A grid-tied solar system consists of solar panels and a grid-tied solar inverter. This is the most common form of solar installed throughout the world. The solar system generates electricity, this electricity is used in the home and the excess is sent back out to the grid. If the solar generation is not enough to cover demand, power will be used from the grid.
Most grid-tied systems will disconnect during a power outage. There are two reasons for this:
- If the lines are down, it would be dangerous to send electricity back to the grid. There is a chance a line worker could get electrocuted.
- The grid is used as a buffer for the ever-changing loads in your household. Without a grid connection, the solar inverter wouldn’t be able to manage the varying demand. For example, you are boiling the kettle using all the solar power you are generating, the kettle flicks off, now where does the solar power go if there is no grid? Inverters cannot react that fast.
The future will see technical advancements, which will allow solar systems to keep running without a battery or the grid. one of these advancements can be seen in the new Fronius Gen 24 inverter. Where it has an output that can provide power in an outage without batteries.
In recent years, some grid-tied solar systems have progressed their monitoring platform to now include consumption monitoring. One of the best platforms is Fronius Solar.Web. Consumption monitoring shows the end-user when and how much electricity is being used in their home. This is great as it allows the end-user to use appliances at the times they are producing the most solar power.
Consumption monitoring allows the end-user to utilise more of the solar energy produced, therefore increasing their return on investment (ROI). Consumption monitoring also records data for solar production, consumption and excess energy over time, so when you are ready for battery, you have the solar excess data to know what size battery you can charge.
This system is a mix between a grid-tied solar system and an off-grid system. It consists of, Solar panels, Solar inverter and a battery bank.
A grid-tied solar system send excess solar energy back to the grid. A hybrid system is designed to capture this excess energy and store it in the batteries. This energy can then be used at night or to meet peak demands, reducing or eliminating energy used from the grid.
A major difference between a hybrid system and off-grid system is the battery bank size. An off-grid system will generally have the battery sized to get through a few days of inclement weather, whereas a hybrid system will usually be sized to store enough energy to get through the night until the sun comes out the next day.
As hybrid systems have a battery you would expect to have backup power in the case of an outage. It pays to be careful with components you choose here as some systems will not have the backup function, they are purely to save excess solar power to be used at night, so in a power cut, you will find yourself without power.
A system like the Tesla Powerwall will give you backup power, so in an outage, you can carry on as usual. In fact, Tesla ensures a fast change over from grid to backup, so your computers and other appliances will carry on running. You will only know there has been a power cut from the notification you’ll get through the app.
A battery can be added to any existing grid-tied solar system to make it a hybrid system. The Tesla Powerwall is usually the best option for doing this.
If you are unsure about installing a battery or not at first, then that’s no problem at all. Just install a grid-tied system, ensure you have consumption monitoring. Then down the track when you have monitored your system, you will know which battery will be right for your system.
In some areas, there is no grid to connect to. To have electricity in an area with no grid you would need a stand-alone system.
Examples of stand-alone systems are:
- A home that is too far from the power lines to get a connection. Typically if a house is more than 300m from power lines, it could be worth thinking about going off-grid.
- Backcountry huts. They are so far from the electricity network that the only option is to install their own stand-alone power system.
- Weather stations. Typically in remote areas, weather stations require their own stand-alone system.
- Radio or phone antennas. Most of this equipment is situated at the top of a hill in order to reach the most people. It can be expensive to run a power cable to the top of these hills, most of the time it makes more sense to have their own off-grid system.
An off-grid system consists of:
- Solar panels – to generate electricity
- Battery storage – to store energy for use at night or in non-sunny weather
- Inverter – to convert DC electricity into AC to use with common appliances
- Monitoring – to monitor battery state of charge and solar input
In recent years the components we use in off-grid are changing, mainly in the area of the battery type. Classically a battery bank of lead-acid batteries was used. In recent years it’s usually beneficial to use lithium batteries such as Tesla, BYD or Pylontech.
To avoid damaging the lead-acid batteries, they can only be discharged around 20-30%. This meant a very large battery bank was needed to allow a few days of energy storage. With Lithium, they can be discharged fully without causing damage to the batteries. Meaning smaller battery banks and a lower risk of damage to the system.
Lithium batteries can be charged much faster than lead-acid, which means if the sun comes out for a short period, the lithium batteries can take full advantage of this energy. Lead-acid batteries generally need 7-8 hours to complete a charge cycle, so more often than not, cannot take full advantage of the energy available.
Off-grid systems generally have a generator input too. This is a backup in case of prolonged inclement weather. Another advantage of Lithium is that in the case of needing to use the generator, the generator will run for much less time to charge the batteries.
Modern-day off-grid systems are able to have online monitoring. this allows monitoring of the system via a cloud platform, so you can keep an eye on your system from anywhere in the world. At Queenstown solar, we love this feature, as it allows us to keep an eye on your system too and help with any queries or system maintenance.
If you are interested in installing solar panels then fill out the form below and one of our team will get in touch with you to see how we can help.