Energy is the basic necessity for the economic development of a country. Many functions necessary to present-day living grind to halt when the supply of energy stops. It is practically impossible to estimate the actual magnitude of the part that energy has played in the building up of present-day civilisation. The availability of huge amount of energy in the modern times has resulted in a shorter working day, higher agricultural and industrial production, a healthier and more balanced diet and better transportation facilities. As a matter of fact, there is a close relationship between the energy used per person and his standard of living. The greater the per capita consumption of energy in a country, the higher is the standard of living of its people. Energy exists in different forms in nature, but the most important form is the ‘electrical energy.’
The modern society is so much dependent upon the use of electrical energy that it has become a part and parcel of our life. In this article, we shall focus our attention on the general aspects of electrical energy. Electrical energy is superior to all other forms of energy due to its cleanliness, convenient form, easy control, greater flexibility and high transmission efficiency.
India is the fourth biggest consumer of electricity after China, USA and Russia. India has the total installed capacity of 254.649 GW by using conventional and non-conventional energy sources. Total generation sources are given in following table with its share in generation.
If we look upon generation and demand of electricity in India, we blindly come on conclusion that we have deficit in energy generation – as its result we face daily load shedding. 17th Electric Power Supply of India survey report states that India’s industrial power demand is 35%, domestic and household 28%, agricultural 9%, and rest of public lighting and other applications. Concern with per capita consumption of India is 918 kWh/Year and the same of worldwide per capita annual average is 2600 kWh/Year. With this fact India has very low per capita consumption compared to the worldwide average per capita energy consumption. Thus, the bottom line is that only 96 kWH/Year energy consumption is of rural area and 288 kWh/Year of urban areas.
As per the report titled Government Of India ‘Executive Summary Power Sector October-14,’ by Ministry of Power Central Electricity Authority, New Delhi: the rural electrification of India is about 95.82%, so there is still 4.2% of people have no access of electricity. Of the 1.4 billion people of the world who have no access to electricity, India accounts for over 300 million. The technologies we use as fuel sources – if that adds to the electricity generation, will make a good impact on global resource and environmental problems. Traditional fuels like fuel wood, cow dung, bio or agricultural waste are inefficient sources, and cause high level of pollution containing NOX, SOX, CO, CO2 and other hazardous pollutants. World Health Organisation report claims that every year 3,00,000 to 4,00,000 people die of indoor air pollution and poisoning of air and other pollutants.
Transmission and Distribution (T&D) losses are the biggest drawback of Indian energy sector as our generating stations are far from utilisation areas.
Reasons of these high T&D losses are technical losses due to too many stages of transformations, improper load management and inadequate reactive compensation. Commercial losses occur due to peoples’ mind setup and willingness, improper energy accountings and impropercalibration and design of meters. According to a CEA (Central Electricity Authority) report, India has 23% T&D losses, where other countries like: Japan has 5%, Australia 7%, the U.K. 8% and average of the world 9.8%. India still needs to add about 218 Giga Watt power to satisfy electricity demand for year 2016-17 and 298 GW for year 2021-22.
Now the most important thing is that, if we try to solve all these issues, it will take too much time and efforts. However, we get an answer as renewable energy is becoming more accessible, electric power is decentralising. So, the solution to overcome these challenges lies in development of Micro-Grid (Gram Power).
What is micro grid?
- An integrated energy system intelligently managing interconnected loads and distributed energy resources – and capable of operating in parallel with, or independently, from the existing utility’s grid.
- Micro grids are electricity distribution systems containing loads and distributed energy resources, (such as distributed generators, storage devices, or controllableloads), which can be operated in a controlled and coordinated way, even when connected to the main power network.
Concept of micro grid…
How does it work?
It works in a manner like our power grid network that consists of the grid that connects to the domestic, industrial and commercial buildings to central power sources – that allow us to use appliances and other utilisation systems.
But at the time of maintenance, power outage or any fault, everyone gets affected due to interconnectedness. Here, micro grid operates while connected to grid. It can break off and operate using local energy generation at the time power outage or faults. It is powered by distributed generators, batteries, renewable energy sources like solar panels, wind mills and biomass.
Micro grid is powered by centralised array of solar panels, wind mills and sometimes hydroelectricity (if possible). This generated electricity is provided to the local consumers or either stored into batteries to provide users continuous supply of energy during peak usage and fault time. When no solar energy is generating at night then batteries or wind power will provide electricity to consumers of that local bounded area. This power is distributed throughout the service area via small overhead lines. The whole system will operate, be monitored and controlled by any smart system like a smart grid system. Each house hold is equipped with smart meters that utilise energy from micro grid and provides feedback to the generating station via smart metering technology.
