FAQ

Solar power is by far the Earth’s most available energy source, easily capable of providing many times the total current energy demand. However, it is an intermittent energy source, meaning that solar power systems usually must be supplemented by another energy source such as grid energy (Grid Connect System) or stored energy (Stand Alone System).

A solar cell or photovoltaic cell (PV) is a device that converts light into electric current using the photoelectric effect, which can be used to power equipment or to recharge a battery. The first practical application of photovoltaics was to power orbiting satellites and other spacecraft, but today the majority of photovoltaic modules are used for grid connected power generation. In this case an inverter is required to convert the DC to AC. Solar power generation is also perfect for off grid power for remote dwellings where grid power is not feasible.

Photovoltaic cells require protection from the environment and are usually packaged tightly behind a glass sheet. When more power is required than a single cell can deliver, cells are electrically connected together to form photovoltaic modules, or solar panels. A single module is enough to power an emergency telephone, but for a house or a power plant the modules must be arranged in arrays.

In Australia, 21% of our energy is sourced from solar power, with 1 in 4 homes now having solar installed.

There are still very attractive government rebates and incentives available for the installation of solar power systems in all states, both on and off the grid. The government rebate is based on Small scale Technology Certificates or (STCs) which are created when a solar system is installed. STCs are similar to the now superseded Renewable Energy Certificates (RECs), having replaced them on the 1st January 2011.

The number of STCs eligible to each customer is based entirely on the size of the solar array and on the zone (or latitude) in which the system will be installed.

Stand-alone power systems are also eligible for STCs provided the system is designed and installed by a CEC SPS accredited person and a secondary power source such as a generator is included in the installation.

You can refer to this link to determine the number of STC’s you are entitled to; https://www.rec-registry.gov.au/rec-registry/app/calculators/sgu-stc-calculator
Trading these STCs in order to sell them can be quite a complicated and time consuming process. This is why Towards Tomorrow Energy (TTE) offer a simple Point of Sale Discount included in our system prices in exchange for the transfer of these STCs from our customer to Towards Tomorrow Energy. TTE do not profiteer from the trade of these STCs but simply pass on the total eligible rebate amount to the customer based on the value of the STCs on the day of installation.

For further information on rebates and incentives please refer to the following link or contact us today on 1300 732 224.

http://www.climatechange.gov.au/government/initiatives/renewable-target/need-ret/solar-credits-faq.aspx

Solar panels convert light from the sun into electricity. The output of the solar panels is direct current (DC) electricity. This is converted to alternating current electricity (AC) by an inverter so that electricity can be supplied to the household. In the case of a grid connect system, any excess power produced by the solar panels is fed back to the electricity grid.

Photovoltaic cells (the technical name for solar panels) were developed at Bell Laboratories in the early 1950s as a spinoff of transistor technology. Very thin layers of pure silicon are impregnated with tiny amounts of other elements. When exposed to sunlight, small amounts of electricity are produced.

As the name suggests, multiples strings originating from the solar panels are attached to the inverters, and the DC electricity produced in them are then transformed into AC current. A solar system located on a roof doesn’t require more than one or a maximum of two string inverters. They are cheaper than other types of inverters and kept in the closer proximity of fuse box and electricity meter. The problem with this kind of inverter is that if one panel is obstructed with shading, the remaining panels will be sabotaged too, and the efficiency will go down to a significant amount- besides, less scope to expand the solar panels for the future. This type of inverters is the main type of solar inverter for home.

These inverters are designed to convert the DC power of each individual solar panel. They are typically installed on the back face of each individual panel and are often used to improve system efficiencies on heavily shaded or multi directional solar arrays. They are only typically used in grid connect solar systems.

These inverters can manage a battery system and allow excess solar energy to be stored in a battery storage system for self-use. Hybrid inverters function like a common grid tie solar inverter but can generally operate in one of several different modes depending on the application, this includes battery backup mode which provides a limited level of backup power in the event of a blackout. Most hybrid inverters can also operate without a battery and function just like a grid-tie solar inverter by exporting excess solar energy to the utility grid.

