Analysis and techno-economic assessment of renewable hydrogen production and blending into natural gas for better sustainability

In this study, comprehensive thermodynamic analysis and techno-economic assessment studies of the renewable hydrogen production and its blending with natural gas in the existing pipelines are performed. Solar and wind energy-based on-grid and off-grid power systems are designed and compared in energy, exergy, and cost. Solar PV panels and wind turbines are particularly considered for electricity and hydrogen production for residential applications in an environmentally benign way. Fuel cell units are included to supply continuous electricity in the off-grid system. Here, the heat required for a community consisting of 100 houses is provided by hydrogen and natural gas mixture as a more environmentally benign fuel. The costs of capital, fuel, operation, and maintenance are calculated and evaluated in detail. The total net present costs are calculated as $6.95 million and $2.47 million for the off-grid and on-grid power systems, respectively. For the off-grid system, energy and exergy efficiencies are calculated as 32.64% and 40.73%, respectively. Finally, the energy and exergy efficiencies of the on-grid system are determined as 26.58% and 35.25%, respectively.     

Economic,environmental, and social impacts of the hydrogen supply system combining wind power and natural gas

Hydrogen economy is one of the most attractive alternatives to the current carbon-based energy system, since it can be produced from diverse resources and used as a carbon-free energy carrier from the end-user's perspective. This study proposes a hybrid hydrogen supply system for the transport sector, which includes all the life stages from production, transport, and storage to final distribution (fueling stations). Particularly, we consider two types of resources for hydrogen production (i.e., renewable wind power and conventional natural gas) to identify the benefits and bottlenecks of hydrogen supply systems from the economic, environmental, and social perspectives. To achieve this goal, rigorous process models for the involved processes (i.e., hydrogen production by steam methane reforming from natural gas and water electrolysis using wind power, and hydrogen storage and transport) are developed. To illustrate the capability of the proposed system, we conducted a design problem within the hydrogen supply system in Jeju Island, Korea. In this case study, three scenarios were generated by combining different hydrogen production options: 1) wind power-based hydrogen production, 2) natural gas-based hydrogen production, and 3) integrated hydrogen production. As a result, we discussed the optimal hydrogen supply system, from the life cycle perspective, by identifying technical bottlenecks, major cost-drivers, and CO₂ burdens.     

Economic study of a large-scale renewable hydrogen application utilizing surplus renewable energy and natural gas pipeline transportation in China

A novel project solution for large-scale hydrogen application is proposed utilizing surplus wind and solar generated electricity for hydrogen generation and NG pipeline transportation for hydrogen-natural gas mixtures (called HCNG). This application can practically solve urgent issues of large-scale surplus wind and solar generated electricity and increasing NG demand in China. Economic evaluation is performed in terms of electricity and equipment capacity estimation, cost estimation, sensitivity analysis, profitability analysis and parametric study. Equipment expenses are dominant in the construction period, especially those of the electrolysers. Electricity cost and transportation cost are the main annual operating costs and greatly influence the HCNG and pure hydrogen costs. The project proves to be feasible through the profitability analysis. The main influence items are tested individually to guarantee project profitability within 22 years. The project can reduce 388.40 M Nm³ CO₂ emissions and increase 2998.52 M$ incomes for solar and wind power stations.     

Assessing complementarity of wind and solar resources for energy production in Italy. A Monte Carlo approach

Wind and solar energy are expected to play a major role in the current decade to help Europe reaching the renewable energy penetration targets fixed by Directive 2009/28/EC. However, it is difficult to predict the actual production profiles of wind and solar energy as they depend heavily on variable meteorological features of solar radiation and wind speed. In an ideal system, wind and solar electricity are both injected in a fast reacting grid instantaneously matching supply and demand. In such a system wind and solar electricity production profiles should complement each other as much as possible in order to minimise the need of storage and additional capacity. In the present paper the complementarity of wind and solar resources is assessed for a test year in Italy.To achieve this goal we employ data at high spatial and temporal resolution data for both solar radiation and wind speed in Italy obtained from running two state of the art models (PVGIS and MINNI). Hourly profiles for solar and wind energy produced are compared in each 4 × 4 km² grid cell in Italy for 2005, and hourly, daily and monthly correlation coefficients are computed in order to assess the local complementarity of the two resources. A Monte Carlo approach is also developed to estimate how large-scale wind and solar energy productions could be potentially involved to complement each other in a scenario with up to 100 production sites across Italy. The results show how local complementarity can be very interesting with monthly correlation coefficients reaching values lower than −0.8 in several areas. Large-scale complementarity is also relevant with nation-wide monthly correlation coefficients showing values between −0.65 and −0.6. These model results indicate that in this sample year of 2005, wind and solar energy potential production have shown complementary time behaviour complementary, favourably supporting their integration in the energy system.     

