Geothermal Energy Challenge Fund: the Guardbridge Geothermal Technology Project

GEOTHERMAL ENERGY CHALLENGE EXECUTIVE SUMMARY This feasibility study investigates whether a geothermal district heating system, which accesses Hot Sedimentary Aquifer (HSA) resources underlying a brownfield site at Guardbridge in northeast Fife, can be developed in a cost-effective manner. This project’s scope is to assess the available geological information and estimate the hot saline aquifer heat supply, calculate the current heat demand at the Guardbridge site, Guardbridge village, and the nearby towns of Leuchars and Balmullo, and to incorporate future Guardbridge development plans (provided by the University of St Andrews) and anticipated growth in housing stock (from Fife Council) to estimate future heat demand. The capital, maintenance and repair costs for the geothermal well and designed district heating network are used to develop economic models for a number of district heat network scenarios. A key aspect of this study is an evaluation of the opportunities to cost effectively de-risk deep geothermal exploration in Central Scotland, and to outline the potential for developing geological heat storage systems. The study identifies the key legislative and environmental issues, risks and uncertainties associated with any exploration and production, involves stakeholder engagement, and makes recommendations for a Phase 2 stage for geothermal heat development at Guardbridge. Two of the key outputs from this feasibility study will be an economic model and business case based on different heat demand options, and an optimised model of well design based on different exploration strategies. Both are transferable to similar operations at other geothermal sites. The key objectives are therefore to: (a)design a geothermal well that will be drilled in Phase 2 of the project, and secure valuable information on Fife regional sub-surface geology and geothermal properties of the primary aquifer, (b)explore how advanced drilling techniques, such as directional drilling, can be deployed to improve geothermal recovery, (c) demonstrate how a geothermal system can integrate with an existing biomass heating installation to optimise both schemes and provide a district heat network for on-site industries and the local community, (d)evaluate the potential for storage of seasonal heat energy in the subsurface (a first in Scotland), and (e)assess the relative merits of water treatment and on-site recycling, reinjection or disposal to sea. A regional geological model was constructed using available data from the British Geological Survey, published data and academic theses. The sub-surface geology was interpreted from surface geology and extrapolating the local behaviour of geological structures into the Guardbridge area. Modelling the geology involved defining the orientation and width of a natural fault zone, which could be a significant influence on the behaviour of the Hot Sedimentary Aquifers. The rock units of interest in this study are the Upper Devonian Scone Sandstone, Glenvale Sandstone, Knox Pulpit and Kinnesswood formations, and the latter two units are previously identified as having the highest potential to be highly productive aquifers. The presence of a major fault near the Guardbridge site means that the target aquifers are at very different depths on either side of the fault. The report therefore investigates and evaluates three well options to target the different aquifers at the varying depths on either side of the fault. Hydrogeological modelling was conducted using FEFLOW® to evaluate the behaviour of the fault on fluid flow rates, and to predict the necessary conductivities to produce reasonable, economic and sustainable rates of fluid extraction. Although not an accurate model of the Guardbridge site, and limited by a significant lack of data constraining the important parameters, the flow simulations suggest that fracture permeability in the aquifers and underlying rocks is needed to sustain the flows recommended by this study, and re-injection would be required if a producing well was to be sustainable over many decades. Regionally developed rock quality predictors have been used to estimate the permeability and temperature of the target aquifer intervals in the three selected well options at, or near, Guardbridge. Oil field well simulation tools have been used to estimate water flow rates, temperature profiles, and circulating rates from different geological models of the wells. Two of the wells, GB-1 and ES-1, are not expected to penetrate enough high permeability sandstone to support the minimum water flow rates of 5 l/s