Role of hydrogen in future North European power system in 2060

The Balmorel model has been used to calculate the economic optimal energy system configuration for the Scandinavian countries and Germany in 2060 assuming a nearly 100% coverage of the energy demands in the power, heat and transport sector with renewable energy sources. Different assumptions about the future success of fuel cell technologies have been investigated as well as different electricity and heat demand assumptions. The variability of wind power production was handled by varying the hydropower production and the production on CHP plants using biomass, by power transmission, by varying the heat production in heat pumps and electric heat boilers, and by varying the production of hydrogen in electrolysis plants in combination with hydrogen storage. Investment in hydrogen storage capacity corresponded to 1.2% of annual wind power production in the scenarios without a hydrogen demand from the transport sector, and approximately 4% in the scenarios with a hydrogen demand from the transport sector. Even the scenarios without a demand for hydrogen from the transport sector saw investments in hydrogen storage due to the need for flexibility provided by the ability to store hydrogen. The storage capacities of the electricity storages provided by plug-in hybrid electric vehicles were too small to make hydrogen storage superfluous.     

Fuel cell electric vehicle as a power plant: Fully renewable integrated transport and energy system design and analysis for smart city areas

Reliable and affordable future zero emission power, heat and transport systems require efficient and versatile energy storage and distribution systems. This paper answers the question whether for city areas, solar and wind electricity together with fuel cell electric vehicles as energy generators and distributors and hydrogen as energy carrier, can provide a 100% renewable, reliable and cost effective energy system, for power, heat, and transport. A smart city area is designed and dimensioned based on European statistics. Technological and cost data is collected of all system components, using existing technologies and well-documented projections, for a Near Future and Mid Century scenario. An energy balance and cost analysis is performed. The smart city area can be balanced requiring 20% of the car fleet to be fuel cell vehicles in a Mid Century scenario. The system levelized cost in the Mid Century scenario is 0.09 €/kWh for electricity, 2.4 €/kg for hydrogen and specific energy cost for passenger cars is 0.02 €/km. These results compare favorably with other studies describing fully renewable power, heat and transport systems.     

Large-scale integration of wind power into different energy systems

The paper presents the ability of different energy systems and regulation strategies to integrate wind power. The ability is expressed by the following three factors: the degree of electricity excess production caused by fluctuations in wind and Combined Heat and Power (CHP) heat demands, the ability to utilise wind power to reduce CO₂ emission in the system, and 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% 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 ancillary grid stability services and investments in electric heating, heat pumps and heat storage capacity. 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.     

Technical, economic and environmental analysis of energy production from municipal solid waste

Four technologies are investigated which produce energy from municipal solid waste (MSW): incineration, gasification, generation of biogas and utilisation in a combined heat and power (CHP) plant, generation of biogas and conversion to transport fuel.Typically the residual component of MSW (non-recyclable, non-organic) is incinerated producing electricity at an efficiency of about 20% and thermal product at an efficiency of about 55%. This is problematic in an Irish context where utilisation of thermal products is not the norm. Gasification produces electricity at an efficiency of about 34%; this would suggest that gasification of the residual component of MSW is more advantageous than incineration where a market for thermal product does not exist. Gasification produces more electricity than incineration, requires a smaller gate fee than incineration and when thermal product is not utilised generates less greenhouse gas per kWh than incineration. Gasification of MSW (a non-homogenous fuel) is, however, not proven at commercial scale.Biogas may be generated by digesting the organic fraction of MSW (OFMSW). The produced biogas may be utilised for CHP production or for transport fuel production as CH₄-enriched biogas. When used to produce transport fuel some of the biogas is used in a small CHP unit to meet electricity demand on site. This generates a surplus thermal product.Both biogas technologies require significantly less investment costs than the thermal conversion technologies (incineration and gasification) and have smaller gate fees. Of the four technologies investigated transport fuel production requires the least gate fee. A shortfall of the transport fuel production technology is that only 50% of biogas is available for scrubbing to CH₄-enriched biogas.     

