| 1. |
- Lundberg, Liv, 1987, et al.
(författare)
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A cobweb model of land-use competition between food and bioenergy crops
- 2015
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Ingår i: Journal of Economic Dynamics and Control. - : Elsevier BV. - 0165-1889. ; 53, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- We present a model of interacting cobweb markets and apply it to land-use competition between food and bioenergy crops. In our model the markets are interlinked on the supply side by the limited availability of land. Therefore, instabilities are transferred between the markets and we find that bioenergy demand affects food price volatility. The agents in the model have heterogeneous production capacities, representing variation in global land quality. When we allow agents to choose price predictor, we find that a more sophisticated (but costly) predictor is concentrated to some key parcels of land, which enables the system to reduce instability significantly. The system can also be brought closer to a stable state by introducing costs for changing production type, but it may then be shifted away from the optimum situation predicted by the corresponding equilibrium model.
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| 2. |
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| 3. |
- Jonson, Emma, 1981
(författare)
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An agent-based approach to supply side modeling of agricultural and power systems
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the modeling of economic systems in the context of agricultural and power systems, and some aspects of the difference between the standard economics equilibrium approach and the agent-based approach. We model the supply side, where agents make decisions on what to produce or in what to invest. These decisions are based on predictions of future prices and other market conditions. In all settings time lags and limited foresight are important. Whereas standard economics is based on the idea of economic equilibrium, agent-based modeling describes dynamic systems based on the interaction of agents who do not necessarily possess perfect information and rationality. This thesis consists of three parts. In papers I-III we present a model of interacting markets with cobweb characteristics, i.e. markets where prices are prone to oscillations due to a time lag between supply and demand decisions. We apply the model to land-use competition between food and bioenergy crops. We show how instability in one agricultural market, e.g. the bioenergy crops market, can be transferred to other agricultural markets, both on the supply side (by the limited availability of land) and on the demand side (by consumers choosing between different goods). Under certain circumstances the agent-based dynamics can be projected to a closed dynamics of aggregate quantities, which allows for the stability characteristics to be analytically approached. In paper IV we present a model of beef cattle dynamics based on decisions taken by boundedly rational farmers. We systematically examine the parameters determining the agents' expectations and decision mechanisms, and their impacts on the dynamics. In paper V we study a power system transition triggered by a carbon tax. We find that the level of carbon tax needed to reach a specific CO$_2$ mitigation target may be significantly higher in an agent-based model than in the corresponding optimization model. In all papers we focus on mechanisms and model characteristics rather than on predictions.
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| 4. |
- Jonson, Emma, 1981, et al.
(författare)
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Electrification potential of the car – estimate from a mid-size Swedish town
- 2010
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Ingår i: 25th World Battery, Hybrid and Fuel Cell Electric Vehicle Symposium and Exhibition: Sustainable Mobility Revolution, EVS 2010; Shenzhen; China; 5 November 2010 through 9 November 2010.
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Konferensbidrag (refereegranskat)abstract
- An electrification of vehicles can contribute to increased energy efficiency and decreased air pollution in urban environments. The high vehicle costs involved, especially for the batteries, means that careful considerations of the options are needed. We have investigated the optimal design and potential for plug-in hybrid electric vehicles (PHEV) under various viability conditions with the help of a data set for individual vehicle movements from a mid-size Swedish town. In the estimates each car is equipped with a battery cost-optimized in size with respect to the individual car movement pattern and charging options expressed as the minimum break time interval required for considering recharging. The resulting optimal battery size is relatively small for lower economic viability, but increases with raised charging options. For high economic competitiveness the optimal sizes are larger but decreasing with better recharging possibilities. The results point to a PHEV design strategy with a small battery in an introductory phase and then an increased size when the economic competitiveness is further enhanced. Still the resulting optimal battery size is highly dependent on the specific movement pattern of the individual car. It is now urgent for the continued development, planning, and estimates of proliferation and impact of electrified vehicles that further statistical data, today mostly lacking, for the movement patterns of individual vehicles in various regions are assembled and utilized.
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| 5. |
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| 6. |
- Jonson, Emma, 1981, et al.
(författare)
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Exploring the competition between variable renewable electricity and a carbon-neutral baseload technology
- 2020
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Ingår i: Energy Systems. - : Springer Science and Business Media LLC. - 1868-3975 .- 1868-3967. ; 11:1, s. 21-44
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we explore the competition between variable renewable energy sources (VRE) and a carbon-neutral baseload technology in the transition to a low-carbon power system. We study a stylized system subject to a gradually increasing carbon tax using an agent-based model where agents are power companies investing in new capacity. The agents make predictions of the profitability of different investment options. Five electricity generating technologies are available in the model: coal, gas, wind, solar PV and a more expensive carbon-neutral baseload technology. We compare the output from our model with a corresponding optimization model. We present two main findings: (1) installed capacity of VRE initially increases with a carbon tax. However, once the carbon tax has reached a certain level the installed capacity of VRE starts to decline due to competition with the stylized carbon-neutral baseload technology. (2) With limited foresight we find that the model underinvests (first 25 years) in wind and then overinvests in wind compared to the optimal solution. The reasons for these dynamic phenomena are explained and an extensive sensitivity analysis is carried out.
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| 7. |
- Jonson, Emma, 1981, et al.