Having all the key features for solar and battery storage in one simple plug-and-play inverter means hybrid inverters are generally much lower cost and easier to install compared to more complex battery storage systems which often require multiple inverters. However, they do have several limitations and are generally not recommended to be used for off-grid solar systems.

Most hybrid inverters can be programmed to function in four different modes:

* Only a select few hybrid inverters are designed to be used for off-grid solar power system and have the capacity to start and run a backup power source such as a generator if required.

These inverters resemble a string inverter, but instead of putting the strings of panels directly into the inverter, they join all of the strings of panels together and insert them into a combiner box. These inverters typically have far higher capacities compared with conventional grid tie string inverters and are primarily used in large-scale commercial applications over 50 KW’s.

Most of the off-grid solar systems tend to charge the battery on its own, but during winter or acute shading, it is often difficult for the solar system to fully charge the battery. Hence, the inverter/charger kicks in to meet the energy requirement of the system. This type of inverter is bi-directional, which means that it can work both as a battery charger and an inverter. In this system, an AC generator is required to trigger the conversion of the AC electricity to DC and vice versa.

This type of inverter can be in an off-grid, grid-tied, or grid-interactive application.
With the help of the inverter/charger, AC power from the generator is converted into DC to feed the battery, whereas the DC is converted into AC to supply the continuous power of the critical loads.

A Grid Connect System or Grid Tie System, as the name suggests requires a connection to the utility grid to work. It supplies solar power through an inverter directly to the household, and in cases where the system provides more energy than the house needs, the remainder is supplied to the electricity grid. When power is supplied to the mains grid, the homeowner receives a credit or a payment for that electricity, usually called a feed-in tariff.

Stand-alone Power Systems, also known as ‘off grid’ or ‘remote area’ power systems are becoming more and more popular with many customers choosing to design their homes to be 100% self-sufficient, even when located where grid power is available. However, they are historically used when there is no access to a public electricity supply, (the grid) usually in remote areas or where the costs to run power to a house site are prohibitive. A Stand-alone system is designed very differently to all other types of solar systems as they are the only source of power and must provide reliable power in all weather conditions at all times of year. These systems must be tailor designed to each customers unique requirements and expectations and should be designed and installed by a professional. Too often these systems are undersized for the customers requirements which ultimately causes the systems to fail prematurely which can be a very costly mistake.

Battery Storage Systems when combined with a Grid Connected Solar System, enable unused solar energy to be stored in the batterie. This enables any excess energy generated by the PV array to be stored in the battery bank which can then be used to power house loads during the night time or during periods of poor weather.. They DO NOT off power during a blackout as the inverters used typically have no way to anti-island themselves from the utility grid.

A Battery Backup System, unlike a Battery Storage System, enables the solar system to remain operational during a black out or power outage. These system require a battery inverter or multi-mode inverter that has the ability to anti-island itself from the utility grid thus enabling the solar array and battery system to still provide power to the home with the risk of it exporting power back into a dead utility grid. These systems are typically designed to only back up essential services such as fridges, lighting and modems etc rather than the entire house which typically requires a far larger battery storage system.

Grid Connect Solar Systems typically cost around $700 per KW to install. Stand Alone Systems typically cost around $4,500 per KW as do Hybrid Systems if they are a complete installation.

A grid connect system owner is paid a feed in tariff for the electricity their system generates by an electricity company or government agency. Net metered solar feed in tariffs are typically between 5-8cents per Kwh of power fed back into the grid. As an example, a 5KW system produces on average 20 kwhs per day. If the owner was away and had all loads turned off, all of this power would be fed back into the grid and potentially earn the owner between $1-$1.60 per day. A grid connect system should be designed to ONLY offset the daytime loads of the owners house and as such minimal power should ideally be fed back into the grid. 100% self-consumption of renewable energy will provide the fastest Return on Investment.

A simple small grid connect system consists of 18 x 370W solar modules and an inverter. The inverter is connected to the power grid through your electricity meter.

A grid connect system is wired into your existing fuse box via a separate AC circuit breaker.

Solar panels require sunlight to produce electricity, so during the night solar panels will not produce any electricity.

