The Solar Power System
The power system will consist of solar panels mounted on a series of frames, which are connected to the electricity grid via an inverter and metering devices.
It is proposed that the system be installed on the site of the disused tennis court at Bendee downs for the following reasons:
• Bendee Downs has lower power bills than Murra Murra so there is more potential to earn money from the solar power system. This is explained in more detail below.
• The site is flat, devoid of plants and is largely unshaded to the north.
• The meter box is located nearby, so connection to the electricity grid will be fairly straightforward.
Inverters are required to convert the electricity generated by the solar panels into electricity that can be used. These inverters will be housed in an enclosure near the main house at Bendee. The cabinet will also contain switches and other safety devices. An image of an inverter similar to one that may be installed at Bendee is shown below.
Net Metering
Source: Solar Net Metering (netmetering.com.ar/solar-net-metering-systems/)
The diagram above illustrates how the solar system at Bendee Downs will be connected to the grid. It is important to remember that the solar system will only generate power during the day.
• Electricity generated by the solar system and used at Bendee Downs will not generate any revenue but will reduce the amount of electricity that needs to be purchased.
• Electricity that is generated by the solar system and not used will be recorded by a meter and exported to the electricity grid, earning $0.44/kWh.
• When the solar system is not generating electricity, such as overnight, or when Bendee Downs is using more electricity than the solar system is producing, electricity will be imported from the electricity grid at a cost of $0.18843/kWh.
Therefore, it is essential that:
• Electricity use at Bendee Downs is minimised during the day when there is the most solar electricity being produced. This will help to export as much solar electricity as possible.
• Overall electricity use at Murra Murra and Bendee Downs is made more efficient. This is necessary to ensure that KTOAI project goals of taking care of the environment, leading by example in terms of sustainable living, and reducing current expenditure on power bills are met.
Becoming energy efficient is an important part of the Kooma Energy Project as it is the cheapest and cleanest way to reduce costs and greenhouse gas emissions associated with energy consumption.
The Solar Installer
EWB obtained quotes from reputable solar companies based in Brisbane. Together, EWB and KTOAI reviewed the quotes, analyzed system performance data and associated costs, and agreed upon the most appropriate system design option.
The solar system to be installed at Bendee Downs will have a capacity of 9.8kW. The installation of the frames will be carried out by members of the Kooma community and EWB. The installation of the solar system will be carried out by Infinity Solar, who have displayed technical proficiency, competitive pricing and enthusiasm about the project.
The system will be made up of several rows of panels with a separation distance between each row so they don't shade each other. It will look similar to the photograph below:
According to preliminary calculations, the Bendee Downs electricity bill will be around $3,000 - $3,500 in credit after one year of operation.
It is important to note that this is only a rough estimation. The actual performance of the solar system, and potential revenue generation, are dependent factors such as:
• Solar Radiation- the amount of electricity generated by the system will fluctuate with weather variations.
• Maintenance of solar panels- it will be vital that Kooma residents conduct regular maintenance to ensure that panels are clean and the system is functioning well. Training for this aspect is part of the project.
• Electricity usage- the amount of revenue generated from the solar system will be heavily dependent on the amount of electricity used at Bendee Downs, particularly electricity used during sunshine hours. During the economic analysis of the system options, it was necessary to determine the electricity use at Bendee Downs for the next 20 years (to estimate how much electricity will be able to be sold to the grid). For simplicity of the model we assumed the electricity used at Bendee will remain the same for the next 20 years. If circumstances at Bendee change significantly over that period, the revenue generating capacity will be affected.
The next phase of the project will be aimed at reducing energy demand at Murra Murra and Bendee Downs. This should be the least costly and most effective part of the project, and will help to ensure that the revenue generated by the solar power system is as high as possible.