An application of a combined wind and solar energy system in Izmir

In this work, a combined system which is produced electrical energy from both solar radiation via solar cells and wind energy by using wind turbine was studied. For wind energy, measurements of wind velocities at 12 m height were taken. Then, these values were calculated for 42 m by using Hellmann equation. After that, wind energy converted to the electrical energy. However, value of solar radiation from solar cells was taken at the optimum slope angle of collector which provided higher energy production for each 1 h during this application. Thus, obtained data from each system were used together for finding total energy. For this study, measurements, which would be used in calculation of wind energy and solar energy were taken for four years between 1995 and 1998 in Izmir. As a result, energy of the combined system could support each other when one of them produces energy insufficiently.     

A solar and wind driven energy system for hydrogen and urea production with CO2 capturing

A novel solar PV and wind energy based system is proposed in this study for capturing carbon dioxide as well as producing hydrogen, urea and power. Both Aspen Plus and EES software packages are employed for analyses and simulations. The present system is designed in a way that PEM electrolyzer is powered by the wind turbines for hydrogen production, which is further converted into ammonia and then synthesizes urea by capturing CO₂ and additional power is supplied to the community. The solar PV is employed to power the cryogenic air separation unit and the additional power is used for the industrial purpose. In the proposed system, ammonia does not only capture CO₂ but also synthesizes urea for fertilizer industry. The amount of electrical power produced by the system is 2.14 MW. The designed system produces 518.4 kmol/d of hydrogen and synthesizes 86.4 kmol/d of urea. Furthermore, several parametric studies are employed to investigate the system performance.     

Solar and wind energy in Poland as power sources for electrolysis process - A review of studies and experimental methodology

The production of hydrogen is still a major challenge, due to the high costs and often also environmental burdens it generates. It is possible to produce hydrogen in emission-free way: e.g. using a process of electrolysis powered by renewable energy. The paper presents the concept of a research, experimental stand for the storage of renewable energy in the form of hydrogen chemical energy with the measurement methodology. The research involves the use of proton exchange membrane electrolysis technology, which is characterized by high efficiency and flexibility of energy extraction for the process of electrolysis from renewable sources. The system consist of PV panel, PEM electrolyzer, battery, programmable logic controller system and optional a wind turbine. Preliminary experimental tests results have shown that the electrolyzer can produce in average 158.1 cc/min of hydrogen with the average efficiency 69.87%.     

Development and assessment of a solar,wind and hydrogen hybrid trigeneration system

A solar-wind hybrid trigeneration system is proposed and analyzed thermodynamically through energy and exergy approaches in this paper. Hydrogen, electricity and heat are the useful products generated by the hybrid system. The system consists of a solar heliostat field, a wind turbine and a thermochemical copper-chlorine (Cu-Cl) cycle for hydrogen production linked with a hydrogen compression system. A solar heliostat field is employed as a source of thermal energy while the wind turbine is used to generate electricity. Electric power harvested by the wind turbine is supplied to the electrolyzer and compressors and provides an additional excess of electricity. Hydrogen produced by the thermochemical copper-chlorine (Cu-Cl) cycle is compressed in a hydrogen compression system for storage purposes. Both Aspen Plus 9.0 and EES are employed as software tools for the system modeling and simulation. The system is designed to achieve high hydrogen production rate of 455.1 kg/h. The overall energy and exergy efficiencies of the hybrid system are 49% and 48.2%, respectively. Some additional results about the system performance are obtained, presented and discussed in the paper.     

Greenhouse gas emissions reduction by use of wind and solar energies for hydrogen and electricity production: Economic factors

This study addresses economic aspects of introducing renewable technologies in place of fossil fuel ones to mitigate greenhouse gas emissions. Unlike for traditional fossil fuel technologies, greenhouse gas emissions from renewable technologies are associated mainly with plant construction and the magnitudes are significantly lower. The prospects are shown to be good for producing the environmentally clean fuel hydrogen via water electrolysis driven by renewable energy sources. Nonetheless, the cost of wind- and solar-based electricity is still higher than that of electricity generated in a natural gas power plant. With present costs of wind and solar electricity, it is shown that, when electricity from renewable sources replaces electricity from natural gas, the cost of greenhouse gas emissions abatement is about four times less than if hydrogen from renewable sources replaces hydrogen produced from natural gas. When renewable-based hydrogen is used in a fuel cell vehicle instead of gasoline in a IC engine vehicle, the cost of greenhouse gas emissions reduction approaches the same value as for renewable-based electricity only if the fuel cell vehicle efficiency exceeds significantly (i.e., by about two times) that of an internal combustion vehicle. It is also shown that when 6000 wind turbines (Kenetech KVS-33) with a capacity of 350 kW and a capacity factor of 24% replace a 500-MW gas-fired power plant with an efficiency of 40%, annual greenhouse gas emissions are reduced by 2.3 megatons. The incremental additional annual cost is about $280 million (US). The results provide a useful approach to an optimal strategy for greenhouse gas emissions mitigation.     

Enhancing information for solar and wind energy technology deployment in Brazil

Brazil's primary energy matrix is based on more than 47% of renewables, and more than 85% of its electricity is generated by hydro power sources. Despite this large fraction of renewable energy resources, less than 0.3% of the national energy supply comes from solar or wind sources. This paper presents a diagnostic review on the penetration of the solar and wind energy technologies in Brazil. It also includes a survey of the latest government policies and incentives for renewable energies deployment by entrepreneurs, industry and commercial and residential consumers. In addition, the paper analyses how to best meet the requirements for policy support and information technology to boost the deployment of solar technology and wind energy in Brazil. This study was mostly based on results of a widely distributed survey covering key issues, and also by personal interviews carried out with key stakeholders in order to better understand the issues highlighted in the survey responses. The study pointed out some of the main obstacles to effectively promote and improve government policies and actions for investment in solar and wind energy market in Brazil.     

