Seminar On Microgrid

1.0 INTRODUCTION
1.1 Background of the study
A microgrid is a self-sufficient energy system that serves a discrete geographic footprint, such as a college campus, hospital complex, business center or neighborhood.

A microgrid is a local electrical grid with defined electrical boundaries, acting as a single and controllable entity. It is able to operate in grid-connected and in island mode. A ‘Stand-alone microgrid’ or ‘isolated microgrid’ only operates off-the-grid and cannot be connected to a wider electric power system (Hu et al., 2019).

A grid-connected microgrid normally operates connected to and synchronous with the traditional wide area synchronous grid (macrogrid), but is able to disconnect from the interconnected grid and to function autonomously in “island mode” as technical or economic conditions dictate.(Hu et al., 2019). In this way, they improve the security of supply within the microgrid cell, and can supply emergency power, changing between island and connected modes.This kind of grids are called ‘islandable microgrids’ (Bhowmick et al., 2020)

A stand-alone microgrid has its own sources of electricity, supplemented with an energy storage system. They are used where power transmission and distribution from a major centralized energy source is too far and costly to operate.They offer an option for rural electrification in remote areas and on smaller geographical islands.A stand-alone microgrid can effectively integrate various sources of distributed generation (DG), especially renewable energy sources (RES) (Hatziargyriou, 2014).

Control and protection are difficulties to microgrids, as all ancillary services for system stabilization must be generated within the microgrid and low short-circuit levels can be challenging for selective operation of the protection systems. An important feature is also to provide multiple useful energy needs, such as heating and cooling besides electricity, since this allows energy carrier substitution and increased energy efficiency due to waste heat utilization for heating, domestic hot water, and cooling purposes (cross sectoral energy usage)(Hatziargyriou, 2014).

Within microgrids are one or more kinds of distributed energy (solar panels, wind turbines, combined heat and power, generators) that produce its power. In addition, many newer microgrids contain energy storage, typically from batteries. Some also now have electric vehicle charging stations.

1.2 Statement of the problem
The initiatives of microgrid came up due to the erratic nature of our national grid. It was due lack of access to the national grid, remoteness of the locations and the economic considerations are among the major factors that justify the deployment of microgrids in off-grid communities. Microgrid systems could be based on different kinds of energy resources, categorized as renewable and conventional sources (Ainah  et al, 2015).A microgrid not only provides backup for the grid in case of emergencies, but can also be used to cut costs, or connect to a local resource that is too small or unreliable for traditional grid use. Microgridallowcommunities to be more energy independent and, in some cases, more environmentally friendly. More companies and governments are considering microgrids as the solution to a variety of challenges.

1.3 Objectives of the study
The objectives of the study are:

• To have a full Knowledge of microgrid
• To study the advantages and application of the microgrid
• To solve unsteady and inefficiency problem of our national grid

1.4 Scope of the study
The microgrid provides electricity and possibly heat and cooling for its customers, delivered via sophisticated software and control systems. This seminar covers the study of microgrid

1.5 Application of the study
Microgrids are used in industries, institutions, communities and other customers in a range of ways.

1.6 Characteristics of microgrid
A microgrid is local
First, this is a form of local energy, meaning it creates energy for nearby customers. This distinguishes microgrids from the kind of large centralized grids that have provided most of our electricity for the last century. Central grids push electricity from power plants over long distances via transmission and distribution lines. Delivering power from afar is inefficient because some of the electricity – as much as 8% to 15% – dissipates in transit. A microgrid overcomes this inefficiency by generating power close to those it serves; the generators are near or within the building, or in the case of solar panels, on the roof.

A microgrid is independent
Second, a microgrid can disconnect from the central grid and operate independently. This islanding capability allows it to supply power to its customers when faults or other calamity causes an outage on the power grid.

While microgrids can run independently, most of the time they do not (unless they are located in a remote area where there is no central grid or an unreliable one). Instead, microgrids typically remain connected to the central grid. As long as the central grid is operating normally, the two function in a kind of symbiotic relationship, as explained below.

A microgrid is intelligent
Microgrid – especially advanced systems – is intelligent. This intelligence emanates from what’s known as the microgrid controller, the central brain of the system, which manages the generators, batteries and nearby building energy systems with a high degree of sophistication. The controller orchestrates multiple resources to meet the energy goals established by the microgrid’s customers. They may be trying to achieve lowest prices, cleanest energy, greatest electric reliability or some other outcome. The controller achieves these goals by increasing or decreasing use of any of the microgrid’s resources – or combinations of those resources – much as a conductor would call upon various musicians to heighten, lower or stop playing their instruments for maximum effect.

A software-based system, the controller can manage energy supply in many different ways. But here’s one example. The microgrid’s solar panels could instead charge its battery systems. Later in the day, when grid power becomes expensive, the microgrid may discharge its batteries rather than use grid power.