and so are ruled out as viable aquifer producers. GB-2 is a deviated well that penetrates the Kinnesswood and Knox Pulpit formations, the best quality regional aquifers, in a zone where the fault may enhance the permeability even more, and has potential to supply 5 to 20 l/s of water at a surface temperature of 25 oC (± 2 oC). Such a well will be produced using an electric submersible pump which will require 20 - 40 kw of power to deliver 15 l/s of flow (although the volumetric rate will vary with the rock quality). GB-2 is taken forward and drilling designs are provided with three outcomes: 1) a dry hole scenario; 2) a 5 l/s scenario; and, 3) a 15 l/s scenario. The vertical wells have been modelled as heat pump circulating wells, and therefore would not produce any aquifer water at the surface. Only deeper wells, up to 2500 m, have the potential to give surface temperature increase of 5 oC at reasonable circulation rates (e.g. 8 l/s). A deep GB-1 well as a heat pump could be taken forward in Phase 2 as an alternative heat source. The proposed GB-2 deviated well can be drilled across the fault from the Guardbridge site to a depth of 1200 m. A casing string set will isolate the shallow geology and a slotted liner used to prevent hole collapse of the target intervals. Such a well will require a 100 tonne conventional drilling rig and well control, logging and coring tools will assess the aquifer quality. In the most likely case, the drilling phase will take 24 days, including rig mobilisation and demobilisation. If coring and logging demonstrate that the well will not flow adequately, then the well will be suspended. Low cost options have been investigated that would allow exploratory wells to be drilled and this could result in the recovery of regionally significant data on the performance of the aquifers at depth, although none of the boreholes could be completed to production stage due the drilling technology employed. The drilling scenarios investigated do not include a re-injection well, in order to create an economically viable district heating network project, even though very preliminary hydrogeological modelling demonstrates that re-injection is required if the geothermal well is to be sustainable over 30+ years. Alternative management of produced water investigated in this report are: water disposal-tosea and partial-full water recycling and re-use on site. The first option could have environmental consequences on the adjacent Eden Estuary, which is part of the Tay River and Eden Estuary Special Protection Area, and these potential impacts would need formal assessment by a competent authority (Fife Council and SNH) as part of a Habitat Regulations Appraisal, and an Environmental Impact Assessment is most likely required. The second option reduces the environmental impacts on the estuary, but has additional CAPEX and OPEX costs which are estimated. The opportunity to be innovative about partial water recycling and resale should be investigated in Phase 2. The heat demand is based on preliminary district heating network layouts at different scales, based on the demand analysis. Demand has been assessed at Guardbridge and the nearby towns of Leuchars and Balmullo, using the Scotland Heat Map and future development data provided by the University of St Andrews and the Fife Development Plan. These various options provide an indication of the potential annual and peak heating demands that can then be compared against the geothermal heating potential, and an economic modelling tool was developed to analyse the performance of the overall system, including key performance indicators to evaluate the financial viability. This analysis leads to a preliminary network design and an economic model of the potential scheme. The District Heating Opportunity Assessment Tool (DHOAT) designed for the Danish Energy Agency analyses the Heat Map data and preliminary network designs and provides peak and annual demands and key performance indicators, namely total heat demand and indicative CAPEX, OPEX, REPEX and heat sales. All input parameters are modelled with an uncertainty of ±10%. Based on this analysis, the proposed development of one well and estimated heat supply is not sufficient capacity to provide heat outside of the Guardbridge site itself. All district heating network designs and economic models were therefore based on the aggregated customer base of the Guardbridge site. The economic model assumes that geothermal heat can supply 50% of the Guardbridge site needs (2,867 MWh/a), with a capacity of 0.42 MW, and the other 50% would be provided by the biomass plant. Revenues from heat sales are based on a heat sale price