Grid code requirements and advanced power electronics solutions [Part 3/8: Smart Grid and grid codes]

After the introduction of grid codes and grid code compliance, this third article will discuss the Smart Grid and grid codes.

Smart Grids are continuously evolving due to new demands on energy supply and consumption. Smart Grid development is nowadays closely linked to the integration of renewable energy sources, electric vehicles (EV for short) and distributed energy resources (DER for short) into the electric power system. This integration brings particularly challenging grid code compliance demands upon new generators and loads. Most of these Smart Grid demands are regulated and enforced by national grid codes.

Smart Grid challenges and grid codes

Some of the most important first steps in Smart Grid expansion are preparation of Smart Grid road maps, capacity building and developing grid codes. Grid code development and implementation are key processes affecting the successful expansion of the Smart Grid. It is important that during these processes, grid codes are aligned with both, country standards and with international standards. 

A strong push by governments for an integrated approach to Smart Grid development is essential. In this approach, modernising the electric power system infrastructure to be compliant with green economic requirements, improving the efficiency in the energy sector and enabling energy access to all as envisaged in the United Nations’ Sustainable Development Goals are required.

Grid codes and energy policies

An energy policy describes how a country addresses its energy needs, including generating and distributing energy from various renewable and non-renewable sources. Governments have specific targets for energy efficiency or renewable energy integration in their energy policies, which they support with incentives such as feed-in tariffs or quota systems like mandatory renewable energy targets.

The main role of grid codes is to provide technical regulations for connecting generators and loads to the electric power system. This means that generators and loads can help to fulfil energy policies. The governmental body responsible for implementing a country’s energy policy may mandate the creation of a grid code. Alternatively, the grid code may be drawn up separately from energy policy making by the different stakeholders involved in the specification of grid code requirements.

Grid codes and renewable energy

The rapid increase of decentralised, variable renewable generation plants in the electric power system is offsetting the traditional centralised electricity generation model. Decentralised solar photovoltaic (PV for short) power plants and wind farms are examples of distributed energy resources with a design based on power electronics that brings several challenges to the electric power system operations, dynamics and performance.

Grid codes around the world are getting continuously updated to include ancillary services, power quality improvement capabilities and interoperability requirements for renewable generators. These services and capabilities provide system operators for example with power system stability and security, new methods for voltage and frequency regulation and bulk system control.

The implementation of grid codes facilitates the integration of renewable generation both at centralised and decentralised locations by:

• Helping the electric power system to manage the variability in renewable generation by using energy storage devices or by sharing remote resources.
• Developing a flexible enough electric power system capable to accept decentralised generation at all voltage levels in the system.
• Preparing the grid for new ways of using electricity.
• Increasing the security of supply.
• Creating a more fault tolerant electric power system.

Grid codes and electric vehicles

Improved battery technologies drive electric vehicles manufacturing costs lower, encouraging more auto manufacturers to enter the electric vehicle market and develop competitive models. The increasing number of electric vehicles that interact with the electric power system requires special attention from grid operators as they represent both an additional load and a distributed flexible resource for grid support services. EV charging has also an impact on transmission and distribution grid infrastructure investments.

The rise in EV deployment significantly increases electricity demand during peak charging times, particularly where concentrations are high. High adoption of EVs can both create and alleviate operational challenges in Smart Grids. EV owners may be able to help balance supply and demand simply by charging during periods of heavy renewable generation, which can alleviate the risk of overgeneration in regions with high renewables adoption. EVs may also be able to reduce peak demand by temporarily discharging power back to the grid when the vehicle is plugged in but not in use.

Grid codes need to be developed so that the electric vehicle charging infrastructure can be easily used for grid support services. Only through an optimal management of their charging process it will be possible to solve the potential system challenges and take advantage of all the potential opportunities.

Grid codes and energy storage

Energy storage devices can consume, store and deliver power, providing a flexible resource to the electric power system unlike other types of distributed energy resources. They enable the electric power system to smoothly accommodate unpredictable consumers and energy production sources and help balance highly variable electricity supply and demand. As a result, energy storage devices have long been attractive solutions to support the operation of the electric power system, but their high cost has been a severe limiting factor until recent years.

Safely, reliably, and cost-effectively connecting energy storage to the electric power system requires that generators, consumers and prosumers follow grid codes that dictate both procedural elements and technical requirements. Grid codes define the requirements for energy storage devices to connect to the grid, the process for interconnection and the parameters that the components of energy storage devices must meet.

These requirements differ depending on where the energy storage device is connecting (e.g., transmission grid, distribution grid, minigrid or microgrid), its size and how the entire system will operate. For the transmission grid, because the number of interconnections is fairly low and the size of each energy storage device is fairly large, the interconnection of these devices is typically managed on a case-by-case basis with much more scrutiny than can be afforded to smaller, more numerous distributed interconnections. For the distribution grid, however, there may simply be too many individual interconnections to review individually in detail. Furthermore, smaller energy storage devices do not tend to have the same level of technical impacts as larger, transmission-level devices.

The next article of this series will discuss ancillary services.

If you would like to receive any of my publications on the topic or to explore how #PowerElectronics solutions can help your installation to achieve grid code compliance, feel free to reach me at [email protected]. 

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About the author:

Pedro Esteban is a versatile, multicultural and highly accomplished marketing, communications, sales and business development leader who holds since 2002 a broad global experience in sustainable energy transition including renewable energy, energy efficiency and energy storage. Author of over a hundred technical publications, he delivers numerous presentations each year at major international trade shows and conferences. He has been a leading expert at several management positions at General Electric, Alstom Grid and Areva T&D, and he is currently working at Merus Power Plc.