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  • 1.
    Abadie, Brendan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Power investment outlook for Chile to 20402020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study aims to build a medium-term (2019-2040) model for the Chilean electricity generation system in the OSeMOSYS software, a linear cost optimisation model, in light of the most recent developments in government policy and targets. In 2019, the Chilean government committed to decommissioning all coal plants by 2040 at the latest, and set out a non-binding target to be carbon neutral by 2050. The carbon neutrality target could be enshrined in the climate change law, which has yet to be ratified. In this thesis, a focus was put on the upfront capital cost of the system, and the emissions attributable to Chile’s GHG Inventory (called the SNI GHG in Chile) from operating the system. Three scenarios are developed within the thesis, in line with three paths the power system may follow: a BAU scenario including current power purchase agreements, a scenario in which power purchase agreements for fossil fuels are bought out and the free market then takes over, and a non-conventional renewable energy (NCRE) scenario in which certain renewable technologies account for 68% of production in 2040. The model is validated against the results from 2019 and a broadly similar model developed in the private sector. Sensitivity analysis scenarios were conducted for the input parameters: price of natural gas, price of coal, capital cost of solar PV, capital cost of wind, capital cost of wind & solar, and the capacity factor of hydropower. The sensitivity analyses show the most sensitive input parameters are the price of natural gas and capital cost of wind with respect to the outputs of capital cost, NCRE production ratio such as the share of all solar, wind, and certain hydro technologies as a percentage of total electricity production and GHG emissions.

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  • 2. Abawallo, S. S.
    et al.
    Brandimarte, Luigia
    Maglionico, M.
    Analysis of the performance response of offline detention basins to inlet structure design2013In: Irrigation and Drainage, ISSN 15310361, Vol. 62, no 4, p. 449-457Article in journal (Refereed)
  • 3.
    Abbasi, Saeed
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A comparison between particle characteristics between two railway brake pads2013Report (Other academic)
  • 4.
    Abbasi, Saeed
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A study of nanostructured particles in railway tunnels2013Report (Other academic)
  • 5.
    Abbasi, Saeed
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Nanostructured particles in/outside compartment of running train, an on board measurement2013Report (Other academic)
  • 6.
    Abbasi, Saeed
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Non-exhaust Nano particle emission in Rail traffic2010Conference paper (Refereed)
  • 7.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Jansson, Anders
    Stockholm University, Applied Environmental Science, Stockholm, Sweden.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A pin-on-disc study of the rate of airborne wear particle emissions from railway braking materials2012In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 284, p. 18-29Article in journal (Refereed)
    Abstract [en]

    The current study investigates the characteristics of particles generated from the wear of braking materials, and provides an applicable index for measuring and comparing wear particle emissions. A pin-on-disc tribometer equipped with particle measurement instruments was used. The number concentration, size, morphology, and mass concentration of generated particles were investigated and reported for particles 10 nm-32 mu m in diameter. The particles were also collected on filters and investigated using EDS and SEM. The effects of wear mechanisms on particle morphology and changes in particle concentration are discussed. A new index, the airborne wear particle emission rate (AWPER), is suggested that could be used in legislation to control non-exhaust emissions from transport modes, particularly rail transport.

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  • 8.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Jansson, Anders
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Particle emissions from rail traffic: a literature review2013In: Critical reviews in environmental science and technology, ISSN 1064-3389, E-ISSN 1547-6537, Vol. 43, no 23, p. 2211-2244Article, review/survey (Refereed)
    Abstract [en]

    Particle emissions are a drawback of rail transport. This work is a comprehensive presentation of recent research into particle emissions from rail vehicles. Both exhaust and non-exhaust particle emissions are considered when examining particle characteristics such as  PM10, and PM2.5 concentration levels, size, morphology, composition, as well as adverse health effects, current legislation, and available and proposed solutions for reducing such emissions. High concentration levels in enclosed rail traffic environments are reported and some toxic effects of the particles. We find that only a few limited studies have examined the adverse health effects of non-exhaust particle emissions and that no relevant legislation exists. Thus further research in this area is warranted.

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  • 9.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Larsson, Christina
    Bombardier Transportation Sweden AB, Västerås, Sweden.
    Jansson, Anders
    Stockholm University, Applied Environmental Science, Stockholm, Sweden.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A field test study of airborne wear particles from a running regional train2012In: IMechE, Part F: Journal of Rail and Rapid Transit, ISSN 0954-4097, Vol. 226, no 1, p. 95-109Article in journal (Refereed)
    Abstract [en]

    Inhalable airborne particles have inverse health affect. In railways, mechanical brakes, the wheel–rail contact, current collectors, ballast, sleepers, and masonry structures yield particulate matter. Field tests examined a Swedish track using a train instrumented with particle measurement devices, brake pad temperature sensors, and speed and brake sensors. The main objective of this field test was to study the characteristics of particles generated from disc brakes on a running train with an on-board measuring set-up.

    Two airborne particle sampling points were designated, one near a pad–rotor disc brake contact and a second under the frame, not near a mechanical brake or the wheel–rail contact; the numbers and size distributions of the particles detected were registered and evaluated under various conditions (e.g. activating/deactivating electrical brakes or negotiating curves). During braking, three speed/temperature-dependent particle peaks were identified in the fine region, representing particles 280 nm, 350 nm, and 600 nm in diameter. In the coarse region, a peak was discerned for particles 3–6 μm in diameter. Effects of brake pad temperature on particle size distribution were also investigated. Results indicate that the 280 nm peak increased with increasing temperature, and that electrical braking significantly reduced airborne particle numbers. FESEM images captured particles sizing down to 50 nm. The ICP-MS results indicated that Fe, Cu, Zn, Al, Ca, and Mg were the main elements constituting the particles.

     

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  • 10.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A study of friction modifiers on airborne wear particles from wheel-rail contact2012Conference paper (Refereed)
    Abstract [en]

    Wheel-rail contact and its wear process are crucial issues in maintenance and operating of rolling stocks. During wheel-rail contact, materials in mating faces are worn off and some of them transferred to airborne particles. Eventhough the wear process in wheel-rail contact are well-known, few studies have been conducted on the airborne particles from wheel-rail contact.

    The purpose of this study is to investigate the effect of using different friction modifier on the amount of airbotne particles from wheel-rail contact in a laboratory simulation. In this regard, a series laboratory tests were used by using round head pin (R=25mm) and dead weight 40 N in a pin-on-disc machine. This set-up simulates a contact pressure around 750 MPa on the pin head.

