44 research outputs found
Does risk aversion affect transmission and generation planning? A Western North America case study
We investigate the effects of risk aversion on optimal transmission and generation expansion planning in a competitive and complete market. To do so, we formulate a stochastic model that minimizes a weighted average of expected transmission and generation costs and their conditional value at risk (CVaR). We show that the solution of this optimization problem is equivalent to the solution of a perfectly competitive risk-averse Stackelberg equilibrium, in which a risk-averse transmission planner maximizes welfare after which risk-averse generators maximize profits. This model is then applied to a 240-bus representation of the Western Electricity Coordinating Council, in which we examine the impact of risk aversion on levels and spatial patterns of generation and transmission investment. Although the impact of risk aversion remains small at an aggregate level, state-level impacts on generation and transmission investment can be significant, which emphasizes the importance of explicit consideration of risk aversion in planning models
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The role of expectations for market design – on structural regulatory uncertainty in electricity markets
Ongoing policy discussions on the reconfiguration of bidding zones in European electricity markets induce structural uncertainty about the future market design. This paper deals with the question of how this structural uncertainty affects market participants and their long-run investment decisions in generation and transmission capacity. We propose a stochastic multilevel model, which incorporates generation capacity investment, network expansion and redispatch, taking into account uncertainty about the future market design. Using a stylized two-node network, we disentangle different effects that uncertainty has on market outcomes. Our results reveal that expectations about future market structures have an important effect on investment decisions. Unlike most parametric uncertainties, structural uncertainty about the future market design can have a positive effect on welfare, even if a market design change does not actually take place, although there are distributional effects. This also implies that the welfare gains of a change to a more efficient market design are lower if market participants already anticipate this change
SENTENCING MATTERS - FACTORS DETERMINING SENTENCE TYPE AND LENGTH: AN EXPLORATORY VIGNETTE STUDY
Genetic complexity of miscanthus cell wall composition and biomass quality for biofuels
BACKGROUND: Miscanthus sinensis is a high yielding perennial grass species with great potential as a bioenergy feedstock. One of the challenges that currently impedes commercial cellulosic biofuel production is the technical difficulty to efficiently convert lignocellulosic biomass into biofuel. The development of feedstocks with better biomass quality will improve conversion efficiency and the sustainability of the value-chain. Progress in the genetic improvement of biomass quality may be substantially expedited by the development of genetic markers associated to quality traits, which can be used in a marker-assisted selection program. RESULTS: To this end, a mapping population was developed by crossing two parents of contrasting cell wall composition. The performance of 182 F1 offspring individuals along with the parents was evaluated in a field trial with a randomized block design with three replicates. Plants were phenotyped for cell wall composition and conversion efficiency characters in the second and third growth season after establishment. A new SNP-based genetic map for M. sinensis was built using a genotyping-by-sequencing (GBS) approach, which resulted in 464 short-sequence uniparental markers that formed 16 linkage groups in the male map and 17 linkage groups in the female map. A total of 86 QTLs for a variety of biomass quality characteristics were identified, 20 of which were detected in both growth seasons. Twenty QTLs were directly associated to different conversion efficiency characters. Marker sequences were aligned to the sorghum reference genome to facilitate cross-species comparisons. Analyses revealed that for some traits previously identified QTLs in sorghum occurred in homologous regions on the same chromosome. CONCLUSION: In this work we report for the first time the genetic mapping of cell wall composition and bioconversion traits in the bioenergy crop miscanthus. These results are a first step towards the development of marker-assisted selection programs in miscanthus to improve biomass quality and facilitate its use as feedstock for biofuel production