Energy Systems and Technologies for the Coming Century ...

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The commercial scale production of first-generation liquid biofuels has resulted in aseries of problems related to food prices, land usage and carbon emissions, while secondgeneration biofuels production suffers with cost effectiveness, technological barriers,feed stock collection networks, etc. (Nigam and Singh, 2011).The food fuel debate, lead to a negative perception of biofuels, while third generationbiofuels i.e. produced from algal biomass are an invoking choice due to its rapid growth,higher lipid content, reduced land usage, limited fresh water consumption and highercarbon absorption rate (Jorquera et al., 2010; Singh et al., 2011a,b).The present paper aims to highlight key issues in the production of biofuels from algalbiomass, their sustainability and life cycle assessment.2 Algal biofuelsAlgae range from small, single-celled organisms to multi-cellular organisms and usuallyfound in damp places or bodies of water, thus are common in terrestrial as well asaquatic environments. Algae include seaweeds (macroalgae) and phytoplanktons(microalgae). Algae require primarily three components (sunlight, water and CO 2 ) toproduce biomass. Using only sunlight and abundant and freely available raw materials(e.g. CO 2 and nutrients from wastewater) algae can synthesize and accumulate largequantities of neutral lipids and carbohydrates along with other valuable co-products (e.g.astaxanthin, omega three fatty acids, etc.). Algae can thus play a major role in thetreatment/utilization of wastewater and reduce the environmental impact and disposalproblems. The existing large-scale natural sources of algae include bogs, marshes,swamps, etc. (Wagner, 2007, Singh and Olsen, 2011, Singh et al., 2011b).The algal biomass as an energy feedstock can be utilized with applications beingdeveloped for the production of biodiesel, bioethanol, biomethane and biohydrogen(Singh and Olsen, 2011). Algae can be grown on saline/coastal sea water and on nonagricultural lands (desert, arid and semi-arid land), reducing the conflicts of energy cropswith food crop and fresh water utilization.Microalgae are single-cell, photosynthetic organisms known for their rapid growth andhigh energy content. Some algal strains are capable of doubling their mass several timesper day. In some cases, more than half of that mass consists of lipids or triacylglycerides.Biomass doubling times during exponential growth are commonly as short as 3.5 h(Chisti, 2007). Oil content in microalgae can be up to 80% of dry biomass depending onspecies (Singh et al., 2011a).The wastewater and seawater offers clear advantages for the cultivation of algal biomassover placing increased pressure on freshwater resources. However, wastewater qualityvaried dramatically from one source to another and also fluctuating over time.Chinnasamy et al. (2010) conducted a study with 85–90% carpet industry effluents alongwith 10–15% municipal sewage, to evaluate the feasibility of algal biomass and biodieselproduction and reported that both fresh water and marine algae showed good growth inwastewaters. Wastewater generated by carpet mills along with sewage from Dalton areain North Central Georgia has potential to generate up to 15,000 tons of algal biomasswhich can produce about 2.5–4 million L of biodiesel and remove about 1500 tons ofnitrogen and 150 tons of phosphorus from the wastewater in one year.Biogas production is a long-established technology and previous trials have indicatedthat anaerobic digestion of seaweed (macroalgae) is technically viable. The lack of easilyfermented sugar polymers such as starch, glucose or sucrose makes fermentation processdifficult as there is little point in pursuing standard sugar fermentation processes. Thepolysaccharides that are present will require a new commercial process to break downinto their constituent monomers prior to fermentation, or a direct fermentation processwill have to be developed. Microalgae have the ability to produce lipids that can be usedfor biodiesel production (Singh et al., 2011b).Risø International Energy Conference 2011 Proceedings Page 276
2.1 Key issuesDifferent algal strains perform differently, therefore it is essential to select strainscapable of growing in variety of wastewaters and producing feedstock for biofuels thatcan compete with biodiesel, biomethane and bioethanol in terms of land and water use,carbon sequestration and GHG emission savings, etc. Capability of algae to consumelarge amounts of CO 2 also makes it an attractive option as the process could be carbonneutral (Wang et al., 2008).Naturally, lipids accumulation increases under specific conditions, thus it is important tomaintain those factors that lead to accumulation of lipids in algae, like nutrients, CO 2concentration and sun light, etc. (Schenk et al., 2008). The best performing micro algaestrain can be obtained by screening of a wide range of naturally available isolates and theefficiency of those can be improved by selection, adaptation and genetic engineering(Singh et al., 2011a).The higher biomass yield with minimal operational cost and energy input is also achallenge to make algal biofuels as a sustainable biofuel. The operational cost andenergy input can be reduced by utilizing nutrients from wastewater and CO 2 fromindustrial flue gases and cultivating at area receiving bright sun shine for longer period.The quality of oil used for the production of biodiesel has a great impact on the qualityof the biodiesel produced. Genetic engineering of key enzymes in specific fatty acidproduction pathways within lipid biosynthesis is a promising target for the improvementof both quantity and quality of lipids. Algae have excellent potential for the geneticmodification of their lipid pathways. Any increase in photosynthetic efficiency willenhance downstream biofuels production as it drives the first stage of all biofuelsproduction processes (Schenk et al., 2008, Singh et al., 2011a).Bioreactor designs vary widely, but there is room for improvement to make systemssimple and cheap enough to be scaled while maintaining the higher productivity andcontrol over the culture than ponds allow. Clearly, an integrative approach where allnutrients are recycled and co-products are generated would be necessary for either pondsor bioreactors to be economic (Chisti, 2008), though this would be easier to achieve forbioreactors because of the greater control over them.Algal strains required physiological and biochemical adaptations for conditions of lowlight, including