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Conventional wisdom suggests that energy efficiency (EE) policies are beneficial because they induce investments that pay for themselves and lead to emissions reductions. However, this belief is primarily based on projections from engineering models. This paper reports on the results of an experimental evaluation of the nation’s largest residential EE program conducted on a sample of more than 30,000 households. The findings suggest that the upfront investment costs are about twice the actual energy savings. Further, the model-projected savings are roughly 2.5 times the actual savings. While this might be attributed to the “rebound” effect – when demand for energy end uses increases as a result of greater efficiency – the paper fails to find evidence of significantly higher indoor temperatures at weatherized homes. Even when accounting for the broader societal benefits of energy efficiency investments, the costs still substantially outweigh the benefits; the average rate of return is approximately -9.5% annually.

Climate change is already affecting the cardiorespiratory health of populations around the world, and these impacts are expected to increase. The present overview serves as a primer for respirologists who are concerned about how these profound environmental changes may affect their patients. The authors consider recent peer‐reviewed literature with a focus on climate interactions with air pollution. They do not discuss in detail cardiorespiratory health effects for which the potential link to climate change is poorly understood. For example, pneumonia and influenza, which affect >500 million people per year, are not addressed, although clear seasonal variation suggests climate‐related effects. Additionally, large global health impacts in low‐resource countries, including migration precipitated by environmental change, are omitted. The major cardiorespiratory health impacts addressed are due to heat, air pollution and wildfires, shifts in allergens and infectious diseases along with respiratory impacts from flooding. Personal and societal choices about carbon use and fossil energy infrastructure should be informed by their impacts on health, and respirologists can play an important role in this discussion.

This study investigates the relationship between violent conflict, food price, and climate variability at the subnational level. Using disaggregated data on 113 African markets from January 1997 to April 2010, interrelationships between the three variables are analyzed in simultaneous equation models. We find that: (i) a positive feedback exists between food price and violence - higher food prices increase conflict rates within markets and conflict increases food prices; (ii) anomalously dry conditions are associated with increased frequencies of conflict; and (iii) decreased rainfall exerts an indirect effect on conflict through its impact on food prices. These findings suggest that the negative effects of climate variability on conflict can be mitigated by interventions and effective price management in local markets. Creating environments in which food prices are stable and reliable, and markets are accessible and safe, can lower the impacts of both climate change and conflict feedbacks.

This study highlights how Chinese economic development detrimentally impacted water quality in recent decades and how this has been improved by enormous investment in environmental remediation funded by the Chinese government. To our knowledge, this study is the first to describe the variability of surface water quality in inland waters in China, the affecting drivers behind the changes, and how the government-financed conservation actions have impacted water quality. Water quality was found to be poorest in the North and the Northeast China Plain where there is greater coverage of developed land (cities + cropland), a higher gross domestic product (GDP), and higher population density. There are significant positive relationships between the concentration of the annual mean chemical oxygen demand (COD) and the percentage of developed land use (cities + cropland), GDP, and population density in the individual watersheds (p < 0.001). During the past decade, following Chinese government-financed investments in environmental restoration and reforestation, the water quality of Chinese inland waters has improved markedly, which is particularly evident from the significant and exponentially decreasing GDP-normalized COD and ammonium (NH4+-N) concentrations. It is evident that the increasing GDP in China over the past decade did not occur at the continued expense of its inland water ecosystems. This offers hope for the future, also for other industrializing countries, that with appropriate environmental investments a high GDP can be reached and maintained, while simultaneously preserving inland aquatic ecosystems, particularly through management of sewage discharge.