Microgrids may contain other energy resources – combined heat and power, wind power, reciprocating engine generators, fuel cells – that add even greater complexity and nuance to these permutations.

1.8 Benefits of microgrid
A microgrid improves electric reliability
Power outages aren’t only an inconvenience, they can be dangerous. When a backup generators failed during faults, microgridskeep the power flowing by disconnecting — or islanding — from the central grid when it begins to fail. The microgrid’s generators, and possibly batteries, then serve the microgrid’s customers until power is restored on the national grid.

A microgrid enhances resilience/recovery
Closely related to electric reliability is the idea of energy resilience. While reliability is about keeping the power on, resilience describes the ability to avoid power outages in the first place or to recover quickly if they do occur.

In some cases, a microgrid immediately restores power to an entire building or operation, leaving occupants barely aware a disturbance occurred.

In other cases, a microgrid is programmed to restore only critical services within a facility.

A microgrid can lower energy costs for consumers and businesses
Microgrids can both reduce costs and provide a revenue stream for their customers. They reduce costs through the efficient management of energy supply. They supply revenue by selling energy and services back to the grid. This gives consumers a new kind of control in energy markets. They no longer just consume energy but also can produce and control it through their microgrids. Microgrids can earn revenue by providing ancillary services to the central grid. Ancillary services provide support functions for the grid, such as frequency control and spinning reserve.

Microgrids also can gain economic benefit by joining utility demand response programs or by participating in state and federal clean energy programs, such as state renewable portfolio standard initiatives or federal production tax credits. Some states have grant programs specifically for microgrids.

In areas where electricity costs are high — microgrids may be able to consistently provide energy at a lower cost. Microgrid customers then receive benefits, such as reliability and cleaner energy, yet pay lower prices for energy.

A microgrid improves the environment and promotes clean energy
Many businesses and communities establish clean energy goals to conserve energy and reduce the environmental impact of their power generation.

Microgrids can employ a wide range of green power production technologies. These include solar, wind, fuel cells, combined heat and power (CHP) plants, and energy storage technologies. Natural gas generators, used in many CHP plants, fall on the cleaner side of fossil fuels.

Microgrids integrate these renewables into the energy mix intelligently. They seamlessly balance the variable output of renewable energy with traditional generation assets. In doing so, the microgrid overcomes the downside of solar and wind energy, which is that they only generate power when the wind blows or sun shines. With no human intervention, a microgrid can tap into other resources when renewable energy is unavailable.

Advanced microgrids can also be programmed to achieve specific sustainability goals, such as use of the lowest carbon resources, to the maximum extent possible.

A microgrid strengthens the central grid
In addition to serving its own customers, a microgrid benefits neighbors as well when it’s used to strengthen the national grid.

It does this in a few ways. One is by augmenting normal grid operation; for example, by participating in demand response programs or providing ancillary services.

Microgrids also can help ease strain on the central grid during periods of peak demand. They act as an additional resource grid operators can call upon during these periods.

The use of microgrids also averts line loss — the dissipation of electricity as it travels over wires.

A microgrid bolsters cybersecurity
The US power grid has not been inflicted with a cyberattack that causes loss of power, but many experts are concerned about its vulnerability and are taking proactive measures. Installing microgrids is among them.

A microgrid brings economic value to society
Microgrids offer economic value to society in several ways. First, they avert loss of product and workdays during a power outage. Second, they attract high quality employers to a region. Third, as local energy plants, they keep jobs within the community.

By islanding from the grid during a power outage — and continuing to supply customers via on-site generators — microgrids avert significant economic loss. Businesses do not have to close; workers can get to their jobs.

Power outages are costly, especially to research facilities, data centers, manufacturers and grocery stores that lose product or services.

Given how expensive outages are to business, it is no surprise that enterprises dependent on premium power are attracted to communities with microgrids. By offering reliable power, these communities can attract high quality employers, such as data centers and pharmaceutical manufacturers.

It’s also important to note that the construction and operation of the microgrid creates local jobs. The community is not using power from a plant hundreds of miles away. As local energy, a microgrid benefits the local economy directly.

For all of these reasons, some communities now make microgrids part of their economic planning.

A microgrid improves community well-being
When a disaster knocks out power, at best it’s an inconvenience; at worst it’s a health and safety threat, especially if critical facilities cannot operate. As a result, more and more communities are installing microgrids to serve hospitals, police stations, fire departments, communications centers and wastewater treatment plants.

The geographic region served by the microgrid becomes an island of power. Sometimes shelters, grocery stores and gas stations are included within the microgrid’s service area. The neighborhood becomes a place of refuge, where community members can come to buy food, get clean water, charge cell phones and gas up cars.