High Mountain Areas

The cryosphere (including, snow, glaciers, permafrost, lake and river ice) is an integral element of high-mountain regions, which are home to roughly 10% of the global population. Widespread cryosphere changes affect physical, biological and human systems in the mountains and surrounding lowlands, with impacts evident even in the ocean. Building on the IPCC’s Fifth Assessment Report (AR5), this chapter assesses new evidence on observed recent and projected changes in the mountain cryosphere as well as associated impacts, risks and adaptation measures related to natural and human systems. Impacts in response to climate changes independently of changes in the cryosphere are not assessed in this chapter. Polar mountains are included in Chapter 3, except those in Alaska and adjacent Yukon, Iceland, and Scandinavia, which are included in this chapter

Establishing an Accurate Numerical Model for the 2D Simulation of Buried Contact Cells

An accurate numerical model is established for the simulation of buried contact cells in two dimensions. The physical parameters and the approximations are discussed as well as the procedures that lead to the foundations of the model. The model is applied to bifacial cells with three different rear surface configurations: (A) passivated by a thermally grown oxide, (B) by a dopand-induced floating junction, and (C) with a contacted junction. Especially when the cell is situated in a light-concentrating roof tile, configuration C performes far better than A and B. The two-dimensional effects of resistive losses in the semiconductor region of the cell are also discusse

Limits to the efficiency of silicon multilayer thin film solar cells

Thin film crystalline silicon solar cells can only achieve high efficiencies if light-trapping can be used to give a long optical path lengtrh, while simulatneously achieving near unity collection probabilities for all generated carriers. This necessitates a supporting substrate of a foreign material, with refractive index compatible with light trapping schemes for silicon. The resulting inability to nucleate growth of crystalline silicon films of good crystallographic quality on such foreign substrates, at present prevents the achievement of high efficiecny devices using conventional single junction solar cell structures. The parallel multijunction solar cell preovides a new approach for achieving high efficiencies from very poor quality material, with near unity collection probabilities for all generated carriers achieved through appropriae junction spacing. Heavy doping is used to minimise the dark saturation current contribution from the layers, therefore allowing respectable voltages. The design strategy, corresponding advantages, theoretical predictions and experimental results are presented