Summary: Bringing about more sustainable consumption patterns is an important challenge for society and science. In this article the concept of household metabolism is applied to analyzing consumption patterns and to identifying possibilities for the development of sustainable household consumption patterns. Household metabolism is determined in terms of total energy requirements, including both direct and indirect energy requirements, using a hybrid method. This method enables us to evaluate various determinants of the environmental load of consumption consistently at several levels—the national level, the local level, and the household level. The average annual energy requirement of households varies considerably between the Netherlands, the United Kingdom, Norway, and Sweden, as well as within these countries. The average expenditure level per household explains a large part of the observed variations. Differences between these countries are also related to the efficiency of the production sectors and to the energy supply system. The consumption categories of food, transport, and recreation show the largest contributions to the environmental load. A comparison of consumer groups with different household characteristics shows remarkable differences in the division of spending over the consumption categories. Thus, analyses of different types of households are important for providing a basis for options to induce decreases of the environmental load of household consumption. At the city level, options for change are provided by an analysis of the city infrastructure, which determines a large part of the direct energy use by households (for transport and heating). At the national level, energy efficiency in production and in electricity generation is an important trigger for decreasing household energy requirements.

The production of concrete is one of the most significant contributors to global greenhouse gas emissions. This work focuses on bio-cementation-based products and their potential to reduce global warming potential (GWP). In particular, we address a proposed bio-cementation method employing bacterial metabolism in a two-step process of limestone dissolution and recrystallisation (BioZEment). A scenario-based techno-economic analysis (TEA) is combined with a life cycle assessment (LCA), a market model and a literature review of consumers’ willingness to pay, to compute the expected reduction of global GWP. Based on the LCA, the GWP of 1 ton of BioZEment is found to be 70–83% lower than conventional concrete. In the TEA, three scenarios are investigated: brick, precast and onsite production. The results indicate that brick production may be the easiest way to implement the products, but that due to high cost, the impact on global GWP will be marginal. For precast production the expected 10% higher material cost of BioZEment only produces a marginal increase in total cost. Thus, precast production has the potential to reduce global GWP from concrete production by 0–20%. Significant technological hurdles remain before BioZEment-based products can be used in onsite construction scenarios, but in this scenario, the potential GWP reduction ranges from 1 to 26%. While the potential to reduce global GWP is substantial, significant efforts need to be made both in regard to public acceptance and production methods for this potential to be unlocked.

The production of concrete for construction purposes is a major source of anthropogenic CO₂ emissions. One promising avenue towards a more sustainable construction industry is to make use of naturally occurring mineral-microbe interactions, such as microbial-induced carbonate precipitation (MICP), to produce solid materials. In this paper, we present a new process where calcium carbonate in the form of powdered limestone is transformed to a binder material (termed BioZEment) through microbial dissolution and recrystallization. For the dissolution step, a suitable bacterial strain, closely related to Bacillus pumilus, was isolated from soil near a limestone quarry. We show that this strain produces organic acids from glucose, inducing the dissolution of calcium carbonate in an aqueous slurry of powdered limestone. In the second step, the dissolved limestone solution is used as the calcium source for MICP in sand packed syringe moulds. The amounts of acid produced and calcium carbonate dissolved are shown to depend on the amount of available oxygen as well as the degree of mixing. Precipitation is induced through the pH increase caused by the hydrolysis of urea, mediated by the enzyme urease, which is produced in situ by the bacterium Sporosarcina pasteurii DSM33. The degree of successful consolidation of sand by BioZEment was found to depend on both the amount of urea and the amount of glucose available in the dissolution reaction.

Purpose – The purpose of this paper is to identify households' barriers to energy saving solutions. Six types of barriers are introduced. The question to be answered is: what is the strength and relevance of the various barriers for changing consumer energy behaviour? Design/methodology/approach – The method is focus group interviews. Focus groups do not aim at giving a representative picture of the population at large, but aim at recording and documenting a wide range of typical responses and reactions. The focus groups were recruited among a group of people who were actively looking for new dwellings and a reference group of environmentally conscious participants. Findings – Three barriers out of the six proposed were found to be relevant in this study: Cultural-normative, economic and information. Research limitations/implications – Energy saving solutions are technically and socially complex matters, so it is important to advice and guide consumers to make changes that contribute substantially, rather than mere symbolic changes. Practical implications – The finding that consumers not only need information on what and how to save energy, but also need help in identifying when they should do their investments is important for various actors involved in implementation of energy saving solutions. Originality/value – Measures in the field of energy savings have had various successes. This article which concentrates on the barriers in this field can contribute to increased success rates.

This article focuses on one important ethical and political element in the development of nanotechnologies: the relevance and importance of the precautionary principle. The principle recommends political actions based upon experiences and early scientific warnings, even when there is no clear scientific evidence to prove causal links. Our chief contribution to the discussion about the precautionary principle in nanotechnologies is the development of the stakeholder approach in a governance perspective. We link our article to the theoretical and empirical discussions on risk society. In at least two ways the risk society of Ulrich Beck seems highly relevant for the precautionary principle within nanotechnologies: Precautionary actions represent one model for the society to deal with modern risks; and Beck redefined the relation between science and society. This article is based upon qualitative interviews with four groups of stakeholders in Norway: (1) non-governmental organizations—consumer, environment, health; (2) political authorities and politicians; (3) industry and businesses; and (4) the scientific community. In the present phase of the development of nanotechnologies, the responsibility for taking precautionary actions are, to a large extent, placed on the individual researcher and the scientific community. We have identified seven issues in the interviews that are pertinent for the scientific and political discourse about nanotechnologies.