Store energy for later
Hybrid solar
Hybrid solar systems combine the best of grid-tied and off grid solar systems.
Get the best of both worlds
If you think about it, the grid is a wonderful piece of technology that makes our lives work. We all need electricity and the grid gives us that infrastructure 99.9% of the time.
Sure, we get the odd power cut and we hate paying high electricity bills, but the grid does serve its purpose.
When you add solar onto your grid-connected house, you immediately get the benefit of reduced electricity costs, however, there are two problems that can occur. First, you might find that you export more power than you like, and second, when there is a power cut, you find that your system shuts down. This shut down is required by electricity standards so that electrical workers who come to repair your power lines during a blackout are not electrocuted by unexpected electricity coming from your system.
Exporting too much power and power cuts can be solved by adding batteries to your system.
Hybrid grid connected solar
…HOW batteries WORK
When the sun shines the power will first go to your loads, then it will fill the batteries, and only then will it be exported. At night you get power from your batteries and import power from the grid only if the batteries are not able to supply all you need.
Effectively your batteries allow you to shift generation from the sunny part of the day (when you might not be home) to the nighttime. Batteries enable you to consume more of your self-generated power. Some more sophisticated systems are also able to charge your batteries at night as well as during the day. Getting a second charging cycle at night allows you to benefit from cheap nighttime tariffs and doubles the benefit of your battery. This effectively cuts the battery repay period in half.
…Some batteries only provide short term backup
The battery inverter in this type of set up has an emergency power system (EPS) that keeps you running during a blackout—but only until the battery runs flat. This is fine for most power cuts that only last a few hours, but your solar panels cannot be used to recharge the batteries. The power available during EPS mode is limited and how long it lasts depends on what devices are using the power and the state of charge in your battery when the power cut occurs.
This option can be great for limited loads like lights, computers and maybe your fridge. However, you have to decide ahead of time how much reserve to keep available in your battery for EPS mode and this then limits the benefit of your battery for self-consumption of solar power.
Hybrid to the rescue
When you add batteries that have backup capability and can also be charged from your solar panels during a power cut, you have what is called a hybrid system.
If you want batteries in your system, it’s important to understand the difference in functionality and cost between the various types of battery-based solar systems. Hybrid systems typically cost twice that of a normal grid connected system whereas adding a small battery for self-consumption may not add that much to the cost. Our solar engineers can explain things and will be happy to walk you through the options—both for new systems and for adding batteries to existing systems.
If you’ve read all the above and realise that adding batteries to solar can be complex, then you’re right, but there is another option…
Hot water diversion
If you heat your water with electricity, then you already have a large ‘battery’ waiting to store your excess solar power. Depending on its size, a hot water cylinder can store between 10-18 kWh of energy. You can take advantage of this resource if a smart hot water diverter is added to your solar electric system.
This is how it works:
A diverter is an intelligent device that detects when your house is about to export power and instead sends that excess solar-generated energy to the hot water cylinder—in direct proportion to the amount of excess solar electricity that is available at any given time. The diverter measures power flowing to and from the grid. When you would be exporting power, the unit instead ‘diverts’ this by sending pulses of power to your hot water cylinder. In this way, it can virtually eliminate all export each day until your cylinder is hot. So, power gets stored for use later when you need energy in the form of hot water.
Installing a hot water cylinder diverter only adds a small premium to the price of a solar electric system. It costs only a fraction of what it would cost for a battery, yet it can store just as much energy. If you have an electric hot water cylinder we highly recommend a smart diverter. You get the benefit of ‘free’ hot water and it reduces the payback time for your solar electric system considerably.