Under cloud the solar panels will not operate at full capacity. The more cloud there is the lower the output of the solar panels. If you have a grid connect system, any deficit will come from the mains grid.

A northerly aspect with the solar panels pitched at a similar angle to the latitude of the location is generally the best rule of thumb to provide the best annual solar generation however it really depends on how and when the homeowner uses power. For example, if the household is empty during the day while the family is out, it is often better to install an East and West solar array which will enable the solar system to generator more power in the morning and afternoons, when the power is being consumed, rather than during the middle of the day.

Shading the solar panels from objects such as trees, aerials, chimneys, other buildings etc. will always decrease their output. Depending on the size and placement of these objects, the decrease in output can be substantial, hence it is best to avoid shading where possible. There are many ways to reduce the impacts of shading on a solar array such as DC Optimizers and Micro Inverters however the latest research has shown that high end string inverters generally provide the best performance overall.

Any grid connect solar power system will reduce your yearly power consumption and consequently your power bill, but in general, the bigger the system, the bigger the benefit.

The size of system your household requires depends entirely on your energy usage and geographical location. A 1kW system is an entry level system for Grid Connect and attracts the most rebate per watt. It will usually cover between 15-25% of the energy consumption of a medium sized household. At the other extreme, a 4kW system will cover 100% of the energy consumption of a medium energy use household.

To make the most of solar power, the key is to implement simple energy efficiency strategies. It is easy to conserve energy by using appropriate lighting and energy efficient appliances. Running high power appliances such as electric bar heaters, electric hot water systems and air conditioners etc. is not economical, nor recommended.

Instead of considering a very large solar system to accommodate existing heavy energy appliances, it is advisable to invest in energy efficient heaters, hot water and design features to compliment your solar system and energy conscious lifestyle.

NO, standard grid connect inverters by law must shut down if the grid fails. This is to prevent power being fed back into the grid while utility workers are repairing the electricity grid. This means that even though you have a solar system, during a blackout you will not have power available.

If you want to have a continuous power supply during a blackout then you would need to have back up batteries installed and/or a backup generator.

In the case of a Stand Alone system, you should never experience a blackout unless your battery supply is depleted due to long periods of cloudy weather, in which case, you will probably have a generator backup to restore power.

Most solar systems should only require one full day for installation.

PV modules last a long time, although exactly how long, we don’t yet know, as the oldest modules are barely 45 years old and still going strong. In decades-long tests, the fully developed technology of single- and polycrystal modules has shown to degrade at fairly steady rates of 0.25%-0.5% per year.

PV technology is closely related to transistor technology. Based on our experience with transistors, which just fade away after 20 years of constant use, most manufacturers have been confidently predicting 20-year or longer life spans. However, keep in mind that PV modules are seeing only six to eight hours of active use per day, so we may find that life spans of 60-80 years are normal. Most solar panels carry an output warranty of 25 years. The electronic components such as inverters, should last 10 -15 years.

In the early years of the PV industry, people said that PV modules would never produce as much power over their lifetimes as it took to manufacture them. During the early years of development, when transistors were a novelty, and handmade PV modules costing as much as $40,000 per watt were being used exclusively for spacecraft, this was true. Now however, PV modules generally pay back their manufacturing energy investment in about 1.6 to 1.8 years’ time in Australia (only a fraction of the typical warranty period), depending on module type, installation climate, and other conditions. The high demand for PV modules around the globe has led to far more efficient and safer manufacturing processes these days.

There is virtually no maintenance required on a solar system as they have no moving parts. Really, all you need to do is keep them clean. It’s best not to clean them while they’re hot in the middle of the day as you could theoretically break the glass if you use cold water on hot panels, so try to limit cleaning to mornings or early evening. Cleaning is typically carried out using a soft bristle broom and water once every 6-12 months depending on the installation environment.

A typical 370W solar module is approx. 1.7m x 1m and weighs approx. 21kgs. In conjunction with the aluminium racking systems, they exert a load of approx. 13 kgs per sqm meter onto the roof structure.

Most insurers will allow you to include the system under your home and contents insurance, but please check with your insurance company first.