In the south west of Western Australia, we are lucky to enjoy a very mild temperate climate, with an abundance of sunshine throughout most of the year to warm and power our houses, and summer breezes to cool them down. In recent years, solar photovoltaic and battery technologies have become much more affordable and accessible, energy efficient appliances are now widely available, and solar passive house design is recognised as best practice. Why is it then that we continue to build energy-guzzling housing developments, which are literally costing people the earth to live in?
One of the key objectives of the Witchcliffe Ecovillage was to be able to supply 100% of all energy consumed on site through renewable sources, and we are very pleased to say this can be achieved. Carefully planned lot layouts, clever house designs and efficient appliances will have a big impact on reducing energy consumption in the Ecovillage, and renewable energy will be generated onsite by rooftop solar PVs.
To ensure a constant supply, the total renewable energy produced within the Ecovillage over a whole year has been designed to be significantly greater than the total energy that residents consume. In fact, we estimate the average household will generate enough surplus solar energy to power an electric vehicle for 15,000 to 20,000 km each year. Our energy modelling has been based on figures that take into account the worst winter weather recorded over the past 30 years, but any shortfall backup required during unusually long cloudy periods will be supplied by accredited GreenPower renewable energy via the Western Power grid.
Solar photovoltaic panels will be the predominant source of energy within the village. Solar PVs were chosen as they provide a very high value, long lasting energy generation solution with little to no maintenance requirements. They are unobtrusive, silent and completely autonomous. Having the generation on rooftops will utilise a structure that is already there, saving open space for other uses. It also improves the efficiency of the building in the heat of summer, acting like an extra layer of insulation. All PV systems will be of a high quality and will supply the Ecovillage with ample power for years to come.
Every home, business and community building in the Witchcliffe Ecovillage will feature rooftop PV systems, just like the ones found on a grid-connected home. This system will supply the household or business with their daily power requirements. Depending on the ultimate system design, the excess energy created will either go to the household’s own battery storage bank or to a central battery storage for each stage. PV capacity for individual buildings will be mandated by sustainability design guidelines to guarantee supply throughout the year.
To ensure a constant supply of power from solar generation, battery storage is required. The rooftop solar PV’s charge batteries during the day and store energy for use at night and in periods of overcast weather. We are currently exploring two different battery storage options. The first provides battery storage at each home and the second proposal includes central battery storage units that will store and supply energy for each home through a large inverter. The benefit of the first option is that each PV and battery storage system could be tailor made for each household’s requirements. The second option would see each stage provided with its own central battery and inverter systems, which may provide a more adaptable and responsive system. Either option will ensure a highly reliable, robust, renewable power system for the Ecovillage.
At this point, lithium technology is leading the pack as the battery of choice for the Ecovillage energy system. However, we are following other battery technologies closely in case a more sustainable solution is available by the time we are ready to purchase.
Lithium batteries are a proven technology with many benefits. They consist of cells similar to those you would find in a laptop computer, mobile phone or electric vehicle but on a much larger scale. They are highly efficient, meaning almost all of the energy that is put into them is stored as electrical energy, unlike some other batteries that waste a lot as heat. They may be charged and discharged at a high rate, allowing all of the energy a sunny day can produce to be stored for later use, as well as allowing periods of high load to be met with ease. Lithium batteries feature a high cycle life, ensuring years of reliable performance. They are also compact, leaving more space for nature and leisure.
Many people these days have already adapted their houses and lifestyles to be more energy efficient, with simple measures like choosing the highest star rated appliances they can afford and switching off appliances when they’re not in use. However, if their house doesn’t face the right way, or is built from the wrong materials, there is a real limit to the efficiencies they can achieve.
Through incorporating energy efficient design into every aspect of the planning of the Ecovillage from lot layout onwards, and providing education and community engagement to future residents, energy usage in the Witchliffe Ecovillage will be minimised without reducing residents’ comfort or affecting their lifestyles.
Energy efficient buildings
All homes, businesses and community facilities must be designed as efficiently as possible. According to yourhome.gov.au, 40% of the average Australian home’s energy usage is in heating and cooling. By building well-insulated, solar passive homes, close to 100% of heating and cooling can be done passively, saving a large amount of energy. Well-designed solar passive homes in Margaret River are surprisingly warm in winter and require heating only after prolonged periods of overcast weather; in summer, cooling is rarely required and can be taken care of by overhead fans. Other factors such as efficient appliance selection and usage habits, LED lighting and community education programs will help to lower energy usage even further without negatively affecting the lifestyle of residents.
Central Cluster inverter/charger
The microgrids supplying each strata cluster with electricity will feature a central inverter/charger. This piece of equipment not only helps to control the charging of the batteries, but also converts the energy in the batteries into AC power for homes and businesses.
As each cluster is constructed, another microgrid will be added with its own inverter/charger connecting the household batteries within that cluster with the existing Western Power grid. This connection will enable excess renewable energy produced by the clusters to be sold back into the grid.
As the microgrids in the Witchcliffe Ecovillage have been designed to operate year-round with very minimal backup during the cloudiest periods of winter, there will be a large amount of excess energy created when the sun is shining. In fact, we are expecting to produce around 1.6 million kWh’s of excess renewable energy each year.
In order to utilise this energy, the Ecovillage’s microgrid will be connected to Western Power’s grid to allow the sale of renewable energy back into the grid. Excess renewable energy will also be utilised within the Ecovillage for irrigation of the community gardens and agricultural areas, electric vehicles and bicycles, and seasonal business uses.
Residents of the Witchcliffe Ecovillage will be provided with the tools they need to live an energy efficient lifestyle, including effective use of their in-home energy monitoring systems. We anticipate that monitoring of energy usage in the Ecovillage will also provide valuable data for future sustainable energy research projects, for example, investigating the impact of solar passive subdivision design on household energy consumption, etc.
Residents and business owners will be provided with training to ensure they get the most out of their energy systems and the overall operation of the microgrid. Topics such as time of use, energy efficiency, standby and base load consumption, and system maintenance and monitoring will be covered. It is expected that with guidance and support, residents will have energy to spare and will not incur any electricity costs living in the Ecovillage.
Each building will have an indoor energy monitoring system, allowing the resident or business owner to keep an eye on their generation and consumption. This will assist them in deciding when to run certain appliances such as the dishwasher or washing machine and allow them to monitor how much energy they have generated and imported.