Nikolaos Hatziargyriou, director of the National Technical University of Athens and winner of the Global Energy Prize, is one of the chief ideologists of modern microgrids. He spoke of the main principles of these micro-networks in an interview with the Global Energy Association.
Global Energy: How are digitalisation and artificial intelligence changing the management or design of modern energy systems? Can we speak of a revolution in energy?
Nikolaos Hatziargyiou: Energy digitalisation is a basic feature of the ongoing energy transition. This transition is characterised by a fast-changing energy generation mix with a clear tendency towards renewable and distributed energy resources, including distributed generators, flexible loads, distributed storage units, electric vehicles, etc.
It includes new market models favoring active participation of consumers and “smartening” of networks with increasing degrees of decentralised control and operation automation. The challenges for the secure and efficient operation of such a complicated system, comprising coupling of various energy sectors, i.e. electricity, natural gas, heating and cooling, liquid fuels, transport, etc. requires reliable and structured data.
Today, there are abundant data available to system operators coming from extended networks of sensors, microprocessors and smart meters installed throughout their networks. These data can provide new digital services and business opportunities for all stakeholders in the energy market for activities related to load management, storage, smart charging of electric vehicles, energy efficiency in the industrial and domestic sector, emergence of prosumers, smart cities and energy communities and finally for creation of open data platforms providing access to information and transparency to all citizens.
Global Energy: Is such a vast mass of data really necessary? Could it lead to a situation in which the system will not be able to cope with it?
Nikolaos Hatziargyriou: For system operators in particular, data exploitation can lead to drastic improvement of services to customers, operating costs reductions, investment deferrals for network upgrades, self-healing by fast fault isolation and recovery after disturbances, predictive maintenance for efficient asset management, etc.
The application of Artificial Intelligence together with technologies for handling large amounts of data (Big Data) and Internet of Things (IoT), that allow digital interaction among electric devices, even at residential level, will provide new opportunities for customer participation in local energy markets and online consumption information to electric utilities, leading to “smart” network management and effective integration of distributed energy resources. The incoming energy revolution will allow automatic uninterrupted satisfaction of individual energy needs at the right time, the right place and lowest possible cost.
Global Energy; Your development of microgrid systems has been applied mainly to remote regions. Would it be possible over time to achieve greater, more widespread use of such systems? Could microgrids in the future replace centralised energy systems?
Nikolaos Hatziargyiou: Microgrids are defined as distribution networks with interconnected distributed energy resources within clearly defined boundaries that can operate in grid-connected or islanded mode.
This idea was first introduced in 2001. Since that time, several research projects and pilot installations have been developed in Europe, the USA, Japan and Canada, followed at an increasing rate in China, Korea, Latin America, and elsewhere. These activities have largely proven the many technical, economic, social and environmental advantages, including higher energy efficiency, minimisation of overall energy consumption, reduced environmental impacts, improvement of reliability and power quality and various network benefits. It is true that actual microgrid applications can be found mostly in non-interconnected islands and remote regions, applied mainly for rural electrification in developing countries without or with weak transmission infrastructures. However, microgrids have been also used by utilities in the USA, mainly to increase resilience against natural disasters, like storms, floods, wildfires, earthquakes, etc. The Borrego Springs Microgrid installed by SDG&E is one such example and many more installations are planned, e.g. in California, utilities install Microgrids to avoid power outages by de-energising lines due to sparking fires. In Europe, microgrids have gained increasing importance as technical infrastructures to support Local Energy Communities. Outside Europe and the USA, China has announced recently 100 RES (renewable energy systems) microgrids to explore relevant technologies and business modes that suit RES development.
Global Energy: If microgrids are growing in popularity so quickly, could they one day replace centralised energy systems?
Nikolaos Hatziagyriou: This trend is expected to accelerate as current power systems, characterised by high amounts of variable RES generation, need increased flexibility and microgrids provide an excellent way of offering flexibility to the upstream network by aggregating distributed energy resources. Although technically feasible, however, I don’t expect that microgrids will replace centralised energy systems. A synergetic co-existence between these two types of organisation models will most probably prevail as the most economic and secure solution.
