Grid-Tie Solar System can Drastically Lower Your Electricity Bill

I have a personal vision. A change that I want to see in this world. There is a famous quote in the movie "Aeronauts" as follows, "You don't change the world just by looking at it. You change it through the way you choose to live in it.

I want to see every household in this world self-sufficient in terms of energy. We have these renewable energy sources. Solar energy is available almost everywhere. Can't we utilize this potential to power our households 365 days a year? 

This vision of mine is the reason why I started this blog and my vlog on YouTube. I'm giving awareness and teaching about renewable energy technologies in a format that is accessible to a global audience.

So if you are a renewable energy enthusiast, kindly subscribe to this blog and my YouTube channel. By the way, let's move on to today's topic. That is On-grid or grid-tie solar power systems. 

Grid-Tie Solar Power Systems

Grid-tie solar systems are designed for those who already have electric utility service, but wish to significantly reduce their electric bill.

A grid-tied home solar system is one that remains connected to the electrical grid. Such a system generates power for the home and it feeds any excess power it generates into the grid. 

The amount of power it feeds into the grid can slow down the home’s electric meter as it measures usage. It can often make the meter go backward. 

When the meter “spins backward” it means that electricity is being fed into the grid. The homeowner is given a credit towards their bill by the utility company for the value of the power they provided to the electrical grid. Grid-tied solar is currently the most popular type of home solar power system on the market.

Net metering: How a grid-tied solar system generates profits for homeowners

Grid-tied home solar panel systems are designed to produce more power than the home uses during the day. The excess power is fed into the grid. That excess power actually causes the homeowner’s meter to spin backward. 

Should the meter spin farther backward during a month than it spins forward, the homeowner receives a credit on their bill. That credit can go toward a future bill. Or at the end of the year, it will be paid to the homeowner by the utility company. 

What happens when the grid is off?

 These systems do not need batteries and use either solar inverters or micro-inverters and are connected to the public electricity grid. Any excess solar power that you generate is exported to the electricity grid and you usually get paid a feed-in-tariff (FiT) or credits for the energy you export.

Unlike hybrid systems, on-grid solar systems are not able to function or generate electricity during a blackout due to safety reasons. Since blackouts usually occur when the electricity grid is damaged; If the solar inverter was still feeding electricity into a damaged grid it would risk the safety of the people repairing the fault/s in the network. 

Most hybrid solar systems with battery storage are able to automatically isolate from the grid (known as islanding) and continue to supply some power during a blackout.

Batteries are able to be added to on-grid systems at a later stage if required. The Tesla Powerwall 2 is a popular AC battery system that can be added to an existing solar system.

What is a grid-tied solar system?

All photovoltaic (PV) solar power systems generate power the same way: by using solar panels to convert sunlight into DC electricity. So, what makes grid-tied solar systems different?

Grid-tied solar systems are connected to the utility grid via a grid-tie inverter. The grid-tie inverter enables a two-way transfer of power between the home’s solar-powered system and the grid.

They don’t include any battery storage — they use the grid as a battery instead.
That means that when a grid-tied system produces more power than the home needs, the surplus power isn’t wasted. The system uses its connection to the grid to export the excess power to the utility.

It also means that the house doesn’t run out of power. When the solar panels aren’t producing enough electricity, the system can import the shortfall from the grid.

There's really only one disadvantage to a grid-connected system:

No power during grid outages: Grid-tied solar systems lack battery storage — which means that they provide no backup power.

When a household installs solar panels and connects them to the grid, the home then becomes both a consumer and producer of electricity. As described earlier, this is possible thanks to the two-way relationship that a grid-tied solar system creates between the home and the utility.

What equipment do you need for a grid-tied solar system?

Grid-tied systems are the easiest solar systems to install. They require the least amount of equipment, as there is no on-site storage equipment or wiring to deal with.

All you need for a grid-tied solar system installation is:

  • Solar panels: These will generate DC electricity. A typical 6-kilowatt solar power system would require roughly 20 individual panels.
  • Racking and mounting: These serve to hold the solar panels in place, as well as allow for ventilation to cool the panels.
  • Wiring: This conducts the power from the solar panels to the inverter, and then onwards to the home or net meter.
  • Solar grid-tie inverter: The grid-tie inverter converts the DC electricity to AC electricity usable by both the house and grid. It also assesses energy flows in real-time to determine if solar output should be used in the home or exported. As this is the most common type of solar inverter, this is often referred to simply as an ‘inverter.’
  • Net meter: This is a meter that allows and monitors the two-way exchange of power between the home and utility company. If not already installed in your home, the net meter will be provided by the utility once the grid-tied solar system is ready to be connected to the grid.

How on-grid solar power works?

  • The sun shines on the solar panels generating DC electricity
  • The DC electricity is fed into a solar inverter that converts it to 240V 50Hz AC electricity.
  • The 240V AC electricity is used to power appliances in your home.
  • Surplus electricity is fed back into the main grid.

Whenever the sun shines (and even in overcast weather), the solar cells generate electricity. The grid connects inverter converts the DC electricity produced by the solar panels into 240V AC electricity, which can then be used by the property/household.

If a grid connects the system is producing more power than the home consumes, the surplus is fed into the power grid. Some electricity companies meter the electricity fed into the grid by your system and provide a credit on your bill. How much you are paid is determined by the feed-in tariff.

When the solar cells are not producing power, for example at night, power comes from the mains power grid as usual. The energy retailer charges the usual rate for the power used.

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