Revisiting Thin Silicon for Photovoltaics: A Technoeconomic Perspective

TL;DR

This paper evaluates the economic and technological benefits of using ultra-thin silicon wafers in photovoltaic modules, demonstrating significant cost reductions and analyzing challenges for future PV deployment and manufacturing.

Contribution

It provides a comprehensive techno-economic analysis of thin silicon wafers, quantifies potential cost savings, and discusses technological challenges for high-yield manufacturing.

Findings

Thinner wafers can achieve similar efficiencies with advanced surface passivation.

LCOE can be reduced by over 5% with thinner wafers.

Further efficiency improvements could cut manufacturing costs and LCOE significantly.

Abstract

Adopting thin Si wafers for PV reduces capital expenditure (capex) and manufacturing cost, and accelerates the growth of PV manufacturing. There are two key questions about thin Si today: (a) how much can we still benefit economically from thinning wafers? (b) what are the technological challenges to transition to thin wafers? In this work, we re-evaluate the benefits and challenges of thin Si for current and future PV modules using a comprehensive techno-economic framework that couples device simulation, bottom-up cost modeling, and a cash-flow growth model. When adopting an advanced technology concept that features sufficiently good surface passivation, similarly high efficiencies are achievable for 50-um wafers as for 160-um ones. We then quantify the economic benefits for thin Si wafers in terms of poly-Si-to-module manufacturing capex, module cost, and levelized cost of electricity (LCOE) for utility PV systems. Particularly, LCOE favors thinner wafers for all investigated device architectures, and can potentially be reduced by more than 5% from the value of 160-um wafers. With further improvements in module efficiency, an advanced thin-wafer device concept with 50-um wafers could reduce manufacturing capex by 48%, module cost by 28%, and LCOE by 24%. Furthermore, we apply a sustainable growth model to investigate PV deployment scenarios in 2030. It is found that the state-of-the-art industry concept could not achieve the climate targets even with very aggressive financial scenarios, therefore the capex reduction benefit of thin wafers is needed to facilitate more rapid PV growth. Lastly, we discuss the remaining technological challenges and areas for innovation to enable high-yield manufacturing of high-efficiency PV modules with thin Si wafers.