What is a Microgrid system?
A Microgrid is a self-contained energy system that serves a discrete geographical footprint, allowing you to generate your own power on site and use it when you need it most. Examples include university campuses, hospital complexes, business centres or communities.
Microgrids have one or more distributed energy sources that generate energy (solar panels, wind turbines, combined heat and power, generators). In addition, many of the newer microgrids contain energy storage, usually by batteries. Some now also have charging stations for electric vehicles. Based on this structure, you can operate the microgrid while connected to the utility grid or in a disconnected 'island' mode.
It is important to note here what is not a micro-grid. Some people use the term to describe simple distributed energy systems, such as rooftop solar panels. A key difference is that the microgrid will keep the power flowing in the event of a central grid failure. Solar panels alone will not. Many homeowners with solar panels are unaware of this fact and, accidentally, they lose power during grid outages. In addition, a simple back-up generator is not a micro-grid. Such systems are only used in emergency situations.
We can learn about microgrids by looking at three characteristics.
1. Layout in the vicinity of the place of use of electricity
Firstly, it is a localised energy source, which means it creates energy for nearby customers, unlike the large central grid that provides us with most of our shops. The central grid pushes the power from the power plant over long distances via transmission and distribution lines. Long-distance power supply is inefficient, as eight to 15 per cent of it is dissipated during transport. Microgrids overcome this inefficiency by generating power close to the power they serve. Generators are located near or inside buildings, or on the roofs of solar panels.
2. Independent of the central grid
Secondly, microgrids can be disconnected from the central grid and operate independently. This islanding capability allows them to supply power to customers in the event of a storm or other disaster that disrupts the grid. In the USA, central grids are particularly vulnerable to outages due to their sheer size and interconnectedness - more than 5.7 million miles of transmission and distribution lines. As in the Northeast blackout of 2003, a single tree falling on a power line can destroy power in several states and even across the international border with Canada. Through islanding, microgrids can avoid such cascading grid failures.
Although microgrids can operate independently, most of the time they usually remain connected to the central grid (unless they are located in remote areas where there is no central grid or where they are unreliable). As long as the central grid is functioning properly, the two functions work in a symbiotic relationship, as described below.
3. Resources can be intelligently controlled
Thirdly, microgrids provide intelligent control over the distribution of resources, especially if they are equipped with advanced systems. This intelligence stems from the microgrid controller, the central brain of the system, which manages the generators, batteries and energy systems of nearby buildings with a high degree of sophistication. The controller programs multiple resources to meet the energy goals established by the microgrid's customers. They may be trying to achieve the lowest price, the cleanest energy, the greatest electrical reliability or some other outcome. The controller achieves these goals by increasing or decreasing the use of any of the microgrid's resources (or a combination of these resources), just as a conductor calls on various musicians to raise, lower or stop playing their instruments for maximum effect.
Working together through complex algorithms, the resources of a microgrid create a whole that is greater than the sum of its parts. They raise system performance to levels of efficiency that no one else can. All these business processes are managed automatically and in an almost instantaneous manner. No human intervention is required.
Microgrids have been around for decades, but it is only recently that their reliability has become more widely known. Due to climate change, ageing infrastructure, cyber-attacks and other threats, the pace of installation of microgrids will gradually accelerate and is expected to increase considerably in the future as the price of distributed energy decreases and concerns about power reliability intensify.
What are the types of microgrids? Microgrids based on the area of use.
Microgrid models can be used in specific areas where uninterrupted energy is needed, such as hospitals or university campuses, or they can be used to provide energy distribution to residential or industrial sites, covering the entire area. There are also examples of microgrids used for strategic reasons, such as securing energy supplies for military bases. Microgrids can be as small as an apartment or as large as a province.
What does a microgrid consist of? How is it accomplished? Microgrid Components
A microgrid basically consists of four different points.
● Distributed energy (generation)
● Energy storage
● Energy consumption
● Connection points to the public (macro) network
Distributed energy: In a microgrid, energy comes from renewable sources, usually solar panels and wind turbines. It also includes a small amount of hydroelectric power, geothermal power and biomass/biogas power plants.
Energy storage system: Energy storage system is needed to eliminate imbalances in renewable energy generation and diurnal production differences in solar power plants. Energy storage also helps to meet sudden load demands and regulate voltage variations. Today, in addition to high-cycle energy storage technologies such as lithium-ion and lithium iron phosphate, lead-acid energy storage technologies such as colloidal batteries are often used.
Energy consumption: The consumption can be in the form of domestic (residential) use, private areas, industrial use or military use. Energy management in microgrids should be arranged according to the consumption demand. The better the demand forecast at the point of energy consumption, the better the generation and storage capacity can be optimized.
Connection points to the general (macro) grid: Microgrids can be designed as power connections or islands. Microgrids connected to the utility can continue to consume without interruption in case of utility outages or changes in demand in different areas. The port design requires the microgrid to be connected to the macrogrid through necessary protection circuits in case of maintenance or excess capacity.
The relationship between renewable energy and microgrids
With the intensification of the use of renewable energy sources, especially land and rooftop solar power plants, the feasibility study of microgrid applications becomes relevant. While the geographic location of hydropower and geothermal renewables as defined by Distributed Energy Sources (DES) cannot be chosen and a power plant should be built in an area where the source is almost, but the situation is different in the utilization of solar energy. In rooftop solar systems where production and consumption are close to the same point, OIZ companies and similar power plant installations are connected to the grid in a micro-grid fashion for mutual benefit at minimal cost.
Advantages and disadvantages of microgrid
◆ It is based on the use of efficient, low-cost clean energy.
◆ It provides uninterrupted energy through secure separation from the regional grid.
◆ It meets the ever-changing needs of the central grid.
◆ It prevents power line losses
◆ Decentralized risk and a stronger central grid
◆ The problem of line interruptions disappears after various disaster situations.
Disadvantages of microgrid.
◆ Complex and costly design of protection circuits due to bi-directional currents
◆ Difficulties in surge and control/damping of AC distribution lines in microgrids
◆ Need for a microgrid modeling and control mechanism
◆ Renewable energy is affected by weather conditions
◆ Energy storage unit investment and maintenance costs
Microgrid Modeling and Control
Immediate production and demand balancing is important in microgrid applications. Microgrids with a carefully designed balance of active and reactive power demand and generation forecasts operate at optimal efficiency. Control can be performed from a single center or in a distributed manner from production and consumption points. Both approaches have their advantages and disadvantages. Many different makes and models of products and system integration options are available on the market.
Microgrid Examples - Global Microgrid Applications
Microgrid systems have long been used on inland islands, in military zones, and in service buildings such as airports and hospitals. However, to give an example of a new type of microgrid for renewable energy to increase viability, there is a current model that began to be built in 2016 in Brooklyn, New York, where energy can be traded between individuals (homeowners), offering blockchain technology settlement. In addition to this, microgrid applications continue to be widely used in organized industrial areas, hospitals and similar locations with high energy continuity as rooftop solar system installation and commissioning becomes more popular.
As a microgrid company, BSLBATT can provide customers with solutions such as hybrid microgrids and utility-scale energy storage systems to minimize power generation costs and provide reliable power in remote areas or reduce electricity bills for businesses and industries.
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