| dc.description.abstract | Growing international consensus on the need to mitigate global climate change recently led UNFCCC
parties to commit to an increase in global mean surface temperature (MST) well below 2ᵒC compared to
pre-industrial levels. In this context, integrated assessment models (IAMs) can provide valuable insights in
the long-term impacts of human development on climate change. This thesis aims to model regional final
energy demand (FED) for two main agricultural processes, irrigation and synthetic fertilizer production,
within the IAM IMAGE 3.0. This is done in a new Agricultural Energy Demand (AED) module. The
methodology for irrigation energy demand consists of two main components; water conveyance from a
withdrawal source to the field; and subsequent distribution across the field by an application system. The
former uses aquifer and groundwater table depths to determine specific energy consumption (SEC), the
latter a region specific mix of three field application systems; surface irrigation, sprinkler and drip. These
systems are characterized by zero, high and low SECs respectively. Since the production of ammonia
dominates world synthetic fertilizer energy demands, it is modelled in more detail than other fertilizer
types. At the heart of the ammonia energy demand methodology is a multinomial logit equation which
assigns regional market shares to four ammonia plant types; natural gas, coal, heavy oil and solid
biomass. SEC for each of these plant types is determined by a technological learning curve. Additionally,
each plant type can be equipped with a carbon capture and storage (CCS) add-on, which reduces net CO2
emissions. Model runs are made for a new set of human development scenarios called the Shared
Socioeconomic Pathways (SSPs). These include three plausible baseline scenarios and one that is
constrained by the 2ᵒC MST limit described earlier. Main results: projected global agricultural energy
demand is dominated by ammonia production in all scenarios, and energy demand is higher for irrigation
than for the production of all other fertilizer types combined. The SSP1 Sustainability scenario projects the
lowest global AED, while the SSP3 Regional Rivalry and RCP2.6 2degree scenarios project the highest.
These differences are mainly explained by the varying energy demands for ammonia production. The high
ammonia energy demand in the 2ᵒC MST limit scenario is explained by its high deployment of biomass
plants, which have a high SEC but very low net CO2 emissions. At the moment, the AED module covers an
estimated 58.5% of world total AED and 2.0% of grand total final energy demand. | |
