Bioenergy with Carbon Capture and Sequestration (BECCS): The Distracting Injustice of an Infeasible and Unlikely Technofix

Smolker, Rachel

doi:10.1057/s41301-019-00213-4

Cited by 10 publications

(1 citation statement)

References 7 publications

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“…As the main NET, BECCS has been the subject of several peer-reviewed articles describing what it is, its technoeconomic characterization, and its application in climate scenarios [5,[12][13][14][15][16]. A few articles have attempted to describe its value as a mitigation technology [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

The Value of BECCS in IAMs: a Review

Köberle

2019

Curr Sustainable Renewable Energy Rep

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Purpose of Review Integrated assessment model (IAM) scenarios consistent with Paris Agreement targets involve large negative emission technologies (NETs), mostly bioenergy with carbon capture and storage (BECCS). Such reliance on BECCS implies IAMs assign it a high value. Past analyses on the value of BECCS in IAMs have not explicitly addressed the role of model structure and assumptions as value drivers. This paper examines the extent to which the value of BECCS in IAMs is enhanced by model structure constraints and assumptions. Recent Findings Predominant use of high discount rates (3.5-5%) means models opt for delayed-action strategies for emissions mitigation that lead to high levels of cumulative net-negative emissions, while lower discount rates lead to reduce reliance on NETs. Until recently in the literature, most models limited NET options to only BECCS and afforestation, but introduction of other CDR options can reduce BECCS deployment. Constraints on grid penetration of variable renewable energy (VRE) is a determining factor on the level of BECCS deployment across models, and more constrained grid penetration of VREs leads to more BECCS in electricity generation. Summary This paper concludes BECCS derives significant value not only from the existing structure of IAMs but also from what is not represented in models and by predominant use of high discount rates. Omissions include NETs other than BECCS and deforestation, low-carbon innovation in end-use technologies, grid resilience to intermittent sources, and energy use in agriculture production. As IAMs increasingly endogenize such constraints, the value of BECCS in resulting scenarios is likely to be dampened.

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Section: Introductionmentioning

confidence: 99%

The Value of BECCS in IAMs: a Review

Köberle

2019

Curr Sustainable Renewable Energy Rep

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Retinal specificity in eye fragments: investigations on the retinotectal projections of different quarter-eyes in Xenopus laevis

Brändle

Degen

1994

Exp Brain Res

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According to Sperry's chemoaffinity hypothesis, the projection of a small eye fragment with a reduced amount of optic fibres should be restricted to that position in the optic tectum corresponding to its own specificity. However, previous investigations on different types of quarter-eyes in Xenopus laevis have revealed that their retinal projection was always restricted to the rostral part of the tectum, no matter what the origin of the remaining retinal quadrant. To get an indication of the state of specificity in such eye fragments, we investigated by electrophysiological and histological methods several features of the retinal projections of tempo-roventral (TV), naso-ventral (NV) and ventral (V) quarter-eyes which referred to their positional identity. Irrespective of their different origins, the projections were always located in the rostral part of the tectum, the size of the innervated tectal area depending for all fragment types on the size of the quarter-eyes, i.e. number of optic fibres. However, quantitative analyses revealed that with increasing eye size the various fragments expand their projections preferentially into those tectal areas that match their original specificity: TV projection is more concentrated in the rostral tectum, NV eyes expand their projections mainly to the caudal tectum, and V eyes enlarge their projections equally into the medial and caudal tectum. In addition, fibre-tracing experiments with cobaltic lysine showed that, according to the different origins of the quarter-eyes, retinal fibres follow the appropriate branch of the optic tract selectively: fibres of NV and V eyes pass mainly through the medial tract, and most fibres of TV eyes innervate the rostral tectum directly from a central position between the two side branches. All these findings suggest that the different types of quarter-eyes retain their original positional identity. Thus, their rostrally located retinotectal projections are not in register with their retinal specificity. We conclude that in X. laevis local positional markers in the tectum, if present at all, do not influence the development of the retinotectal projection. Instead we suggest a concept of self-sorting of the optic fibres, which can account for the partial innervation of the rostral tectum in different types of quarter-eyes.

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Post-metamorphic retinal growth in Xenopus

Straznicky

Hiscock

1984

Anat Embryol

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The postmetamorphic growth of the retina in Xenopus was studied using 3H-thymidine ( 3HT ) autoradiography and quantitative morphometric assays. 3HT was administered to tadpoles at stages 58, 62 and 66 and the animals sacrificed between 3 weeks and 12 months after metamorphosis. Reconstructions were made from serial sections and the position of labelled cell groups in the retina were established. On the reconstructed retina, regions formed up to stage 58, between stages 58 and 66 and after metamorphosis were measured. The area of the dorsal, ventral, temporal and nasal retinal halves was also determined from stage 58 through to adult. The entire retinal area increased 10-fold from stage 58 to 12 months after metamorphosis, the fastest growing region being the retinal periphery due to continuous cell addition at the ciliary margin. Concommitant with the retinal area growth, the number of ganglion cells increased from 20,000 to 85,000 over the time of investigation. Asymmetric cell addition to the ciliary margin from stage 58 onwards resulted in a predominantly crescentic retinal growth along the nasoventral ciliary margin. Consequently, the optic nerve head became displaced away from the geometric centre of the eye into the dorso-temporal retinal quadrant. These results suggest that besides a sustained cell production exclusively at the ciliary margin, a passive area expansion contributes to the overall retinal growth from the metamorphic climax to adulthood. It is also apparent that the steady increase of the number of retinal ganglion cells and optic fibers necessitates a continuous remodelling of the retinotectal connections throughout the lifespan of the animal.

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Bioenergy with Carbon Capture and Sequestration (BECCS): The Distracting Injustice of an Infeasible and Unlikely Technofix

Cited by 10 publications

References 7 publications

The Value of BECCS in IAMs: a Review

The Value of BECCS in IAMs: a Review

Retinal specificity in eye fragments: investigations on the retinotectal projections of different quarter-eyes in Xenopus laevis

Post-metamorphic retinal growth in Xenopus

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