Assessing the need for critical minerals to shift the German energy system towards a high proportion of renewables

Abstract

a b s t r a c tThe German government has set itself the target of reducing the country's GHG emissions by between 80 and 95% by 2050 compared to 1990 levels. Alongside energy efficiency, renewable energy sources are set to play the main role in this transition. However, the large-scale deployment of renewable energies is expected to cause increased demand for critical mineral resources. The aim of this article is therefore to determine whether the transformation of the German energy system by 2050 ("Energiewende") may possibly be restricted by a lack of critical minerals, focusing primarily on the power sector (generating, transporting and storing electricity from renewable sources). For the relevant technologies, we create roadmaps describing a number of conceivable quantitative market developments in Germany. Estimating the current and future specific material demand of the options selected and projecting them along a range of long-term energy scenarios allows us to assess potential medium-or long-term mineral resource restrictions. The main conclusion we draw is that the shift towards an energy system based on renewable sources that is currently being pursued is principally compatible with the geological availability and supply of mineral resources. In fact, we identified certain sub-technologies as being critical with regard to potential supply risks, owing to dependencies on a small number of supplier countries and competing uses. These sub-technologies are certain wind power plants requiring neodymium and dysprosium, thin-film CIGS photovoltaic cells using indium and selenium, and largescale redox flow batteries using vanadium. However, non-critical alternatives to these technologies do indeed exist. The likelihood of supplies being restricted can be decreased further by cooperating even more closely with companies in the supplier countries and their governments, and by establishing greater resource efficiency and recyclability as key elements of technology development.

Site-Dependent Environmental Impacts of Industrial Hydrogen Production by Alkaline Water Electrolysis

“…Due to the use of photovoltaic and wind power datasets from databases a detailed description of single processes of these technologies is not possible, as they are provided in an aggregated form only. However, a former study [26] on energy technologies emphasizes the relevance of critical mineral resources use, especially indium or selenium for photovoltaics and neodymium for wind power. Increasing EP fw impacts go along with the expected further extension of bio-energy based electricity generation.…”

The Growing Global Demand for Element Gallium: Electrical and Electronic Waste and Coal Fly Ash as Alternative Sources for its Sustainable Supply

“…Since silicon is cheap and plenty and that CPT have demonstrated good performance it would thus appear to be a recommendable substitute. However, when large space installations are needed, thin-film photovoltaic technology which is gallium-based outperforms the CPT [9]. Thus, even though silicon can substitute gallium in photovoltaic devices; gallium-based devices are more efficient than silicon devices [8].…”

“…At the core of solar energy is the photovoltaic technology that uses elements such as gallium and silicon in thin film and crystalline photovoltaic (PV) cells respectively [3]. In thin film PV cells, gallium is used together with other metals such as copper, indium, and selenium in the form of CopperIndium-Gallium-diSelenide (CIGS) [3,7,9]. Typical concentration of gallium in CIGS rages between 2.3 and 19.7 kg per mega-watt of power or 0.53 g/m3 of the unit [6,10].…”

“…In 2010, the market share of silicon-based photovoltaics was 90% and that of gallium-based only 10% [10]. However, the market share of gallium-based photovoltaic cells increased from 10% in 2010 to 25% in 2012 [9]. No wonder then that, projections indicate a decreased silicon share in the photovoltaic production to 20% by 2050 [11].…”

Supply risks associated with CdTe and CIGS thin-film photovoltaics

“…Several authors have recently considered thin-film CdTe and CIGS photovoltaics from the point of view of technological relevance [3], environmental impacts [41], demand-and supplyside economics or costs [42][43][44][45][46][47], and materials supply risk [20,[48][49][50][51][52][53]. Graedel and Nuss [50] have made a multi-element, multi-indicator study of supply risk for CdTe and CIGS absorber materials based on their extensive ''criticality" data bank of the elements [18,54,55].…”