LCA of CCS and CCU compared with no capture: How should multi-functional systems be analysed?

CCS (carbon capture and storage) is a means of reducing greenhouse gas emissions by capturing and subsequently storing the CO2, while CCU (carbon capture and utilisation) is a way of recycling the carbon in the captured CO2 by converting it into new products. CCS aims at improving the results for one environmental indicator while CCU represents a multi-functional system. It is therefore crucial, when comparing CCU with CCS or no capture, that more than one indicator is used. Also vital is the need to establish relevant system boundaries and to define a joint functional unit, so as to create a robust decision basis for the selection of the environmentally preferable option

Allocation of water consumption in multipurpose reservoirs

acceptedVersio

Review Calculation of Residual Electricity Mixes when Accounting for

energie

Life cycle greenhouse gas (GHG) emissions from the generation of wind and hydro power

This paper presents a comprehensive overview of the life cycle GHG emissions from wind and hydro power generation, based on relevant published studies. Comparisons with conventional fossil, nuclear and other renewable generation systems are also presented, in order to put the GHG emissions of wind and hydro power in perspective. Studies on GHG emissions from wind and hydro power show large variations in GHG emissions, varying from 0.2 to 152 g CO2-equivalents per kW h. The main parameters affecting GHG emissions are also discussed in this article, in relation to these variations. The wide ranging results indicate a need for stricter standardised rules and requirements for life-cycle assessments (LCAs), in order to differentiate between variations due to methodological disparities and those due to real differences in performance of the plants. Since LCAs are resource- and time-intensive, development of generic GHG results for each technology could be an alternative to developing specific data for each plant. This would require the definition of typical parameters for each technology, for example a typical capacity factor for wind power. Such generic data would be useful in documenting GHG emissions from electricity generation for electricity trading purposes.LCA Greenhouse gases Wind power Hydro power Electricity

Calculation of Residual Electricity Mixes when Accounting for the EECS (European Electricity Certificate System) — the Need for a Harmonised System

According to the Electricity Directive, suppliers of electricity must disclose their electricity portfolio with regards to energy source and environmental impact. This paper gives some examples of disclosure systems and residual electricity mixes in Norway, Sweden and Finland, compared to an approach based on a common regional disclosure. Disclosures based on the E-TRACK standard are presented, as well as the variation in CO2 emissions from different residual mixes. The results from this study clearly show that there is a need for a harmonised, transparent and reliable system for the accounting of electricity disclosure in Europe

Allocation of water consumption in multipurpose reservoirs

The Intergovernmental Panel on Climate Change Special Report on Renewable Energy Sources represented a benchmark in the assessment of water consumption from electricity production. The numbers for hydropower ranged from very low to much larger than the other renewable technologies, partly explained by methodological problems. One of the methodological shortcomings identified was the lack of guidance on how to allocate the water consumption rates in multipurpose reservoirs. This paper is, according to the authors’ knowledge, the first attempt to evaluate, test and propose a methodology for the allocation of water consumption from such reservoirs. We tested four different allocation methods in four different cases, all serving three to five functions, including drinking water supply, irrigation, flood control, industrial water, ecological flow and power generation. Based on our case studies we consider volume allocation to be the most robust approach for allocating water consumption between functions in multipurpose reservoirs. The spatial boundaries of the analysis should follow the boundaries of the hydraulic system. We recommend that data should preferably be gathered from one source for all functions, to ensure a consistent calculation approach. We believe the findings are relevant for similar allocation problems, such as allocation of energy investments and green-house gas emissions from multipurpose reservoirs