    The amount of airborne particles and their characteristics were investigated in dry-contact, and non-dry contacts whereas a lubricant, Binol rail 510 and a friction modifier, tramsilence were used. According to the results, the effects of using Binol rail to reduce the amount of airborne particles were considerable.

  • 11.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Airborne wear particles from train traffic2010Conference paper (Refereed)
  • 12.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Experiences of measuring airborne wear particles from braking materials and wheel-rail contact2012Conference paper (Refereed)
    Abstract [en]

    During braking both of the discs and pads of disc brakes are worn. Since disc brakes are not sealed, some of the generated wear particles can become airborne.  Wheel-rail is also subjected to wear process during braking as well as normal running. They also contribute to generate airborne particles. Several studies have found an association between adverse health effects and the concentration of particles in the atmosphere, so it is of interest to improve our knowledge of the airborne wear particles generated by disc brakes.

    The present work includes results from full scale testing of rail vehicles. Particle size distribution, morphology and elemental contents are presented and discussed for different combinations of disc and pad materials. Due to high back ground concentration levels in field tests, dedicated laboratory test set ups on a reduced scale were designed and utilized for airborne particle studies with zero background level.

    Promising correlation between field test and the lab set up is identified. Different ways of using this test set up for evaluating how the composition of the airborne particles is classified with respect to their health effects are discussed. Furthermore, different ways of using the proposed method to rank and to quantify airborne particle emission factors are presented.

  • 13.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Lack of applicable criteria in non-exhaust emission legislation: AWPER index a practical solution2011Conference paper (Refereed)
  • 14.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    A field investigation of the size and morphology and chemical composition of airborne particles in rail transport2010Conference paper (Refereed)
  • 15.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    Larsson, christina
    A field investigation of the size, morphology and chemical composition of airborne particles in rail transport2010Conference paper (Refereed)
    Abstract [en]

    The health effects of inhalable airborne particles are well documented. In the European Union the European Council mandates that the level of airborne particles with a diameter smaller than 10 µm (PM10) must not exceed an annual average of 40 µg/m3. Examples of possible sources from rail transport are mechanical brakes, wheel rail contact, current collectors, ballast, sleepers and masonry structures. In this regard, a series of field tests have been conducted on a regular Swedish track using a regional train instrumented with: particle measurement devices, temperature sensors in brake pads and sensors to measure the magnitude of train speed and a GPS.

    Two sampling points for airborne particles were designated in the train under frame. One of the sampling points was near a pad to rotor disc brake contact and a second global sampling point was chosen under the frame, but not near a mechanical brake or the wheel-rail contact. The first one was highly influenced by brake pad wear debris and the other one was influenced by all of the brake pads, wheel and rail wear debris as well as re-suspension. In each sampling points, three tubes were linked to three particle measurement devices. Two sets of Ptrak, Dustrak and Grimm devices were used. The Ptrak 8525 was an optical particle measurement device which could measure particle diameter in the size interval of 20 nm up to 1 micrometer. The Dustrak was used to measure particle mass concentration. The Grimm 1.109 was an aerosol spectrometer which counted number of particles from 0.25 micrometer to 32 micrometer in 31 intervals. These two Grimm devices were equipped with Millipore filters in the devices outlets to capture particles for further studies on morphology and matter of particles.

    The total number and size distribution of the particles for these two sampling points were registered and evaluated in different situations such as activating and deactivating electrical brake or train curve negotiating.

    During braking, three peaks of 250 nm, 350 nm and 600 nm in diameter, with the 350 nm peak dominating were identified in the fine particle region. In the coarse particle region, a peak of around 3-6 µm in diameter was discovered. The brake pad temperature effects on particle size distribution were also investigated and the results showed that the peak around 250 nm increased. Furthermore, the activation of electrical braking significantly reduced the number of airborne particles.

    A SEM was used to capture the images from collected particles on filters. Furthermore, an ICP-Ms method was used to investigate the elemental contents of the particulates on the filter.  In this case the main contribution belonged to Fe, Si, Al, Ca, Cu, Zn. The higher amount of some elements weights such as calcium, silicon, sodium and aluminum in the global sampling point filters revealed that ballast and concrete sleepers were the main sources for these particles although some of them originated from rail, wheel, brake disc and brake pad as well.

  • 16.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Tritscher, Trosten
    TSI.
    Krinke, Thomas
    TSI.
    On-board study of nano- and micrometer-particle characteristics of a running electric train2013Conference paper (Refereed)
  • 17.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Zhu, Yi
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Pin-on-disc study of the effects of railway friction modifiers on airborne wear particles from wheel-rail contact2013In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 60, p. 136-139Article in journal (Refereed)
    Abstract [en]

    Knowledge of wheel–rail interaction is crucial to wheel and rail maintenance. In this interaction, some of theworn-off material is transformed into airborne particles. Although such wear is well understood, few studiestreat the particles generated. We investigated friction modifiers' effects on airborne particles characteristicsgenerated in wheel-rail contacts in laboratory conditions. Pin-on-disc machine testing with a round-head pinloaded by a dead weight load 40 N simulated maximum contact pressure over 550 MPa. Airborne particlecharacteristics were investigated in dry contacts and in ones lubricated with biodegradable rail grease andwater- and oil-based friction modifiers. The number of particles declined with the grease; the number ofultrafine particles increased with the water-based friction modifier, mainly due to water vaporization.

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  • 18.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Particle emission from rail vehicles: A literature review2012In: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Sage Publications, 2012Conference paper (Refereed)
    Abstract [en]

    Emission of airborne particles is a side effect from rail transport. This work reviews recent research on particle emissions from rail vehicles. Both exhaust and non-exhaust particle emissions are characterized by size, morphology, composition, and size distribution. Current legislation, knowledge of adverse health effects, and available and proposed solutions for emission reductions are also treated. There has been much focus on exhaust emissions, but only a few limited studies have investigated non-exhaust particle emissions, which contain a significant amount of metallic materials. A new method for measuring the airborne wear particle emission rate (AWPER) is proposed as a first step to guide new legislations and to focus further research on non-exhaust airborne emission, i.e., research on the generation mechanisms for particle emissions and their adverse health effects.

