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Pregled bibliografske jedinice broj: 189171

Description of system configurations and model design, results and analysis for selected integrated RES/H2 systems and H2 end-uses, Deliverable 2


Bürer, Meinrad; Foradini, Flavio; Bauen, Ausilio; Duić, Neven; Lerer, Maria; Fonseca, Jose Pedro; Alves, Luis Manuel; Carvalho, Maria Graça; Nakken, Torgeir; Hansen, Anne Marit et al.
Description of system configurations and model design, results and analysis for selected integrated RES/H2 systems and H2 end-uses, Deliverable 2, 2005. (elaborat).


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Naslov
Description of system configurations and model design, results and analysis for selected integrated RES/H2 systems and H2 end-uses, Deliverable 2

Autori
Bürer, Meinrad ; Foradini, Flavio ; Bauen, Ausilio ; Duić, Neven ; Lerer, Maria ; Fonseca, Jose Pedro ; Alves, Luis Manuel ; Carvalho, Maria Graça ; Nakken, Torgeir ; Hansen, Anne Marit ; Gonzales, Penelope Ramirez ; Marrero, Augustin ; Suarez, Salvador ; Oliveira, Filipe ; Henriques, Claudia ; Psarras, John ; Zevgolis, Dimitris ; Coroyannakis, Panos

Izvornik
IST - NNE5-2002-00073

Vrsta, podvrsta
Ostale vrste radova, elaborat

Godina
2005

Ključne riječi
hydrogen; renewable energy; islands

Sažetak
The higher penetration of renewable energy sources in islands is limited by its intermittent nature, and a solution to the problem requires energy storage. A promising storage technology is chemical storage in the form of hydrogen, which can then be used in fuel cells or engines to provide clean heat and electricity or used on-board vehicle for clean transport applications. The objective of this work was to identify and assess the feasibility of integrating intermittent renewables, wind and solar, with hydrogen storage in islands. This report first describes the opportunities for hydrogen storage in islands. The alternatives differ in terms of storage location and end-uses. Two types of applications are investigated in details with the existing software Homer in order to characterise system components for different possible configurations. The first application considers hydrogen as an instrument for peak shaving in the overall grid of a given island, while the second illustrates hydrogen use within distributed energy systems. Configurations with and without hydrogen storage are described both technically and economically so that the benefits in terms of environment and greater energy autonomy can be highlighted and balanced with incremental costs. The report then describes a new modeling tool, H2RES, which has been developed within this project for the assessment of water or hydrogen storage systems, both allowing greater renewable energy penetration in islands. A general methodology for the assessment of alternatives for the introduction of renewable energy and hydrogen based energy systems in islands is also presented. Finally, the proposed methodology together with the new modeling tool are used within three extensive case studies which look at greater renewable sources penetration in respectively Porto Santo (Madeira Archipelago), Corvo (Azores Archipelago), and Sal (Cape Verde) from a global perspective and through the analysis of different scenaria differentiated by the goals and technologies applied. H2RES is based on hourly time series analysis of water, electricity and hydrogen demand, wind potential, solar insulation and precipitation. The wind module uses the wind velocity data, typically from the meteorological station, at 10 m height, and adjusts them to the wind turbines hub level, and, for a given choice of wind turbines, converts the velocities to the output. The solar module converts the total radiation on the horizontal surface, obtained typically from the meteorological station, to the inclined surface, and then to output. The hydro module, takes into account precipitation data, typically from the nearest meteorological station, and water collection area, and evaporation data, based on the reservoir free surface, to predict the water net inflow into the reservoir. Load module, based on a given criteria for the maximum acceptable renewable electricity in the power system, puts a part or all of wind and solar output into the system and discards the rest of the renewable output. The excess renewable electricity is then stored either as hydrogen, pumped water or electricity in batteries, or for some non-time critical use. The energy that is stored can be retrieved later, and supplied to the system as electricity. The rest is covered from Diesel blocks. The model can also optimise the supply of water and hydrogen demand. Hydrogen storage in islands can be considered as a way to make use of excess renewable electricity delivered by existing or new renewable capacity. In such a context, hydrogen storage is used for solving mismatch between overall demand and supply patterns. This choice is associated with a more effective use of installed renewable technology capacity as it makes use of otherwise wasted renewable energy sources available at times when electricity demand is low. Although the hydrogen production and use is associated with a relatively low round-trip efficiency, it avoids simply dumping electricity, or disconnecting part of renewable capacity, and can contribute to a faster amortisation of the renewable capacity which has been invested in. Furthermore, it can displace the use of fossil based electricity at times when the output from renewable sources is not sufficient to meet the demand, and or avoid or postpone the investment in additional non renewable capacity which would be otherwise required to cover the peaks. Modelling activities undertaken in this work have confirmed that replacing a share of existing thermal plants capacity in the grid of an island requires a comparatively very large additional wind capacity. This is due to the combination of significant peaks in the demand profile of islands and of the highly intermittent nature of wind. In an example investigated, it is shown for example that displacing a diesel engine peak unit can halve total annual fuel consumption and emission rate. The choice of a very large hydrogen storage capacity reduces significantly the number of wind turbines to be installed, leading to a better use of the installed capacity along the year. The introduction of significant photovoltaic cells capacity for an unchanged storage capacity achieves similar fuel consumption and emissions rates with a much lower number of wind turbines, and a lower amount of electricity generated in excess. From an economic point of view however, such options are associated with very high investment costs. Furthermore, for reasons such as landscape concerns, or lack of experience in high wind penetration in weak grids, local stakeholders may not favour the introduction of a large wind capacity in their island. Therefore, although technically it is possible to achieve a reduction of fuel consumption and emissions rate by half compared to the Business as Usual, site specific circumstances and economics require smaller-scale systems for an actual implementation in the short to medium term. The use of a new modeling tool developed within this work and applied to different case studies has confirmed that using a hydrogen loop technically allows the renewable penetration rate to reach 100%. However, since such an option would currently be too expensive, a possible first step is to consider peak shaving schemes with fuel cells fuelled with renewable hydrogen. Such an option has been investigated for the islands of Porto Santo and Sal, and it was shown that with such schemes, the renewable penetration could reach respectively 16% and 18% in those two islands. When deciding whether to install photovoltaic cells as part of the main electrical system, either in a 100% renewable scenario or as complement to the Diesel blocks, one must consider the investment regarding the yearly energy output. Although the diversification of energy sources can be an advantage, because the overall intermittence is reduced and security of supply is increased, the decision must consider geographical and economical concerns as well as strategy arguments. In case of peak shaving, one has to find the balance between the price of photovoltaic cells and price of hydrogen storage. Hydrogen storage can also be seen as an instrument for more flexibility in the planning of island grid capacity and operation. It can solve eventual congestion problems without investing in additional grid connection capacity. Typically, in a situation where a community is weakly connected while its demand is growing year after year, hydrogen storage at the community location can be a substitute to grid capacity expansion. Hydrogen storage can also be a solution for a greater penetration of renewable electricity in islands which are characterised by weak grids. The share of renewables in the electricity supply is typically limited to around 30% on an instantaneous basis by grid owners, or even by law, due to grid stability concerns. Hydrogen storage allows a greater share by distributing renewable sources’ contribution more evenly over the year. Distributed energy systems for on-site generation of electricity, heating and cooling are also of interest and possible niche markets for hydrogen technology. Although the use of hydrogen within centralised energy conversion systems allow a greater penetration of renewable energy into the electricity grid, it suffers from low overall energy chain efficiency due to limitations on the share of intermittent sources accepted by the grid operator for stability issues. Such limitations induce the conversion of a large share of the renewable based electricity generated into hydrogen even at times when electricity demand is high. Distributed applications are not limited by such constraints, and therefore allow a greater proportion of renewable sources direct use, with hydrogen conversion only applied when electricity is generated in excess. Moreover, such schemes can make use of the heat released from the hydrogen to electricity conversion process, increasing the overall energy conversion efficiency. Modelling activities undertaken in this work have shown that when excess electricity can not be exported to the grid at any time, there are environmental benefits associated with hydrogen storage due to a lower amount of fossil-based electricity imported from the grid. The annual cost of energy supply is however several times greater than Business as Usual even under optimistic assumptions. For stand-alone systems which aim at 100% renewable energy, hydrogen is of interest either by itself or in association with batteries, as it has the potential to be more economic than batteries by themselves over the system lifetime. On the other hand, when excess electricity can be exported to the grid at any time, there is no rationale for the introduction of hydrogen storage within grid-connected distributed energy systems if the electricity selling and buying prices are uniform along the day. It is much more costly than configurations without storage, while in the same time less environmental, as direct use of renewable sources is much more energy efficient and displaces fossil-based electricity into the grid. Some specific circumstances might however still justify its introduction, i.e. the grid reliability is low enough to induce an identifiable and quantifiable impact on the hotel business, or hydrogen is needed locally for another type of service, i.e. as a fuel for the hotel shuttle.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika, Strojarstvo



