Solar Power Solutions

Solar systems explained

"Getting off the Grid" - Solar systems

There’s no doubt, to be totally self-sufficient and independent from the National grid would be amazing!

In South Africa it would mean freedom from the dreaded outages which have become part of our daily diet and have taken a heavy toll on our lives and productivity.

However, when dealing with solar power, there are a few things you should know.

Some Facts

Off the grid is a term that gets thrown around easily but entails more than a flick of the switch. It is a little more intricate than that. Especially when you are investigating the most viable alternative: Solar.

Understanding Solar panels

Firstly, your peak energy requirements (Hot water and mealtimes) normally occur early in the morning and late during the day or evening. Your solar panels on the other hand will be producing their peak power around mid-day.

Secondly the daily power production from your solar panels is dependent on sunshine hours. They can fluctuate from one day to the other. A rainy overcast day will drop your power production substantially. In wintertime sunlight hours decrease.

As a result, you will need to store the energy on site. This means you will require batteries.

In this short blog entry, we pick apart the 3 main options available when looking at a Solar energy system:

 

Off Grid

Diagram of components of Off grid Solar installation with writing: GENERGY Inspired Sustainability

If you are convinced you want to be self-sufficient or your location limits the access to the National Grid, then a pure Off-grid solar solution is for you.

An Off-grid system will consist of Solar panels, Solar charge controller, Off-grid inverter, DC disconnect switch, back up.

Batteries.

Battery technology has come a long way in the last few years. It is constantly improving. However, choosing a quality product will still make it the biggest expense in your system.
There are two types of Batteries available, Lead Acid batteries and Lithium-Ion batteries. For the purpose of an Off-grid system, Lithium-Ion batteries are the better choice. They outperform the Lead Acid batteries in every requirement.
However, they are more expensive.

https://www.power-sonic.com/blog/lithium-vs-lead-acid-batteries/

Lead Acid batteries are suitable when the system is not used frequently.

Solar Charge Controller.

A solar charge controller is a battery regulator that protects the battery from overcharging. It limits the rate of current being delivered to the battery. A top-quality controller will ensure the health and life span of your batteries. The solar charge controller can be included in the Inverter.

Off grid inverter.

The purpose of the inverter is to transform the DC power produced by your solar panels and battery bank into AC power. You household appliances run on AC power.
As opposed to grid tied inverters, the off-grid inverter does not require to match the grid’s sine wave (frequency) as it is not connected.

DC Disconnect Switch.

Safety AC and DC disconnect switches are mandatory for all solar installations. However, for an Off-grid system an additional DC disconnect switch is required. It is placed between the battery bank and the inverter. This allows the current to be switched off between the two components. This is important for protection and during troubleshooting. It also allows safe access during maintenance work.

Back up.

You should consider back up. A lack of sunshine during a few days or a problem with the system could leave you stranded with no electricity at all. The backup can be a connection to the grid (if nearby). If you do not have access to the grid, you should consider a generator or perhaps an additional UPS system.

 

Grid tied solar system

Diagram of grid tied Solar installation with writing GENERGY Inspired sustainability

At present Grid tied solar systems have the best economical return. That is if your utility supplier at your location allows net metering.

Net metering is a rate structure that allows your utility company to purchase / Net Meter the excess energy produced by your solar panels.
Basically, the Grid is your virtual battery without the hassle of maintenance and replacement cycles. It also cuts down on the original capital investment. Batteries are one of the most expensive component of your system.

Grid tied systems are made up of solar panels, inverter, and a power metre.

 

Power Meter

A power meter is a special usage meter that allows Net Metering with your Electricity provider. In a very basic explanation; it will go forward when you use the electricity and backwards when you feed electricity back into the grid.
It will replace your current meter.

If you can match your solar panels to your usage, you could technically no longer have an electricity bill to pay.

Inverter

As previously stated, an inverter will transform the DC power into AC. However, you will require an inverter able to match the grid’s frequency.

Keep some candles.

The downside of a Grid-tied solar system is that it doesn’t protect you from power outages (load shedding). To do that you would have to look at a Hybrid Solar system. . In order for your system to be operational, the grid needs to operational too.

 

Hybrid solar system

 

The easiest way to describe a Hybrid system is to see it as a Grid tied system with an extra battery back up built in. This allows you to overcome load shedding.

 
Being connected to the grid, you will not need your batteries constantly. During outages you can reduce your electricity consumption by switching off non essential appliances. The battery pack will be significantly smaller than in an Off-Grid system. This makes Hybrid systems cheaper than a Off Grid system.
Besides the panels, charge controller, DC Disconnect, a power metre and the batteries, An intelligent battery-based Inverter will be required. It will draw electrical power to and from the battery bank. It is also required to synchronise with the utility Grid.

Hopefully net metering is also an option making the Hybrid system the most flexible of all systems.

Diagram of components of Hybrid Solar installation with writing: GENERGY Inspires Sustainability

Conclusion

 
Each household or small office has different necessities. You need to carefully consider your requirements and budget before taking a step into the world of sustainable solar power. You can decide to go all out or perhaps take a gradual step by step approach. Whichever it may be, it will be crucial to have the right components put in place.
We suggest you talk to a GENERGY consultant to direct you to the best solar panel system for you.

Psst Let's Tell Some Friends?

Sustainable Solar Solutions

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