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  • 19.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements. KTH, School of Engineering Sciences (SCI), Centres, The KTH Railway Group.
    Technical note: Experiences of studying airborne wear particles from road and rail transport2013In: Aerosol and Air Quality Research, ISSN 1680-8584, Vol. 13, no 4, p. 1161-1169Article in journal (Refereed)
    Abstract [en]

    Airborne particles and their adverse effects on air quality have been recognized by humans since ancient times. Current exhaust emission legislations increase the relative contribution of wear particles on the PM levels. Consequently, wearbased particle emissions from rail and road transport have raised concerns as ground transportation is developing quickly. Although scientific research on airborne wear-based particles started in 1909, there is almost no legislation that control the generation of wear-based particles. In addition, there is no accepted and approved standard measurement technique for monitoring and recording particle characteristics. The main objective of this study is to review recent experimental work in this field and to discuss their set-ups, the sampling methods, the results, and their limitations, and to propose measures for reducing these limitations.

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  • 20.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Larsson, Christina
    Bombardier Transportation Sweden AB, Västerås, Sweden.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A study of airborne wear particles generated from organic railway brake pads and brake discs2011In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 273, no 1, p. 93-99Article in journal (Refereed)
    Abstract [en]

    Brake pads on wheel-mounted disc brakes are often used in rail transport due to their good thermal properties and robustness. During braking, both the disc and the pads are worn. This wear process generates particles that may become airborne and thus affect human health. The long term purpose of ‘Airborne particles in Rail transport’ project is to gain knowledge on the wear mechanisms in order to find means of controlling the number and size distribution of airborne particles. In this regard, a series of full-scale field tests and laboratory tests with a pin-on-disc machine have been conducted. The morphology and the matter of particles, along with their size distribution and concentration, have been studied. The validity of results from the pin-on-disc simulation has been verified by the field test results. Results show an ultra-fine peak for particles with a diameter size around 100 nm in diameter, a dominant fine peak for particles with a size of around 350 nm in diameter, and a coarse peak with a size of 3-7 μm in diameter. Materials such as iron, copper, aluminium, chromium, cobalt, antimony, and zinc have been detected in the nano-sized particles.

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  • 21.
    Abbott, Michele
    et al.
    RAND Corp, Pardee RAND Grad Sch, Santa Monica, CA 90406 USA..
    Bazilian, Morgan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Columbia Univ, Swedish Royal Inst Technol, Ctr Global Energy Policy, New York, NY 10027 USA..
    Egel, Daniel
    RAND Corp, Santa Monica, CA 90406 USA..
    Willis, Henry H.
    RAND Corp, Santa Monica, CA 90406 USA..
    Examining the food-energy-water and conflict nexus2017In: Current Opinion in Chemical Engineering, E-ISSN 2211-3398, Vol. 18, p. 55-60Article, review/survey (Refereed)
    Abstract [en]

    There is growing evidence of a strong linkage or 'nexus' between conflict - both domestic and international - and food, energy, and water (FEW) resources and services. This article demonstrates a positive, significant correlation between two measures, FEW security and political stability, and reviews the evidence for how each of these three types of resource insecurities affects political and social stability. We describe what is known about the FEW-conflict nexus itself, note that remaining knowledge gaps include evidence on developing governance structures and preparing for climate change, and examine the types of policies that countries and international donors might take to help mitigate the role that FEW can play in affecting stability.

  • 22. Abderrazek, K.
    et al.
    Uheida, Abdusalam
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Seffen, M.
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Srasra, N. Frini
    Srasra, E.
    Photocatalytic degradation of indigo carmine using [Zn-Al] LDH supported on PAN nanofibres2015In: Clay minerals, ISSN 0009-8558, E-ISSN 1471-8030, Vol. 50, no 2, p. 185-197Article in journal (Refereed)
    Abstract [en]

    Zn-Al layered double hydroxides (LDH), before and after calcination, were tested for the removal of indigo carmine (IC) dye from solution. These LDH photocatalysts were characterized by powder x-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry/differential thermogravimetry (TG/DTG), nitrogen physisorption at -196 degrees C, scanning electron microscopy (SEM) and diffuse reflectance spectrophotometry (DRS). The different photocatalysts were supported on polyacrylonitrile (PAN) nanofibres, so that filtration was unnecessary. The PXRD and FTIR analyses showed that the IC adsorption on c-Zn-Al-3-500 (LDH calcined at 500 degrees C) was enhanced by construction of the hydrotalcite matrix intercalated with the dye. The intercalation was clearly evidenced by the appearance of a peak at low degrees 2 theta values. All of the materials prepared exhibited photocatalytic activity, which for the c-Zn-Al-3-500 was comparable to that of commercial PAN-supported ZnO nanoparticles (100% degradation after 180 min). Kinetic studies showed that the degradation of the IC followed a pseudo-first order rate. The high activity and the ease of both synthesis and separation processes rendered this photocatalyst a promising candidate for environmental remediation.

  • 23.
    Abdi, Amir
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    State of the art in hydrogen liquefaction2020In: Proceedings of the ISES Solar World Congress 2019 and IEA SHC International Conference on Solar Heating and Cooling for Buildings and Industry 2019, International Solar Energy Society , 2020, p. 1311-1320Conference paper (Refereed)
    Abstract [en]

    Hydrogen is a potential option to replace fossil fuels considering the increasing demand of energy applications. It is naturally abundant and is regarded as a suitable energy carrier. There has been extensive research to improve the efficiency of storing hydrogen with different methods, including gas compression, liquefaction and sorption in metal hydrides or carbon nanotubes. A comparison of the storage methods shows that liquefaction of hydrogen is more beneficial than compression of hydrogen in terms of higher volumetric capacity, and it is more technologically mature than sorption technologies. This makes it more plausible for long distance distribution. On the other hand, the obstacles in full exploitation of the method are low energy efficiency of the liquefaction process and associated high cost. The recent research has been focusing on increasing the energy efficiency of the storage process. This paper provides, with regard to the conventional methods, a state of the art review of the novel and modified liquefaction process and the latest developments in increasing the efficiency of the energy intensive process. Furthermore, the developments in combining the hydrogen liquefaction plants with renewable energy sources are covered and reviewed. Finally, the ongoing development of hydrogen liquefaction is highlighted.

