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Papahristodoulou, ChristosORCID iD iconorcid.org/0000-0002-1545-3956
Publications (10 of 38) Show all publications
Eriksson, C., Lindén, J. & Papahristodoulou, C. (2019). Modelling the value of variable renewable electricity. In: Energy Procedia: . Paper presented at 10th International Conference on Applied Energy (ICAE2018), 22-25 August 2018, Hong Kong, China (pp. 3358-3362). Elsevier Ltd, 158
Open this publication in new window or tab >>Modelling the value of variable renewable electricity
2019 (English)In: Energy Procedia, Elsevier Ltd , 2019, Vol. 158, p. 3358-3362Conference paper, Published paper (Refereed)
Abstract [en]

This paper analyzes a simple microeconomic model of electricity market equilibrium. The parameter that shifts the demand between different points of time appears as an additive term. The equilibrium analysis can then be conveniently focused on the relation between two quantities, namely the electricity supply from intermittent sources and the subsistence level of electricity use. Our model is able to mimic the common empirical finding that a higher penetration of variable renewable electricity leads to a lower value factor for this type of power sources.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Economic evaluation, Electricity market equilibrium, Intermittent supply
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:mdh:diva-43130 (URN)10.1016/j.egypro.2019.01.960 (DOI)2-s2.0-85063894796 (Scopus ID)
Conference
10th International Conference on Applied Energy (ICAE2018), 22-25 August 2018, Hong Kong, China
Note

Export Date: 18 April 2019; Conference Paper; Correspondence Address: Lindén, J.; Mälardalen University (EST), Box 883, Sweden; email: johan.linden@mdh.se

Available from: 2019-04-18 Created: 2019-04-18 Last updated: 2019-04-18
Eriksson, C., Lindén, J. & Papahristodoulou, C. (2017). Human Capital and Innovations. In: : . Paper presented at EEA-ESEM 2017.
Open this publication in new window or tab >>Human Capital and Innovations
2017 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

This paper explores the interaction between human capital and innovations in the process of economic growth. Using a model of endogenous economic growth, the focus of our analysis is on the incentives to acquire human capital and how they are affected by taxes on human capital and other policy instruments. In contrast to many other growth models we find that the taxation on human capital has a substantial negative effect on the accumulation of it. This in turn lowers the income growth rate. While subsidies to research and to intermediate inputs have positive effects on growth (and must be strictly positive in social optimum), they do not necessarily imply that there will be larger stock of human capital in the economy. If the elasticity of intertemporal substitution in consumption is sufficiently low, these policy instruments stimulate growth by inducing a reallocation of a shrinking stock of human capital in the direction of research.

Keywords
Technological Change, Human capital, Economic Growth, Taxation
National Category
Economics
Research subject
Industrial Economics and Organisations
Identifiers
urn:nbn:se:mdh:diva-36568 (URN)
Conference
EEA-ESEM 2017
Available from: 2017-09-29 Created: 2017-09-29 Last updated: 2017-12-22Bibliographically approved
Herre, L., Kovala, T., Söder, L. & Papahristodoulou, C. (2016). ON THE FLEXIBILITY OF ELECTRICTY CONSUMERS: Modelling, Quantification and Analysis of Notice Time. In: : . Paper presented at Swedish Association for Energy Economics (SAEE) Conference 2016, Luleå, August 23-24, 2016.
Open this publication in new window or tab >>ON THE FLEXIBILITY OF ELECTRICTY CONSUMERS: Modelling, Quantification and Analysis of Notice Time
2016 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Power systems with a large share of inherently intermittent renewable energy sources require new approaches to system operation. Demand response is seen as a potential possibility for contributing to maintaining power balance in a future energy system with large amounts of volatile renewable energy generation (Bartusch et al., 2011; Torriti, Hassan & Leach, 2010). It would be a measure to reduce costs for maintaining the power balance, which is believed to become more expensive if traditional measures is to handle the increasing intermittency (Albadi & El-Saadany, 2008; Kirschen, 2003; Siano, 2014). The study of the flexibility of electricity demand is an essential key to exploring the current and future potential of demand side response for power system services.  

For both solar and wind power, forecasts for several hours ahead may have a lower accuracy. Statistically, the forecasts become better the closer they approach real operation. In practice however, this does not happen in each case. This means that the flexibility need for a certain hour will be different, depending on when the need is identified, i.e. different notice times.

For consumers to be flexible, there are several parameters that impact their ability and willingness to react to incentives with a change of load. Elasticity (self- and cross-elasticity) has been defined in literature to describe consumer flexibility with respect to a change of electricity price and is often referred to when modelling the flexibility of consumers (Albadi & El-Saadany, 2008; Lijesen, 2007). Flexibility with respect to electricity prices or other financial incentives has been widely studied in literature on smart grids and demand response.