Vor dem Hintergrund eines zunehmenden globalen Energiebedarfs und der Gefahr einer anthropogenen Störung des Klimasystems durch die Emission von Treibhausgasen gilt es, tragfähige Strategien und Perspektiven für eine nachhaltige Energieversorgung zu entwickeln. Der verstärkten Nutzung erneuerbarer Energien wird dabei vielfach eine Schlüsselrolle zur Bewältigung dieser Herausforderungen zugesprochen. Einer weit verbreiteten Ausschöpfung der auch in Deutschland in großem Maße verfügbaren Potenzialen an regenerativen Energieträgern stehen jedoch häufig noch die damit verbundenen hohen Kosten im Vergleich zu fossilen Energieträgern entgegen. Ziel der vorliegenden Arbeit ist es daher zu untersuchen, welchen Beitrag erneuerbare Energieträger in einem wettbewerblichen Marktumfeld langfristig zur Energieversorgung leisten können und in welchem Umfang erneuerbare Energieträger durch die Internalisierung der Treibhausgasvermeidungskosten in den Energiepreisen profitieren können. Zur Bewertung der Rolle erneuerbarer Energieträger sind mit Blick auf das Gesamtenergiesystem Interdependenzen zwischen der Nutzung erneuerbarer Energieträger und den übrigen Sektoren des Energiesystems zu berücksichtigen. Neben der Vernetzung des Energiesystems in horizontaler Richtung durch Prozessketten über Sektoren hinweg und in vertikaler Richtung durch die Konkurrenz regenerativer mit fossilen Energietechnologien sind dabei auch Kopplungen über Energiepreise, deren Höhe über die Wettbewerbsfähigkeit einer regenerativen Energietechnologie entscheidet, sowie die energie- und preisseitigen Effekte durch Einführung energiepolitischer Instrumente zu beachten. Aufgrund dieser Systemzusammenhänge wird daher ein auf dem Ansatz der linearen Programmierung basierendes intertemporales Energiesystemmodell verwendet, in dem die Energiewirtschaft Deutschlands von der Primär- bis zur Nutzenergie technologisch detailliert abgebildet und hinsichtlich der Systemkosten optimiert wird. Um die Wechselwirkungen innerhalb des Energiesystems aufzuzeigen, werden sich z. T. ergänzende methodische Verfahren entwickelt und eingesetzt. Neben einem Bilanzierungsmodell zur Ermittlung von die Prozessvorketten berücksichtigender Indikatoren zählen hierzu ein auf der Dualitätstheorie beruhendes Verfahren zur Dekomposition der Energie- und Zertifikatspreise, Methoden der Sensitivitätsanalyse zur Ermittlung der fundamentalen preisbestimmenden Faktoren und Techniken der parametrischen Programmierung, um neben Variationen der Modelleingangsdaten Treibhausgasvermeidungskostenkurven und Angebotskurven regenerativ erzeugten Stroms unter Berücksichtigung der systemaren Zusammenhänge im Energiesektor abzuleiten. Mit Hilfe des entwickelten Energiesystemmodells und der Analysemethoden werden die zukünftigen Entwicklungsperspektiven erneuerbarer Energien im deutschen Energiesystem bis zum Jahr 2050 szenariogestützt untersucht. In den Szenarien werden einerseits die mit einer Quote erneuerbarer Energien in der Stromerzeugung verbundenen energie-, kosten- und emissionsseitigen Auswirkungen betrachtet und andererseits der Beitrag erneuerbarer Energien in Konkurrenz mit alternativen Minderungsoptionen zur Erreichung von Treibhausgasminderungszielen dargestellt. Weiterhin werden in simultanen Variationen die Wechselwirkungen zwischen beiden Instrumenten und ihre Auswirkungen speziell auf die Stromerzeugungsstruktur und die Strompreise beleuchtet. Against the background of an increasing global energy demand and the danger of an anthropogenic disturbance of the climate system by the emission of greenhouse gases, it is necessary to develop sustainable strategies and perspectives for the future energy system. The increased usage of renewable sources is identified from many sides as a key element in strategies to overcome these challenges. However, a widely utilisation of the also in Germany large existing potentials of renewable energy carriers is currently still opposed by the associated high costs relative to fossil energy sources. The intention of the submitted thesis is to analyse the contribution of renewable energy sources in the long-run under competitive market conditions to the energy supply and to study the extent to which renewable energy sources can benefit from the internalisation of greenhouse gas abatement costs in the energy prices. To assess the role of renewable energy sources in the context of the entire energy system, interdependencies between the utilisation of renewable energy sources with other aspects and sectors of the energy system have to be taken into account. In addition to the interconnectedness of the energy system in the horizontal direction by process chains across sectors and in the vertical direction by the competition of renewable with conventional fossil technologies also the linkage by energy prices, which serve as benchmark for the competitiveness of a renewable energy technology, and the energy and price related effects caused by the introduction of policy instruments have to be considered. Due to these interactions within the system, a linear programming based dynamic energy system model is used, which depicts technologically detailed the German energy sector from the primary energy supply to the end-use energy demand side and optimises the energy system with respect to its total costs. In order to reveal the interactions and dependencies within the energy system, several partially complementary methodologies have been developed and applied to the model. Apart from a balance model that allows the calculation of specific indicators under consideration of previous process chains, the methodology comprises a method for decomposing energy and certificate prices based on the duality theory, the method of sensitivity analysis to identify the fundamental price-determining activities and parametric programming techniques to derive greenhouse gas abatement cost curves and renewable electricity supply cost curves. With the help of the developed energy system model and analysis tools, the future development perspectives of renewable energy in the German energy system until the year 2050 are studied in various scenarios. In these scenarios, on the one side the energy-, cost- and emission related effects associated with a quota for the electricity production from renewable sources are studied, on the other side the contribution of renewable energy sources to given greenhouse gas abatement targets in competition with alternative abatement measures is examined. Furthermore the interdependencies between these two policy instruments on each other and their effects on the structure of the electricity sector and on the electricity prices are highlighted.

Abstract The housing growth programme could offer an opportunity for accelerating the deployment of decentralised renewable energy systems (DRES) in the UK. The Government hopes to leverage private sector investment into DRES as part of new housing projects. The aim of this paper is to assess whether current regulatory and funding frameworks are sufficient to achieve this. The question is explored by drawing on the experience of developers, local authorities, energy utilities and service companies operating in the largest housing growth region in the UK–Thames Gateway. Their experience suggests that the current low intervention approach will be insufficient to generate the shift required in both industries. In order to be more successful economic and regulatory instruments should focus on producers (house-builders and energy providers) rather than consumers (households). Tighter regulation is needed to ensure that producers have a responsibility to install DRES as part of new developments, to enable connection to the grid, to ensure a sustained financial return from investment and revenue is spent on the expansion of new renewable energy infrastructure. This regulatory framework must be under-pinned by substantial funds focused on producers. Greater intervention is needed if DRES is to be included in new housing development.

The assessment of the ‘quality’ of built heritage is a complex transdisciplinary issue, which both public administrations and real estate developers need to carefully consider when making any interventions. Recent international climate regulations underline that currently around 75% of buildings in the EU are not energy efficient. In Italy, those inefficient buildings are more than 50 years old and, if subjected to retrofit interventions, risk being totally transformed and losing their historical value in favor of a more contemporary use. This work aimed to study the residential heritage of the second half of the 20th century in the real estate market and to understand if, how, and in what measure the building and architectonical qualities are recognized and monetized by buyers. The city of Turin was chosen as a study area, and residential building qualities were analyzed using two quality indicators to perform a GWR on market POIs. The results highlighted that housing historical qualities are not homogeneously recognized by the real estate market, in favor of green ones. This work can help both public and private bodies to identify which ‘invisible’ quality residential buildings are immediately exploitable for enhancement strategies, with more respectful retrofitting interventions and a modern protection policy.