  • 24.
    Abid, Hamza
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Techno-economic analysis of energy storage integration for solar PV in Burkina Faso2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Electrification in rural areas of West African countries remain to be a challenge for the growth of the region. The Economic Community of West African States (ECOWAS) has set a target of 2030 to achieve 100% electrification in all member countries. Burkina Faso is one of the least electrified countries in the world, where only 9 % of the rural population has access to electricity. This study presents a conceptualization of techno-economic feasibility of pumped hydro storage (PHS) and electric batteries with solar photovoltaics (PV) in the context of Burkina Faso. The results are explored for an off grid standalone PV plus storage system for a rural setting and a grid connected PV system for an urban setup. The least cost configurations for both the cases are determined using HOMER (Hybrid Optimization Model for Electric Renewables). The results indicate the need of extended solar penetration in Burkina Faso in response to the challenges of low electrification rates in the country. Adding more PV to the present electricity mix of Burkina Faso could drive down the cost of energy by 50 % compared to the present grid electricity prices by making cheap electricity available to the local population. Adding PHS to grid connected PV leads to a cost reduction of 8% over a lifetime of 25 years which does not provide enough motivation for the high investments in storage at present. Policy interventions that allow stacking up of revenues and benefits of storage are needed to make it more competitive. PV plus pumped hydro storage remains the optimal system architecture as compared to PV plus electric batteries for off grid standalone systems provided the geographic availability of lower and upper reservoirs. The capital cost of PV remains to be the most dominating factor in the cost of optimal system for both the urban and the rural cases, and driving down the costs of PV would have the most positive effect for increased electricity access in the country.

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  • 25.
    Abid, Hamza
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Thakur, Jagruti
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems.
    Khatiwada, Dilip
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Bauner, David
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Sustainability, Industrial Dynamics & Entrepreneurship. Renetech AB, Sweden.
    Energy storage integration with solar PV for increased electricity access: A case study of Burkina Faso2021In: Energy, E-ISSN 0360-5442, Vol. 230, no 120656, p. 120656-Article in journal (Refereed)
    Abstract [en]

    Electricity access remains a challenge for the majority of the West African countries, wherein 5 out of 16 have an electrification rate of less than 25%, with Burkina Faso having only 9% of the rural population with electricity access in 2017. This study presents a techno-economic feasibility analysis of solar PV system integration with conceptualized Pumped Hydro Storage (PHS) and electric batteries for Burkina Faso. The study explores two cases (a) an off-grid PV with a storage system for rural areas and (b) a grid-connected PV system for an urban location. The least-cost configuration of PV with feasible storage is investigated using HOMER. The results show that Solar PV with PHS remains the optimal system configuration for both rural and urban cases even when the construction costs of lower and upper reservoirs are considered. Battery energy storage systems remain an economically expensive solution even when the added costs of pumped hydro storage are included, owing to the low lifetime and high capital costs of battery storage. The capital cost of PV remains to be the most dominating factor for both cases, signifying the importance of policy interventions for cost reduction of PV for increased green electrification in West African countries.

  • 26.
    Abrehdary, Majid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning. Univ Karlstad, Sweden.
    Sjöberg, Lars
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Bagherbandi, Mohammad
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning. Univ Gävle, Sweden.
    Sampietro, D.
    Towards the Moho depth and Moho density contrast along with their uncertainties from seismic and satellite gravity observations2017In: Journal of Applied Geodesy, ISSN 1862-9016, E-ISSN 1862-9024, Vol. 11, no 4, p. 231-247Article in journal (Refereed)
    Abstract [en]

    We present a combined method for estimating a new global Moho model named KTH15C, containing Moho depth and Moho density contrast (or shortly Moho parameters), from a combination of global models of gravity (GOCO05S), topography (DTM2006) and seismic information (CRUST1.0 and MDN07) to a resolution of 1 degrees x 1 degrees based on a solution of Vening Meinesz-Moritz' inverse problem of isostasy. This paper also aims modelling of the observation standard errors propagated from the Vening Meinesz-Moritz and CRUST1.0 models in estimating the uncertainty of the final Moho model. The numerical results yield Moho depths ranging from 6.5 to 70.3 km, and the estimated Moho density contrasts ranging from 21 to 650 kg/m(3), respectively. Moreover, test computations display that in most areas estimated uncertainties in the parameters are less than 3 km and 50 kg/m(3), respectively, but they reach to more significant values under Gulf of Mexico, Chile, Eastern Mediterranean, Timor sea and parts of polar regions. Comparing the Moho depths estimated by KTH15C and those derived by KTH11C, GEMMA2012C, CRUST1.0, KTH14C, CRUST14 and GEMMA1.0 models shows that KTH15C agree fairly well with CRUST1.0 but rather poor with other models. The Moho density contrasts estimated by KTH15C and those of the KTH11C, KTH14C and VMM model agree to 112, 31 and 61 kg/m(3) in RMS. The regional numerical studies show that the RMS differences between KTH15C and Moho depths from seismic information yields fits of 2 to 4 km in South and North America, Africa, Europe, Asia, Australia and Antarctica, respectively.

  • 27. Abubakar, Abdulkareem
    et al.
    Al-Wahaibi, Yahya
    Al-Wahaibi, Talal
    Al-Hashmi, Abdul-Aziz R.
    Al-Ajmi, Adel M.
    Eshrati, Mohammad
    Effect of Water-Soluble Drag-Reducing Polymer on Flow Patterns and Pressure Gradients of Oil/Water Flow in Horizontal and Upward-Inclined Pipes2017In: SPE Journal, ISSN 1086-055X, E-ISSN 1930-0220, Vol. 22, no 1, p. 339-352Article in journal (Refereed)
    Abstract [en]

    Experimental investigations of flow patterns and pressure gradients of oil/water flow with and without drag-reducing polymer (DRP) were carried out in horizontal and upward-inclined acrylic pipe of 30.6-mm inner diameter (ID). The oil/water flow conditions of 0.1- to 1.6-m/s mixture velocities and 0.05-0.9 input oil volume fractions were used, and 2,000 ppm master solution of the water-soluble DRP was prepared and injected at controlled flow rates to provide 40 ppm of the DRP in the water phase at the test section. The flow patterns at the water-continuous flows were affected by the DRP, whereas there were no tangible effects of the DRP at the oil-continuous flow regions. The upward inclinations shifted the boundaries between stratified flows and dual continuous flows, and the boundaries between dual continuous flows and water-continuous flows to lower mixture velocities. This means that the inclinations increased the rate of dispersions. The frictional pressure gradients for both with and without DRP slightly decreased with inclinations especially at low mixture velocities, whereas the significant increases in the total pressure gradients with the inclinations were more pronounced at low mixture velocities. The inclinations did not have a major effect on the drag reductions by the DRP at the high mixture velocities and low input oil-volume fractions where the highest drag reductions recorded were 64% at 0 degrees inclination and 62% at both + 5 degrees and +10 degrees inclinations.  However, the inclinations increased the drag reductions as the input oil-volume fractions were increased before phase-inversion points.