Another important parameter for electric demand to be flexible is the notice time, i.e. the time span between informing the consumer about a future need for reorganizing their consumption and providing a change of consumption as a system service. The impact of notice time on the flexibility of electricity consumers has not yet been systematically researched. It is logical that the willingness and ability of certain consumers to provide flexibility decreases as notice time becomes shorter. There are, however, some loads that even may become more flexible, the shorter the notice time, such as e.g. the charging of electric vehicles.  

An essential basis for flexible consumers is the communication infrastructure that is used for sending price signals, bids and further market parameters depending on the demand response program. The type and information content of such communication is enabled through technological devices. These smart devices – which in most cases must exceed the function of only smart metering (Siano, 2014) – can have different properties and requirements that are determined by the demand response program and its respective requirements on data exchange. Therefore, the technological implementation and the impact of the limitations originating from the same are discussed in this study as well.  

For a quantitative analysis of customer flexibility, both price and notice time are imperative parameters. Former has been studied in numerous references (Bartusch et al., 2011; Gyamfi, Krumdieck & Urmee, 2013; Kirschen et al., 2000; Lijesen, 2007) whereas the impact of the latter has not yet been examined in depth. In this paper, a study on consumer flexibility with respect to notice time is presented. It is analyzed how the ability to reschedule electricity demand during a time interval in the future is impacted by terms of notifying and updating flexible consumers. For this, a market and demand response program optimizing social welfare is developed that allows for an analysis of notice time dependent consumers.

Keywords
communication infrastructure, demand response program, electricity consumption, flexibility, notice time, power system services, price elasticity, renewable energy, wind power forecast
National Category
Economics Energy Systems
Identifiers
urn:nbn:se:mdh:diva-34963 (URN)
Conference
Swedish Association for Energy Economics (SAEE) Conference 2016, Luleå, August 23-24, 2016
Projects
Flexibla elkunders roll i ett framtida förnybart kraftsystem
Funder
Swedish Energy Agency, P39736-1
Available from: 2017-02-28 Created: 2017-02-28 Last updated: 2017-02-28Bibliographically approved
Papahristodoulou, C. (2014). Evaluating the Performance of UEFA Champions League Scorers. International Journal of Sports Science, 4(6A), 1-11
Open this publication in new window or tab >>Evaluating the Performance of UEFA Champions League Scorers
2014 (English)In: International Journal of Sports Science, ISSN 2169-8759, Vol. 4, no 6A, p. 1-11Article in journal (Refereed) Published
Abstract [en]

The ranking of football players has always engaged media and supporters worldwide. The different views on ranking are due to two reasons. First, leagues are heterogeneous with various qualities. Second, fans often rely on different performance measures and statistics, or just unmeasurable actions. Despite the fact that team and player bias will never disappear, this paper aims to objectively evaluate the efficiency of 42 top scorers who have played in the UEFA Champions League (UCL) over a six years period, (2006/07 - 2011/12), based on official match-play “multi-input and output” statistics, using input- and output oriented DEA models.

Keywords
performance efficiency, scorers, UEFA Champions League, DEA
National Category
Social Sciences Sport and Fitness Sciences
Research subject
Industrial Economics and Organisations
Identifiers
urn:nbn:se:mdh:diva-26630 (URN)article.sapub.org/10.5923.s.sports.201401.01.html (DOI)
Available from: 2014-11-27 Created: 2014-11-27 Last updated: 2018-09-08Bibliographically approved
Papahristodoulou, C. (2014). Imperfect Cartel: Wolfram Demonstrations Project, Published: January 10, 2014.
Open this publication in new window or tab >>Imperfect Cartel: Wolfram Demonstrations Project, Published: January 10, 2014
2014 (English)Other (Other academic)
Abstract [en]

When some firms of a cartel cheat and produce more than their allocated quota, cartels fail to maximize their profit or surplus, while consumers benefit. Similar effects appear when more fringe (or noncartel) firms exist in a market, which is called an "imperfect cartel". Consequently, the cartel firms would welcome more fringe firms to join their cartel. On the other hand, when some firms have joined the cartel, other fringe firms would prefer to stay out: they can increase their production because of higher prices due to the cartel. [more] A numerical example (modified [1]), illustrates the effects of both the number of cartel and fringe firms. The market consists of up to 40 identical firms (without entry), with cartel firms and fringe firms, facing a linear demand curve, . The fringe firms are price takers, while the cartel behaves as a monopolist for the residual demand. Both fringe and cartel firms' Marginal Costs are, . The graphic shows two representative firms, the fringe (left graph) and the cartel (right graph). The left graph displays also, the total production, the total cartel production and the total fringe production, as well as the representative fringe's production. The right graph displays the cartel surplus (green) and the Dead Weight Loss (red) from the cartel price. Notice however, that the Residual Demand is discontinuous below €10 and should be identical to the Total Demand, but that part is of no interest.

