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[en] Highlights: • A systems approach is suggested when investigating the benefits of energy savings. • The effect of savings is analysed on a Danish case. • Synergies between different types of savings are investigated. • System effects can be very significant for the performance of savings. • Different types of energy savings must be coordinated. - Abstract: In the transition towards a 100% renewable energy system, energy savings are essential. The possibility of energy savings through conservation or efficiency increases can be identified in, for instance, the heating and electricity sectors, in industry, and in transport. Several studies point to various optimal levels of savings in the different sectors of the energy system. However, these studies do not investigate the idea of energy savings being system dependent. This paper argues that such system dependency is critical to understand, as it does not make sense to analyse an energy saving without taking into account the actual benefit of the saving in relation to the energy system. The study therefore identifies a need to understand how saving methods may interact with each other and the system in which they are conducted. By using energy system analysis to do hourly simulation of the current Danish energy system, the combination of reductions in heat and electricity demands is analysed within the Danish district heating sector to show the benefits of coordinating savings in the electricity and district heating sectors
[en] Transport is one of the most challenge sectors when addressing energy security and climate change due to its high reliance on oil products and lack of the alternative fuels. This paper explores the ability of three transport strategies to contribute to the development of a sustainable transport in China. With this purpose in mind, a Chinese transport model has been created and three current transport strategies which are high speed railway (HSR), urban rail transit (URT) and electric vehicle (EV) were evaluated together with a reference transport system in 2020. As conservative results, 13% of the energy saving and 12% of the CO2 emission reduction can be attained by accomplishing three strategies compared with the reference transport system. However, the energy demand of transport in 2020 with the implementation of three strategies will be about 1.7 times as much as today. The three strategies show the potential of drawing the transport demand to the more energy efficient vehicles; however, more initiatives are needed if the sustainable transport is the long term objective, such as the solutions to stabilise the private vehicle demands, to continuously improve the vehicle efficiency and to boost the alternative fuels produced from the renewable energy sources. - Highlights: • A Chinese transport model was created and three transport strategies were evaluated • Transport is the biggest driver of the oil demand in China not the industry • The energy demand of transport in 2020 will be twice as much as today • Strategies contribute 13% energy saving and 12% CO2 emission reduction • More initiatives are needed if a sustainable transport is the long-term objective
[en] The paper presents the results of two research projects conducted by Aalborg University and financed by the Danish Energy Research Programme. Both projects include the development of models and system analysis with focus on large-scale integration of wind power into different energy systems. Market reactions and ability to exploit exchange on the international market for electricity by locating exports in hours of high prices are included in the analyses. This paper focuses on results which are valid for energy systems in general. The paper presents the ability of different energy systems and regulation strategies to integrate wind power, The ability is expressed by three factors: One factor is the degree of electricity excess production caused by fluctuations in wind and CHP heat demands. The other factor is the ability to utilise wind power to reduce CO2 emission in the system. And the third factor is the ability to benefit from exchange of electricity on the market. Energy systems and regulation strategies are analysed in the range of a wind power input from 0 to 100% of the electricity demand. Based on the Danish energy system, in which 50 per cent of the electricity demand is produced in CHP, a number of future energy systems with CO2 reduction potentials are analysed, i.e. systems with more CHP, systems using electricity for transportation (battery or hydrogen vehicles) and systems with fuel-cell technologies. For the present and such potential future energy systems different regulation strategies have been analysed, i.e. the inclusion of small CHP plants into the regulation task of electricity balancing and grid stability and investments in electric heating, heat pumps and heat storage capacity. Also the potential of energy management has been analysed. The results of the analyses make it possible to compare short-term and long-term potentials of different strategies of large-scale integration of wind power
[en] In the transition to renewable energy systems, fluctuating renewable energy, such as wind and solar power, plays a large and important role. This creates a challenge in terms of meeting demands, as the energy production fluctuates based on weather patterns. To utilise high amounts of fluctuating renewable energy, the energy system has to be more flexible in terms of decoupling demand and production. This paper investigates two potential ways to increase flexibility. The first is the interconnection between energy systems, for instance between two countries, labelled as cross-border interconnection, and the second is cross-sector interconnection, i.e., the integration between different parts of an energy system, for instance heat and electricity. This paper seeks to compare the types of interconnectivity and discuss to which extent they are mutually beneficial. To do this, the study investigates two energy systems that represent Northern and Southern Europe. Both systems go through three developmental steps that increase the cross-sector interconnectivity. At each developmental step an increasing level of transmission capacities is examined to identify the benefits of cross-border interconnectivity. The results show that while both measures increase the system utilisation of renewable energy and the system efficiency, the cross-sector interconnection gives the best system performance. To analyse the possible interaction between cross-sector and cross-border interconnectivity, two main aspects have to be clarified. The first part defines the approach and the second is the construction of the two archetypes. - Highlights: • A method to investigate system integration and system interconnection is suggested. • The implementation is investigated across a Northern and Southern energy system. • The study identifies benefits of system integration and system interconnection. • The performance of the energy system benefits most from system integration.