tightly stacked thylakoids and large light-harvesting antenna complexesthat allow them to effectively capture light energy. Optimizing stress conditions to obtainthe highest possible yields of lipids in the cells is very important to make it economicallyviable biofuel. Stimulated evolution is one option commonly used for bacteria and stressconditions can induce spontaneous mutation in cultivated strains. Selection of thesenatural mutants can improve production yields. Another option is to select wild localspecies that are already adapted to local growth conditions. Genetic modification (GM)is another option to improve production efficiency of algal strain. One current example isthe Algenol Company which is developing a strain of GM cyanobacteria capable ofproducing ethanol. Improved harvesting technologies are also needed. Lipid extractionprior to esterification is an area for further research. It would be an important advance ifmethods without drying or solvent extraction of the algae slurry could be developed as itwould significantly reduce the cost of biomass pre-treatment (Singh et al., 2011b).2.2 SustainabilityWorld Commission on Environment and Development defined the term ‘sustainability’as “the development that meets the needs of the present without compromising theability of future generations to meet their own needs” (UNCED, 1992). Sustainabilityassessment of products or technologies is normally seen as encompassing impacts inthree dimensions i.e. social, environmental, and economic (Elkington, 1998).Sustainability has become an unavoidable issue in all major planning and undertakingsthat involve future use of energy, water and other natural resources. The sustainability ofbiofuels production depends on the net energy gain fixed in the biofuels that depends onRisø International Energy Conference 2011 Proceedings Page 277
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Energy Systems and Technologies for
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ContentsSessions overview 1Programm
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sessions overview08:00-09:00Coffee
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11:00 - 12:30 session 6A - Bioenerg
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ContactSustainable Energy, Technica
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Penetration of new energy technolog
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how decisions are made and by whom
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(9) is the logaritimic expansion of
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(16)we may finally write Eq(14) in
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Table 1: Fast track cases for new r
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Peterka V. Macrodynamics of technol
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Growth in clean and reliable energy
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Conclusion - an ambitious vision an
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"Spurring investments in renewable
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Integrating climate change adaptati
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transport, and finance. Energy prov
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northern South America, the Caribbe
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Table 1: Energy system adaptation s
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More generally, a number of no- or
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6 ReferencesADB, 2005. Climate proo
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Sailor, D.J., Smith, M., Hart, M.,
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Factors affecting stakeholder perce
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Another study conducted in Japan wa
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4 The effect of information on stak
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Furthermore, communication to stake
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Shackley S, McLachlan C, Gough C (2
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Figure 1: Potential CO 2 storage si
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The Upper Jurassic - Lower Cretaceo
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The majority of the individual stru
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Development. Project no. ENK6-CT-19
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Section 5 summarises the key issue
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Table 1. Efficiencies for new large
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In addition, district heating syste
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6.4 Model results from EFDA-TIMESIn
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Maisonnier, D., et al. (2007), Powe
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1Efficiency and effectiveness of pr
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3Stromerzeugung [TWh/a]250200150100
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54 Country-specific Lessons learned
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7100%90%80%quota fullfilment (%)70%
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[5] Haas R., et al: Efficiency and
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The development and diffusion of re
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a. Offshore wind in DenmarkDenmark
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applicants are invited to submit a
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nies that provide upstream and down
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for both technology users and produ
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Trade Disputes over Renewable Energ
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treatment to imported renewable ene
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In Canada, the federal government i
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grid access, subsidies and land off
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In 2010, China’s total wind insta
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Source: Renewables 2010 Global Stat
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Source: REN 21, Renewables 2010 Glo
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Source: adapted from REN21, 2010It
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their precise scope and nature diff
