Efficient and well-timed investments in electric transmission networks that cope with the large ongoing power market uncertainties are currently an open issue of significant research interest. Strategic flexibility for seizing opportunities and cutting losses contingent upon an unfavorable unfolding of the long-term uncertainties is an attribute of enormous value when assessing irreversible investments. In this sense, flexible AC transmission systems (FACTS) devices appear as an effective manner of adding flexibility to the transmission expansion planning. This article proposes an investment valuation approach which properly assesses the option value of deferring transmission lines investments whereas gaining flexibility by investing in FACTS devices. The flexibility provided by FACTS investments-option to abandon and to relocate-is assessed through a real option valuation approach based on the novel least square Monte Carlo method. In order to illustrate the practicability of the proposed valuation approach, a traditional expansion strategy (lines) and a flexible investment strategy (lines and FACTS) are compared in a real study case. The article shows that a proper combination of lines and FACTS leads to efficient investments by allowing a progressive adaptation of the transmission grid to the changing scenarios.
9 Semitransparent (ST) organic photovoltaics (OPVs) are demonstrating great potential 10 for building integration applications, especially in windows. For that purpose, ST-OPVs 11 should achieve adequate transparency and performance stability. In this regard, the 12 present research deals with the experimental performance of three different building-13 integrated ST-OPV technologies (technology A: developed in the frame of the present 14 study; technologies B and C: commercial modules). More specifically, spectral 15 transmittance and electrical measurements have been conducted in order to determine 16 the characteristics of the modules for building integration and electricity generation 17 purposes. Results regarding the transmittance reveal that technology A outperforms 18 technologies B and C. The stability analysis of the modules verifies that module C is the 19 most stable one with almost no decrease (3.6%) in the power conversion efficiency 20 (PCE). Furthermore, the PCE of technology B is slightly higher than in the case of 21 technology C, which experiences a PCE degradation of about 10-15% over the whole 22 time period. Finally, technology A presents a 20% reduction in PCE at around 500 23 hours. 24 Ag Silver 28 AgNW Silver nanowire 29 AVT Average visual transmittance [%] 30 BIPV Building-integrated photovoltaic 31 DAQs Data acquisition systems 32 D λ Spectral distribution [-] 33 48 PCBM [6,6]-phenyl-C61-butyric acid methyl ester 49 PCE Power conversion efficiency [%] 50 PEDOT Poly(3,4-ethylenedioxythiophene) 51 PET Polyethylene terephthalate 52 PSS Poly(styrenesulfonate) 53 PTBT Poly(4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-54 alt-3-fluoro-2-[(2-ethylhexyl)carbonyl] thieno[3,4-b]thiophene-4,6-diyl) 55 PWM Pulse Width Modulation 56 3 R.H. Relative humidity 57 ST Semitransparent 58 T Module temperature [ o C] or thermal cycling 59 TiO 2 Titanium dioxide 60 UV Ultraviolet 61 V(λ) Photopic vision efficiency [-] 62 V cell Potential of the OPV modules [V] 63 V oc Open-circuit potential [V] 64 WO x Tungsten oxide 65 ZnMgO Zinc magnesium oxide 66 Greek symbols 67 λ Wavelength [nm] 68 Transmittance [-] 69 Visible transmittance in agreement with EN 410:2011 [-] 70 71 films, lightweight, semitransparent, free form and flexible, widening the possible 83 applications in comparison to conventional silicon-based photovoltaic panels. 84 With respect to the electrical performance, in the literature remarkable advances by 85 utilizing bulk heterojunction organic devices that combine donor and acceptor 86 substances in the blend have been reported [3]. Also, molecular optimization to tune the 87 optoelectronic properties of photovoltaic materials by chemical modulation is an 88 effective strategy to enhance efficiency. More specifically, the present efficiency record 89 of 13.1% has been obtained for a cell where the small molecule acceptor was 90 synthesized via fluorination [4]. This impressive value of 13.1%, even to be very high in 91 terms of OPV cells, is quite far from the percentages obtai...
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