installing a second system. Renewable Solutions are happy to inspect any existing systems and advise accordingly.

A Renewable Solutions Consultant will be happy to answer any other questions you might have and look forward to working with you.