← OFF-GRID POWER INTRODUCTION
Off-Grid Solar Power Systems
Off-Grid solar power systems – also known as Stand-alone power systems (SAPS or SPS) are available in various types and sizes, ranging from small portable kits or pre-wired plug & play systems, to medium-sized systems for sheds, weekenders, cottages, and large capacity systems for off-grid homes and rural business.
The smallest – most basic setups are often DC only systems that don’t include an inverter for AC supply. These systems usually have a 12V battery bank and are designed to power 12volt lighting and appliances such as DC fridges, DC pumps, laptops and phone chargers.
12V DC systems will have a relatively low power delivery & energy storage capacity.
A small portable plug-in inverter can be used to operate low power 240V AC equipment occasionally if required.
As the power and storage capacity of a system increases, the battery bank voltage will also be increased up to 24V for small systems or 48V for medium and above. They will also incorporate an integrated inverter to supply AC power for appliances. The power rating of the inverter will increase as the system capacity increases.
Off-Grid System Components
What are the components of an off-grid / stand-alone power system?
Solar PV Panels
(Solar Array)
– Provides power production
– System production capacity is rated in kilowatts (kW)
Because the panels in an off-grid power system are the primary (and sometimes only) power source,
we recommend using LG NeON2 high-performance panels.
LG’s NeON2 panels have:
• Improved high-temperature performance – higher output in hot weather conditions
• Enhanced low light performance – better performance under low light (early morning, late afternoon, overcast days)
• Low Light Induced Degradation (LID) – Less degradation in output over the lifespan of the panel
Battery Bank
(typically 12V, 24V, or 48V)
– Provides energy storage
– System storage capacity is rated in kilowatt-hours (kWh) or ampere-hours (Ah)
– Battery chemistry is typically Lead-Acid or Lithium-Ion
Inverters and Chargers
An off-grid system will include one or more of the following components, depending on system type & configuration:
○ Solar Inverter
○ Battery Inverter
○ Charge controller
○ Battery charger
○ Multi-mode inverter
○ All-in-One unit
Backup Generator
(Genset)
Provides back-up power supply, can be either:
– Permanently connected with an auto-start function controlled by the system
– Temporarily connected if required via a generator input socket (small systems)
System Monitoring, Management & Control
Monitoring can be local only or include remote access.
Components include status display screens, internet connection & communication devices, control & management interfaces.
Panel Mounting System
The method used for mounting the solar panel array will depend on the specific situation and application.
The three main types of solar panel mounting are:
• Roof Mount (mounted on a house or other building structure)
• Post Mount (mounted on rails secured to posts that are concreted in the ground)
• Ground Mount (mounting on a frame secured to concrete footings – near to ground level for stability)
The mounting frames and rails should have engineering certification, and be installed according to the manufacturer’s instruction manual & the relevant Australian standards.
Balance of System
The balance of system (BOS) refers to the components of a PV system other than the panels and other main components including:
• Switches, isolators, fuses & circuit breakers
• Electrical cabling and connectors for DC, AC, data & comms
• Battery cabinets
• Enclosures for switchgear, circuit protection, monitoring and communication devices.
• Conduits, ducting & fittings, and all other miscellaneous components.
Although these are lesser components, the use of inferior quality materials can lead to system failures. Therefore, high-quality balance of system components must be used to ensure overall system performance and reliability. This is especially important in off-grid situations, as system downtime could mean loss of power supply for an extended period.
Off-Grid Power Systems – Design Considerations
The first and most important step when designing an off-grid power system is to assess your energy requirements. Knowing how much power the system will need to supply is necessary to determine the required size for the solar panel array and battery bank, and also to decide which inverters and chargers will be most suitable.
When it comes to off-grid solar power systems there is no one size fits all approach, and there is certainly no room for guesswork when it comes to off-grid system planning. Correct system sizing by an experienced designer is crucial to having an efficient & reliable off-grid power supply.
We also need to ensure the battery bank has enough capacity for periods of bad weather, and the solar panel array can generate enough energy to cover consumption even during the months with the lowest solar production conditions.
Our design will also take other factors into consideration including:
Environmental
– Site-specific irradiance levels (peak sun hours)
– Maximum and minimum temperatures
– Shading
– Snow / Dust
– Battery location (Temperature controlled room?)
