Typically, solar produces the most energy between 9am to 3pm, with more power being generated during the long days of summer compared to the much shorter days of winter. With solar panels, the yearly electricity production graph usually resembles a bell curve. The low end of the curve represents the winter months and the peak is reached during summer.
By aligning your electricity consumption to your solar generation you will maximise the savings potential of solar. That does not mean you should turn on all your appliances from dawn to dusk. Here are some tips and tricks.
Energy efficient products
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Making the link between solar power and appliance power ratings
The first step is to understand how much power the solar system is generating and how much power your electrical appliances are using. Your solar specialist/energy advisor, or installer, can also help you build an energy profile for your home.
Here are some general numbers to give you a guide.
|Homeowner||Power bill/month||Solar system size (kW)|
The per kW figure is important as it is the maximum amount of power your system can produce when the sun is shining, Now, compare this with the power rating of standard appliances in New Zealand.
|Fan or two bar heater||2.4|
|Heat pump||0.7 - 2.0|
Wattage varies from model to model. Figures are examples only.
To calculate how much the solar system can power in your home at any one time, start by listing the appliances that run continuously such as your fridge and the freezer. This is called the base load. You can then add other appliances that are used intermittently. This is the variable load which, ideally, is used during the daytime.
It is wise to stagger the use of high wattage appliances, like the dishwasher and washing machine, otherwise you may exceed the system's capacity and start using grid power as well. In other words, if you are using a 3kW solar system and run a 2kW dishwasher and a 2kW washing machine at the same time, you will need more power than the system can supply (even in perfect, sunny conditions). This means the 1kW shortfall (or more, depending on what other appliances are being used) will automatically come from the grid.
Monitor your consumption
Making the most of solar power means adapting the way you use electricity. If you stagger the use of major appliances so they are not all drawing power at the same time, you will minimise the power drawn from the grid. Knowing how much electricity you are generating and consuming, at any time, helps you squeeze every last drop of savings out of your solar panels, plus it teaches you the best time of day to run certain appliances. If you are a current solarZero customer, you have access to our basic online solar monitoring platform which measures solar generation. In partnership with Enphase, we will roll out an upgraded device in 2016, called the Envoy S, to improve your ability to see your in-home solar consumption.
Use energy intensive appliances during the day
Even top energy rated washing machines, tumble dryers and dishwashers can easily consume 1 kWh per cycle, so it makes sense to run them only when the sun is producing the maximum amount of energy - typically between 9am and 3pm. If you are going to be out, set your appliances to run while you are away by using the in-built timer, or by adding a plug-in timer for each device. Set them to run in a staggered fashion as you may exceed your solar capacity if they are all using power at the same time.
Cut your water heating bills
A good way to ensure excess solar energy is not exported to the grid is to use it to heat up your hot water cylinder. Households typically consume hot water early in the morning and in the evening so, if your hot water cylinder is on a timer, programme it to reheat between 12-3pm when you have plenty of solar power. You can also retrofit a device to divert spare solar energy to your hot water cylinder. With either of these options you may need the help of an electrician.
Use a slow cooker
The slow cooker has long been a friend of the working mum, but they are also perfect for making excellent use of unused electricity during the day, plus they save you tapping into the grid to power your conventional oven when you get home. With power consumption as little as 200 watts, they will save your money on cloudy days as well as sunny ones.
Make more of your microwave
If you have a gas hob, and you lunch at home, consider heating your meal using your microwave while the sun is shining to help cut your gas bills. In fact, if you have a decent microwave, switch to cooking what you can in that instead of your main oven. Your microwave uses less kW and will cook the meal much faster, saving more energy in the process.
Take remote control
Setting your appliances to run on a timer will save you money. Invest in a remote control device and you can control your appliances remotely, letting you take a look at the local weather forecast before switching an appliance on, when you're away from the house.
Replace old appliances
Armed with our previous tips, even less efficient appliances may well cost you nothing to use during daylight hours when the sun is shining, but it is still worth looking for the most energy efficient appliances when it's time to upgrade. This is particularly important for washing machines, dishwashers and tumble dryers. If you choose the most energy efficient appliances, you can use them earlier or later in the day, or when the conditions are not perfect, all without drawing power from the grid.
Upgrade your kettle
Kettles are power-hungry appliances. A typical kettle is rated at 2.4kW which takes a huge draw on a 3kW solar system, even though it is only on for a short time. A vacuum kettle has the ability to store the heat better, meaning it will take less time to heat if it has been used recently.
Pre-heat or cool your home
During winter you can pre-heat your home using your solar power. You can set your electric heaters, or heat pump, to come on earlier so they start pre-heating the home in their economy mode. You can do the same for cooling in the summer.
Adding a battery to a solar system lets you store excess solar power generated during the day so it can be used at night and when power prices are high. A battery can be installed at the same time as the panels or retrofitted to an existing system.