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60 daysBy 2 nd DSBmeetingConsultati
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discriminatory manner on domestic a
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the European Union, the North Ameri
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ended. China lost this case because
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As most countries in the world are
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Session 3A - Energy SystemsRisø In
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1 IntroductionWith the introduction
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occur. This is an undesirably burea
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This curve could be used as a new t
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ut for the total consumption, and i
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This gives the LBR an opportunity t
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concludes that the subsurface conta
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to constrain the evaluation. In add
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Fig. 2 SW-NE trending seismic profi
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Fig. 5. Petrophysical evaluation of
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ConclusionsThe Danish subsurface co
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Performance of Space Heating in aMo
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[5],[10],[11],[16],[18],[20],[26].
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2/3 Sun1 Coal1/3 ElPower plantHP1 H
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25002000Surplus(min(wind,prod-cons)
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160CO 2 emission per unit heat prod
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The calculations have been based on
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Session 3B - smart gridsRisø Inter
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2 Myopic Investments2.1 The Balmore
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Moreover, this model is formulated
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Reducing Electricity Demand Peaks b
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3 Event Driven Scheduling Algorithm
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5 Mapping Teletraffic Theory to Ene
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6.2 Results and Performance Metrics
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Energy Efficient Refrigeration and
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Virtual Power PlantAggregatorSuperm
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C p,rC p,fT rT fW cφ sT a(UA) raHe
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Total PowerP.G. #1P.G. #2C.R. #1201
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the availability payment.Simulation
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The constraint in Eq. (16) has the
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The FlexControl concept - a vision,
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can react on requests for power reg
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3 ControlThe concept is based solel
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one hour to the next - correspondin
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4 ProtectionThe protection of the p
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Session 4 - Efficiency Improvements
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the product portfolio point of view
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Figure 4: Principle flow sheet of t
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process information needed are seld
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AIRFINE®(Reference)MEROS®Ca(OH)2M
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4 Conclusion & DiscussionThe Eco-Ca
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1 Energy policy and EU directivesTh
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iomass CHP, heat pumps, electric bo
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Fig. 1: How to supply a growing hea
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Session 5A - Wind Energy IRisø Int
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The average cumulative growth rate
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turbines is expected to create a st
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O&MGridWindturbineSubstructureFigur
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Another idea is to harvest energy f
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9. Shimon Awerbuch, Determining the
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engaged in wind energy assessment,
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treated in such a way to make them
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Figure 5: Map showing the estimated
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Figure 9: The annual mean power den
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mix is required. For example diurna
Page 230 and 231: Session 5B - Wind Energy IIRisø In
Page 232 and 233: TABLE ISOME OF THE WIND TURBINE MAN
Page 234 and 235: China, has prompted all parties, in
Page 236 and 237: to the high shaft speed. Furthermor
Page 238 and 239: Superconductors must be kept cold b
Page 240 and 241: an annual increase in demand of 6%,
Page 242 and 243: Improved High Temperature Supercond
Page 244 and 245: our study to a single set of deposi
Page 246 and 247: 3.2 Yttrium-enriched YBCO thin film
Page 248 and 249: Fig. 5. AC-susceptibility dependenc
Page 250 and 251: The j C (B) dependence at 50 K for
Page 252 and 253: Session 6A - Bioenergy IRisø Inter
Page 254 and 255: The European politicians are faced
Page 256 and 257: The fast growing demand for biomass
Page 258 and 259: Figure 2: Avedøre Power Plant in C
Page 260 and 261: Figure 5: Concept for a sustainable
Page 262 and 263: The role of biomass and CCS in Chin
Page 264 and 265: 2.2.1 CCS Potential for ChinaCCS is
Page 266 and 267: 80%70%60%China's share ofglobal CO
Page 268 and 269: In general, if the CCS technology d
Page 270 and 271: with high implementation of CCS Chi
Page 272 and 273: The European Biofuels Policy: from
Page 274 and 275: aimed to promote agriculture-based
Page 276 and 277: (EC, 2009b), and internationally vi