  • 28.
    Ackermann, Thomas
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Historical Development and Current Status of Wind Power2005In: Wind Power in Power Systems, John Wiley & Sons, 2005, 1, p. 5-24Chapter in book (Other academic)
  • 29.
    Ackermann, Thomas
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Historical Development and Current Status of Wind Power2012In: Wind Power in Power Systems, Second Edition, John Wiley & Sons, 2012, p. 21-24Chapter in book (Refereed)
    Abstract [en]

    The chapter provides an overview of the historical development (mechanical and electrical power generation) of wind power. It also present the current status of wind power world-wide (capacity installed) together with a discussion of the main drivers for the wind power development, e.g. feed-in tariffs, green certificates etc. Furthermore, the chapter briefly discuss the current trends in wind turbine technology, e.g. larger turbines, and projects development, e.g. offshore wind power.

  • 30.
    Ackermann, Thomas
    KTH. Energynautics GmbH, Germany; Technical University in Darmstadt (TUD), Germany..
    Introduction2012In: Wind Power in Power Systems, Second Edition, Wiley , 2012, p. 1-5Chapter in book (Refereed)
  • 31.
    Ackermann, Thomas
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Transmission Systems for Offshore Wind Farms2005In: Wind Power in Power Systems, John Wiley & Sons, 2005, p. 479-503Chapter in book (Other academic)
  • 32.
    Ackermann, Thomas
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Wind Power in Power Systems2005Book (Other academic)
    Abstract [en]

    As environmental concerns have focussed attention on the generation of electricity from clean and renewable sources, wind energy has become the world's fastest growing energy source. The authors draw on substantial practical experience to address the technical, economic and safety issues inherent in the exploitation of wind power in a competitive electricity market. Presenting the reader with all the relevant background information key to understanding the integration of wind power into the power systems, this leading edge text: Presents an international perspective on integrating a high penetration of wind power into the power system Offers broad coverage ranging from basic network interconnection issues to industry deregulation and future concepts for wind turbines and power systems Discusses wind turbine technology, industry standards and regulations along with power quality issues Considers future concepts to increase the penetration of wind power in power systems Presents models for simulating wind turbines in power systems Outlines current research activities Essential reading for power engineers, wind turbine designers, wind project development and wind energy consultants dealing with the integration of wind power systems into distribution and transmission networks, this text would also be of interest to network engineers working for power utility companies dealing with interconnection issues and graduate students and researchers in the field of wind power and power systems.

  • 33.
    Ackermann, Thomas
    KTH.
    Wind Power in Power Systems, Second Edition2012Collection (editor) (Refereed)
    Abstract [en]

    The second edition of the highly acclaimed Wind Power in Power Systems has been thoroughly revised and expanded to reflect the latest challenges associated with increasing wind power penetration levels. Since its first release, practical experiences with high wind power penetration levels have significantly increased. This book presents an overview of the lessons learned in integrating wind power into power systems and provides an outlook of the relevant issues and solutions to allow even higher wind power penetration levels. This includes the development of standard wind turbine simulation models. This extensive update has 23 brand new chapters in cutting-edge areas including offshore wind farms and storage options, performance validation and certification for grid codes, and the provision of reactive power and voltage control from wind power plants. Key features: Offers an international perspective on integrating a high penetration of wind power into the power system, from basic network interconnection to industry deregulation; Outlines the methodology and results of European and North American large-scale grid integration studies; Extensive practical experience from wind power and power system experts and transmission systems operators in Germany, Denmark, Spain, UK, Ireland, USA, China and New Zealand; Presents various wind turbine designs from the electrical perspective and models for their simulation, and discusses industry standards and world-wide grid codes, along with power quality issues; Considers concepts to increase penetration of wind power in power systems, from wind turbine, power plant and power system redesign to smart grid and storage solutions. Carefully edited for a highly coherent structure, this work remains an essential reference for power system engineers, transmission and distribution network operator and planner, wind turbine designers, wind project developers and wind energy consultants dealing with the integration of wind power into the distribution or transmission network. Up-to-date and comprehensive, it is also useful for graduate students, researchers, regulation authorities, and policy makers who work in the area of wind power and need to understand the relevant power system integration issues.

  • 34.
    Ackermann, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Holttinen, H.
    Overview of Integration Studies - Methodologies and Results2012In: Wind Power in Power Systems, Second Edition, John Wiley & Sons, 2012, 2, p. 361-386Chapter in book (Refereed)
  • 35.
    Ackermann, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Energynautics GmbH, Germany; Technical University in Darmstadt (TUD), Germany.
    Morthorst, P. E.
    Economic Aspects of Wind Power in Power Systems2005In: Wind Power in Power Systems, John Wiley & Sons, 2005, p. 383-410Chapter in book (Other academic)
  • 36.
    Ackermann, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Orths, A.
    Rudion, K.
    Transmission Systems for Offshore Wind Power Plants and Operation Planning Strategies for Offshore Power Systems2012In: Wind Power in Power Systems, John Wiley & Sons, 2012, 2, p. 293-327Chapter in book (Refereed)
    Abstract [en]

    The electric system within an offshore wind power plant and its connection to the main power system pose new challenges to the experts. The best way of interconnecting the wind turbines inside a wind farm has to be found, fulfilling both, redundancy requirements without compromising economic feasibility. The best choice between technologies (HVAC, HVDC - VSC or LCC) for connecting windfarms to shore has to be made, depending on several criteria. The risk of losing this connection versus redundancy has to be economically evaluated. By combining interconnectors and offshore windfarm connections in a modular way, a DC offshore grid can be developed. Anyhow, already during the planning phase the secure operation should be considered thoroughly, because the optimal architecture has to be found, minimizing the necessary assets ensuring secure operation and facilitating later expansion options. The interaction with the onshore grid has to be investigated as well. To enable investigations covering these issues a benchmark offshore test system has been developed which is described in this chapter.

  • 37.
    Ackermann, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    The Value of Wind Power2012In: Wind Power in Power Systems, John Wiley & Sons, 2012, 2, p. 131-155Chapter in book (Refereed)
    Abstract [en]

    The aim of the power plants in a power system is to supply the load in an economical, reliable and environmentally acceptable way. Different power plants can fulfil these requirements in different ways. In order to select the right sources it is important to compare the value of the different sources using an objective approach. The aim of this chapter is describe the different needs of a power system and how these needs can be met with wind power, that is, the value of wind power in a certain system. The values are operating cost value, capacity value, control value, grid loss reduction value and grid investment value. The values can be calculated for different types of power plants, they can be both positive and negative, and they can be calculated both as a physical cost value and a market value.