Electrical
– Continuous load demand
– Surge demand (peak power demand)
– Time of energy usage (energy profile)
– Load power factor
– Maximum charge & discharge rates
– Required battery autonomy
System
– System inefficiencies (inherent and site-specific)
– De-rating factors
– Panel mounting/location
– Panel orientation & tilt
– System installation location
Off-Grid Power Systems – Design & Quote Process
What are the steps involved in getting an off-grid power system design & quote?
The process can be summarised into 6 stages as follows.
[ 1 ] Assessment of energy requirements and site location.
As mentioned in the previous section, this is the most important step in the process.
Because each aspect of system design that follows will depend on this information, it is worth spending the time to complete this step as thoroughly as possible.
Preliminary system size and price range can be advised after a few questions about the purpose of the system and the main power-consuming appliances that it will supply power to.
i.e. Is the system for a farm shed? Irrigation pumps? family home? summer weekender? stockyard lights & power?
Proceeding further will involve a deeper look into the site specifics and energy requirements.
There are a few ways to do this and a common method is to fill out a load assessment sheet with appliance power consumption and estimated run times. From this, we can determine the daily kWh energy requirement.
Additionally, we’ll gather information about some other aspects that can affect design options.
For example:
• major appliances
– air conditioning, hot water, cooking, large pumps, workshop equipment (welders/air compressors/hoists)
• seasonal or year-round use, occasional or full-time use
• effect of seasonal variations – eg; winter heating, summer irrigation, summer AC
• time of consumption – day/night
• your choices & preferences
• battery autonomy – 2 days, 3 days? (affects the size of the battery bank)
• backup generator options
• upsizing solar array or battery bank capacity
• future considerations – for example; plans to increase capacity or add wind/hydro in future
[ 2 ] Designing the system
The next stage will be to produce the system design – with assistance from our specialised system design software. This will be carried out by our qualified, accredited, and experienced off-grid design team.
[ 3 ] System proposal
Once we have completed the design stage, we’ll present to you a comprehensive system proposal that includes energy production and consumption estimates, solar potential & yield estimates, financial simulations (ROI, system lifetime savings, etc), system component info & specs.
At this time we’ll consult with you to discuss your option preferences and any budget considerations.
[ 4 ] Design approval and quote acceptance.
Upon your acceptance of the system proposal, we will finalise the design for the chosen system and options.
A job order will be created and we’ll send details for a deposit payment to get things underway.
[ 5 ] System building and testing
Our technicians will build your system in our workshop, program the configuration settings, and run it through a testing procedure. Once testing has been completed, we’ll get the system ready for deployment to the site, or pack it for delivery in the case of Plug and Play/DIY kits.
[ 6 ] Installation & Commissioning
The final step will be to coordinate with you to schedule installation.
Your system will then be installed and commissioned by our technicians.
Monitoring & communications access will be set up and we’ll provide you with a system introduction and briefing on operation and maintenance, along with a comprehensive system owner’s manual.
Customised Systems
Building & Testing
Installation & Commissioning
Off-Grid Power Systems – Price Range
The cost of an off-grid system will depend on a number of factors, the main ones being:
- Power generation capacity (kW) – the number, rating, and type of panel used.
- Energy storage capacity (kWh) – the capacity and type of batteries installed.
- The type of Inverters & Chargers used in the system, along with monitoring & communications components.
For an indication of what you could expect to pay for an off-grid system, here are 3 broad categories based on system size with price range.
Small
1.5kWh - 5kWh/day
Water pumps
Electric gates
Stockyard lighting
Security cameras
Perimeter lighting
$1500 to $10,000
Medium
5kWh - 12kWh/day
Weekender
Small workshop
Cabin/Cottage
Site office
Shed
$10,000 to $30,000
Large
12kWh - 24kWh/day
Off-grid home
Large workshop
Small business
$30,000 to $50,000
X-Large (25kWh+) & 3 Phase systems - $50k+
Clean Energy Council Accredited Installers
Stand-Alone Power Systems - PV Design & Install
Make an Enquiry
When choosing SolarWise Wagga, you can feel confident that you will have a professionally designed system that meets your present and future energy requirements, is well suited to your property, and will provide a great return on your investment.
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