On-Grid vs Off-Grid: What is the difference?

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On-Grid vs Off-Grid: What is the difference?

Quick Summary

In this article, Rachel Sekibo, a Southampton University Student and Tony Tiyou are revisiting the concept of On-grid vs Off-grid in simple terms. Points covered are:

  • General context
  • ON-GRID power
  • OFF-GRID power
  • Which one to choose?

Article

As people, one of the basics we need to survive is energy.  Energy comes in various shapes and forms and is being used for multiple purposes, for examples using heat to cook our foods, iron our clothes or fuel to power our cars. An indispensable form of energy that has made our lives significantly more comfortable is electricity.  

General context

In this article, we are looking at Solar Energy. As commonly understood Solar Energy is the energy we get from the Sun. The energy is trapped by a device called a solar panel and does get its renewable credentials from the fact that it doesn’t release harmful waste into the atmosphere, mitigating pollution. Solar energy is generally used to produce electricity for homes and businesses. As global population increases and economies expand, the total demand for energy is rising fast, with world total energy consumption increasing by 56% between 2010 and 2040 according to Science Direct. It then becomes necessary to generate more electricity to light houses as well as to produce goods. Achieving this is having significant impacts on people lives as it would for example help the fish seller in the market as any fish that wasn’t sold can be stored overnight in a fridge and also would allow people living in and around rural areas access to energy-linked activities like watching television at night. You would have certainly heard the words ON-GRID and OFF-GRID before, especially in solar applications and most likely would have wanted to understand them a little bit more.

ON-GRID Power

These are terms associated with Solar power to provide us electricity. On-grid generates power using a solar power system and is working in conjunction with the national grid. In the case of a residential installation, the system could be placed on the roof or any safe ground area around the house that receives good sunlight. From this configuration, the actual customer receives electricity from two sources. On bright sunny days, the solar system will feed power to the house and at night or during cloudy days, the local utility company will supply electricity from the grid to the house. The free energy from the sun could help decrease energy bills. In the event more than enough power is generated, the extra can be returned to the utility company and the customer could get paid for that or could acquire some credits that could be used to offset electricity bills at later stage. This is the principle used in net-metering.
To explain in other words, It would be like a farmer that harvested plenty of yams but could not consume them all at a particular period and decides to sell the excess to another yam farmer at a price they agree on so that the extra yams do not go to waste.
The benefit of this system is to generate a side income which would be very beneficial for consumers and provide incentives to switch to solar power.

Grid connected house - On-Grid vs Off-Grid: What is the difference?
Figure 1- Grid Connected House (Image by Clker-Free-Vector-Images from Pixabay)

OFF-GRID Power

Off grid power system does not have any connection with the grid. The utility company providing power is completely independent from any national networks and is thus fully responsible to service customers in the region. Any excess of electricity supplied is stored in batteries and can be re-used at night. In this instance, instead of the yam farmer selling the excess yams to another farmer, he or she would need to have a good storage area to keep the yams long enough without spoiling to be able to resell them later.

Offgrid power is very helpful in rural areas that the grid may not be able to reach. The village or community could gather resources to get a system that supplies and stores power for themselves without having to rely on somebody else to do it for them. While It is more expensive (between USD 4,000 and USD 8,000 for a 4 kW Solar system without storage costs added) to set up an offgrid solar system at the beginning, it may work out better after a number of years and could end up being cheaper in the long run as grid electricity costs keep escalating.

solar panel Offgrid - On-Grid vs Off-Grid: What is the difference?
Figure 2 – Offgrid Solar House (Image by teresa cotrim from Pixabay)

Which one to choose?

Choosing on-grid or off-grid depends on what works best for the specific environment and the personal circumstances of the customer. So before making this important decision of what system to prioritise, one would like to particularly analyse local configuration and parameters that are likely to impact situations. An urban customer who is living in an are where grid is available would most likely find an on-grid solar system more convenient while in rural areas where grid is absent, the off-grid solar solution would be most recommended, providing the customer could afford it.

Authors:

Rachel Sekibo, Electrical and Electronic Engineering Student at Southampton University.
Tony Tiyou, CEO of Renewables in Africa

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