  • 38.
    Ackermann, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Tröster, E.
    New Control Concept for Offshore Wind Power Plants: Constant-Speed Turbines on a Grid with Variable Frequency2012In: Wind Power in Power Systems, John Wiley & Sons, 2012, 2, p. 345-359Chapter in book (Refereed)
    Abstract [en]

    By using a permanent magnet induction machine as wind generator, the gearbox and converter can be omitted, and the total number of parts reduced leading to a low maintenance and reliable turbine for offshore application. The rotation speed of the turbine however cannot be matched to the wind speed, reducing the energy yield at part load. To overcome this drawback, a central converter can be used, which adjusts the frequency of the local grid in the wind park; this is the so-called park-variable concept. This concept has been compared with respect to energy yield with constant speed and variable speed turbines. Overall, the differences in energy yield of the investigated concepts are so small that other criteria, such as reliability or cost, may be relevant for the selection of one or the other approach. Above all, the park-variable concept represents an interesting alternative to today's common concepts.

  • 39.
    Acuña, José
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Distributed thermal response tests: New insights on U-pipe and Coaxial heat exchangers in groundwater-filled boreholes2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    U-pipe Borehole Heat Exchangers (BHE) are widely used today in ground source heating and cooling systems in spite of their less than optimal performance. This thesis provides a better understanding on the function of U-pipe BHEs and Investigates alternative methods to reduce the temperature difference between the circulating fluid and the borehole wall, including one thermosyphon and three different types of coaxial BHEs.

    Field tests are performed using distributed temperature measurements along U-pipe and coaxial heat exchangers installed in groundwater filled boreholes. The measurements are carried out during heat injection thermal response tests and during short heat extraction periods using heat pumps. Temperatures are measured inside the secondary fluid path, in the groundwater, and at the borehole wall. These type of temperature measurements were until now missing.

    A new method for testing borehole heat exchangers, Distributed Thermal Response Test (DTRT), has been proposed and demonstrated in U-pipe, pipe-in-pipe, and multi-pipe BHE designs. The method allows the quantification of the BHE performance at a local level.

    The operation of a U-pipe thermosyphon BHE consisting of an insulated down-comer and a larger riser pipe using CO2 as a secondary fluid has been demonstrated in a groundwater filled borehole, 70 m deep. It was found that the CO2 may be sub-cooled at the bottom and that it flows upwards through the riser in liquid state until about 30 m depth, where it starts to evaporate.

    Various power levels and different volumetric flow rates have been imposed to the tested BHEs and used to calculate local ground thermal conductivities and thermal resistances. The local ground thermal conductivities, preferably evaluated at thermal recovery conditions during DTRTs, were found to vary with depth. Local and effective borehole thermal resistances in most heat exchangers have been calculated, and their differences have been discussed in an effort to suggest better methods for interpretation of data from field tests.

    Large thermal shunt flow between down- and up-going flow channels was identified in all heat exchanger types, particularly at low volumetric flow rates, except in a multi-pipe BHE having an insulated central pipe where the thermal contact between down- and up-coming fluid was almost eliminated.

    At relatively high volumetric flow rates, U-pipe BHEs show a nearly even distribution of the heat transfer between the ground and the secondary fluid along the depth. The same applies to all coaxial BHEs as long as the flow travels downwards through the central pipe. In the opposite flow direction, an uneven power distribution was measured in multi-chamber and multi-pipe BHEs.

    Pipe-in-pipe and multi-pipe coaxial heat exchangers show significantly lower local borehole resistances than U-pipes, ranging in average between 0.015 and 0.040 Km/W. These heat exchangers can significantly decrease the temperature difference between the secondary fluid and the ground and may allow the use of plain water as secondary fluid, an alternative to typical antifreeze aqueous solutions. The latter was demonstrated in a pipe-in-pipe BHE having an effective resistance of about 0.030 Km/W.

    Forced convection in the groundwater achieved by injecting nitrogen bubbles was found to reduce the local thermal resistance in U-pipe BHEs by about 30% during heat injection conditions. The temperatures inside the groundwater are homogenized while injecting the N2, and no radial temperature gradients are then identified. The fluid to groundwater thermal resistance during forced convection was measured to be 0.036 Km/W. This resistance varied between this value and 0.072 Km/W during natural convection conditions in the groundwater, being highest during heat pump operation at temperatures close to the water density maximum.

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    José Acuña - Doctoral Thesis
  • 40.
    Acuña, José
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Improvements of U-pipe Borehole Heat Exchangers2010Licentiate thesis, monograph (Other academic)
    Abstract [en]

    The sales of Ground Source Heat Pumps in Sweden and many other countries are having a rapid growth in the last decade. Today, there are approximately 360 000 systems installed in Sweden, with a growing rate of about 30 000 installations per year. The most common way to exchange heat with the bedrock in ground source heat pump applications is circulating a secondary fluid through a Borehole Heat Exchanger (BHE), a closed loop in a vertical borehole. The fluid transports the heat from the ground to a certain heating and/or cooling application. A fluid with one degree higher or lower temperature coming out from the borehole may represent a 2-3% change in the COP of a heat pump system. It is therefore of great relevance to design cost effective and easy to install borehole heat exchangers. U-pipe BHEs consisting of two equal cylindrical pipes connected together at the borehole bottom have dominated the market for several years in spite of their relatively poor thermal performance and, still, there exist many uncertainties about how to optimize them. Although more efficient BHEs have been discussed for many years, the introduction of new designs has been practically lacking. However, the interest for innovation within this field is increasing nowadays and more effective methods for injecting or extracting heat into/from the ground (better BHEs) with smaller temperature differences between the heat secondary fluid and the surrounding bedrock must be suggested for introduction into the market.

    This report presents the analysis of several groundwater filled borehole heat exchangers, including standard and alternative U-pipe configurations (e.g. with spacers, grooves), as well as two coaxial designs. The study embraces measurements of borehole deviation, ground water flow, undisturbed ground temperature profile, secondary fluid and groundwater temperature variations in time, theoretical analyses with a FEM software, Distributed Thermal Response Test (DTRT), and pressure drop. Significant attention is devoted to distributed temperature measurements using optic fiber cables along the BHEs during heat extraction and heat injection from and to the ground.

