Investigating the impact of flexible demand on market-based generation investment planning

Demand flexibility has attracted significant interest given its potential to address techno-economic challenges associated with the decarbonisation of electricity systems. However, previous work has investigated its long-term impacts through centralized generation planning models which do not reflect the current deregulated environment. At the same time, existing market-based generation planning models are inherently unable to capture the demand flexibility potential since they neglect time-coupling effects and system reserve requirements in their representation of the electricity market. This paper investigates the long-term impacts of demand flexibility in the deregulated environment, by proposing a time-coupling, bi-level optimization model of a self-interested generation company’s investment planning problem, which captures for the first time the energy shifting flexibility of the demand side and the operation of reserve markets with demand side participation. Case studies investigate different cases regarding the flexibility of the demand side and different market design options regarding the allocation of reserve payments. The obtained results demonstrate that, in contrast with previous centralised planning models, the proposed model can capture the dependency of generation investment decisions and the related impacts of demand flexibility on the electricity market design and the subsequent strategic response of the self-interested generation company

Sperm abnormalities and libido assessment of West African dwarf rams fed diets containing Tetrapleura tetraptera (African Porridge) fruit meal

The effect of Tetrapleura tetraptera fruit meal (TTFM) on the sperm abnormalities and libido test of West African Dwarf rams was assessed in a 20 week study. Thirty five (35) West African dwarf rams weighing between 12.80 and 13.20kg were randomly allotted to five dietary treatments in a completely randomized design. The diets formulated: 0% TTFM, 0.5% TTFM, 1.0% TTFM, 1.5% TTFM and 2.0% TTFM as treatments 1, 2, 3, 4 and 5 respectively. Libido assessment was carried out at 0, 4, 8, 12 and 16th weeks of the experiment. Semen was collected twice at the beginning and at the end of the experiment from five replicates in each treatment using electro- ejaculator. The results showed that the libido increased progressively with the inclusion of TTFM which was only significantly different (p<0.05) at 16th week. The best libido was observed with rams fed diets containing 1.5 and 2.0% TTFM. The sperm abnormalities were minimal in all parameters except in abnormal head which ranged from 0.4-1.20% with diet 4 exhibited the most abnormal head. It was therefore concluded that the TTFM can be incorporated between 1.5% and 2.0% into diet of rams to improve the sex drive and reduced sperm abnormalities

Carbon taxation and feed-in tariffs: evaluating the effect of network and market properties on policy effectiveness

This paper evaluates how the effect of introducing a carbon emission tax and/or feed-in tariffs on capacity expansion decisions of generating companies varies depending on the number and size of competing firms and technical conditions of the network. To do so, it uses a Nash–Cournot model of the electricity market. This model is then applied to the IEEE 6-bus network. We study three cases: one with only a carbon tax consistent with current carbon prices; one with only a feed-in tariff consistent with current US levels, and one with simultaneous carbon taxation and feed-in tariff. We show that, at least in our case, the quantity of renewable capacity expansion and the electricity prices depend more significantly on the technical conditions of the network and the number of competitors in the market than it depends on the presence of economic penalties or incentives. We also show how interactions between imperfectly competitive markets and physical networks can produce counterintuitive results, such as an increase in consumer prices as a result of a reduction in network congestion. Our results imply that no two countries would experience the same effects from a policy on carbon tax and feed-in tariff if their electricity market does not have similarities in technical and competitive conditions

Incorporating demand flexibility in strategic generation investment planning

The envisaged decarbonization of electricity systems has attracted significant inte rest around the role and value of demand flexibility . However, the impact of this flexibility on generation investments in the deregulated electricity industry setting remains a largely unexplored area, since previous relevant work neglects the time - coupli ng nature of demand shifting potentials. This paper addresses this challenge by proposing a strategic generation investment planning model expressing the decision making process of a self - interested generation company and accounting for the time - coupling o perational characteristics of demand flexibility. This model is formulated as a multi - period bi - level optimization problem, which is solved after converting it to a Mathematical Program with Equilibrium Constraints (MPEC). Case studies with the proposed mo del demonstrate that demand flexibility reduces the total generation capacity investment, enhances investments in baseload generation and yield s significant economic benefits in terms of total system costs and demand payments

Impact of energy storage on market-based generation investment planning

Previous work has analyzed the role of energy storage (ES) on generation investment planning through centralised cost-minimization models which are inherited from the era of regulated electricity utilities. This paper investigates this issue in the context of the deregulated market environment by proposing a new strategic generation investment planning model. The decision making of a strategic generation company is modeled through a multi-period bi-level optimization problem, where the upper level determines the profit-maximizinginvestment decisions of the generation company and the lower level represents themarket clearing process, accounting for the time-coupling operational characteristics of ES. This bi-level problem is solved after converting it to a single-level mixed-integer linear problem (MILP). Case studies demonstrate thatthe introduction of ES reduces the total generation capacity investment and enhances investments in “must-run” baseload generation over flexible peaking generation, yielding significant system cost savings

Evaluating different scenarios for Tradable Green Certificates by game theory approaches

Right now employment of polices and tools to decrease the carbon emission through electricity generation from renewable resources is one of the most important problem in energy policy. Tradable Green Certificate (TGC) is an economics mechanism to support green power generation. Any country has the challenge to choose an appropriate policy and mechanism for design and implementation of TGC. The purpose of this study is to help policy makers to design and choose the best scenario of TGC by evaluating six scenarios, based on game theory approach. This study will be useful for increasing the effectiveness of TGC system in interaction with electricity market. Particularly, the competition between thermal and renewable power plants is modeled by mathematical modeling tools such as cooperative games like Nash and Stackelberg. Each game is modeled by taking into account of the two following policies. The results of the six scenarios and the sensitivity analysis of some key parameters have been evaluated by numerical studies. Finally, in order to evaluate the scenarios we calculated the level of social welfare in the all scenarios. The results of all models demonstrate that when the green electricity share (minimum requirement) increases the TGC price decreases. Moreover, in all scenarios when the minimum requirement is 100% then the maximum level of social welfare is not met. Also when the minimum requirement is less than 50%, the scenarios with the market TGC price policy have more social welfare in comparison with the scenarios with fixed TGC price policy