Any small scale local station, which has its own power sources, generation centresand loads to the definite boundaries, qualifies as a micro grid.
Working of micro grid…
It can be intended as backup power to bolster the main power grid during periods of heavy or peak demand. It involves multiple energy sources – as the way of incorporating renewable power. It is also integrated with utility grid, which ensures that the infrastructure is not wasted when the utility grid reaches the village, and in turn makes the utility grid more reliable by adding in decentralised generation.
Major components of micro grid…
Micro grid master controller:
- Its function is to optimise load with the generation in island mode or grid connected mode.
- Real time response and fault protection.
- Connections and disconnections from grid.
- Predictive and forecasting of analysis.
Energy resources and generation system:
- Generally renewable energy sources are used for generation.
- Solar, wind, hydropower, biomass are used for generation.
- Sometimes diesel generators are also used for energy source.
Communication network:
- There is use of integrated communication system.
- Data is collected via modems rather than direct network connections.
- Of late fibre optics is also used for communications.
Control systems:
- All system are controlled by automation.
- Substation Automation, Demand Response, Distribution Automation, Supervisory Control And Data Acquisition System (SCADA), Energy Management System (EMS), Power Line Carrier Communication (PLCC).
Utilisation system:
- This system consists of residential load, commercial load of villages and selected areas of installation.
- Villages are the best locations to install micro grid.
Actual installations of micro grid (Gram Power) in India
- India’s first micro grid system was installed at Tonk district of Rajasthan in 2012.
- 150 consumers, 2 kWP System.
- 24 * 7 on demand power supply for domestic.
- 10 systems were operational in 2012 scaling 200 in 2013, and now expanding access to Bihar & Uttar Pradesh.
Gram power in Rajasthan…
Advantages of micro grid over convectional utility grid
Efficiency
- Reduced fuel consumption
- Supply close to demand minimising distribution losses.
Reliability
- Optimally managed on-site energy resources 24/7
- Power quality and reliability at the local level.
Energy security
- Ensured energy supply for critical loads utilising on-site generation.
- Grid independence capability.
Economic benefit
- Peak saving/Load shifting and supply management with demand response.
- Reduction of cost of electricity with on-site generation & effective energy management.
Sustainability
- Reduction of carbon footprint by integrating cleaner fuel resources.
Applications of micro grid
- Institutional/campus sites, hospitals, universities.
- Commercial/industrial facilities.
- Remote ‘off grid’ communities.
- Military bases.
- Data centres.
- Municipalities.
- Small villages.
Technical challenges of micro grid and possible solutions
Micro grid protection:
- Challenge – Protection of two operational grids like Island and utility grid.
- Generation system in both medium and low voltage makes bidirectional flow.
- Solution – Differential protection system is useful to protect bidirectional power flow.
- Challenge – To reduce tripping and maintain stability of grid.
- Solution – Distance protection scheme can be used to reduce or detect fault and trip adequately. Inverse time relays are best solutions for stability issues.
Voltage and frequency control:
- Challenge – The unbalanced condition occurs when power generated is not equal to the power demanded. This unbalance will cause a deviation of the system frequency (50 Hz).
- Solution – Voltage and frequency can be regulated by using voltage versus reactive power drop controller for reliability and system stability.
Generation sources:
- Challenge – Intermittence in generation of several micro sources.
- Solution – Use of diesel generators in case of peak demand even when connected with the main grid.
Conclusion
It is the best solutions for energy deficiency and dependency of India. It is challenging for consumers, utilities and developers – still it is able to generate electricity in safe, reliable and consistent mode. This job is not easy that wide spread and successful implementations of micro grid will power up India. But, we should not stay away from this opportunity to cope with our dream of vision 2020.
It has the following future potentials also:
- We can make our independent grid systems after complete implementation of this Gram Power technology
- India is an agricultural country, so we have the best opportunity to utilise renewable sources plus agricultural wastes and biomass.
Successful implementation of micro grid (Gram Power) in India will provide greater reliability, resiliency and security of power supply. It is not only beneficial to consumers, but utility grids also will find reduction in pollution level. Global warming will reduce. Dependency on other countries for fuel will go. So, we should not stay away from this opportunity to complete our dream of vision 2020.
