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Guide to going solar!

Are you thinking about solar power for your home? Use this guide as well as the Clean Energy Council’s Guide to installing solar PV for households to learn what size system you will need, the amount of power you will generate, installation and credits and rebates that are available.

1. How much power do you use?

Use your power bills to find out how much power you are already using. Be sure to look at a whole year’s worth of bills so that you see the differences in usage between the dry season, the build up and the wet season.

You can calculate the average daily usage (in kWh) using the data on the back of your power bills.

Think to yourself: “Can I be more efficient?” because it is important to reduce your energy consumption as much as possible before you invest in solar power.

2. What size system will you need?

Once you know the average daily kWh usage you need in your household, you can choose the size of your solar photovoltaic (PV) system. You can choose between having a system that completely covers your power needs, or covers a proportion of your usage (you can always upgrade or increase the number of panels down the track)

Country Solar NT have a guide on their website estimating the cost of various sized systems, including estimated pay back periods.

You can also find price estimates in The Clean Energy Council‘s Guide-to-installing-solar-PV-for-households.

According to the Clean Energy Council, on average a 2.0 kW system in Darwin can produce around 8.8 kWh of electricity or greater per day. Your panels will produce more power on sunny days compared to cloudy days, so you will see a difference in power generation depending on the local weather conditions of particular days.

Due to the geographic location of Darwin (with our latitude being close to the Equator) a low pitch roof of 10-12 degrees is ideal for solar power production.

For more information on the types of solar panels go to the Australian Government’s ‘Your Home’ website.

As of 1 June 1 2017, Power and Water  has re-assessed the maximum size that can be installed on a normal residential dwelling, the restrictions are now inverter based with single phase dwellings able to have a maximum grid connected inverter of 5KVA and for dwellings with a 3 phase connection a 7KVA is permitted. For larger size residential systems and application process applies.

3. Choose a reputable retailer & installer

There are a number of companies, both local and interstate, offering to fit solar panels to your roof. The good news is PV Systems are becoming cheaper! Competitive offers are frequent.

When selecting your solar retailer, make sure you go with a reputable company with proven experience. You should find out things like how long they have been in the solar industry, and whether they are an established company that will be around in the future if things go wrong. Warranties and workmanship guarantees cease if the company goes out of business.

Selecting a Clean Energy Council Approved Solar Retailer is a way to make sure you will be dealing with a company that prides itself on being an industry leader.

In 2019, Country Solar NT quoted that the most common sized system they are installing in Darwin is 6.5kW, which costs on average between $9-12,000.

There are a number of companies willing to fit various brands of panels in Darwin. See COOLmob’s list of products and suppliers but please note these are not necessarily recommendations or endorsements.

4. Installation

You will need to consider a number of important factors when installing solar panels on your roof. Some of these are:

  • warranty of the panels
  • household insurance
  • Positioning and possible shading

Fitting PV panels involves:

5. STC’s

Renewable Energy Certificates (REC), now called small-scale technology certificates (STCs) are a currency for renewable energy in the renewable energy market. The value of one STC is equal to one mega-watt of renewable electricity generation and avoided power consumption, such as in the case of producing solar hot water.

You can visit the Australian Government’s REC website and use the STC calculator to determine the approximate number of small-scale technology certificates (STCs) that may be created under the Small-scale Renewable Energy Scheme (SRES) in relation to an installation.This tool is designed to expire in 2030. 

You can choose to reduce the price of your system by selling your STC’s to your supplying company, or you can claim the STCs yourself. You will need to clarify this in your contract.

6. Feed-In Tariff

Power authorities will buy the power you produce from your solar panels if you feed that power into the electricity street grid (ie grid connected). In the NT, Jacana Energy (the retailer) will credit your power bill for the amount of power you produce and feed into the grid. PowerWater pay for your power at a lower rate that you buy it from them (this is called a feed-in tariff). For example, if you use 300kWh and produce 300kWh from your solar panels, you will pay nothing for power consumption, but will still pay the daily connection fee of about 50c per day. If you produce more power than you use, the credit can be used towards your daily use fee or your water and sewerage costs. Any additional credit would need to be transferred to you as a payment.

From May 2020, all new behind-the-meter solar installations of up to 30kW in size is a new feed-in-tariff of 8.3 cents per kWh. (An important side note: all businesses and households who currently receive the premium one-for-one FiT will continue to do so. They will only surrender the “premium FiT” if they upgrade the capacity of their system, move premises or take advantage of the battery subsidy.) 8.3 cents per kWh is a huge drop, so in order to support the continued uptake of renewable energy we are calling on the government to implement an optional time-of-day tariff. 

It is possible to be independent from the grid and buy a stand alone system. However due to the batteries involved in storing the power this is much most costly.

7. Solar Credits

Solar Credits is a mechanism that increases the number of REC’s created for eligible installations of PV systems up to a 1.5 kW capacity. REC’s are not means tested though. If fitting additional panels you can still sell your RECs at market prices, but you will not receive the extra multiplier value paid for solar credits.

From July 2011 REC’s for the first 1.5 kW system will be 3 times the value. From July 2012 they will be 2 times the value, and 1 times the value thereafter.

8. How quickly can I pay off my investment?

Check out the Energy Matters tool to calculate how long your investment may take to pay off. You can enter in your postcode and the designer uses BOM data based on he nearest weather station

9. Solar Panels at your rental property

When a domestic solar power system is connected to a household, the home owner signs a Power Purchase Agreement (PPA) that says they will sell the power from that system back to PowerWater Corporation.

The PPA is always between the bill-payer (i.e. the current account holder at the property, but not necessarily the property owner) and PowerWater. Any energy produced can only be credited to the account associated with the physical meter it’s connected to.

A tenant (the bill-payer) moving into a property with a solar array on the roof will sign a new PPA, while the landlord will continue to have the NCA (Network Connection Agreement) with PowerWater.

When the new tenant opens an electricity account, Power Water Billing Team (should) supply them with a new PPA to sign, as the household will be flagged as having solar power in their system. This process only became automated by Power Water in September 2011. Prior to this date no new PPAs were automatically issued when tenants opened new electricity accounts, and so meters connected to solar systems continued to ‘clock’ the energy produced regardless of who had ownership of the electricity account. To resolve this, Power Water will credit account-holders for the energy that was produced from the solar PV system since they opened their electricity account.

As a landlord you do have the option of keeping the power account in your name and on billing the tenant and hope that they reimburse you for the power they used!

10. More information

You can find more information on solar systems and batteries in Darwin on the Environment Centre NT's website, under the Repower NT campaign

Clean Energy Council Consumer Guide to solar PV

Office of the Clean Energy Regulator

Clean Energy Council – Guide to installing solar PV for household

Updated June 2020