(455c) GHG Life Cycle Assessment for the United Arab Emirates Electricity Sector Combining Optimization and Simulation Tools

Over the last decade, the rapid economic and demographic growth of the United Arab Emirates (UAE) has pushed the countryâ??s electricity grid to its limits. The countryâ??s installed electricity generation capacity reached 27 GW in 2013, and remains growing. Most of the UAEâ??s generation capacity is natural gas-based. Although natural gas is considered to be a relatively clean primary energy source, it is still a fossil fuel source that generates significant Greenhouse Gas (GHG) emissions. The UAE electricity demand reached a domestic record of 105 billion kWh in 2013, placing the country as one of the highest per capita consumers in the world. Nuclear and renewable power capacities are currently being added to increase the countryâ??s energy mix and reduce GHG emissions. As a result of the steadily growing electricity demand, the UAE plans to increase natural gas production to meet the domestic demand. The majority of the growth will come from the countryâ??s largely sour (high-sulfur content) gas reservoirs. The UAEâ??s gas reservoirs have a relatively high sulfur content, which makes it corrosive and difficult to process. The process is particularly very energy intensive and environmentally challenging. Thus, the process is highly GHG-intensive, as well vast amounts of sulfur are generated as by-product.

There is currently a need to assess the environmental footprints of the UAE electricity sector in terms of the GHG emission life cycle. This could allow benchmarking the UAEâ??s electricity sector against other nations, while finding suitable niches for GHG mitigation strategies. Moreover, since over 98% of the electricity generated in the UAE is gas-based, an analysis on the UAEâ??s natural gas life cycle represents a key factor on determining the overall environmental impact of the electricity sector. The present analysis considers a cradle-to-gate GHG inventory approach; which consists of upstream and downstream inventories. The upstream inventory includes all the activities before fuel is combusted at a power plant. Such activities comprise: sour natural gas extraction, sour gas sweetening process, and sweet gas transport to the power plant gate. On the other hand, the downstream inventory includes the electricity generation and transmission processes. For the present study, fundamental engineering principles were used to mathematically estimate process specific energy consumption and related life cycle GHG emissions for: sour gas extraction, sweet gas transport, and electricity transmission activities. Additionally, ProMax® v3.2 was used to simulate the sour gas sweetening process, while performing a parametric analysis to improve the performance of this process. Also, an optimization mathematical model developed in the General Algebraic Modeling System (GAMS) was used to illustrate the design and operation of the UAE power sector.