Global Energy: Will it be possible to set up large centralised systems using artificial intelligence? To what extent will this be effective and economically feasible?
Nikolaos Hatziagyriou: Artificial intelligence may be described as the science of making machines do things that would require intelligence available by humans. It encompasses effective technologies, like artificial neural networks (ANNs) and fuzzy logic applied for data processing and knowledge extraction from vast amounts of data. Their applications to power systems extend from load and renewable production forecasting, real-time control and protection, maintenance, etc. leading to higher efficiency, economy and operational security. Despite their advantages, however, it is highly unlikely that large centralised systems will rely purely on artificial intelligence beyond their role as valuable tools. Human operators will remain the indispensable critical decision makers ensuring the security of energy systems operation.
Global Energy: Microgrids involve the use of various energy sources, both traditional and non-traditional (diesel fuel, gas, renewable energy sources). Do you support parallel development of traditional and non-traditional energy sources? Will this not create stiff competition between the two?
Nikolaos Hatziargyriou: Microgrids are distribution structures that integrate distributed energy sources of any technology in a most effective way.
Modern energy solutions however need to satisfy in a balanced way three basic requirements, i.e. energy security, including security of supply, economic efficiency and environmental protection. These three requirements are many times conflicting and solutions depend on local climatic conditions, local resource availability, costs, social factors, etc. The solution of this multi-objective optimisation problem will provide the optimal development between traditional and non-traditional energy sources.
Global Energy: How can the development of microgrids be achieved in view of plans in Europe to move away from hydrocarbons as an energy source?
Nikolaos Hatziargyriou: The essence of microgrids is the co-ordination of distributed generators and flexible demand in order to maximise their benefits to customers and grids.
The local generation sources employed are mostly renewable, comprising PV (photovoltaic) systems, especially in countries with long sunny environments, small wind turbines, biomass units and mini hydro stations. In fact, microgrids in Europe are seen as an effective way to increase renewable energy penetration and to empower active citizens through the establishment of renewable energy communities.
At the same time, in colder countries, there has been significant progress in developing small, kW-scale, CHP (combined heat and power) applications to serve both electricity and thermal needs of microgrid customers. The application of RES-based generators, together with micro CHP, increases the overall efficiency of utilising primary energy sources and consequently provides substantial environmental gains regarding the curtailment of carbon emissions, which is a basic cornerstone of EU energy policies.
Global Energy: The main issue with smart microsystems is the extremely high costs associated with them. How can such projects be made more economically viable? Can such systems be set up in less developed regions experiencing energy shortages?
Nikolaos Hatziargyriou: Microgrids are based mainly on renewable energy sources and storage. The costs of these technologies are constantly falling and have now reached levels compatible or even cheaper than traditional thermal technologies. For example, the cost of lithium-ion batteries per kilowatt hour (kWh) has fallen by almost 90% since 2010 and similarly the levelised cost of energy generated by solar plants has fallen by 82% since 2010, while their price fell by 13% in the last year alone. Distributed generation located close to loads does not need transmission and distribution network infrastructures with two important effects: loss reduction and ability to potentially substitute for network assets. In conclusion, I believe that microgrids are currently a preferred solution for less developed regions to replace or support unreliable energy supplies.
Global Energy: So microgrids could gradually be set up in the world’s less developed regions subject to energy shortages?
Nikolaos Hatziargyriou: I believe that microgrids are currently a preferred solution for less developed regions to replace or support unreliable energy supplies.
Global Energy: Russia is proceeding actively with development of the Arctic. What sort of microgrid could be envisaged in conditions of low population density, the polar day and night, very low temperatures, hard-to-reach areas and polar fuel shipments?
Nikolaos Hatziargyriou: For the Arctic region, as a remote area with very special conditions and low-density population, electricity provision through microgrids looks much more cost-effective compared to expanding the centralised energy system.It is clear that specific characteristics require specialised studies in order to employ the most suitable generation sources considering the locally available resources, the environmental conditions of very low temperatures, polar days and nights, the needs for storage and polar fuel shipments. Moreover, remote, hard to reach areas pose specific challenges regarding maintenance and easy repair of trivial discrepancies requiring training of local people for basic engineering works.