The effectiveness of storage and relocation options in renewable energy systems

Across the world, energy planners and transmission system operators are faced with decisions on how to deal with challenges associated with high penetration levels of intermittent energy resources and combined heat and power (CHP). At the same time, distributed plant operators are eager to reduce uncertainties related to fuel and electricity price fluctuations. These interests meet-up for options in distributed supply that introduces the principle of storage and relocation, typically by integrating heat pumps (HP) or electric boilers (EBs) into the operational strategies of existing CHP plants. This paper introduces the principle of storage and relocation by energy system design, and proposes for the storage and relocation potential of a technology option to be found by comparing options by their storage and relocation coefficient R_c, defined as the statistical correlation between net electricity exchange between plant and grid, and the electricity demand minus intermittent renewable electricity production. Detailed operational analyses made for various CHP options within the West Danish energy system, point to the concepts of CHP-HP and CHP-HP cold storage for effectively increasing energy system flexibility. For CHP-HP cold storage, R_c increases from 0.518 to 0.547, while the plant's fuel efficiency increases from 92.0% to 97.2%. These findings are discussed within frameworks of renewable energy systems, suggesting principles for 1st, 2nd, and 3rd generation system designs.     

Management of fluctuations in wind power and CHP comparing two possible Danish strategies

Both CHP (combined heat and power production) and wind power are important elements of Danish energy policy. Today, approximately 50% of both the Danish electricity and heat demand are produced in CHP and more than 15% of the electricity demand is produced by wind turbines. Both technologies are essential for the implementation of Danish climate change response objectives, and both technologies are intended for further expansion in the coming decade. Meanwhile, the integration of CHP and wind power is subject to fluctuations in electricity production. Wind turbines depend on the wind, and CHP depends on the heat demand. This article discusses and analyses two different national strategies for solving this problem. One strategy, which is the current official government policy known as the export strategy, proposes to take advantage of the Nordic and European markets for selling and buying electricity. In this case, surplus electricity from wind power and CHP simply will be sold to neighbouring countries. Another strategy, the self-supply strategy, runs the CHP units to meet both demand and the fluctuations in the wind scheduling. In this case, investments in heat storages are necessary and heat pumps have to be added to the CHP units. Based on official Danish energy policy and energy plans, this article quantifies the problem for the year 2015 in terms of the amount of surplus electricity, and investments in heat pumps, etc. needed to solve the problem are calculated. Based on these results between the two different strategies, the conclusion is that the self-supply strategy is recommended over the official export strategy.     

Materials for energy conservation and storage

Some areas of energy use where improved materials could lead to energy savings are surveyed. Current energy use patterns and their likely evolution to the end of the century are also reviewed so that particular applications may be seen in perspective against overall energy consumption and other energy conservation measures. Energy conservation is viewed both from the point of view of energy inputs to materials and how process improvements might permit savings, and also by considering general modes of energy use—transport and combustion in particular—and assessing some general ways in which conservation could be achieved. Areas such as improved engine-management of internal combustion engined vehicles and improved batteries for electric vehicles, where progress depends very much on materials developments, are surveyed in more detail. The need for improved sensors to measure exhaust gas composition in vehicles is one particular aspect of a general need for improved monitoring to permit better quality control and hence optimal fuel input for industrial processes requiring heat. Energy storage procedures are surveyed, together with a discussion of electricity generating methods and future electricity use. Attention is given to current fuel cell programmes, which offer the potential of increased conversion efficiency of fossil fuel to electricity compared with conventional power stations but where materials problems are critical in determining commercial success, to heat storage materials, and to water electrolysis and hydrogen production as a means of energy storage. The utilisation of electrochemical processes in solids or at surfaces or interfaces is a general theme underlying many of the technologies discussed.     

