Microgrids: A solution for energy challenges and ambitions

Microgrids are electricity distribution systems containing interconnected loads and distributed energy resources that can be operated in a controlled and coordinated way. They can be operated independently as an island or in connection with the main grid. Microgrids improve the balance between local production and local consumption by optimizing the usage of its different energy resources (thermal sources, renewables sources, electric vehicles, storage systems…) to respond to the energy demand (at residential, commercial and industrial levels). Replacing the traditional microgrid approach, traditional microgrids are now becoming “smart microgrids” as they increasingly integrate the information and communication technologies of smart grids.

There are several use cases for microgrids including:

• Providing energy access to isolated areas
• Maintaining power during shortages and constraints caused by an overload of the main grid by allowing grid operators to switch to island mode and ensuring that critical loads still benefit from uninterrupted power supply from generation units or integrated storage systems
• Optimizing energy consumption and reducing energy waste through load management strategies, demand response programs or energy efficiency measures which can lead to lower electricity bills
• Improving the sustainability footprint of the power grid by incorporating more renewable energy sources to the power generation mix thus reducing dependency on fossil fuels and emissions.

Microgrids can play a major role in the improvement of grid planning, coordination and control by system operators. The integration of microgrids coupled with energy modelling and forecasting software can be a key solution to enhance grid planning and operations coordination by using real-time and historical data to analyze power generation and demand response capacities within the grid. These features would enable transmission and distribution operators to track supply and demand balance nearly in real-time, minimize costs and maximize efficiency and profits.

Moreover, the flexibility brought by microgrids contributes to the main grid resilience and reliability. Building on existing resilience standards and metrics, coupling the main grid with multiple microgrids can improve the resilience of the overall system under unexpected situations such as demand peaks periods or natural disasters.

Microgrid solutions in response to main System Operator challenges

Given their decentralized and autonomous nature, microgrids can help in solving several current challenges faced by System Operators on a wide range of operations and activities. Heading to the future, these challenges range from basic operational needs such as grid sustainability, resilience and reliability to specific evolving objectives as the efficient integration of various sources of renewable energy and support for local energy independence in isolated areas.

Microgrids can also play a significant role in System Operators’ performance by helping them face their evolving technical challenges while making them benefit from innovative opportunities. By operating in both grid-connected and islanded modes, microgrids can ensure that power supply to critical loads is not interrupted even if the main grid fails thus improving the overall reliability of the grid. They can also improve the quality of delivered power and reduce outages or disruptions by improving voltage and flexibility control and enhancing grid operational flexibility. In addition to that, microgrids help reduce grid losses and overall operating costs, as generation sources are located relatively closer to end-users in comparison to traditional grids.

Grid Resilience Improvement

• Local Power Generation
• Islanding Capability
• Load Shedding
• Power Energy Storage
• Response to unexpected situations

Voltage and Frequency Control

• Local Voltage Regulation
• Reactive power compensation
• Frequency Regulation
• Demand Response
• Grid Support Service

Peak Demand Management

• Additional power generation capabilities
• Grid congestion reduction
• Overloading prevention
• Line losses reduction
• Distributed Generation

Integration of Renewable Energy

• Management of renewable power generation systems
• Clean energy support
• Footprint reduction
• Renewable energy intermittence integration

Local Energy Independence

• Local power generation
• Isolated grid areas support
• Small-Scale Power generation management
• Humanist and development projects facilitation

Unlock distributed energy resources

• Effective management of locally generated energy
• Integration of small-scale energy sources such as solar, wind or hydropower
• DER control and monitoring

Demand Response Management

• Demand and supply balance efficient management
• Peak demand and fluctuation reduction
• Energy storage systems to reduce stress on the grid

System Planning and Operation

• Grid resilience improvement
• Dynamic control capabilities in response to power demand and supply changes
• Load balancing capabilities enhancement

Grid Resilience

• Grid reliability improvement
• Voltage & frequency control
• Grid operational flexibility enhancement
• Localized power generation sources to support the grid

Regulatory compliance

• Compliance with Renewable Energy Standards
• Compliance with grid codes
• Demand response programs
• Flexibility to match energy efficiency standards

Microgrids represent major benefits for system operators. However, their efficient integration to existing grids is subject to some technical requirements:

In addition to these requirements, system operators need to tackle challenges related to:

• Power transformation: microgrids can transport power differently compared to the main grid (lower voltage or DC current). Advanced transformers and power protections must be implemented to convert the power properly and use it in the main grid.
• Cybersecurity: increased use of digital technology in microgrids leads to higher vulnerability to cyber-attacks, which could then spread to the main grid through the communication interface. Standardized security and communication protection standards must be set up for higher grid safety.
• Grid stability: intermittency and congestion management challenges due to increasing decentralization and variability of renewables. Smart infrastructure and implementation of innovative technologies (e.g batteries) must be used to maintain frequency and voltage within acceptable ranges for system stability.

Sia Partners analyzed more than 30 microgrids and identified best practices and innovative solutions necessary to the successful implementation of a microgrid project:

• The Eaton Arecibo microgrid project in Puerto Rico: After the hurricane of 2017 in Puerto Rico, Enel X and Eaton designed a microgrid to provide continuous electricity at a manufacturing site on the island. This microgrid provides resilient and clean energy to the main grid even during periods of instability and helps reduce greenhouse gas emissions. This example not only demonstrates the role microgrids play in maintaining the stability of the main grid but also shows that microgrids can be a promising business development opportunity for utilities.
•  The Siemens campus microgrid in Vienna: this project demonstrates the benefits of combining an electricity storage system with a microgrid controller to manage peak loads. This combination also represents an opportunity for the development of future solutions to manage building energy efficiency or optimize electric vehicle charging in according to consumption patterns. This will play a major role in the future of microgrid design. Power system operators will have to overcome some challenges to integrate microgrids into their existing grids, however, microgrids provide answers to main TSO and DSO operational challenges. Indeed, they are emerging as a critical means to achieved energy sector ambitions in terms of grid performance, resilience and efficiency as well as renewable integration and sustainability.