• Energy Research
• clinical medicine close
• DK close
• English close

The articlw addresses an important challenge ahead the integration of the electricity generated by wave energy conversion technologies into the electric grid. Particularly, it looks into the role of wave energy within the day-ahead electricity market. For that the predictability of the theoretical power outputs of three wave energy technologies in the Danish North Sea are examined. The simultaneous and co-located forecast and buoy-measured wave parameters at Hanstholm, Denmark, during a non-consecutive autumn and winter 3-month period form the basis of the investigation.The objective of the study is to provide an indication on the accuracy of the forecast of i) wave parameters, ii) the normalised theoretical power productions from each of the selected technologies (Pelamis, Wave Dragon and Wavestar), and iii) the normalised theoretical power production of a combination of the three devices, during a very energetic time period.Results show that for the 12 to 36 hours time horizon forecast, the accuracy in the predictions (in terms of scatter index) of the significant wave height, zero crossing period and wave power are 22%, 11% and 68%, respectively; and the accuracy in the predictions of the normalised theoretical power outputs of Pelamis, Wave Dragon and Wavestar are 44%, 52% and 62%, respectively. The best compromise between forecast accuracy and mean power production results when considering the combined production of the three devices.

Climate change is a global issue that has come to the forefront of environmental concern. With the increasing emissions of greenhouse gases, efforts have increased to reduce carbon dioxide (CO2) emissions. Regulatory guidelines are becoming more stringent and efforts for long-term reduction are being investigated and implemented [1]. Carbon Capture and Storage (CCS) is the dominant method that is discussed. However, CO2 utilization is receiving increased attention for its ability to help in long-term CO2 reduction and the formation of various chemical products. One of the primary elements of utilization is the conversion of CO2 to valuable products via chemical reactions with other raw materials. In order for this to be implemented at a large and industrial level, further work is necessary. As part of this, the work focuses on the formulation and design of a CO2 utilization network via a superstructure-based methodology. The sustainability and feasibility of linking carbon capture and CO2 conversion is studied in detail in a case study. CCS is still under development and CO2 utilization is showing great promise as an additional method of combatting CO2 emissions [2]. The method developed involves three stages: a process synthesis stage, a design stage and an innovation stage. Following a superstructure based approach, a network of conversion processes is created. This network links CO2 and products through various processing blocks. The network also links carbon capture to ensure the sustainability. Each processing block within the developed network needs to be mathematically described for optimization. The second stage is the detailed design of a path within the network, followed by analysis and improvement by creating a more sustainable design in the innovation stage. However, as not all information is available to describe the network mathematically, the most promising paths based on known technologies are designed and analyzed first. This makes the stages iterative rather than purely sequential. As part of this, the network is analyzed in the conceptual example of methanol synthesis via CO2 hydrogenation. This case study illustrates the utility of the utilization network and elements of the methodology being developed. In addition, the conversion process is linked with carbon capture to evaluate the overall sustainability. Finally, the production of the other raw materials is also analyzed for economic feasibility and environmental sustainability. Using computer-aided methods, the feasibility and sustainability of CO2 conversion is shown through the design and optimization of a methanol synthesis process.

The article is a critique of the requirements for a commission to investigate the options for mitigating climate change, established by the Danish Minister for Climate, Hedegaard. The minister does not allow the commission include lower economic growth as an option, although this is the main driver behind these environmental problems.

A SOFC (solid oxide fuel cell) cycle running on natural gas was integrated with a ST (steam turbine) cycle. The fuel is desulfurized and pre-reformed before entering the SOFC. A burner was used to combust the remaining fuel after the SOFC stacks. The off-gases from the burner were used to produce steam in a HRSG (heat recovery steam generator). The bottoming steam cycle was modeled with two configurations: (1) a simple single pressure level and (2) a dual pressure level with both a reheat and a pre-heater. The SOFC stacks in the present SOFC-ST hybrid cycles were not pressurized. The dual pressure configuration steam cycle combined with SOFC cycle (SOFC-ST) was new and has not been studied previously. In each of the configuration, a hybrid recuperator was used to recovery the remaining energy of the off-gases after the HRSG. Thus, four different plants system setups were compared to each other to reveal the most superior concept with respect to plant efficiency and power. It was found that in order to increase the plant efficiency considerably, it was enough to use a single pressure with a hybrid recuperator instead of a dual pressure Rankine cycle.

The focus of this paper is how we can facilitate problem based learning (PBL) more creatively. We take a closer look upon the connection between creative processes and social communication in the PBL group including how difficulties in the social interplay may hinder creativity. The paper draws on group dynamic theory, and points out the importance of building a reflexive milieu in the group. Musical concepts are used to illustrate the communicative and creative aspects of PBL and the paper uses the analogy between improvising together and do a project work together. We also discuss the role of the supervisor in a PBL group process. Further we argue that creativity is rooted deep in our consciousness and connected to our ability to work with a flexible mind. In order to enhance the cohesion as well as the creativity of the group a model of music listening as a concrete intervention tool in PBL processes is proposed. Journal of Problem Based Learning in Higher Education, Vol 3 No 1 (2015): Special Issue: PBL and Creative Processes

Research within agricultural technology focuses mainly on increasing the efficiency of crop production. Electric powered machines have several advantages. The machine control is much easier in terms of sensor integration, active navigation and task application compared with traditional machine types. Furthermore, low machine weights and the use of renewable energy to provide the necessary energy contribute to soil protection and low emissionperformance. The aim of the paper was to describe the design, the control and the renewable energy supply for a small electric powered robot for outdoor field monitoring and other operations. Furthermore the energy consumption for the different operations scenarios was determined based on power consumption measurements for the basic navigation modes. Additionally two different charging scenarios have been investigated. The investigation has shown that it is possible to power a robot using PV cells for an operation time of 11 to 13 hours. The PV charging solutions are expensive compared with using thepublic power grid. They are only viable when there is no access to the grid.