[en] Climate change response, including the implementation of the Kyoto targets as the first step, calls for technological innovation of future sustainable energy systems. Based on the Danish case, this paper evaluates the type of technological change necessary. During a period of 30 years, Denmark managed to stabilize primary energy supply, and CO2 emissions decreased by 10%, during a period of 20 years. However, after the introduction of the Kyoto Mechanisms, Denmark has changed its strategy. Instead of continuing the domestic CO2 emission controls, Denmark plans to buy CO2 reductions in other countries. Consequently, the innovative technological development has changed. This paper evaluates the character of such change and makes preliminary recommendations for policies to encourage the use of the Kyoto Mechanisms as an acceleration of the necessary technological innovation. (author)
[en] Future sustainable energy systems call for the introduction of integrated storage technologies. One of these technologies is compressed air energy storage (CAES). In Denmark at present, wind power meets 20% and combined heat and power production (CHP) meets 50% of the electricity demand. Based on these figures, the paper assesses the value of integrating CAES into future sustainable energy systems with even higher shares of fluctuating renewable energy sources. The evaluation is made on the basis of detailed energy system analyses in which the supply of complete national energy systems is calculated hour by hour in relation to the demands during a year. The Danish case is evaluated in a system-economic perspective by comparing the economic benefits achieved by improving the integration of wind power to the costs of the CAES technology. The result is compared to various other storage options. Furthermore, a business-economic evaluation is done by calculating the potential income of the CAES technology from both spot markets and regulating power markets. The evaluation includes both historical hour by hour prices during a 7-year period on the Nordic Nord Pool market as well as expected future price variations. The conclusion is that even in energy systems with very high shares of wind power and CHP, neither the historical nor the expected future price variations on the spot market alone can justify the investment in CAES systems. Other storage technology options are significantly more feasible. CAES may operate both on the spot market and the regulating power market, which indicates potential feasibility. However, such strategy is highly risky because of the small extent of the regulating power market and if CAES is to become feasible it will depend on incomes from auxiliary services. (author)
[en] In 2005, wind power supplied 19% of the 36 TWh annual electricity demand in Denmark, while 50% was produced at combined heat-and-power plants (CHP). The installed wind-turbine capacity in Western Denmark exceeds the local demand at certain points in time. So far, excess production has been exported to neighbouring countries. However, plans to expand wind power both in Denmark and in its neighbouring countries could restrain the export option and create transmission congestion challenges. This results in a need to increase the flexibility of the local electricity-system. Compressed-Air Energy-Storage (CAES) has been proposed as a potential solution for levelling fluctuating wind-power production and maintaining a system balance. This paper analyses the energy-balance effects of adding CAES to the Western Danish energy-system. Results show that even with an unlimited CAES plant capacity, excess power production is not eliminated because of the high percentage of CHP production. The optimal wind-power penetration for maximum CAES operation is found to be around 55%. The minimum storage size for CAES to fully eliminate condensing power plants operation in the optimized system is over 500 GWh, which corresponds to a cavern volume of around 234 Mm3 at an average pressure of 60 bar. Such a storage size would be technically and economically unfeasible. The analysis, however, did not include the potential role of a CAES plant in regulating the power services. (author)
[en] Aalborg Municipality, Denmark, wishes to investigate the possibilities of becoming independent of fossil fuels. This article describes a scenario for supplying Aalborg Municipality's energy needs through a combination of low-temperature geothermal heat, wind power and biomass. Of particular focus in the scenario is how low-temperature geothermal heat may be utilised in district heating (DH) systems. The analyses show that it is possible to cover Aalborg Municipality's energy needs through the use of locally available sources in combination with significant electricity savings, heat savings, reductions in industrial fuel use and savings and fuel-substitutions in the transport sector. With biomass resources being finite, the two marginal energy resources in Aalborg are geothermal heat and wind power. If geothermal heat is utilised more, wind power may be limited and vice versa. The system still relies on neighbouring areas as an electricity buffer though. The costs of the scenario are at a comparable level with the reference situation, but with significantly higher needs for investments and lower fuel costs. Implementation of the scenario would therefore have a positive socio-economic impact as investments are more local labour-intensive than fuel supply. (author)
[en] Significant benefits are connected with an increase in the flexibility of the Danish energy system. On the one hand, it is possible to benefit from trading electricity with neighbouring countries, and on the other, Denmark will be able to make better use of wind power and other types of renewable energy in the future. This paper presents the analysis of different ways of increasing flexibility in the Danish energy system by the use of local regulation mechanisms. This strategy is compared with the opposite extreme, i.e. trying to solve all balancing problems via electricity trade on the international market. The conclusion is that it is feasible for the Danish society to include the CHP plants in the balancing of fluctuating wind power. There are major advantages in equipping small CHP plants as well as the large CHP plants with heat pumps. By doing so, it will be possible to increase the share of wind power from the present 20 to 40% without causing significant problems of imbalance between electricity consumption and production. Investment in increased flexibility is in itself profitable. Furthermore, the feasibility of wind power is improved
[en] In 2009, Jiangsu province of China supplied 99.6 percent of its total energy consumption with fossil fuels, of which 82 percent was imported from other provinces and countries. With rising energy demand, frequent energy shortages, and increasing pollution, it is essential for Jiangsu to put more emphasis on improving its energy efficiency and utilizing its renewable resources in the future. This paper presents the integrated energy pathway for Jiangsu during its social and economic transformation until 2050. EnergyPLAN is the chosen energy system analysis tool, since it accounts for all sectors of the energy system that needs to be considered when integrating large-scale renewable energy. A current policy scenario (CPS) based on current energy policies and an ambitious policy scenario (APS) based on large-scale integration of renewable energy and ambitious measures of energy efficiency improvement are proposed. The two energy pathways are modeled and compared in terms of technology combination, non-fossil fuel shares of primary energy supply, socioeconomic costs, and CO2 emissions. The insights from these pathways can provide valuable input for Jiangsu's future energy policies. - Highlights: ► An integrated energy pathway is designed for Jiangsu province by 2050. ► A current policy scenario and an ambitious policy scenario are modeled and assessed. ► The ambitious policy scenario can help stabilize CO2 emissions and achieve better economy. ► The next 5–10 years would be a key period for Jiangsu's energy system transition. ► Several policy suggestions have been proposed.