56 research outputs found
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
Interactive effects of mGlu5 and 5-HT2A receptors on locomotor activity in mice
RationaleMetabotropic glutamate (mGlu) receptors have been suggested to play a role in neuropsychiatric disorders including schizophrenia, drug abuse, and depression. Because serotonergic hallucinogens increase glutamate release and mGlu receptors modulate the response to serotonin (5-HT)(2A) activation, the interactions between serotonin 5-HT(2A) receptors and mGlu receptors may prove to be important for our understanding of these diseases.ObjectiveWe tested the effects of the serotonergic hallucinogen and 5-HT(2A) agonist, 2,5-dimethoxy-4-methylamphetamine (DOM), and the selective 5-HT(2A) antagonist, M100907, on locomotor activity in the mouse behavioral pattern monitor (BPM) in mGlu5 wild-type (WT) and knockout (KO) mice on a C57 background.ResultsBoth male and female mGlu5 KO mice showed locomotor hyperactivity and diminished locomotor habituation compared with their WT counterparts. Similarly, the mGlu5-negative allosteric modulator 2-methyl-6-(phenylethynyl)pyridine (MPEP) also increased locomotor hyperactivity, which was absent in mGlu5 KO mice. The locomotor hyperactivity in mGlu5 receptor KO mice was potentiated by DOM (0.5 mg/kg, subcutaneously (SC)) and attenuated by M100907 (1.0 mg/kg, SC). M100907 (0.1 mg/kg, SC) also blocked the hyperactivity induced by MPEP.ConclusionsThese studies demonstrated that loss of mGlu5 receptor activity either pharmacologically or through gene deletion leads to locomotor hyperactivity in mice. Additionally, the gene deletion of mGlu5 receptors increased the behavioral response to the 5-HT(2A) agonist DOM, suggesting that mGlu5 receptors either mitigate the behavioral effects of 5-HT(2A) hallucinogens or that mGlu5 KO mice show an increased sensitivity to 5-HT(2A) agonists. Taken together, these studies indicate a functional interaction between mGlu5 and 5-HT(2A) receptors
Modeling “psychosis” in vitro by inducing disordered neuronal network activity in cortical brain slices
# The Author(s) 2009. This article is published with open access at Springerlink.com Introduction Dysregulation of neuronal networks has been suggested to underlie the cognitive and perceptual abnor-malities observed schizophrenia. Discussions An in vitro model of psychosis is proposed based on the two different approaches to cause aberrant networ
Improving mathematical learning in Scotland’s Curriculum for Excellence through problem posing:An integrative review
The architecture of the disaster
This essay considers the irruption of the designed destructive event in the order of the project of architecture. The artificial disaster brings onto architecture destructive sudden forces that operate against it with an intensity and a speed that are different from those that are at play in it. It imposes on architecture the man-devised, forceful and violent interference of a project that is alien to that of architecture. The violent orchestrated event in space is interpreted here as a paroxysmal - explicit, sudden, violent - actualization of the forces that contribute to the shaping of the environment. Design and planning are about space definition and form making, while the destruction inflicted by the disaster concerns the undoing of form, of planned orders, of structures (be they societal, urban, economic, national).
Through a series of examples, this text explores those practices which - in architecture and around architecture - work on and with the energy released by the disastrous event. It aims to understand the effects of the planned disaster on the wider questions that the discipline of architecture needs to ask, and suggests that silence – or, the project of silence of architecture - is an act of design too
Vision and Methodology to Support Sustainable Architecture Through Building Technology in the Digital Era
A Study on Gordon Matta-Clark's 'Building-Cuts': Psychological and Sociological Significance of the Physical Holes
Mismatch negativity encoding of prediction errors predicts S-ketamine-induced cognitive impairments
Psychotomimetics like the N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine and the 5-hydroxytryptamine2A receptor (5-HT(2A)R) agonist psilocybin induce psychotic symptoms in healthy volunteers that resemble those of schizophrenia. Recent theories of psychosis posit that aberrant encoding of prediction errors (PE) may underlie the expression of psychotic symptoms. This study used a roving mismatch negativity (MMN) paradigm to investigate whether the encoding of PE is affected by pharmacological manipulation of NMDAR or 5-HT(2A)R, and whether the encoding of PE under placebo can be used to predict drug-induced symptoms. Using a double-blind within-subject placebo-controlled design, S-ketamine and psilocybin, respectively, were administrated to two groups of healthy subjects. Psychological alterations were assessed using a revised version of the Altered States of Consciousness (ASC-R) questionnaire. As an index of PE, we computed changes in MMN amplitudes as a function of the number of preceding standards (MMN memory trace effect) during a roving paradigm. S-ketamine, but not psilocybin, disrupted PE processing as expressed by a frontally disrupted MMN memory trace effect. Although both drugs produced positive-like symptoms, the extent of PE processing under placebo only correlated significantly with the severity of cognitive impairments induced by S-ketamine. Our results suggest that the NMDAR, but not the 5-HT(2A)R system, is implicated in PE processing during the MMN paradigm, and that aberrant PE signaling may contribute to the formation of cognitive impairments. The assessment of the MMN memory trace in schizophrenia may allow detecting early phases of the illness and might also serve to assess the efficacy of novel pharmacological treatments, in particular of cognitive impairments.Neuropsychopharmacology advance online publication, 26 October 2011; doi:10.1038/npp.2011.261
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