• Energy Research
• Restricted close
• CH close
• GB close
• AU close
• ETH Zurich close

The potential for global forest cover The restoration of forested land at a global scale could help capture atmospheric carbon and mitigate climate change. Bastin et al. used direct measurements of forest cover to generate a model of forest restoration potential across the globe (see the Perspective by Chazdon and Brancalion). Their spatially explicit maps show how much additional tree cover could exist outside of existing forests and agricultural and urban land. Ecosystems could support an additional 0.9 billion hectares of continuous forest. This would represent a greater than 25% increase in forested area, including more than 200 gigatonnes of additional carbon at maturity.Such a change has the potential to store an equivalent of 25% of the current atmospheric carbon pool. Science , this issue p. 76 ; see also p. 24

Shallow Geothermal Systems (SGS) are widely used to provide low-cost heating and cooling of residential and commercial buildings. SGS can be an economically-viable solution even for commercial buildings, where controlled temperature is fundamental for the production processes. To assess the thermal resistance of the soil and the performance of a SGS, Thermal Response Tests (TRT) must be performed. TRT machines are today designed mainly for short term monitoring, for relatively deep SGS (up to 200 m) and for being used by expert operators. Lightweight, low-cost machines for both fast and long term, reliable and unattended TRT for very Shallow Geothermal Systems (vSGS) are not available today. This paper describes the design of a micro-TRT machine (mTRT) for vSGS, which is gaining interest in the civil engineering, environmental, energy and food chain sectors. The paper describes the features of the wireless monitoring system, the design choices to achieve the required accuracy and the software developed for adding remote control capability. Experimental validation in a real test field demonstrates the quality of measurements collected for analysing the TRT data.

Nordhaus (1973) has in his seminal contribution addressed two emerging questions in the field of energy economics. First, how do current market prices of natural resources reflect true scarcity fro...

AbstractWe have investigated the spectroscopic properties (absorption spectra, emission spectra, emission lifetimes) of three triads in CH2Cl2: C2‐M‐C2, C343‐M‐C343, and C2‐M‐C343, in which M is a shape‐persistent macrocyclic hexagonal backbone composed of two 2,2′‐bipyridine (bpy) units embedded in opposing sides, and C2 and C343 are coumarin 2 and coumarin 343, respectively. All the components are strongly fluorescent species (Φ=0.90, 0.79, and 0.93 for M, C2, and C343, respectively, as established by investigating suitable model compounds). In each triad excitation of M leads to almost quantitative energy transfer to the lowest coumarin‐localised excited state. Upon addition of acid, the two bpy units of the M component undergo independent protonation leading to monoprotonated (e.g., C2‐M⋅H+‐C2) and diprotonated (e.g., C2‐M⋅2 H+‐C2) species. Further addition of acid leads to protonation of the coumarin component so that each triad is involved in four protonation equilibria. Protonation causes strong (and reversible, upon addition of base) changes in the absorption and fluorescence properties of the triads because of inversion of the excited‐state order and/or the occurrence of electron‐transfer quenching processes.

Life Cycle Assessment is a tool to assess the environmental impacts and resources used throughout a product's life cycle, i.e., from raw material acquisition, via production and use phases, to waste management. The methodological development in LCA has been strong, and LCA is broadly applied in practice. The aim of this paper is to provide a review of recent developments of LCA methods. The focus is on some areas where there has been an intense methodological development during the last years. We also highlight some of the emerging issues. In relation to the Goal and Scope definition we especially discuss the distinction between attributional and consequential LCA. For the Inventory Analysis, this distinction is relevant when discussing system boundaries, data collection, and allocation. Also highlighted are developments concerning databases and Input-Output and hybrid LCA. In the sections on Life Cycle Impact Assessment we discuss the characteristics of the modelling as well as some recent developments for specific impact categories and weighting. In relation to the Interpretation the focus is on uncertainty analysis. Finally, we discuss recent developments in relation to some of the strengths and weaknesses of LCA.

The future trajectory of greenhouse gas concentrations depends on interactions between climate and the biogeosphere. Thawing of Arctic permafrost could release significant amounts of carbon into the atmosphere in this century. Ancient Ice Complex deposits outcropping along the ~7,000-kilometre-long coastline of the East Siberian Arctic Shelf (ESAS), and associated shallow subsea permafrost, are two large pools of permafrost carbon, yet their vulnerabilities towards thawing and decomposition are largely unknown. Recent Arctic warming is stronger than has been predicted by several degrees, and is particularly pronounced over the coastal ESAS region. There is thus a pressing need to improve our understanding of the links between permafrost carbon and climate in this relatively inaccessible region. Here we show that extensive release of carbon from these Ice Complex deposits dominates (57 ± 2 per cent) the sedimentary carbon budget of the ESAS, the world’s largest continental shelf, overwhelming the marine and topsoil terrestrial components. Inverse modelling of the dual-carbon isotope composition of organic carbon accumulating in ESAS surface sediments, using Monte Carlo simulations to account for uncertainties, suggests that 44 ± 10 teragrams of old carbon is activated annually from Ice Complex permafrost, an order of magnitude more than has been suggested by previous studies. We estimate that about two-thirds (66 ± 16 per cent) of this old carbon escapes to the atmosphere as carbon dioxide, with the remainder being re-buried in shelf sediments. Thermal collapse and erosion of these carbon-rich Pleistocene coastline and seafloor deposits may accelerate with Arctic amplification of climate warming.

Photovoltaics (PV)-coupled battery energy storage systems (BESSs) are becoming more popular due to the reduction of BESS costs as well as the decreased remuneration of PV grid injection over the last few years. This paper compares the techno-economic system performance of two sizing approaches of PV-coupled BESSs - using mixed integer linear programming - for a case study in the Netherlands. The first approach uses a static sizing methodology to size the BESS based on the daily PV grid injection. While the second approach considers the BESS energy and power capacity as decision variables in an optimization problem to optimally size the BESS. The results demonstrate that the total costs can be reduced by 41% with our second approach - when the BESS is optimally sized considering annual demand and generation profiles.