Urban GHG emissions and resource flows : methods for understanding the complex functioning of cities
(2015)
This paper sums up the recent developments in concepts and methods being used to measure the impacts of cities on environmental sustainability. It differentiates between a dominant trend in research literature that concentrates on the accounting and allocation of greenhouse gas (GHG) emissions and energy use to cities, and a re-emergence of studies focusing on the direct and indirect urban material and resource flows. The availability of reliable data and standard protocols is greater in the GHG accounting field and continues to grow rapidly.
The German federal state of North Rhine-Westphalia (NRW) is home to one of the most important industrial regions in Europe, and is the first German state to have adopted its own Climate Protection Law (CPL). This paper describes the long-term (up to 2050) mitigation scenarios for NRW’s main energy-intensive industrial sub-sectors which served to support the implementation of the CPL. It also describes the process of scenario development, as these scenarios were developed through stakeholder participation. The scenarios considered three different pathways (best-available technologies, break-through technologies, and CO2 capture and storage). All pathways had optimistic assumptions on the rate of industrial growth and availability of low-carbon electricity. We find that a policy of "re-industrialisation" for NRW based on the current industrial structures (assumed here to represent an average growth of NRWs industrial gross value added (GVA) of 1.6% per year until 2030 and 0.6% per year from 2030 to 2050), would pose a significant challenge for the achievement of overall energy demand and German greenhouse gas (GHG) emission targets, in particular as remaining efficiency potentials in NRW are limited. In the best-available technology (BAT) scenario CO2 emission reductions of only 16% are achieved, whereas the low carbon (LC) and the carbon capture and storage (CCS) scenario achieve 50% and 79% reduction respectively. Our results indicate the importance of successful development and implementation of a decarbonised electricity supply and breakthrough technologies in industry - such as electrification, hydrogen-based processes for steel, alternative cements or CCS - if significant growth is to be achieved in combination with climate mitigation. They, however, also show that technological solutions alone, together with unmitigated growth in consumption of material goods, could be insufficient to meet GHG reduction targets in industry.
The industry sector accounted for just over 30% of global GHG emissions in 2010 and scenarios envisage a continuing rise in demand for energy-intensive materials. This article sums up the most recent international analysis (IPCC, IEA, UNIDO, Global Energy Assessment) to give a broad view of the current prospects for reducing GHG emissions in industry. It does so from a global perspective, complementing where necessary where regional and sector-specific case studies. The article addresses the portfolio of options available, their technical and economic potentials, the experience in the use of policy instruments in industry, the synergies and tradeoffs that mitigation in the industry sector can have with other policy objectives, and the specific concerns of developing countries. Long-term decarbonisation pathways for the sector are also presented.