What are the benefits of grid-connected solar panels vs. living off the grid?
Deciding whether or not to grid-tie your solar panels is usually pretty straightforward – the clear-cut benefits of being grid-tied appeals to the majority of homeowners. There are, however, some people that choose to live off the grid.
What would be the best in your situation?
Let’s look closer at the benefits and downsides of grid-tied, off-grid and hybrid solar systems.
Grid-Tied Solar Systems
Grid-tied, on-grid, utility-interactive and grid backfeeding are all terms used to describe the same concept – a solar system that is connected to the utility power grid.
Grid-Tie Inverters take DC power from the solar panels and invert it to AC power so it can be fed into the electric utility company grid. The grid tie inverter (GTI) must synchronize its frequency with that of the grid (e.g. 50 or 60 Hz) using a local oscillator and limit the voltage to no higher than the grid voltage. A high-quality modern GTI has a fixed unity power factor, which means its output voltage and current are perfectly lined up, and its phase angle is within 1 degree of the AC power grid.
The inverter has an on-board computer which senses the current AC grid waveform, and output a voltage to correspond with the grid. However, supplying reactive power to the grid might be necessary to keep the voltage in the local grid inside allowed limitations. Otherwise, in a grid segment with considerable power from renewable sources, voltage levels might rise too much at times of high production, i.e. around noon.
Grid-tie inverters are also designed to quickly disconnect from the grid if the utility grid goes down, that ensures that in the event of a blackout, the grid tie inverter will shut down to prevent the energy it transfers from harming any line workers who are sent to fix the power grid.
Properly configured, a grid tie inverter enables a home owner to use an alternative power generation system like solar or wind power without extensive rewiring and without batteries. If the alternative power being produced is insufficient, the deficit will be sourced from the electricity grid. But due to grid code in Nigeria, Feed back to the grid is not allowed or if a home owner decides to feedback then their is no amount paid to back in such cases.
Off-Grid Solar Systems
An off-grid solar system (off-the-grid, standalone) is the obvious alternative to one that is grid-tied. For homeowners that have access to the grid, off-grid solar systems are usually out of question. Here`s why:
To ensure access to electricity at all times, off-grid solar systems require battery storage and a backup generator (if you live off-the-grid). On top of this, a battery bank typically needs to be replaced after 2 - 10 years. Batteries are complicated, expensive and decrease overall system efficiency.
Advantages of Off-Grid Solar Systems
1. No access to the utility grid : Off-grid solar systems can be cheaper than extending power lines in certain remote areas.
2. Become energy self-sufficient : Living off the grid and being self-sufficient feels good. For some people, this feeling feeling is worth more than saving money. Energy self-sufficiency is also a form of security. Power failures on the utility grid do not affect off-grid solar systems.
Hybrid Solar Systems
Hybrid solar systems combines the best from grid-tied and off-grid solar systems. These systems can either be described as off-grid solar with utility backup power, or grid-tied solar with extra battery storage.
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