POVEZANOST RADA


Projekti:
0120037

Ustanove:
Fakultet strojarstva i brodogradnje, Zagreb

Profili:

Avatar Url Neven Duić (autor)


Citiraj ovu publikaciju:

Bürer, Meinrad; Foradini, Flavio; Bauen, Ausilio; Duić, Neven; Lerer, Maria; Fonseca, Jose Pedro; Alves, Luis Manuel; Carvalho, Maria Graça; Nakken, Torgeir; Hansen, Anne Marit et al.
Description of system configurations and model design, results and analysis for selected integrated RES/H2 systems and H2 end-uses, Deliverable 2, 2005. (elaborat).
Bürer, M., Foradini, F., Bauen, A., Duić, N., Lerer, M., Fonseca, J., Alves, L., Carvalho, M., Nakken, T. & Hansen, A. (2005) Description of system configurations and model design, results and analysis for selected integrated RES/H2 systems and H2 end-uses, Deliverable 2. IST - NNE5-2002-00073. Elaborat.
@unknown{unknown, year = {2005}, keywords = {hydrogen, renewable energy, islands}, title = {Description of system configurations and model design, results and analysis for selected integrated RES/H2 systems and H2 end-uses, Deliverable 2}, keyword = {hydrogen, renewable energy, islands} }
@unknown{unknown, year = {2005}, keywords = {hydrogen, renewable energy, islands}, title = {Description of system configurations and model design, results and analysis for selected integrated RES/H2 systems and H2 end-uses, Deliverable 2}, keyword = {hydrogen, renewable energy, islands} }




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