Decarbonising road transport with hydrogen and electricity: Long term global technology learning scenarios

Both fuel cell and electric vehicles have the potential to play a major role in a transformation towards a low carbon transport system that meets travel demands in a cleaner and more efficient way if hydrogen and electricity was produced in a sustainable manner. Cost reductions are central to this challenge, since these technologies are currently too expensive to compete with conventional vehicles based on fossil fuels. One important mechanism through which technology costs fall is learning-by-doing, the process by which cumulative global deployment leads to cost reduction. This paper develops long-term scenarios by implementing global technology learning endogenously in the TIAM-UCL global energy system model to analyse the role of hydrogen and electricity to decarbonise the transport sector. The analysis uses a multi-cluster global technology learning approach where key components (fuel cell, electric battery and electric drive train), to which learning is applied, are shared across different vehicle technologies such as hybrid, plug-in hybrid, fuel cell and battery operated vehicles in cars, light goods vehicles and buses. The analysis shows that hydrogen and electricity can play a critical role to decarbonise the transport sector. They emerge as complementary transport fuels, rather than as strict competitors, in the short and medium term, with both deployed as fuels in all scenarios. However, in the very long-term when the transport sector has been almost completely decarbonised, technology competition between hydrogen and electricity does arise, in the sense that scenarios using more hydrogen in the transport sector use less electricity and vice versa.     

Comparative study of different fuel cell technologies

Fuel cells generate electricity and heat during electrochemical reaction which happens between the oxygen and hydrogen to form the water. Fuel cell technology is a promising way to provide energy for rural areas where there is no access to the public grid or where there is a huge cost of wiring and transferring electricity. In addition, applications with essential secure electrical energy requirement such as uninterruptible power supplies (UPS), power generation stations and distributed systems can employ fuel cells as their source of energy.The current paper includes a comparative study of basic design, working principle, applications, advantages and disadvantages of various technologies available for fuel cells. In addition, techno-economic features of hydrogen fuel cell vehicles (FCV) and internal combustion engine vehicles (ICEV) are compared. The results indicate that fuel cell systems have simple design, high reliability, noiseless operation, high efficiency and less environmental impact. The aim of this paper is to serve as a convenient reference for fuel cell power generation reviews.     

Value of electric heat boilers and heat pumps for wind power integration

The paper analyses the economic value of using electric heat boilers and heat pumps as wind power integration measures relieving the link between the heat and power production in combined heat and power plants. Both measures have different technical and economic characteristics, making a comparison of the value of these measures relevant. A stochastic, fundamental bottom‐up model, taking the stochastic nature of wind power production explicitly into account when making dispatch decisions, is used to analyse the technical and economical performance of these measures in a North European power system covering Denmark, Finland, Germany, Norway and Sweden. Introduction of heat pumps or electric boilers is beneficial for the integration of wind power, because the curtailment of wind power production is reduced, the price of regulating power is reduced and the number of hours with very low power prices is reduced, making the wind power production more valuable. The system benefits of heat pumps and electric boilers are connected to replacing heat production on fuel oil heat boilers and combined heat and power (CHP) plants using various fuels with heat production using electricity and thereby saving fuel. The benefits of the measures depend highly on the underlying structure of heat production. The integration measures are economical, especially in systems where the marginal heat production costs before the introduction of the heat measures are high, e.g. heat production on heat boilers using fuel oil. Copyright © 2007 John Wiley & Sons, Ltd.     