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  • 41.
    Acuña, José
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Distributed thermal response tests on pipe-in-pipe borehole heat exchangers2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, no SI, p. 312-320Article in journal (Refereed)
    Abstract [en]

    Borehole Thermal Energy Storage systems typically use U-pipe Borehole Heat Exchangers (BHE) having borehole thermal resistances of at least 0.06 K m/W. Obviously, there is room for improvement in the U-pipe design to decrease these values. Additionally, there is a need for methods of getting more detailed knowledge about the performance of BHEs. Performing Distributed Thermal Response Tests (DTRT) on new proposed designs helps to fill this gap, as the ground thermal conductivity and thermal resistances in a BHE can be determined at many instances in the borehole thanks to distributed temperature measurements along the depth. In this paper, results from three heat injection DTRTs carried out on two coaxial pipe-in-pipe BHEs at different flow rates are presented for the first time. The tested pipe-in-pipe geometry consists of a central tube inserted into a larger external flexible pipe, forming an annular space between them. The external pipe is pressed to the borehole wall by applying a slight overpressure at the inside, resulting in good thermal contact and at the same time opening up for a novel method for measuring the borehole wall temperature in situ, by squeezing a fiber optic cable between the external pipe and the borehole wall. A reflection about how to calculate borehole thermal resistance in pipe-in-pipe BHEs is presented. Detailed fluid and borehole wall temperatures along the depth during the whole duration of the DTRTs allowed to calculate local and effective borehole thermal resistances and ground thermal conductivities. Local thermal resistances were found to be almost negligible as compared to U-pipe BHEs, and the effective borehole resistance equal to about 0.03 K m/W. The injected power was found to be almost evenly distributed along the depth.

  • 42.
    Adem Esmail, Blal
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment.
    Geneletti, Davide
    An Operational Approach for Watershed Investments2020In: Ecosystem Services for Urban Water Security: Concepts and Applications in Sub-Saharan Africa, Cham: Springer Nature , 2020Chapter in book (Refereed)
    Abstract [en]

    This chapter focuses on Watershed Investments for securing water for cities. It starts with a brief account of the application of ecosystem services for decision-making and a theoretical background of boundary work. Accordingly, it proposes an operational approach developed for designing and assessing impact of watershed iInvestments to secure water for cities. The developed approach distin- guishes between a “strategic” and a “technical” component. The strategic component identifies as key inputs of the process of Watershed Investment design and assess- ment, the definition of objectives and visioning of feasible and desirable scenarios by stakeholders. The technical component applies spatially explicit modelling to design Watershed Investments, hence to model the impacts on selected ecosystem services. The chapter concludes highlighting the potential of the approach to contribute to adaptive management in the urban water sector, by addressing the challenges of linking diverse stakeholders and knowledge system across management levels and institutional boundaries.

  • 43. Adem Esmail, Blal
    et al.
    Geneletti, Davide
    Challenges for Water Security in Asmara, Eritrea2020In: Ecosystem Services for Urban Water Security: Concepts and Applications in Sub-Saharan Africa, Cham: Springer Nature , 2020Chapter in book (Refereed)
    Abstract [en]

    This chapter presents a case study of urban water sector selected to apply a novel approach for designing and assessing impacts ofWatershed Investments and more generally to explore the challenges of urban water security in a Sub-Saharan Africa context characterized by limited resources. The case is about the city of Asmara—the city capital of Eritrea—and its main water supply, the Toker water- shed. The chapter illustrates the main socio-ecological challenges and opportunities for promoting adaptive management in the case study. In particular, to illustrate contextual and contingent factors characterizing the case study, three examples of ongoing soil and water conservation activities are presented. The chapter concludes with a focus on the Asmara Water Supply Department (AWSD), a key stakeholder in the selected case study. Specifically, the AWSD is analysed through an approach for conceptualizing water utilities as “learning organization” and assessing their institutional capacity.

  • 44.
    Adem Esmail, Blal
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment.
    Geneletti, Davide
    Conclusions2020In: Ecosystem Services for Urban Water Security: Concepts and Applications in Sub-Saharan Africa, Cham: Springer Nature , 2020Chapter in book (Refereed)
    Abstract [en]

    This chapter summarizes the main messages of the book, as well as dis- cusses the challenges for future research and practice to contribute to achieving water security and to implementing adaptive management in the urban water sector. Briefly, the first main message is that achieving urbanwater security through adaptive watershed planning and management, in Sub-Saharan Africa context, is a complex issue. Thus, an intuitive and flexible conceptual framework of the urban water sector from an ecosystem services perspective was proposed. It provides an overview of the main challenges and trends that characterize the sector, highlighting the specificities of the Sub-Saharan context, setting the background for further analysis. Second, if properly designed, Watershed Investments can become an important financial and governance mechanism to promote the implementation of adaptive watershed man- agement to achieve urban water security. Third, a good case study application, even if only based on desk research, can serve to inspire stakeholder and possibly prepare the ground for real-life implementation of science-informed measures to promote urban water security alongside other social goals, coordinating ongoing watershed initiatives.

  • 45.
    Adem Esmail, Blal
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment.
    Geneletti, Davide
    Designing Watershed Investments for Asmara and the Toker Watershed2020In: Ecosystem Services for Urban Water Security: Concepts and Applications in Sub-Saharan Africa, Cham: Springer Nature , 2020Chapter in book (Refereed)
    Abstract [en]

    This chapter presents an application of a novel operational approach for designing and assessing the impacts ofWatershed Investments, developed in Chap. 3, to the Asmara and Toker Watershed case study. Assuming urban water security and rural poverty alleviation as two objectives for Watershed Investments, the case study application explores all the steps ofthe proposed approach. The results ofthe applica- tion include spatially explicit data that allowquantitatively assessing the performance of differentWatershed Investment scenarios in terms of changes in a selected ecosys- tem service, answering to important planning and management questions. The appli- cation to the Asmara and Toker Watershed case study also highlights the challenges of addressing stakeholders’ concerns through relevant boundary work strategies.

  • 46. Adem Esmail, Blal
    et al.
    Geneletti⁠, Davide
    Ecosystem services for urban water security.: Concepts and applications in Sub-Saharan Africa2020 (ed. 1)Book (Refereed)
    Abstract [en]

    The book addresses the challenges of urban water security and adaptive management in Sub-Saharan Africa, exploring and interlinking novel concepts of ecosystems services, watershed investments, and boundary work. Specifically, the book’s goals are to (i) present a conceptual framework for the urban water sector from an ecosystem services perspective, highlighting the specificities of the Sub-Saharan context; (ii) develop an operational approach to designing and assessing the impacts of watershed investments, based on ecosystem services and boundary work; and (iii) test the approach through a case study in Asmara, Eritrea, and discuss the findings and lessons learned that can be applied in other contexts. 