scaling (MWh and p/kWh) and costs of heat from the biomass plant. An Excel model calculates the profitability of the scheme based on a CAPEX of £530,000 for the heating network and £1,517,000 for the well completion, flow tests and water treatment. OPEX and REPEX costs are principally power consumption for the heat and distribution pumps (£280,000), and a ESP and heat pump replacement after 10 years (£250,000). NPV and IRR are used to demonstrate viability for potential investors over a 21-year period; the best case scenario shows that the scheme might achieve a 10% IRR and a positive NPV. However, the heat sale price is too low to create sufficient margin to make the economic performance attractive. This is principally due to the cost of the geothermal heat. The capital cost of the geothermal well is a significant portion of the project CAPEX and does not vary with the well heat potential, which is a relatively modest value given the temperature and flow rate estimates presented. Flow rate is highly uncertain, while temperature is better constrained and low due to the shallow depth of the proposed well. The district heating network requires higher temperatures and the addition of a heat pump increases the capital costs and adds a relatively high operating cost for the electricity to run the pump. The carbon emissions reductions are compared to an individual gas boiler alternative (business as usual [BAU]) and the geothermal-biomass heat network shows an 84% reduction in carbon emissions, assuming that the biomass boilers and geothermal heat pumps each supply 50% of the network demand. About 58% of the emissions reduction (13,878 tonnes CO2/kWh relative to BAU) is attributed to heat generation from the biomass plant and the remaining 42% (9,812 tonnes CO2/kWh relative to BAU) is attributed to the geothermal well and the heat pump. These figures are based on a model lifetime of 20 years. The value of this carbon saving has not been included in the economic model, however it could be considered to represent an additional savings compared to the business-as-usual alternative. The heating network can be enhanced at a subsequent stage to provide combined heating and cooling for the site. This would increase the utilisation of the heat pump by operating in combined heating and cooling mode during interseasonal periods. Although not explored in any extensive technical or economic sense, the system could also potentially be used to fill separate hot and cold seasonal heat stores. Requirements for Phase 2 would begin with a non-invasive geophysical survey to provide imaging of the fault and the target aquifers in the subsurface. This could be completed in three months. Phase 2 would most likely require the preparation of an Environmental Statement before any drilling could commence on site, particularly addressing the viability of disposal of water to the sea. However, current developments at Guardbridge have required Environmental Statements (i.e. since 2014) and much baseline data already exists. The time required to complete an EIA range from 12 weeks to prepare the report, or up to one year of time if SNH and Fife Council require additional new data. A benefit of the Guardbridge site is therefore its status as an industrial site with a pre-existing history in terms of Environmental Statements. Ideally, Phase 2 would culminate in revised well designs, procurement of the drilling rig, and test drilling to intercept the fault and target aquifers. The time and costs are estimated and depend on the choice of drilling option. A positive outcome from a test borehole would lead to the design of a full production well and progression of the project as a Technology Demonstrator. Regardless of whether the test borehole proves that the Guardbridge District Heating Network project is viable, the data recovered as part of the test drilling (core samples, flow tests and water chemistry) will be highly significant for de-risking hot sedimentary aquifer exploration across central Scotland. The economic feasibility of the Guardbridge geothermal heat project is dependent on the best case scenario for flow rates, along with a large number of other poorly constrained variables. It could be economic, but there is a very large uncertainty in the geothermal heat estimates. However, the additional value in the potential research that can be achieved at Guardbridge in de-risking hot sedimentary aquifer exploration in the Central Belt of Scotland, as well as integrating low carbon heat source exploration with other technologies, including dual heating and cooling and water recycling, should be considered when deciding to progress this project

