Have you heard about solar mini-grid systems and now you are wondering what are the basic components of a solar mini-grid system?
If this is you, then you are about to read in detail the basic technical components of a mini-grid system.
What are the Basic Technical Components of a Solar Mini-Grid?
A combination of three major systems makes up the basic technical components of a solar mini-grid.
- Production System
- Distribution System
- End-User System
These basic components of a solar mini-grid are not so different from that found in the conventional electricity production system.
For every solar mini-grid system you see out there, it is a combination of these three sub-systems.
The solar mini-grid system begins with the production system component that has to do with the generation of electricity.
After generating electricity, there is a second component which is the distribution system that distributes electricity to the end-users.
At the end of the chain, we have the end-users. The end-user system provides connections that allow customers to use electricity in their homes and offices.
Let’s break it down in details.
1. Production System
It is important to pay attention to the production system when setting up the solar mini-grid system.
This is because the production system determines the mini grid’s overall capacity to provide electricity to end-users.
Whatever quantity of electricity the production system is able to produce, that is what the distribution system will transmit to the end-users.
The components of a solar mini-grid production system consist of the following
- A set of energy generation technologies; for generating electricity through various means
- Power inverters; for converting DC to AC and vice versa
- A management system; for controlling the charging of batteries and distribution of electricity.
- Batteries; for storage.
Energy Generation Technologies
As part of the solar mini-grid energy generation technologies, we have the following:
- Diesel generators
- Hydropower systems
- Solar photovoltaic (PV) modules
- Wind turbines
- Biomass-powered generators
- Geothermal-powered generators
A mini-grid may use a single energy source or a mix of sources (hybrid) that are either renewable or nonrenewable.
For instance, an off-grid mini-grid system may use only solar photovoltaic (PV) modules to generate electricity.
Some energy generation technologies produce direct current (DC) while others produce alternating current (AC).
For instance, a solar photovoltaic (PV) module generates DC, whereas nearly all mainstream appliances require AC.
The conversion is mostly dependent on the end user’s requirement.
Especially when end-users need a different type of electrical current than what the energy production technology generates.
Inverters in the electricity production system helps to convert electric current from DC to AC making it usable for most end-users.
Therefore, a solar-powered mini-grid serving several households would need an inverter as part of its production system.
Unlike the mainstream appliances which end-users use, charging of power storage batteries requires a DC power.
So, an inverter would convert electrical current from AC to DC if the current were coming from a grid-tied (utility) system or from a diesel generator.
In an AC-coupled configuration with storage (a battery), the energy generation and storage systems each have their own inverter.
These separate inverters connect to one another on the AC side of the system.
Operators can use the battery inverter to control charging and discharging.
In a DC-coupled PV configuration, the energy generation and energy storage systems share an inverter.
DC coupling tends to provide better performance.
This is because battery charging is more efficient when there are fewer power conversion steps.
Management systems form part of the basic components in a solar mini-grid – under the production system.
The management system measure, monitor and control electrical loads.
Let’s use the charge controller as an example.
To prevent the battery from charging and overcharging, connect a charge controller between the solar panel and the battery or inverter/charger.
Also, metering and monitoring equipment allow mini-grid managers to gather data about energy use across end-users, which informs operational decisions.
In order to optimize performance, management systems often couple computerized energy management tools with smart metering.
Some management systems allow operators to control the system remotely, including shedding loads as per requirement.
Some mini-grid production systems require energy storage units such as batteries to be able to supply electricity all the time.
This is true especially for solar and wind resources that only produce power when the renewable resources are available.
Because these renewable resources are not always available round the clock, they cannot produce electricity according to user demand.
For such a mini-grid system to be able to meet the power requirement of the end-users on-demand, it must store energy and supply it when resources are not available.
One awesome benefit of energy storage is that it adds stability to the system by storing energy for peak consumption.
Large mini-grid systems that run diesel generators continuously do not require batteries.
However, nearly all other mini-grid systems require some type of energy storage.
To optimize system performance, longevity and cost, project developers need to identify the most appropriate energy storage technology for their mini-grid.
Lead-acid batteries are the most common, but fuel cells and advanced battery technologies—like lithium-ion, nickel-metal hydride and sodium-ion batteries—are generally more efficient and last longer.
Interestingly, the costs for these new battery technologies continue to decrease as they become advance in technology.