Page 278 and 279: Session 6B - Bio Energy IIRisø Int
Page 282 and 283: the production process parameters,
Page 284 and 285: NutrientWaterAlgal cultureproductio
Page 286 and 287: Schenk, P.M., Thomas-Hall, S.R., St
Page 288 and 289: Liquid biofuels from blue biomassZs
Page 290 and 291: Even though final ethanol yields we
Page 292 and 293: Integrated Gasification SOFC Plant
Page 294 and 295: 2.1 Modelling of SOFCThe SOFC model
Page 296 and 297: where g 0 , R an T are the specific
Page 298 and 299: hand side y-axis corresponds to eff
Page 300 and 301: The moister content for these three
Page 302 and 303: Use of Methanation for Optimization
Page 304 and 305: power production from utilizing the
Page 306 and 307: 2.1 Model DescriptionThe developed
Page 308 and 309: Figure 3: Flow sheet of methanation
Page 310 and 311: efficiency and turbine inlet temper
Page 312 and 313: [14] DNA - A Thermal Energy System
Page 314 and 315: On the effectiveness of standards v
Page 316 and 317: educing new car emissions to 120 g
Page 318 and 319: In addition energy consumption E an
Page 320 and 321: coefficient γ for the impact of fu
Page 322 and 323: 400200Change in energy (PJ)01980 19
Page 324 and 325: Figure 9 depict scenarios for the f
Page 326 and 327: What are customers willing to pay f
Page 328 and 329: Randomly, continuous up to ±50%Acc
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The likelihood for the model is giv
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eally means that this factor and no
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Table 5-1 Parameter estimates from
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Table 6-2 Willingness to pay for 10
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Session 12 - Energy for Developing
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Risø International Energy Conferen
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existing renewable energy technolog
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useful energyend energysecondary en
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parts or the means of enforcing war
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The development of micro-hydro proj
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Table 1. Electric power generation
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5 ReferencesBajgain, S., Shakya, I.
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IntroductionElectricity has become
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of 2008, 43.6% of the total populat
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Hilmand provinces have comparativel
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….. eq. 5LCOE is the net present
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case of Nepal, it is 5% (Trading ec
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ing down the cost of solar PV modul
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3.3 Serving the rural areas with na
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The levelized costs of electricity
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Figure 4. Variation in LCOE with si
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The analysis reveals that fuel cost
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In case of DG, we have looked with
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Gross, R., Blyth, W., Heptonstall,
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Mode of Transport to Work, Car Owne
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power parity (PPP) basis, GDP per c
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83,385 to 109,108 while the number
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other purposes so that reduced fare
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emissions studies is that they were
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where I (·) is the indicator funct
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increases, individuals acquire more
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while that of other means of transp
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into CO 2 . For all oil and oil pro
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impact. In general, income is found
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7 ReferenceAlperovich, G., Deutsch,
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Table 1: Definitions of Variables a
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Session 13 - Energy StorageRisø In
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2 Storage demand and resulting stor
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compressed air storages, demand sit
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Fig. 3: Options for underground sto
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3.5 Geological potential in EuropeF
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Sensitivity on Battery Prices and C
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3.1 Base caseA northern European en
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4 ResultsThe model is run on a comp
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Furthermore, a slight decrease in t
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Night time charging increases with
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Lithuanian Energy Institute, PSE In
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atteries, Compressed Air Energy Sto
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negative net load, can be expected
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25%Pct. of the year20%15%10%5%0.5-0
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800006000040000MWh200000Netload-200
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[4] B. V. Mathiesen and H. Lund, "C
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Compressed Air Energy Storage in Of
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compressed air caverns, corrosion-r
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Figure 3: Distribution of salt depo
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Figure 6: EWEA's 20 year Offshore N
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spinning reserves can be provided b
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7 Discussion and conclusionsThis pa
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Risø DTU is the National Laborator
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