Pedi-IKDC or KOOS-child: Which questionnaire should be used in children with knee disorders?

Background: The Pedi International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) child are validated questionnaires for children with knee disorders. The aim of this study was to translate these questionnaires in Dutch and to recommend which questionnaires should - based on their psychometric properties - be used in clinical practice. Methods: The English Pedi-IKDC and KOOS-Child were translated by the forward-backward procedure. Subsequently, content validity of the Pedi-IKDC and KOOS-Child was evaluated by both patients (n = 18) and experts (n = 18). To evaluate construct validity and interpretability participants with knee disorders (n = 100) completed the Numeric Rating Scale Pain, Lysholm Knee Scoring Scale, EuroQol-5 Dimension, Pedi-IKDC and KOOS-Child at baseline. Participants completed the anchor question, Pedi-IKDC and KOOS-child two weeks (n = 54) and one year (n = 71) after baseline, for evaluating the test-retest reliability and responsiveness. Psychometric properties were interpreted following the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) criteria. Results: The Pedi-IKDC showed adequate test-retest reliability (intraclass correlation coefficient (ICC) 0.9; standard error of measurement (SEM) 8.6; smallest detectable change (SDC) 23.8), adequate content validity (> 75% relevant), adequate construct validity (75% confirmed hypotheses), low floor or ceiling effects (scores between 5 and 95) and adequate responsiveness (> 75% confirmed hypotheses). The KOOS-Child showed an adequate test-retest reliability (ICC 0.8-0.9; SEM 8.9-16.9; SDC 24.7-46.9), adequate content validity (> 75% relevant, except KOOS-Child subscale ADL), adequate construct validity (75% confirmed hypotheses), low floor and ceiling effects (scores between 5 and 95, except KOOS-Child subscale activities of daily living and Sport/play) and moderate responsiveness (40% confirmed hypotheses). Conclusions: The Pedi IKDC showed better psychometric properties than the KOOS-Child and should therefore be used in children with knee disorders

“Spontaneous” late recovery from stuttering: Dimensions of reported techniques and causal attributions

Purpose: (1) To survey the employed techniques and the reasons/occasions which adults who had recovered from stuttering after age 11 without previous treatment reported as causal to overcome stuttering, (2) to investigate whether the techniques and causal attributions can be reduced to coherent (inherently consistent) dimensions, and (3) whether these dimensions reflect common therapy components. Methods: 124 recovered persons from 8 countries responded by SurveyMonkey or paper-and-pencil to rating scale questions about 49 possible techniques and 15 causal attributions. Results: A Principal Component Analysis of 110 questionnaires identified 6 components (dimensions) for self-assisted techniques (Speech Restructuring; Relaxed/Monitored Speech; Elocution; Stage Performance; Sought Speech Demands; Reassurance; 63.7% variance explained), and 3 components of perceived causal attributions of recovery (Life Change, Attitude Change, Social Support; 58.0% variance explained). Discussion: Two components for self-assisted techniques (Speech Restructuring; Elocution) reflect treatment methods. Another component (Relaxed/Monitored Speech) consists mainly of items that reflect a common, non-professional understanding of effective management of stuttering. The components of the various perceived reasons for recovery reflect differing implicit theories of causes for recovery from stuttering. These theories are considered susceptible to various biases. This identification of components of reported techniques and of causal attributions is novel compared to previous studies who just list techniques and attributions. Conclusion: The identified dimensions of self-assisted techniques and causal attributions to reduce stuttering as extracted from self-reports of a large, international sample of recovered formerly stuttering adults may guide the application of behavioral stuttering therapies