Despite the need to store electricity for when there is a need for it, it is worthy to note that large battery banks pose serious safety hazards.
High concentrations of hydrogen gas can cause explosions, and leaks can cause electrolyte spills.
To curtail these hazards, installers should locate batteries in locations with good ventilation such as utility rooms or outbuildings.
Also, purchasing and operating a battery can sometimes cost more than operating a diesel generator continuously.
This may be the case when the operators are unlikely to maintain and use the battery correctly.
2. Distribution System
The distribution system is the second basic component of a solar mini-grid system.
After generating electricity in the production system, the distribution system transmits the electric power from the energy production system to end-users.
Distribution and/or transmission lines, transformers and the infrastructure to support the lines, such as poles are key components of a distribution system.
Lines can be overhead or underground. Overhead transmission is most common as it is comparatively cheaper and easy to connect to the end-user.
The distribution system uses a variety of voltages when transmitting electricity from the production system to the end-users.
It can be either be AC or DC, and either a single- or three-phase power supply.
AC voltage levels in a mini-grid network covering a large area can be changed by transformers.
To transmit electricity more efficiently over a distance, AC output voltage can be increased by step-up transformers.
On the other hand, step-down transformers decrease the voltage from high- or medium-voltage transmission lines to 120 V or 220 V for residential use.
Distribution network costs and system losses in AC mini-grids can be minimized by transformers.
Distributing electricity at medium voltage allows systems to use smaller conductors, minimizing cable costs.
A higher voltage causes greater safety risks for operators and users. Therefore, special training is required for operators.
There are various efficiencies in various components. Therefore, the determining of voltage, current and transformers impact energy losses.
The cost setting up the distribution system usually dictates which option project developers choose.
DC is generally less expensive than AC because AC requires power conditioning equipment.
The availability of appliances for different currents is also consideration developers must take note of.
The end-user systems provide an interface for electricity consumers to access, use and monitor electricity from the mini-grid.
It takes into account consumers’ needs and energy uses to determine the type of system that will be fit for the connection.
For example, a business that uses large machinery for production purposes will need a different system than households that use electricity for lighting and small appliances.
The end-user system consists of three basic components;
- Connections to and from the mini-grid
- Systems to prevent electrical shocks and harm to both equipment and users
- Power consumption metering.
Benefits of an end-user system component in solar mini-grid systems
The end-user system has some important uses and benefits to both the consumers and the operators.
- End-user systems provide information to consumers, that allow them to monitor their energy consumption, estimate the cost of their consumption and understand the current status of the system.
- They also provide useful data back to the system operator, reporting on consumption rate and timing, like when and how much energy is used.
- These data provide valuable feedback to system operators, which enables them to estimate and predict demand and consumption patterns.
- The data also allows regulators to establish tariffs that balance the needs of the operator and the consumer. While ensuring differing use cases are priced fairly and competitively.
- Finally, the end-user system provides important electrical bond and grounding mechanisms. This helps to ensure the safety of its users and protect valuable and expensive equipment.
Power consumption metering
Mini-grid enterprises rely on frequent, small payments from their customers for the use of electricity.
This makes metering, billing and collection time-consuming and expensive too.
Innovative metering and payment systems automate these otherwise complex tasks.
Individual meters (one per end-user) provide the greatest degree of control over energy use.
Meters can be pre- or post-paid; pre-paid meters typically are called pay-as-you-go (PAYG) metering.
Newer generation meters are typically considered “smart meters.”
Although older, traditional meters are still in use, both have advantages and disadvantages.
Green Village Electricity Mini-Grid Installation
Having read to this point, we believe you now understand the various components of a solar mini-grid system.
The basic components of a solar mini-grid system consist of the production system, distribution system and end-user system.
Each of these components has sub-systems via which electricity is produced, distributed and used by end-users.
GVE Projects Ltd has a track record of setting up efficient mini-grids in Nigeria.
It is part of our services to bridge the electricity gap in Nigeria by designing and installing solar mini-grids, home solar installations etc.
You can read about some of the solar mini-grids we designed and installed in Nigeria.
If you are up for a partnership or you wish to provide electricity to an area as part of your company’s CSR activity, you can send an email to firstname.lastname@example.org.
We are always ready to deploy our solar mini-grid system to meet the electricity need of people.
Call +234 909 2227 483 to communicate with one of our representatives immediately for more inquiry.