Search

Projections of decarbonisation pathways have typically involved reducing dependence on natural gas grids via greater electrification of heat using heat pumps or even electric heaters. However, many technical, economic and consumer barriers to electrification of heat persist. The gas network holds value in relation to flexibility of operation, requiring simpler control and enabling less expensive storage. There may be value in retaining and repurposing gas infrastructure where there are feasible routes to decarbonisation. This study quantifies and analyses the decarbonisation potential associated with the conversion of gas grids to deliver hydrogen, focusing on supply chains. Routes to produce hydrogen for gas grids are categorised as: reforming natural gas with (or without) carbon capture and storage (CCS); gasification of coal with (or without) CCS; gasification of biomass with (or without) CCS; electrolysis using low carbon electricity. The overall range of greenhouse gas emissions across routes is extremely large, from − 371 to 642 gCO 2 eq/kW h H2 . Therefore, when including supply chain emissions, hydrogen can have a range of carbon intensities and cannot be assumed to be low carbon. Emissions estimates for natural gas reforming with CCS lie in the range of 23–150 g/kW h H2 , with CCS typically reducing CO 2 emissions by 75%. Hydrogen from electrolysis ranges from 24 to 178 gCO 2 eq/kW h H2 for renewable electricity sources, where wind electricity results in the lowest CO 2 emissions. Solar PV electricity typically exhibits higher emissions and varies significantly by geographical region. The emissions from upstream supply chains is a major contributor to total emissions and varies considerably across different routes to hydrogen. Biomass gasification is characterised by very large negative emissions in the supply chain and very large positive emissions in the gasification process. Therefore, improvements in total emissions are large if even small improvements to gasification emissions can be made, either through process efficiency or CCS capture rate.

Supported by policy, electric vehicles (EVs) powered by lithium batteries are being commercialised in an increasing number of models and their global stock surpassed two million units in 2016. However, there is uncertainty around the future price and availability of lithium, which has consequences on the feasibility of manufacturing lithium batteries at scale. Reaching the EV penetration levels foreseen by governments implies a substantial growth in lithium demand. In this chapter, we review the evidence around future lithium availability for the manufacturing of EV batteries. We examine the methods used to estimate both lithium demand from EVs and lithium supply from brines and ore. The main variables influencing demand are the future size of the EV market, the average battery capacity and the material intensity of the batteries. Supply projections depend on global reserve and resource estimates, forecast production and recyclability. We find that the assumptions made in the literature on the key variables are characterised by significant uncertainty. However based on the available evidence, it appears that lithium production may be on a lower trajectory than demand and would have to rapidly increase in order not to prove a bottleneck to the expansion of the EV market. More research is needed in order to reduce uncertainty on lithium intensity of future EVs and improve understanding of the potential for lithium production expansion and recycling.

Decarbonisation goals have triggered photovoltaic (PV) sector expansion and cost reductions in PV technologies. Thin film (TF) PV technologies are currently the cheapest to manufacture and offer the possibility of attaining lower costs. However, scarcity of key component materials has been highlighted as a potential barrier to both large scale deployment and reductions in technology cost. This paper explores this claim for cadmium telluride (CdTe) and copper indium gallium (di)selenide (CIGS) TF technologies and their potentially constraining materials, tellurium and indium. It reviews key literature, highlighting the high uncertainty in the estimates of the resource constrained TF PV potential as well as in data and methodologies used to assess future availability of the targeted materials. The reviewed evidence does not support the contention that the availability of tellurium and indium will necessarily constrain CdTe and CIGS technologies respectively in their ability to supply expected future PV market growth. However, future escalation in indium and tellurium price resulting from demand–supply imbalances could have a negative impact on CdTe and CIGS cost reduction ambitions. Factors influencing indium and tellurium price and their relative contribution to TF PV module production cost need further investigation.