Author
Miika Rämä
Bio: Miika Rämä is an academic researcher from VTT Technical Research Centre of Finland. The author has contributed to research in topics: Renewable energy & Cogeneration. The author has an hindex of 10, co-authored 28 publications receiving 367 citations.
Papers
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TL;DR: The results show that, although most of the models perform similarly, they do not equally reproduce the dynamics, and the methodology for developing reduced mathematical models, implemented in Simulink®, is presented.
Abstract: Within the framework of AMBASSADOR, a collaborative project funded by European Commission under FP7, a Modelica® library for the modelling of thermal-energy transport in district heating systems has been developed. This library comprises detailed models of the distribution and consumption components commonly found in district heating systems. In this paper, the detailed models are discussed, along with their validation against Apros® and IDA-ICE® Software. The results show that, although most of the models perform similarly, they do not equally reproduce the dynamics. Some of the limitations detected from the simulation results are currently being solved in new developments within the EU-funded INDIGO project. Furthermore, with the aim of avoiding problems derived from the simulation of large models, the methodology for developing reduced mathematical models, implemented in Simulink®, is also presented in this research work. This methodology includes identifying the relevant includes identifying the relevant model dynamics. During the procedure, additional information about the models can be obtained. For instance, the mass flow rate and the temperature can be assumed to be decoupled, without losing accuracy in the case of the distribution pipe model.
97 citations
TL;DR: In this paper, a review of potential means to increase flexibility of Finnish energy systems by comprehensively regarding both electricity and thermal systems is presented, and several technological options to meet the increased flexibility needs are described and Finnish examples are given.
59 citations
TL;DR: In this article, a case study of a local district heating system in Finland with an annual heat consumption of 1.2 GWh and a heat demand density of 0.74 MWh/m is presented.
46 citations
TL;DR: In this article, the authors investigated the forces and obstacles to nuclear cogeneration by looking at the Loviisa 3 district heating project in Finland and found that the key obstacles are split incentives, electricity prices volatility, inexpediency of business models and regulatory frameworks, electioneering of local authorities and pessimist expectations with regards to project financing.
41 citations
TL;DR: In this article, the effects of new heat pump and solar collector capacity in an existing district heating system were investigated by using Helsinki as a case study, and the potential benefit of low distribution temperatures was evaluated.
40 citations
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TL;DR: This paper reviews local flexibility markets, which are currently being discussed and designed to provide trading platforms for local participants, including distribution system operators and aggregators, and summarizes the key elements, technologies and participants.
178 citations
TL;DR: In this paper, the authors delineate the key challenges associated with nuclear energy and renewable energy sources while operating as an independent power generation system, and highlight the various aspects associated with integrated nuclear-renewable energy systems.
168 citations
TL;DR: A mathematic program with equilibrium constraints (MPEC) model is proposed to study the strategic behaviors of a profit-driven EH in the electricity and heating markets under the background of energy system integration.
Abstract: Integration of electricity and heat distribution networks offers extra flexibility to system operation and improves energy efficiency. The energy hub (EH) plays an important role in energy production, conversion and storage in such coupled infrastructures. This paper provides a new outlook and thorough mathematical tool for studying the integrated energy system from a deregulated market perspective. A mathematic program with equilibrium constraints (MPEC) model is proposed to study the strategic behaviors of a profit-driven EH in the electricity and heating markets under the background of energy system integration. In the upper level, the EH submits bids of prices and quantities to a distribution power market and a heating market. In the lower level, these two markets are cleared and energy contracts between the EH and two energy markets are determined. Network constraints of physical systems are explicitly represented by an optimal power flow problem and an optimal thermal flow problem. The proposed MPEC formulation is approximated by a mixed-integer linear program via performing integer disjunctions on the complementarity and slackness conditions and binary expansion technique on the bilinear product terms. Case studies demonstrate the effectiveness of the proposed model and method.
161 citations
TL;DR: In this article, the authors provide a perspective on the development of future district heating systems and technologies and their role in future smart energy systems, and elaborate on or otherwise contribute to the theoretical scientific understanding of how we can design and implement a suitable and least-cost transformation into a sustainable energy future focusing on the important role of the next generation of district heating and cooling technologies.
157 citations
TL;DR: In this article, the authors provide a comprehensive overview of technologies, operational strategies, modelling aspects and the trends towards integration of heat, electricity and gas infrastructures for better managing energy sources, reducing consumption and waste as well as enabling a higher share of renewables, lower environmental impact and lower costs.
148 citations