(författare)
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Impacts on Stability of Interdependencies Between Markets in a Cobweb Model
- 2015
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Ingår i: Lecture Notes in Economics and Mathematical Systems. - Cham : Springer International Publishing. - 2196-9957 .- 0075-8442. ; 676, s. 195-205
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Tidskriftsartikel (refereegranskat)abstract
- We present a cobweb model of interdependent markets on both the sup- ply and demand sides and apply it to a food and bioenergy framework. The supply side is represented by an agent based model of global land use while the consumer side consists of interlinked demand functions. We find that the two kinds of inter- dependencies have opposing effects. Linking markets on the supply side transfers instabilities within the system and may cause price fluctuations in previously sta- ble markets. Market interdependency on the demand side, on the other hand, has a stabilizing effect.
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| 8. |
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| 9. |
- Karlsson, Sten, 1951, et al.
(författare)
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Electrification potential of the car – an estimate from a mid-size Swedish town
- 2011
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Ingår i: World Electric Vehicle Journal. - : MDPI AG. - 2032-6653. ; 4:1, s. 82-90
-
Tidskriftsartikel (refereegranskat)abstract
- An electrification of vehicles can contribute to increased energy efficiency and decreased air pollution in urban environments. The high vehicle costs involved, especially for the batteries, means that careful considerations of the options are needed. We have investigated the optimal design and potential for plug-in hybrid electric vehicles (PHEV) under various viability conditions with the help of a data set for individual vehicle movements from a mid-size Swedish town.In the estimates each car is equipped with a battery cost-optimized in size with respect to the individual car movement pattern and charging options expressed as the minimum break time interval required for considering recharging. The resulting optimal battery sizes are relatively small for lower economic viability, but increase with raised charging options. For high economic competitiveness the optimal sizes are larger, but decrease with better recharging possibilities.The results point to a PHEV design strategy with a small battery in an introductory phase and then an increased size when the economic competitiveness is further enhanced. Still the resulting optimal battery size is highly dependent on the specific movement pattern of the individual car. It is now urgent for the continued development, planning, and estimates of proliferation and impact of electrified vehicles that further statistical data, today mostly lacking, for the movement patterns of individual vehicles in various regions are assembled and utilized.
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| 10. |
- Karlsson, Sten, 1951, et al.
(författare)
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The effect of PHEV battery range distributions on competitiveness: Implications for design strategy and energy-efficiency policy
- 2011
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Ingår i: proceedings of Energy efficiency first: The foundation of a low-carbon society, European Council for an Energy Efficient Economy (ECEEE) 2011 Summer Study 6–11 June 2011 Belambra Presqu'île de Giens, France.
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Konferensbidrag (refereegranskat)abstract
- Electric vehicles have the potential to contribute to increased energy efficiency. However, competition is fierce among designs, energy carriers, and powertrains; electric vehicles must be economically viable from a consumer point of view. Batteries are still expensive; short of a breakthrough, the energy battery will constitute a considerable share of the vehicle cost for the foreseeable future. Economically efficient battery use is therefore very important. Plug-in hybrid electric vehicles (PHEV) constitute a response to this efficiency requirement. PHEVs rely on a relatively small battery, while still allowing a considerable share of the driving to be powered by electricity. In previous studies, we investigated optimal battery sizes, from the individual consumer’s perspective. In reality, only a limited number of battery sizes will be available. Understanding the relationship between a limited choice of battery sizes and the potential for PHEVs should be of value to car manufacturers, in constructing battery range strategies, as well as to policymakers, in formulating policies for encouraging the introduction of electric vehicles. Here we investigate this relationship by analyzing how various battery range strategies influence PHEV viability, efficiency, and potential. We use a data set on car use from a mid-size Swedish town covering 201 individual cars for 100 days. The results are presented in terms of the possible loss in net revenue, electrification potential, and energy efficiency for different distributions of battery ranges, which reflect a limited number of optimized sizes and a modular design. We apply our analysis to current conditions and a range of possible future techno-economic and recharging conditions, making it possible to estimate the importance of the different strategies in a variety of future scenarios. For the investigated non-optimal battery strategies, the estimated loss in average net revenue is up to 20-25% of the battery cost, the possible loss in fleet electrification potential is at least up to 10% of the distance driven, and the potential loss in average vehicle energy efficiency is also around 10%.
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| 11. |
- Karlsson, Sten, 1951, et al.
(författare)
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The importance of car movement data for determining design, viability and potential of PHEVs
- 2011
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Ingår i: Proceedings of International Advanced Mobility Forum (IAMF) 2011, March 8-9, 2011, Geneva Switzerland.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We demonstrate that representative car movement data is a crucial factor in determining viability, potentials, and design strategies for PHEVs, by assessing these parameters with the help of a specific data set for individual vehicle movements from a mid-size Swedish town. We then present the ongoing Swedish car movement data project and some early results and experience.
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| 12. |
- Lindgren, Kristian, 1960, et al.
(författare)
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Projection of a Heterogenous Agent-Based Production Economy Model to a Closed Dynamics of Aggregate Variables
- 2015
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Ingår i: Advances in Complex Systems. - 0219-5259. ; 18:5-6, s. 1550012-
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Tidskriftsartikel (refereegranskat)abstract
- A model framework that describes a simple production economy is presented, in which the micro-dynamics can be projected to a closed dynamics of aggregate variables. The construction is based on an agent-based model with heterogeneity both regarding pro- duction characteristics and the strategies agents use to predict future prices as a basis for choosing what to produce. The world is divided into a number of regional markets that collect the locally produced goods and via inter-market trade supply regional demands with goods. We discuss the model features that make it possible to project the agent- based micro-dynamics to a closed form dynamics on the level of regionally aggregate quantities. One advantage of such a projection from a high dimensional agent-based dynamics to a low dimensional dynamical system is that the stability characteristics can be analytically approached, and this is illustrated by a derived condition for when a mix of naive and rational agents can stabilize the system. Some illustrations of the general framework in a model of global agricultural land-use are also given.
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