Christiana Papapostolou

Modelling biomass and biofuels supply chains

Abstract Traditionally, biomass derived energy, due the dispersed character of its primary recourses and the easiness in their processing, has been mainly exploited at a local level by employing well-known practices. Today, various types of biomass may be converted through specific conversion routes to either heat, power or/and biofuels or to a combination of the above. The aim of the present work is the analysis of the biomass and biofuels supply chain and the development of a generic mathematical model for the optimal exploitation of the biomass for heat, power and/or biofuels production. Model implementation can support the decision making in planning and operational issues such as infrastructure investments, the quantities of raw materials to be cultivated, the quantities of biofuels and / or heat and power to be produced and/ or to be imported, the extent of the cultivated land for the feedstock production, with the main goal being the identification of the best available solution for the optimal design and operation of the biofuels and biomass supply chain, per case considered.

Energy Supply Chain Optimisation: Special Considerations for the Solution of the Energy Planning Problem

Abstract The present work is a part of a major research project aiming to the development of the methodology and the corresponding integrated tool for the economic, social and environmental evaluation of various alternative energy and fuel Supply Chains (SCs). With special consideration of the energy supply options and dimensions, the applicability of the present modelling approach to the energy systems planning is examined. The energy system of an isolated area consists of a set of energy inputs – supply sources, storage facilities as well as a certain profile of energy demand. The optimisation model may include various economic, environmental or optimisation criteria such as cost minimisation, environmental impacts minimisation, profit maximisation as well as a set of constraints expressing the design, operation and limits of the system. A very interesting issue of the present research work is that it introduces an approach that may be followed equally well in energy as well in water systems with the same characteristics, i.e. in isolated areas with a variety of supply sources and users as well as with various criteria and considerations such as technical, environmental, social and economic.

Energy Supply Chain modeling for the optimisation of a large scale energy planning problem

Abstract The energy planning problem becomes increasingly important during the recent years mainly due to the pressing needs that need to be taken into account in terms of economic, environmental and social aspects. At the same time, technology supports many options and alternative solutions in the design of energy and fuel supply chains (SCs), based on more holistic approaches that have their origin in the production management. Considering the introduction of an integrated framework of evaluation for alternative energy supply options, the present work applies a RTN (Resource Task Network) based representation of the Energy SCs (ESCs) along with a mathematical programming optimisation model in order to analyse and model a location specific energy planning problem. Special emphasis is given to fuel mix optimisation in terms of maximising the economic, social and environmental performance of ESCs. Furthermore, the interaction between aspects and implications under the existing limitations both in the design and technical characteristics of the system as well as in the environmental / air quality limitations, will be also revealed. On top of the results obtained, the present work’s added value relates to the development of the proposed model for the analysis of various energy planning scenarios, comprising in this way a very useful decision making tool.

Optimisation of water supply systems in the water – energy nexus: Model development and implementation to support decision making in investment planning

Abstract Water resources availability, in terms of quality and quantity, is a very crucial issue in many areas of the world; especially in areas with water shortage and varying and time dependent water demand. Lately, it has become obvious that water supply chain problems are also inherently linked to the energy availability and quality of an area, leading to the so called water – energy nexus problems. The present work is a continuation of our ongoing research in the optimisation of water and energy supply chain in terms of maximising the overall benefit of the integrated system, whilst satisfying the conflicting demands. The objective of the work is to expand the model for water supply optimisation to take into account all the potential water supply sources intending to support decision making in investments planning, with environmental considerations.

Optimising the total benefit of water resources management in combination with the local energy systems in remote communities taking into account sustainability considerations

Abstract Reliable energy and water supply is an essential condition for human, economic and technological development. The level of access to these resources may also represent an index of prosperity for the community and/or individual. Water resources scarcity becomes a continuously increasing problem since there are various parts in the world where water resources are very constrained, either permanently or seasonally. The problem becomes more and more intensive and it is believed that water resources management will evolve as the most crucial technical and social problem in the next years. Today, in most cases, water and energy systems are interdependent. Water is used in all phases of energy production and electricity generation. Energy is required to extract, produce and deliver water of appropriate quality for diverse human uses, and then again to treat wastewater and return it to the environment or - even more significantly - to produce recycled water. The objective of this work is to address in an integrated way the water supply problem in areas with limited water resources integrating it with the corresponding design and operation of the local energy system. Following that goal, in this paper the optimisation framework of water supply chain is presented taking into account the links of the energy system and the entire energy supply chain in terms of maximising the overall benefit of the integrated system, whilst satisfying the conflicting demands. On top of the framework, model parameters, considerations, and implementation possibilities of the proposed approach of the energy and water supply problem integrated optimisation, are analysed through an indicative case study in a Greek-medium sized, island.