Smart Mini-Grid: An intelligent way to distribute clean energy

The SMG combines renewable resources like wind, solar energy, and biomass gasifier
The SMG combines wind generator, solar PVs, and
biomass gasifier
Energy is the key to economic development. In India alone, the demand is expected to grow at an annual rate of 6% in the next decade. Estimates by the Ministry of Power suggest that by 2011-12, India will need over 1,00,000MW of additional capacity installation to meet its power requirements. Few power stations of desired capacity can be installed in order to meet the demand. But power stations alone cannot meet the small dispersed loads in remote areas. Globally, the trend is towards managing existing energy resources and demand in an optimal and efficient manner. Over the years, smart grids have evolved for this purpose. Advanced sensing, communication, and control technologies are used in these smart grids not only for generation and transmission of power, but also distribution and utilization of electricity in an intelligent and effective manner.
This distributed generation-based power system/mini-grids can be installed and subsequently integrated to the conventional utility grid or used to provide electricity for localised loads only. It not only fosters effective inter-connection and utilization of multiple renewable energy resources, but also helps in advancing access to energy to the last mile in the most optimum manner by improving the efficiency of the overall system. Besides, it offers immense potential for improving energy access in both urban and rural areas.

TERI has designed, developed, and demonstrated the country's first-of-its-kind Smart Mini-Grid system. The objective is to optimally use smarter control of distributed energy sources combined with intelligent management of loads to improve the efficiency and reliability of the overall mini-grid system. The Smart Mini-Grid, built with the support of the Ministry of New and Renewable Energy (MNRE), was recently inaugurated at the TERI Retreat in Gual Pahari, Gurgaon.

The Intelligent Dispatch Controller regulates the power load and energy supply
Intelligent Dispatch Controller
A Smart Mini-Grid system is an application of digital technology which optimizes electrical power generation and delivery (see box). The system is based on the integration of multiple distributed energy resources (DERs) into the same grid. This system is also based on intelligent load and energy resource management. It is designed with local controllers for each of the distributed generation technologies as well as a central controller called intelligent dispatch controller (IDC) which communicates with the each local controller. Whereas the local controllers ensure maximum utilization of energy resources with permissible output power, the IDC performs complex system control functions and takes critical decisions such as automating the demand response, dynamically adding or removing DERs in a seamless manner (based on the existing demand) without affecting the grid stability.

The workings of the Smart Mini-Grid system A schematic representation of the Smart Mini-Grid system

A Smart Mini-Grid has greater resilience to loading as compared to the conventional grid system. It is marked by power flow through multiple routes, a feature common to the conventional grid system. However, unlike the conventional grid system, it is designed to avoid cascade tripping of network elements.

The system also has the capability to respond automatically to network problems and minimize network disruptions. It can anticipate and respond to system network problems and avoid or mitigate power outages, power quality problems, and service disruptions using real-time information from embedded sensors and automated controls. The grid is also equipped with a self healing system that enables it to rapidly detect, analyze, respond to power disturbances and restore power supply.

The TERI Smart Mini-Grid facility combines the following distributed generation resources--3.3 kWp wind generator, 1 kWp thin-film solar PV, 12.5 kW solar PV, 100 kWe biomass gasifier, 600 Ah, 48 V storage battery, and a diesel generator. The diesel generator has been added to the system to meet the intermittency of the renewable resources and hence ensure reliable power supply.

Such Smart Mini-Grid systems have great potential, not only in commercial and industrial complexes, but also in hospitals, shopping malls, apartments, residential complexes, educational institutions, remote un-electrified as well as electrified locations to ensure maximum flexibility, reliability, and safety with enhanced efficiency of the overall system.

The Smart Mini-Grid can provide solutions to problems of energy security, sustainability, and ensure reliable quality power. It can be used to strengthen the country's electricity sector and enhance the performance of rural electricity supply systems. This system enhances energy efficiency and offers maximum reliability flexibility, safety etc. in the overall electricity distribution network. Large-scale implementation of such systems will go a long way in meeting the energy needs of the country. It can also be integrated with the existing programmes of the Ministry of New and Renewable Energy (MNRE) such as the Jawaharlal Nehru National Solar Mission as well as the national rural electrification programme.

Sponsor(s): Ministry of New and Renewable Energy
Duration of the project: 18 months
Key Stakeholders: Commonwealth Scientific and Industrial Research Organization (CSIRO), Australia; Solar Energy Centre (SEC), India
Beneficiaries: Utilities, regulators, energy service providers, technology and automation experts, and all consumers of electric power
  • To develop and demonstrate distributed generation based smart mini-grid models and control techniques which would be applicable to Indian sites/conditions;
  • To demonstrate how smarter control of distributed energy sources combined with intelligent management of loads can improve both efficiency and reliability of the overall mini-grid system.
What is Smart Mini-Grid?
A Smart Mini-Grid (SMG) is an intelligent electricity distribution network, operating at or below 11 KV, where the energy demand is effectively and intelligently managed by diverse range of Distributed Energy Resources (DERs) such as solar PV, micro-hydro power plants, wind turbines, biomass, small conventional generators such as diesel gensets etc. in combination with each other through smart control techniques. This integrated energy system comprises:
  • Variable loads which are connected to the distribution grid;
  • Diverse range of small, local generators based on distributed energy resources, for example, solar, wind energy, storage system; and
  • Control and power conditioning systems.
Benefits of Smart Mini-Grid
  • Foster demand side management & response;
  • Reduce power outages, increasing reliability, efficiency, and safety;
  • Reduce carbon footprint and minimize fossil fuel consumption
  • Provide customers autonomy to manage their electricity needs.
Unique features of the TERI Smart Mini-Grid Model:
  • Integration of multiple DERs, ensuring maximum utilization of renewable energy sources;
  • Resource and load profiling, controlling, and forecasting;
  • Centralized control (Smart Hybrid Controller/Intelligent Dispatch Controller) for resource optimization and demand management;
  • Load prioritization;
  • Integrated, high-speed, Field Programmable Gate Array (FPGA) -based digital communication on LabVIEW (a software platform for acquiring data and sending and receiving controls) platform;
  • Real-time data acquisition and monitoring of thousands of electrical and physical signals;
  • Minimized outages and fast response to network disturbances through automatic connect/disconnected of system components.
Posted on: 13 July 2011  |   Project status: Completed