Efficient utilization of waste heat from molten carbonate fuel cell in parabolic trough power plant for electricity and hydrogen coproduction

Direct steam generating parabolic trough power plant is an important technology to match future electric energy demand. One of the problems related to its emergence is energy storage. Solar-to-hydrogen is a promising technology for solar energy storage. Electrolysis is among the most processes of hydrogen production recently investigated. High temperature steam electrolysis is a clean process to efficiently produce hydrogen. In this paper, steam electrolysis process using solar energy is used to produce hydrogen. A heat recovery steam generator generates high temperature steam thanks to the molten carbonate fuel cell's waste heat. The analytical study investigates the energy efficiency of solar power plant, molten carbonate fuel cell and electrolyser. The impact of waste heat utilization on electricity and hydrogen generation is analysed. The results of calculations done with MATLAB software show that fuel cell produces 7.73 MWth of thermal energy at design conditions. 73.37 tonnes of hydrogen and 14.26 GWh of electricity are yearly produced. The annual energy efficiency of electrolyser is 70% while the annual mean electric efficiency of solar power plant is 18.30%.The proposed configuration based on the yearly electricity production and hydrogen generation has presented a good performance.     

Sustainable small-scale CHP technologies for buildings: the basis for multi-perspective decision-making

Generally speaking, the concept “small-scale CHP” (combined heat and power) means combined heat and power generation systems with electrical power less than 200 kW. The significant benefit of CHP is its overall efficiency, which can be as much as 85–90%. One of the most promising targets in the application of CHP lies in energy production for buildings. The most important competing technologies in this regard are reciprocating engines, micro-turbines, Stirling engines, and fuel cells. The benefit of these technologies is their ability to utilize sustainable fuels, like regenerative biomass, which makes them attractive. In spite of many technical and economic obstacles limiting the availability and feasibility of these technologies at the moment, the literature is optimistic about their future. The breakthrough of new technology is often regarded simply as a matter of decision-making.This article is a general review of issues that can be supposed to influence decisions when considering small-scale CHP as an alternative energy source for buildings. Firstly, a brief review is presented concerning the political, economic, social, and technological environment of small-scale energy production. Obstacles limiting the market potential of the new technologies are then listed, and solutions are suggested to improve their potential in Europe’s liberalizing energy market. The relevant interest groups influencing decisions both for and against the introduction of the new technologies, as well as their status are recognized. Finally, the advantages and disadvantages of relevant small-scale CHP technologies are briefly discussed, with respect to building energy generation. Finland’s role in this study is emphasized, but the international perspective is also dealt with.     

Decentralised optimisation of cogeneration in virtual power plants

Within several projects we investigated grid structures and management strategies for active grids with high penetration of renewable energy resources and distributed generation (RES & DG). Those ”smart grids” should be designed and managed by model based methods, which are elaborated within these projects. Cogeneration plants (CHP) can reduce the greenhouse gas emissions by locally producing heat and electricity. The integration of thermal storage devices is suitable to get more flexibility for the cogeneration operation. If several power plants are bound to centrally managed clusters, it is called “virtual power plant”. To operate smart grids optimally, new optimisation and model reduction techniques are necessary to get rid with the complexity.There is a great potential for the optimised management of CHPs, which is not yet used. Due to the fact that electrical and thermal demands do not occur simultaneously, a thermally driven CHP cannot supply electrical peak loads when needed. With the usage of thermal storage systems it is possible to decouple electric and thermal production. We developed an optimisation method based on mixed integer linear programming (MILP) for the management of local heat supply systems with CHPs, heating boilers and thermal storages. The algorithm allows the production of thermal and electric energy with a maximal benefit. In addition to fuel and maintenance costs it is assumed that the produced electricity of the CHP is sold at dynamic prices. This developed optimisation algorithm was used for an existing local heat system with 5 CHP units of the same type. An analysis of the potential showed that about 10% increase in benefit is possible compared to a typical thermally driven CHP system under current German boundary conditions. The quality of the optimisation result depends on an accurate prognosis of the thermal load which is realised with an empiric formula fitted with measured data by a multiple regression method.The key functionality of a virtual power plant is to increase the value of the produced power by clustering different plants. The first step of the optimisation concerns the local operation of the individual power generator, the second step is to calculate the contribution to the virtual power plant. With small extensions the suggested MILP algorithm can be used for an overall EEX (European Energy Exchange) optimised management of clustered CHP systems in form of the virtual power plant. This algorithm has been used to control cogeneration plants within a distribution grid.     

