Reply to C. K. Brooks

Abstract

Reply When writing that some petrologists have chosen to get around the problem caused by oxidation of Fe-Ti-oxides during the initial cooling of basalts by using an arbitrary value of the Fe203/FeO ratio instead of the one given by the analysis, it was not my intention to disparage the aims of petrologists concerned with genetic problems - rather to make a suggestion I hope will be helpful....

Life Cycle Assessment of an Advanced Bioethanol Technology in the Perspective of Constrained Biomass Availability

“…We have assessed the physical biomass availability on a European and global scale toward 2030. A European perspective is relevant since biofuel trade is to some extent regionally oriented, and a global perspective has relevance since the market for liquid biofuels and for some solid biofuels (wood pellets, wood chips, tree trunks, and straw pellets) is expected to become very internationally oriented in the future .…”

“…The power plant integration means that in periods with low or no district heating demand, steam for the bioethanol process can be extracted from the power plant with low or no additional fuel use. As a result of this synergy effect, the average fossil fuel consumption for producing steam for the ethanol process is low (approximately 0.60 GJ coal/GJ steam) compared to using a separate boiler . However, it is questionable whether the gain of this synergy effect can be attributed to the ethanol production, since alternative utilizations of the low fuel steam extraction exist, and since a longer term aim of the energy system infrastructure is to plan for reducing these excess heat losses from power production.…”

“…The assessment concerns whole-crop based bioethanol production, representing a large-scale production stretching further than use of biomass residues or waste. In order for bioethanol to become a major global transport fuel, energy crop production in temperate regions would also be required . Against this background, energy crop production in a temperate climate, represented by Danish conditions, is considered.…”

“…For biogas production, whole-crop maize is assumed used as well, while the perennial crop, willow, is applied for heat and power production. The biomass technologies compared are currently at pilot or demonstration scale and are expected to reach commercial level toward 2030 , .…”

“…The system delimitation in all of the above studies is, however, inadequate for supporting decisions on bioethanol, because the implications of the constraints on the biomass and land resources are ignored. Only three studies are known to adequately consider the implications of biomass constraints − , and the results of these studies do not suggest an environmental benefit of bioethanol. This article is based on these studies.…”