Microgrid Deployment and Integration to the Grid


Microgrid is a collection of DG systems deployed in a community level to provide an independent and self-sufficient small scale power grid system, together with connected and disconnected capability to the main grid depending on usage and requirement.  While independent DG systems such as solar PV and wind faces power generation instability due to weather conditions, the microgrid system leverages on different DG system advantages and is capable of achieving a 24 hours self-sufficient power generation in the community.

With the microgrid system integrated to the main grid, the microgrid served area or community enjoys two alternative streams of electricity sources, seamlessly and intelligently connected, providing a high quality and almost fail-proof electricity supply to the location. 


On the one hand, the microgrid itself provides a high quality distributed power generation solution.  On the other hand, it also provides valuable energy resources to the main grid with valuable contribution such as supplying peak load supply and reactive power correction, etc.

The two layers of grid supply system (the main grid and the microgrid) form the foundation of future fault proof grid system.

SIS Smart Grid Technologies Solution provides turn key microgrid solution and project deployment using technologies similar to Smart Grid DG System Integration, but with even more versatile control technologies.





What is Microgrid? 


 A Microgrid is defined as an integrated power delivery system consisting of interconnected loads and distributed generation units which, as an integrated system, can operate in grid-connected mode, autonomous (islanded)  mode, and ride-through between these two modes.      (Source:  IEEE Canada, Electrical Power Conference on "Renewable and Alternative Energy Resources" 2007)

 A Microgrid is a group of interconnected loads and distributed energy resources within clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid.  A Microgrid can connect and disconnect from the grid to enable it to operate in both grid-connected or island-mode.  (Source:  US DOE, October 2011)




Benefits of Microgrid 


Microgrid deployment will bring in tangible and intangible benefits in the following areas.

- Increased Reliability -    Microgrids increase reliability locally through the establishment of a specific reliability improvement plan that integrates redundant distribution, smart switches, automation, power generation, power storage and other smart technologies.  Microgrids actively control the network to eliminate blackouts for great reliability.

- Savings -    Smart microgrids' reliabiity significantly reduces the costs of outages (for instance, about $150 billion a year in the US).  Local power generation helps to hedge peak power costs, and is typically more efficient.  It reduces the distance for energy to travel, i.e. fewer costs from transmission losses, congestion pricing and customer service overhead.  Microgrids diminish significant infrastructure improvement costs that are passed on to ratepayers.

- Generate Revenue -    Power generated from local microgrids can supply valuable services to the grid in return for payments from the serving utility or independent system operator.  This includes demand response, realtime price response, voltage support, capacity support, etc.  These microgrids also set the stage for additional revenues from distributed power generation, plug-in electric vehicles, and carbon credits.

- Make the grid "Future Proof" -    Microgrids are much better positioned than the centralized grid to meet the known and unknown needs of the future.  They allow local communities to increase the overall electricity supply quickly and efficiently through local generation.  In addition, microgrids' energy management technology enables plug-in electric vehicles to be connected to the electricity system as smart power storage resources rather than simply another electricity user.

- Reduces carbon footprint -    Microgrids get the most from clean, renewable energy because they have the flexibility needed to use a wider range of energy sources, including those that present a challenge for the current centralized system such as wind and solar PV.  The "bottom-up" consumer approach can reduce reliance on fossil fuels and lower greenhouse gas emissions based on open market economic value. 







Microgrid Technologies 


Similar technologies as Smart Grid DG System Integration, though with a different level of complexity and sophistication:

- Sensor and Measurement

- Advanced Components

- Advanced Control Methods

- Decision Support and Improved Interfaces

- Integrated Communications



Objectives of Microgrid 


Local power generation and storage in a Microgrid allow portions of the grid and critical facilities to operate independent of the larger grid when necessary, and thus eliminate blackouts.  Technologies such as smart switches and sensors automatically fix - and even anticipate - power disturbances.  Redundant sources ensure that power supply continues during power interruptions caused by storms, ice or other reasons.  Microgrids also back up the bulk power grid when power demand and cost are highest by supplying electricity ancillary services.

Designed to proactively ensure reliability, improve economics and manage renewables, Microgrids provides these functions:

Integrating distributed energy resources, including - 

  • Utility-scale energy storage, building energy storage, community energy storage
  • Rooftop solar PV, ground PV solar array
  • Micro-turbines
  • Distributed generation
  • Home energy system
  • PHEVs

Information, such as -

  • Electricity pricing
  • DER status, demand response program, load and resources profiles
  • Network status
  • Community objectives

Grid resources, including -

  • Capacitor banks
  • Voltage regulators
  • Automated switches
  • Power electronics
  • Communications