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- Aidas, Kestutis, et al.
(författare)
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The Dalton quantum chemistry program system
- 2014
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Ingår i: WIREs Computational Molecular Science. - : Wiley. - 1759-0876 .- 1759-0884. ; 4:3, s. 269-284
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Tidskriftsartikel (refereegranskat)abstract
- Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, MOller-Plesset, configuration-interaction, and coupled-cluster levels of theory. Apart from the total energy, a wide variety of molecular properties may be calculated using these electronic-structure models. Molecular gradients and Hessians are available for geometry optimizations, molecular dynamics, and vibrational studies, whereas magnetic resonance and optical activity can be studied in a gauge-origin-invariant manner. Frequency-dependent molecular properties can be calculated using linear, quadratic, and cubic response theory. A large number of singlet and triplet perturbation operators are available for the study of one-, two-, and three-photon processes. Environmental effects may be included using various dielectric-medium and quantum-mechanics/molecular-mechanics models. Large molecules may be studied using linear-scaling and massively parallel algorithms. Dalton is distributed at no cost from for a number of UNIX platforms.
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| 2. |
- Floors, Rogier, et al.
(författare)
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From lidar scans to roughness maps for wind resource modelling in forested areas
- 2018
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Ingår i: Wind Energy Science. - : COPERNICUS GESELLSCHAFT MBH. - 2366-7443 .- 2366-7451. ; 3:1, s. 353-370
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Tidskriftsartikel (refereegranskat)abstract
- Applying erroneous roughness lengths can have a large impact on the estimated performance of wind turbines, particularly in forested areas. In this study, a new method called the objective roughness approach (ORA), which converts tree height maps created using airborne lidar scans to roughness maps suitable for wind modelling, is evaluated via cross predictions among different anemometers at a complex forested site with seven tall meteorological masts using the Wind Atlas Analysis and Application Program (WAsP). The cross predictions were made using ORA maps created at four spatial resolutions and from four freely available roughness maps based on land use classifications. The validation showed that the use of ORA maps resulted in a closer agreement with observational data for all investigated resolutions compared to the land use maps. Further, when using the ORA maps, the risk of making large errors (>25%) in predicted power density was reduced by 40-50% compared to satellite-based products with the same resolution. The results could be further improved for high-resolution ORA maps by adding the displacement height. The improvements when using the ORA maps were both due to a higher roughness length and due to the higher resolution.
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| 3. |
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| 4. |
- Sovacool, Benjanmin, et al.
(författare)
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Cost Performance and Risk in the Construction of Offshore and Onshore Wind Farms
- 2017
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Ingår i: Wind Energy. - : Wiley. - 1099-1824 .- 1095-4244. ; 20:5, s. 891-908
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Tidskriftsartikel (refereegranskat)abstract
- This article investigates the risk of cost overruns and underruns occurring in the construction of 51 onshore and offshorewind farms commissioned between 2000 and 2015 in 13 countries. In total, these projects required about $39 billion in investmentand reached about 11 GW of installed capacity. We use this original dataset to test six hypotheses about constructioncost overruns related to (i) technological learning, (ii) fiscal control, (iii) economies of scale, (iv) configuration, (v)regulation and markets and (vi) manufacturing experience. We find that across the entire dataset, the mean cost escalationper project is 6.5% or about $63 million per windfarm, although 20 projects within the sample (39%) did not exhibit costoverruns. The majority of onshore wind farms exhibit cost underruns while for offshore wind farms the results have a largerspread. Interestingly, no significant relationship exists between the size (in total MWor per individual turbine capacity) of awindfarm and the severity of a cost overrun. Nonetheless, there is an indication that the risk increases for larger wind farmsat greater distances offshore using new types of turbines and foundations. Overall, the mean cost escalation for onshoreprojects is 1.7% and 9.6% for offshore projects, amounts much lower than those for other energy infrastructure.
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