Autonomous power systems

Market Potential of Hydrogen-based Autonomous Power Systems.137... 

At the beginning, the book includes definitions, technical overview and economic evaluation of conventional fossil fuel and Renewable Energy-based autonomous power systems, which are currently in operation all over the world. The most common autonomous power systems configurations are being described and all technical, financial and environmental problems associated with such systems are also presented. 

The basic principles for the design and pre-feasibility analysis of hydrogen-based autonomous power systems are also given. The main outcome of the techno-economic analysis is the identification of technical and non-technical barriers and respective potential benefits for the implementation of hydrogen-based autonomous power systems in the short term and medium term as well. The analysis performed in this section of the book is based on real technology and market parameters acquired during the operation of these autonomous power systems rather than on theoretical assumptions. 

Then, the market potential for hydrogen-based autonomous power systems is analysed both from demand and supply side points of view and the emerging market is qualitatively estimated. Based on the techno-economic analyses and the analysis of the market potential presented before, barriers and benefits for the introduction of hydrogen in stand-alone power systems are stressed and a detailed strengths, weaknesses, opportunities and threats (SWOT) Analysis is given. The SWOT analysis will be a valuable tool for possible investors in the field. 

Autonomous power systems (APS) comprise a solution for the electrification of applications when the access to a large transmission network is not economically viable or even impossible. Their size can range from few hundred Watts to tens or hundreds of MW. 

Rural areas in developing and developed countries, without the necessary grid infrastructure, are a characteristic example of applications with a high potential for the development of autonomous power systems. Taking into account the strong correlation between the economic development in these areas and their electrification, the importance of powering them is evident. Other application fields include holiday houses, physical islands and remote telecommunication and industrial installations. 

Autonomous power systems can be based on renewable energy (RE) units, such as wind turbines, photovoltaic systems or small hydro power stations and fossil-fuel generators. Due to the intermittent nature of renewable energy, storage devices and/or appropriate demand management strategies are necessary when conventional generators are not included in the system. 

Technical Overview of Fossil-fuel and RE-based Autonomous Power Systems... 

Preservation of acceptable levels of power quality is an essential requirement for the operation of power systems, APS included. Frequency stability and voltage control are the most important aspects of this issue. The European Standard EN-50160 (European Standard EN-50160, 1994) requires that for a non-interconnected (i.e. autonomous) power system, frequency and voltage should be within a range of ... 

So far, issues related to the frequency stability of an APS have been presented. Maintaining voltage levels in the AC buses of an autonomous power system close to their nominal value is a similar problem. Such an objective can be obtained if equilibrium can be achieved between produced and consumed reactive power in the system. The influence of renewable generators on voltage control depends on the type of the interface used for the connection to the grid. Induction generators in wind turbines or small hydro plants, consume reactive power. A partial compensation can be achieved using local capacitors. Power electronic inverters used for the connection of photovoltaic systems and wind turbines are reactive power neutral. 

Energy management is a functionality that aims at the achievement of a reliable and efficient operation of an autonomous power system. The first objective is related to the capability of the system to serve the loads with minimum interruptions caused by insufficient power supply. The second objective is related to the minimisation of fossil-fuel generator costs and thus the cost of produced energy. An increased renewable penetration level, makes the fulfilment of these... 

The main characteristics of the simulation tools used for the sizing and performance evaluation of autonomous power systems in the design stage, include the way of representing the system, the definition of the APS control strategy, the simulation time step and methodology and finally the output of the simulation process. 

Simulation principles presented in this section will be used in Chapter 5 for the analysis of 5 existing autonomous power systems and their optimum redesign as hydrogen-based systems. 

Integration of Hydrogen Energy Technologies in Autonomous Power Systems 25... 

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