Novel genetic loci associated with hippocampal volume

The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness

The genetic architecture of the human cerebral cortex

INTRODUCTION The cerebral cortex underlies our complex cognitive capabilities. Variations in human cortical surface area and thickness are associated with neurological, psychological, and behavioral traits and can be measured in vivo by magnetic resonance imaging (MRI). Studies in model organisms have identified genes that influence cortical structure, but little is known about common genetic variants that affect human cortical structure. RATIONALE To identify genetic variants associated with human cortical structure at both global and regional levels, we conducted a genome-wide association meta-analysis of brain MRI data from 51,665 individuals across 60 cohorts. We analyzed the surface area and average thickness of the whole cortex and 34 cortical regions with known functional specializations. RESULTS We identified 306 nominally genome-wide significant loci (P < 5 × 10−8) associated with cortical structure in a discovery sample of 33,992 participants of European ancestry. Of the 299 loci for which replication data were available, 241 loci influencing surface area and 14 influencing thickness remained significant after replication, with 199 loci passing multiple testing correction (P < 8.3 × 10−10; 187 influencing surface area and 12 influencing thickness). Common genetic variants explained 34% (SE = 3%) of the variation in total surface area and 26% (SE = 2%) in average thickness; surface area and thickness showed a negative genetic correlation (rG = −0.32, SE = 0.05, P = 6.5 × 10−12), which suggests that genetic influences have opposing effects on surface area and thickness. Bioinformatic analyses showed that total surface area is influenced by genetic variants that alter gene regulatory activity in neural progenitor cells during fetal development. By contrast, average thickness is influenced by active regulatory elements in adult brain samples, which may reflect processes that occur after mid-fetal development, such as myelination, branching, or pruning. When considered together, these results support the radial unit hypothesis that different developmental mechanisms promote surface area expansion and increases in thickness. To identify specific genetic influences on individual cortical regions, we controlled for global measures (total surface area or average thickness) in the regional analyses. After multiple testing correction, we identified 175 loci that influence regional surface area and 10 that influence regional thickness. Loci that affect regional surface area cluster near genes involved in the Wnt signaling pathway, which is known to influence areal identity. We observed significant positive genetic correlations and evidence of bidirectional causation of total surface area with both general cognitive functioning and educational attainment. We found additional positive genetic correlations between total surface area and Parkinson’s disease but did not find evidence of causation. Negative genetic correlations were evident between total surface area and insomnia, attention deficit hyperactivity disorder, depressive symptoms, major depressive disorder, and neuroticism. CONCLUSION This large-scale collaborative work enhances our understanding of the genetic architecture of the human cerebral cortex and its regional patterning. The highly polygenic architecture of the cortex suggests that distinct genes are involved in the development of specific cortical areas. Moreover, we find evidence that brain structure is a key phenotype along the causal pathway that leads from genetic variation to differences in general cognitive function

Measurement of prompt D0^{0} and D‾\overline{D}0^{0} meson azimuthal anisotropy and search for strong electric fields in PbPb collisions at root SNN\sqrt{S_{NN}} = 5.02 TeV

The strong Coulomb field created in ultrarelativistic heavy ion collisions is expected to produce a rapiditydependent difference (Av2) in the second Fourier coefficient of the azimuthal distribution (elliptic flow, v2) between D0 (uc) and D0 (uc) mesons. Motivated by the search for evidence of this field, the CMS detector at the LHC is used to perform the first measurement of Av2. The rapidity-averaged value is found to be (Av2) = 0.001 ? 0.001 (stat)? 0.003 (syst) in PbPb collisions at ?sNN = 5.02 TeV. In addition, the influence of the collision geometry is explored by measuring the D0 and D0mesons v2 and triangular flow coefficient (v3) as functions of rapidity, transverse momentum (pT), and event centrality (a measure of the overlap of the two Pb nuclei). A clear centrality dependence of prompt D0 meson v2 values is observed, while the v3 is largely independent of centrality. These trends are consistent with expectations of flow driven by the initial-state geometry. ? 2021 The Author. Published by Elsevier B.V. This is an open access article under the CC BY licens

Performance of the CMS Level-1 trigger in proton-proton collisions at √s = 13 TeV

At the start of Run 2 in 2015, the LHC delivered proton-proton collisions at a center-of-mass energy of 13\TeV. During Run 2 (years 2015–2018) the LHC eventually reached a luminosity of 2.1× 10$^{34}$ cm$^{-2}$s$^{-1}$, almost three times that reached during Run 1 (2009–2013) and a factor of two larger than the LHC design value, leading to events with up to a mean of about 50 simultaneous inelastic proton-proton collisions per bunch crossing (pileup). The CMS Level-1 trigger was upgraded prior to 2016 to improve the selection of physics events in the challenging conditions posed by the second run of the LHC. This paper describes the performance of the CMS Level-1 trigger upgrade during the data taking period of 2016–2018. The upgraded trigger implements pattern recognition and boosted decision tree regression techniques for muon reconstruction, includes pileup subtraction for jets and energy sums, and incorporates pileup-dependent isolation requirements for electrons and tau leptons. In addition, the new trigger calculates high-level quantities such as the invariant mass of pairs of reconstructed particles. The upgrade reduces the trigger rate from background processes and improves the trigger efficiency for a wide variety of physics signals