A Life Cycle Assessment of lithium battery and hydrogen-FC powered electric bicycles: Searching for cleaner solutions to urban mobility

Smart mobility is day by day becoming one of the crucial issues to address in order to reduce environmental impacts such as global warming, acidification, photochemical smog, among others. The growing concerns about urban air quality are the driving force for cleaner and more efficient transport systems. Several new transport technologies are being developed, in particular concerning electric vehicles, considered a suitable solution to urban air pollution problems. However, these vehicles require electric and electronic devices that might give rise to a new set of environmental problems in their production, operation and disposal phases. Are electric vehicles a really cleaner solution? This paper aims at answering this question, by comparing two kinds of vehicle, a lithium battery powered electric bike and a hydrogen-fuel cell operated one, using internal combustion engine vehicles as benchmark. The fuel cell bike uses a proton exchange membrane fuel cell (PEMFC) to convert hydrogen into electricity. In this study, Life Cycle Assessment is applied to evaluate the environmental burdens of the production of these two vehicles and compare their environmental performances per 100 km travelled. The study, not only includes vehicle road operation but also embraces production and distribution of bikes, electric battery, PEMFC and energy carriers (electricity and hydrogen) over the vehicle's entire lifetime. The LCA evaluation of the vehicle production phases shows that the construction of the H-bike results more impacting than the E-bike in all the considered categories due to the presence of more complex components technology. Instead, when the boundary is shifted to the operational phases of the vehicles including the energy carriers production, the situation is reversed and the environmental performance of the H-bike results better than the one of E-bike.     

Design of experiment study of the parameters that affect performance of three flow plate configurations of a proton exchange membrane fuel cell

Low temperature hydrogen fuel cells are electrochemical devices which offer a promising alternative to traditional power sources. Fuel cells produce electricity with a reaction of the fuel (hydrogen) and air. Fuel cells have the advantage of being clean; only producing water and heat as by products. The efficiency of a fuel cell varies depending on the type; SOFC with CHP for example, can have a system efficiency of up to 65%.     

Integration of renewable energy into the transport and electricity sectors through V2G

Large-scale sustainable energy systems will be necessary for substantial reduction of CO₂. However, large-scale implementation faces two major problems: (1) we must replace oil in the transportation sector, and (2) since today's inexpensive and abundant renewable energy resources have fluctuating output, to increase the fraction of electricity from them, we must learn to maintain a balance between demand and supply. Plug-in electric vehicles (EVs) could reduce or eliminate oil for the light vehicle fleet. Adding “vehicle-to-grid” (V2G) technology to EVs can provide storage, matching the time of generation to time of load. Two national energy systems are modelled, one for Denmark, including combined heat and power (CHP) and the other a similarly sized country without CHP (the latter being more typical of other industrialized countries). The model (EnergyPLAN) integrates energy for electricity, transport and heat, includes hourly fluctuations in human needs and the environment (wind resource and weather-driven need for heat). Four types of vehicle fleets are modelled, under levels of wind penetration varying from 0% to 100%. EVs were assumed to have high power (10 kW) connections, which provide important flexibility in time and duration of charging. We find that adding EVs and V2G to these national energy systems allows integration of much higher levels of wind electricity without excess electric production, and also greatly reduces national CO₂ emissions.     

Biomass-Based Combined Heat and Power Systems

This study aims to identify and evaluate the biomass utilization options and evaluate the sustainable biomass production for combined heat and power (CHP) in Turkey. The total biomass energy potential of Turkey is about 32 Mtoe. The amount of usable biomass potential of Turkey is approximately 17 Mtoe. Among the biomass energy sources, fuel wood seems to be one of the most interesting because its share of the total energy production of Turkey is high at 21%. The use of biofuels for CHP on a large scale is focused mainly on forest industry sites, where considerable quantities of biomass are available. Biomass available for energy can be converted to different types of final energy (e.g., electricity, heat), of these, the production of electricity appears to be particularly important. While CHP provides several environmental benefits by making use of waste heat and waste products, air pollution is a concern any time fossil fuels or biomass are burned.     