Keywords
microeconomics, optimization, mathematics, graph theory
National Category
Economics and Business
Identifiers
urn:nbn:se:mdh:diva-24205 (URN)
Note

Mathematical software

Available from: 2014-01-15 Created: 2014-01-15 Last updated: 2014-01-15Bibliographically approved
Papahristodoulou, C. (2014). Limit Pricing: Wolfram Demonstrations Project, Published: November 10, 2014.
Open this publication in new window or tab >>Limit Pricing: Wolfram Demonstrations Project, Published: November 10, 2014
2014 (English)Other (Other academic)
Abstract [en]

An incumbent is limit pricing if it produces more than its optimal quantity, so that there is not sufficient demand for a potential entrant. The lowest price that it sets is the "limit price" that excludes a profitable entry. [more] A numerical example (based on [1]) illustrates how the profits of both the incumbent and the entrant change with and without limit pricing, for various fixed costs common to both firms. Initially, in the absence of entrant, the incumbent is a monopolist and maximizes its profit (green rectangle). The entrant estimates the residual demand, optimizes its production level, and makes profit (blue rectangle), affecting the profits of the incumbent. To avoid entry, the incumbent must increase its production so that the entrant cannot make profits if it enters. In order to succeed with that, it needs to equate the slope of the residual demand with the slope of average costs. Notice that there are scale economies (decreasing average costs). Consequently, the incumbent's profit is reduced to the gray rectangle while the profits of entrant are zero. Finally, if the entrant exits due to the limit price, the incumbent makes a higher profit (yellow rectangle).

Keywords
microeconomics, optimization, mathematics, graph theory
National Category
Economics and Business
Identifiers
urn:nbn:se:mdh:diva-24206 (URN)
Note

Mathematical software

Available from: 2014-01-15 Created: 2014-01-15 Last updated: 2014-02-24Bibliographically approved
Papahristodoulou, C. (2014). Monopolistic Competition with a Homogenous Product.
Open this publication in new window or tab >>Monopolistic Competition with a Homogenous Product
2014 (English)Other (Other academic)
Keywords
Industrial Economics
National Category
Social Sciences
Research subject
Industrial Economics and Organisations
Identifiers
urn:nbn:se:mdh:diva-24316 (URN)
Available from: 2014-01-26 Created: 2014-01-26 Last updated: 2014-02-24Bibliographically approved
Papahristodoulou, C. (2013). Dynamic Profit Maximization for a Monopolist: Wolfram Demonstrations Project, Published: November 25, 2013.
Open this publication in new window or tab >>Dynamic Profit Maximization for a Monopolist: Wolfram Demonstrations Project, Published: November 25, 2013
2013 (English)Other (Other academic)
Abstract [en]

Assuming a monopoly with a dynamic cost function, with both economies of scale and learning effects over time and a dynamic linear demand function, this demonstration shows how the optimal decisions change over time and also how the profit surface in three dimensions, as a function of output and time, changes.

Keywords
microeconomics, optimization, mathematics, graph theory
National Category
Economics and Business
Identifiers
urn:nbn:se:mdh:diva-23034 (URN)
Note

Mathematical software

Available from: 2013-11-28 Created: 2013-11-28 Last updated: 2015-11-13Bibliographically approved
Papahristodoulou, C. (2013). Evaluating the performance of UEFA Champions League scorers. In: : . Paper presented at 26th European Conference on Operational Research, Rome, July 1-4, 2013.
Open this publication in new window or tab >>Evaluating the performance of UEFA Champions League scorers
2013 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Economics
Identifiers
urn:nbn:se:mdh:diva-19087 (URN)
Conference
26th European Conference on Operational Research, Rome, July 1-4, 2013
Available from: 2013-06-04 Created: 2013-06-04 Last updated: 2015-11-16Bibliographically approved
Papahristodoulou, C. (2012). The Optimal Layout of Football Players: A case study of AC Milan.
Open this publication in new window or tab >>The Optimal Layout of Football Players: A case study of AC Milan
2012 (English)Other (Other academic)
Abstract [en]

Using the classic Quadratic Assignment Problem or Facility Layout problem, this paper attempts to find the optimal formation of three midfielders and three forward football players on ground. Players are treated as “machines”, their positions as locations, and the flow of materials between machines as both “flow of passes” and “flow of markings”. Based on detailed statistics from four matches of AC Milan, and formulated the problem as minimum (quick strategy), maximum (slow strategy), and mixed or balanced strategies, a number of various layouts emerged. The efficiency time gains in the unconditioned layouts are between 3 - 6.8%. When the manager claims that his three forwards shouldn’t shift positions with the midfielders, the unrestricted optimal layouts deteriorate by 7´´ to 20´´, or about 1% of the team’s effective playing time.

Keywords
layout, assignment, football, players, passes, markings
National Category
Social Sciences
Research subject
Industrial Economics and Organisations
Identifiers
urn:nbn:se:mdh:diva-17996 (URN)
Available from: 2013-01-24 Created: 2013-01-22 Last updated: 2013-11-08Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1545-3956

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