    Through a fully worked out case study, from identification of water challenges and opportunities to spatially explicit modelling, the book offers a sound and accessible, coverage of issues and proposed solutions to better operationalize ecosystem services, watershed investments and boundary work, to promote adaptive management, and achieve water security in the context of rapidly developing cities in Sub-Saharan Africa. The book is an effective tool for capacity building of diverse stakeholders on the urban water sector, including water managers, local and national policy-makers as well as a suitable resource for both undergraduate and post-graduate courses in planning and geography.

  • 47.
    Adem Esmail, Blal
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment. Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.
    Geneletti, Davide
    Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.
    Introduction2020In: Ecosystem Services for Urban Water Security: Concepts and Applications in Sub-Saharan Africa, Cham: Springer Nature , 2020Chapter in book (Refereed)
    Abstract [en]

    This chapter sets the context of the book by providing a brief account of the challenges and opportunities of urbanization in Sub-Saharan Africa, with a focus on the urban water sector. Watershed investments are here emphasized as a promising opportunity to effect large-scale transformative change promoting human wellbeing while conserving life-supporting ecosystems. The chapter concludes by illustrating the three specific objectives of the book.

  • 48.
    Adem Esmail, Blal
    et al.
    Univ Trento, Dept Civil Environm & Mech Eng.
    Geneletti, Davide
    Univ Trento, Dept Civil Environm & Mech Eng.
    Albert, Christian
    Leibniz Univ Hannover, Inst Environm Planning, Herrenhauser Str 2, D-30419 Hannover, Germany; UFZ Helmholtz Ctr Environm Res, Dept Environm Polit, Permoserstr 15, D-04318 Leipzig, Germany.
    Boundary work for implementing adaptive management: A water sector application2017In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 593-594, p. 274-285Article in journal (Refereed)
    Abstract [en]

    Boundary work, defined as effort to mediate between knowledge and action, is a promising approach for facilitating knowledge co-production for sustainable development. Here, we investigate a case study of knowledge co-production, to assess the applicability of boundary work as a conceptual framework to support implementing adaptive management in the water sector. We refer to a boundary work classification recently proposed by Clark et al., (2016), based on three types of knowledge uses, i.e. enlightenment, decision-, and negotiation-support, and three types of sources, i.e. personal expertise, single, and multiple communities of expertise. Our empirical results confirm boundary work has been crucial for the three types of knowledge use. For enlightenment and decision support, effective interaction among knowledge producers and users was achieved through diverse boundary work practices, including joint agenda setting, and sharing of data and expertise. This initial boundary work eased subsequent knowledge co-production for decision-support and negotiations, in combination with stepping up of cooperation between relevant actors, suitable legislation and pressure for problem solving. Our analysis highlighted the temporal dimension matters-building trust around enlightenment first, and then using this as a basis for managing knowledge co-production for decision-, and negotiation support. We reconfirmed that boundary work is not a single time achievement, rather is a dynamic process, and we emphasized the importance of key actors driving the process, such as water utilities. Our results provide a rich case study of how strategic boundary work can facilitate knowledge co-production for adaptive management in the water sector. The boundary work practices employed here could also be transferred to other cases. Water utilities, as intermediaries between providers and beneficiaries of the important water-related ecosystem service of clean water provision, can indeed serve as key actors for initiating such boundary work practices. (C) 2017 Elsevier B.V. All rights reserved

  • 49.
    Adem Esmail, Blal
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment.
    Suleiman, Lina
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Urban and Regional Studies.
    Analyzing Evidence of Sustainable Urban Water Management Systems: A Review through the Lenses of Sociotechnical Transitions2020In: Sustainability, E-ISSN 2071-1050, Vol. 12, no 11, p. 4481-Article in journal (Refereed)
    Abstract [en]

    Sustainability concerns and multiple socio‐environmental pressures have necessitated a shift towards Sustainable Urban Water Management (SUWM) systems. Viewing SUWM systems as sociotechnical, this paper departs from eight factors previously identified by transition research: Pressures, Context, Purposes, Actors, Instruments, Processes, Outputs, and Outcomes as a methodological framework for a structured review of 100 articles. The study seeks to analyze empirical cases of planning and implementing SUWM systems worldwide. A wide range of public actors—driven by social and environmental factors rather than by economic pressures—have initiated SUWM projects so as to locally fulfill defined social and environmental purposes. We provide evidence on the emergence of new actors, such as experts, users, and private developers, as well as on the diverse and innovative technical and societal instruments used to promote and implement SUWM systems. We also explore their contexts and institutional capacity to deal with pressures and to mobilize significant financial and human resources, which is in itself vital for the transition to SUWM. Planned or implemented SUWM outputs are divided into green (wet ponds, raingardens, and green roofs) and gray (rain barrels and porous pavements) measures. The outcomes of SUWM projects— in terms of societal and technical learning, and their institutional uptakes—are often implicit or lacking, which seemingly reduces the rate of desirable change.

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  • 50.
    Adesanya, Adewale A.
    et al.
    Energy and Environmental Analysis Group, New York State Energy Research and Development Authority (NYSERDA), Albany, NY, 12203, USA; Havenergy Consulting Inc, Albany, NY, 12203, USA.
    Sommerfeldt, Nelson
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Pearce, Joshua M.
    Department of Electrical and Computer Engineering, Ivey School of Business, University of Western Ontario, London, ON, N6A 5B9, Canada.
    Achieving 100% Renewable and Self-Sufficient Electricity in Impoverished, Rural, Northern Climates: Case Studies from Upper Michigan, USA2022In: Electricity, E-ISSN 2673-4826, Vol. 3, no 3, p. 264-296Article, review/survey (Refereed)
    Abstract [en]

    The development of 100% renewable electricity (RE) systems play a pivotal role in ensuring climate stability. Many municipalities blessed with wealth, an educated and progressive citizenry, and large RE resources, have already reached 100% RE generation. Impoverished municipalities in unwelcoming environments both politically and climatically (e.g., northern latitudes with long, dark winter conditions) appear to be incapable of transitioning to renewables. This study challenges that widespread assumption by conducting a detailed technical and economic analysis for three representative municipalities in the Western Upper Peninsula of Michigan. Each municipality is simulated with their own hourly electricity demand and climate profiles using an electrical supply system based on local wind, solar, hydropower, and battery storage. Sensitivities are run on all economic and technical variables. Results show that transition to 100% RE is technically feasible and economically viable. In all baseline scenarios, the 100% RE systems produced a levelized cost of electricity up to 43% less than the centralized utility rates, which are predominantly fueled by gas and coal. Current policies, however, prevent such self-sufficient systems from being deployed, which are not only detrimental to the global environment, but also aggravate the economic depression of such regions. Potential energy savings advance the prohibitive energy justice principle.

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