An experimental investigation of a PEM fuel cell to supply both heat and power in a solar-hydrogen RAPS system

The potential for both heat and power extraction from a PEM fuel cell is investigated experimentally and using computer simulation to improve the economics of a solar-hydrogen system supplying energy to a remote household. The overall average energy efficiency of the fuel cell was measured to be about 70% by utilizing the heat generated for domestic water heating, compared to only 35-50% for electricity generation alone. The corresponding round-trip energy efficiency of the hydrogen storage sub-system (electrolyzer, storage tank, and fuel cell) was raised from about 34% in a power-only application to about 50% in combined heat and power (CHP) mode. The economic benefit of using the fuel cell heat for boosting an LPG hot water system over a 30-year assessment period is estimated to be equivalent to about 15% of the total capital cost of the solar-hydrogen system. The stoichiometry of the input air, and the fuel cell operating temperature, were found to influence significantly the overall performance of the solar-hydrogen CHP system.     

Black liquor gasification—consequences for both industry and society

The pulp and paper industry consumes large quantities of biofuels to satisfy process requirements. Biomass is however a limited resource, to be used as effectively as possible. Modern pulping operations have excess internal fuels compared to the amounts needed to satisfy process steam demands. The excess fuel is often used for cogeneration of electric power. If market biofuel availability at a reasonable price is limited, import/export to/from a mill however changes the amount of such biofuel available for alternative users. This work compares different mill powerhouse technologies and CHP plant configurations (including conventional recovery boiler technology and black liquor gasification technology) with respect to electric power output from a given fuel resource. Different process steam demand levels for different representative mill types are considered. The comparison accounts for decreased/increased electricity production in an alternative energy system when biofuel is imported/exported to/from the mill. The results show that black liquor gasification is in all cases considered an attractive powerhouse recovery cycle technology. For moderate values of the marginal electric power generation efficiency for biofuel exported to the reference alternative energy system, excess mill internal biofuel should be used on mill site for gas turbine based CHP power generation. The remaining excess biofuels in market pulp mills should be exported and used in the reference alternative energy system in this case. For integrated pulp and paper mills, biofuel should be imported, but only for cogeneration usage (i.e. condensing power units should be avoided). If biofuel can be used elsewhere for high efficiency CHP power generation, mill internal biofuel should be used exclusively for process heating, and the remainder should be exported.     

Comparative life cycle assessment of hydrogen pathways from fossil sources in China

Emissions of multiple hydrogen production pathways from fossil sources were evaluated and compared with that of fossil fuel production pathways in China by using the life cycle assessment method. The considered hydrogen pathways are gasoline reforming, diesel reforming, natural gas reforming, soybean‐derived biodiesel (s‐biodiesel) reforming, and waste cooking oil‐derived biodiesel reforming. Moreover, emissions and energy consumption of fuel cell vehicles utilizing hydrogen from different fossil sources were presented and compared with those of the electric vehicle, the internal combustion engine vehicle, and the compression ignition engine vehicle. The results indicate both fuel cell vehicles and the electric vehicle have less greenhouse gas emissions and energy consumption compared with the traditional vehicle technologies in China. Based on an overall performance comparison of five different fuel cell vehicles and the electric vehicle in China, fuel cell vehicles operating on hydrogen produced from natural gas and waste cooking oil‐derived biodiesel show the best performance, whereas the electric vehicle has the worse performance than all the fuel cell vehicles because of very high share of coal in the electricity mix of China. The emissions of electric vehicle in China will be in the same level with that of natural gas fuel cell vehicle if the share of coal decreases to around 40% and the share of renewable energy increases to around 20% in the electricity mix of China. Copyright © 2016 John Wiley & Sons, Ltd.