Energy efficiency is becoming an increasingly important issue for homeowners across Australia. With rising electricity prices and growing concerns about climate change, many Australians are looking for ways to reduce their energy consumption and lower their carbon footprint. We all know about reducing our usage to be more efficient but lets talk about another strategy; Time shifting our demand.
First, let's consider where energy comes from in Australia. Most of the energy used in homes across the country is generated by burning fossil fuels like coal, oil, and natural gas. However, there is also a growing share of renewable energy sources like wind and solar power in the National Energy Market (NEM). The Australian Energy Market Operator (AEMO) is responsible for managing the NEM and ensuring that there is a reliable supply of electricity to meet demand across the country.
Image: NEM Fuel Mix 6/2/23. Source: https://www.aemo.com.au/energy-systems/electricity/national-electricity-market-nem/data-nem/data-dashboard-nem
One challenge with renewable energy sources like solar power is that they are not always available when demand for electricity is highest. For instance, solar energy is abundant during the middle of the day, but demand for electricity is highest in the early morning and evening. This creates a mismatch between supply and demand that can lead to problems for the electricity grid and your hip pocket.
Solar energy has become the cheapest form of energy in Australia, and this has significant implications for energy efficiency in residential buildings. By taking advantage of cheap daytime renewable energy prices in the NEM, households can time shift their energy use to reduce costs and support the grid.
So what is time shifting our energy demand? Let me explain with an analogy. For centuries humans stored summer sunshine in the form of food to use it in winter when the sun was not abundant enough to support food production, and we lived on the planet sustainably, making hay while the sun was shining! Now we have to do this with electricity, but on a more daily basis.
For example, an energy-efficient home that is well-insulated and airtight can time shift its demand for heating and cooling by storing that thermal energy until market demand for energy is low again. By using smart thermostats and a heating or cooling systems that can be programmed to turn on or off during periods of low demand, homeowners can reduce their reliance on the electricity grid during peak demand periods and still maintain a stable internal temperature even when the heating or cooling system is turned off. You effectively turn your home into a thermal battery!
Hot water systems are another major energy consumer in the home, particularly during peak demand periods when multiple people may be showering or using hot water for other purposes. Energy-efficient homes can use hot water systems that can be programmed to operate during periods of low demand and can use heat pump technology to heat the water more efficiently. A heat pump with a hot water tank can then store this hot water for use during peak times or when the sun is not shining. This is effectively another thermal battery
Home batteries are becoming an increasingly popular option for energy-efficient homes to time shift their demand for electricity. By storing surplus solar energy during periods of high supply and using it during periods of high demand, homeowners can reduce their reliance on the electricity grid and save money on their electricity bills. With surplus solar in the NEM you can charge your battery with solar energy even if you don't actually have solar panels yourself. Then you can use this cheap energy during peak times or through the night when the sun is not shining.
Solar Production (blue), Energy Consumption (orange), and energy exported (grey) at the SustainaBuilding demonstration home.
The consumption peak in the morning is the battery recharging as solar comes online and the heat pump hot water service heats up.
NOTE; The battery will not allow grid importing while the sun is down.
Image Source: Enphase Enlighten App.
In conclusion, an energy-efficient home doesn't necessarily need to reduce the amount of energy it uses. Instead, it needs to be adaptable to time shifting its usage to take advantage of periods of surplus energy in the NEM, from your own solar panels and low energy prices. If we can time shift our demand for times when there is surplus energy (which just so happens to be renewable Solar energy) we are also helping to stabilize the grid.
With a high-performance envelope, a heat pump hot water system, efficient electric heating and cooling, a home battery, and the right energy provider, homeowners can time shift their energy usage and use 100% renewable energy even if there are still dirty coal plants in the NEM. This not only helps to balance the electricity grid and reduce our reliance on fossil fuels, but it can also save us money on our electricity bills.
Cover Photo: Australian made Tindo Solar panels on the SustainaBuilding demonstration home.
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