Business model innovations for renewable energy prosumer development in Germany

In Germany, the number of renewable energy prosumers has increased rapidly since 2000. However, the development of prosumers has faced and will continue to face various economic, social, and technological challenges, which have triggered the emergence of a number of innovative business models (BM). This paper enriches the empirical basis for prosumer-oriented BMs by investigating two BM innovations in Germany (P2P electricity trading and aggregation of small-size prosumers) drawing on business model and socio-technical transition theories. A mix of qualitative data collection methods, including document analysis and semi-structured expert interviews, was applied. We found that while both BMs can potentially address the challenges associated with renewable energy prosumer development in Germany, small-scale prosumers’ participation in both BMs has been limited so far. We identified various internal and external drivers and barriers for scaling up these BMs for prosumer development in Germany. Despite these barriers, both aggregation and centralized P2P targeting prosumers may potentially be also taken up by incumbent market actors such as utilities. Decentralized P2P on the other hand still faces significant internal and external barriers for upscaling. Based on the analysis, the paper provides policy recommendations with respect to the identified drivers and barriers. From a theoretical perspective, our findings provide further evidence to challenge the dichotomous understanding of niche actors and incumbents, the latter of which are often theorized to be resistant to radical innovations

Ensuring an effective global stocktake with a sectoral perspective

A sectoral perspective can help the Global Stocktake (GST) to effectively achieve its objective to inform Parties' in enhancing subsequent NDCs and in enhancing international cooperation. Specifically, granular and actionable sectoral lessons, grounded in country-driven assessments, should be identified and elaborated. To be effective, conversations on sectoral transformations need to synthesise key challenges and opportunities identified in the national analyses and link them to international enablers; focus on systemic interdependencies, involve diverse actors, and be thoroughly prepared including by pre-scoping points of convergences and divergence across transformations. We specifically recommend that: the co-facilitators of the Technical Dialogue use their (limited) mandate to facilitate an effective conversationon sectoral transformations e.g. by organising dedicated informal seminars in between formal negotiation sessions; key systemic transformations necessary toachieve net-zero by mid-century should be spelled out and included in the final decision or political declaration of the GST; and the political outcome of the GST should mandate follow-up processes at the regional level and encourage national-level conversations to translate the collective messages from GST into actionable and sector-specific policy recommendations

Hubble Space Telescope WFC3 Early Release Science: Emission-Line Galaxies from Infrared Grism Observations

We present grism spectra of emission-line galaxies (ELGs) from 0.6-1.6 microns from the Wide Field Camera 3 on the Hubble Space Telescope. These new infrared grism data augment previous optical Advanced Camera for Surveys G800L 0.6-0.95 micron grism data in GOODS-South from the PEARS program, extending the wavelength covereage well past the G800L red cutoff. The ERS grism field was observed at a depth of 2 orbits per grism, yielding spectra of hundreds of faint objects, a subset of which are presented here. ELGs are studied via the Ha, [OIII], and [OII] emission lines detected in the redshift ranges 0.2<z<1.4, 1.2<z<2.2 and 2.0<z<3.3 respectively in the G102 (0.8-1.1 microns; R~210) and G141 (1.1-1.6 microns; R~130) grisms. The higher spectral resolution afforded by the WFC3 grisms also reveals emission lines not detectable with the G800L grism (e.g., [SII] and [SIII] lines). From these relatively shallow observations, line luminosities, star-formation rates, and grism spectroscopic redshifts are determined for a total of 48 ELGs to m(AB)~25 mag. Seventeen GOODS-South galaxies that previously only had photometric redshifts now have new grism-spectroscopic redshifts, in some cases with large corrections to the photometric redshifts (Delta(z)~0.3-0.5). Additionally, one galaxy had no previously-measured redshift but now has a secure grism-spectroscopic redshift, for a total of 18 new GOODS-South spectroscopic redshifts. The faintest source in our sample has a magnitude m(AB)=26.9 mag. The ERS grism data also reflect the expected trend of lower specific star formation rates for the highest mass galaxies in the sample as a function of redshift, consistent with downsizing and discovered previously from large surveys. These results demonstrate the remarkable efficiency and capability of the WFC3 NIR grisms for measuring galaxy properties to faint magnitudes and redshifts to z>2.Comment: Accepted for publication in AJ. Updated to include referee comments. Updated sample using improved reduction contains 23 new galaxies (Table 1; Figures 2 & 3

Ensuring an Effective Global Stocktake with a Sectoral Perspective

A sectoral perspective can help the Global Stocktake (GST) to effectively achieve its objective to inform Parties' in enhancing subsequent NDCs and in enhancing international cooperation. Specifically, granular and actionable sectoral lessons, grounded in country-driven assessments, should be identified and elaborated. To be effective, conversations on sectoral transformations need to synthesise key challenges and opportunities identified in the national analyses and link them to international enablers; focus on systemic interdependencies, involve diverse actors, and be thoroughly prepared including by pre-scoping points of convergences and divergence across transformations

Spintronics: Fundamentals and applications

Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes from the published versio