Methanol production using hydrogen from concentrated solar energy

Concentrated solar thermal technology is considered a very promising renewable energy technology due to its capability of producing heat and electricity and of its straightforward coupling to thermal storage devices. Conventionally, this approach is mostly used for power generation. When coupled with the right conversion process, it can be also used to produce methanol. Indeed methanol is a good alternative fuel for high compression ratio engines. Its high burning velocity and the large expansion occurring during combustion leads to higher efficiency compared to operation with conventional fuels. This study is focused on the system level modeling of methanol production using hydrogen and carbon monoxide produced with cerium oxide solar thermochemical cycle which is expected to be CO₂ free. A techno-economic assessment of the overall process is done for the first time. The thermochemical redox cycle is operated in a solar receiver-reactor with concentrated solar heat to produce hydrogen and carbon monoxide as the main constituents of synthesis gas. Afterwards, the synthesis gas is turned into methanol whereas the methanol production process is CO₂ free. The production pathway was modeled and simulations were carried out using process simulation software for MW-scale methanol production plant. The methanol production from synthesis gas utilizes plug-flow reactor. Optimum parameters of reactors are calculated. The solar methanol production plant is designed for the location Almeria, Spain. To assess the plant, economic analysis has been carried out. The results of the simulation show that it is possible to produce 27.81 million liter methanol with a 350 MW_th solar tower plant. It is found out that to operate this plant at base case scenario, 880685 m² of mirror's facets are needed with a solar tower height of 220 m. In this scenario a production cost of 1.14 €/l Methanol is predicted.     

Complimentary nature of wind and solar energy at a continental mid-latitude station

Daily values of solar and wind energy have been used (i) to study renewable energy availability at various times of year, (ii) to test the level of persistence for inferences about the practicality of energy storage and (iii) to examine the complementary behaviour of these two daily time series on both seasonal and daily bases. Results for the station studied (central Iowa) show a bimodal distribution for winter solar energy, whereas non-winter solar and wind (all seasons) show unimodal distributions. Wind and solar energy were observed to be highly complementary on an annual basis, but only slightly complementary on a daily basis.     

Techno-economic assessment of green hydrogen and ammonia production from wind and solar energy in Iran

This paper presents a comprehensive technical and economic assessment of potential green hydrogen and ammonia production plants in different locations in Iran with strong wind and solar resources. The study was organized in five steps. First, regarding the wind density and solar PV potential data, three locations in Iran were chosen with the highest wind power, solar radiation, and a combination of both wind/solar energy. All these locations are inland spots, but since the produced ammonia is planned to be exported, it must be transported to the export harbor in the South of Iran. For comparison, a base case was also considered next to the export harbor with normal solar and wind potential, but no distance from the export harbor. In the second step, a similar large-scale hydrogen production facility with proton exchange membrane electrolyzers was modeled for all these locations using the HOMER Pro simulation platform. In the next step, the produced hydrogen and the nitrogen obtained from an air separation unit are supplied to a Haber-Bosch process to synthesize ammonia as a hydrogen carrier. Since water electrolysis requires a considerable amount of water with specific quality and because Iran suffers from water scarcity, this paper, unlike many similar research studies, addresses the challenges associated with the water supply system in the hydrogen production process. In this regard, in the fourth step of this study, it is assumed that seawater from the nearest sea is treated in a desalination plant and sent to the site locations. Finally, since this study intends to evaluate the possibility of green hydrogen export from Iran, a detailed piping model for the transportation of water, hydrogen, and ammonia from/to the production site and the export harbor is created in the last step, which considers the real routs using satellite images, and takes into account all pump/compression stations required to transport these media. This study provides a realistic cost of green hydrogen/ammonia production in Iran, which is ready to be exported, considering all related processes involved in the hydrogen supply chain.     

A regional decision support system for onsite renewable hydrogen production from solar and wind energy sources

Hydrogen technologies driven by renewable energy sources (RES) represent an attractive energy solution to ensure environmental sustainability. In this paper, a decision support system for the hydrogen exploitation is presented, focusing on some specific planning aspects. In particular, the planning aspects regard the selection of locations with high hydrogen production mainly based on the use of solar and wind energy sources. Four modules were considered namely, the evaluation of the wind and solar potentials, the analysis of the hydrogen potential, the development of a regional decision support module and a last module that regards the modelling of a hybrid onsite hydrogen production system. The overall approach was applied to a specific case study in Liguria region, in the north of Italy.     

Assessing the lifecycle greenhouse gas emissions from solar PV and wind energy: A critical meta-survey

This paper critically screens 153 lifecycle studies covering a broad range of wind and solar photovoltaic (PV) electricity generation technologies to identify 41 of the most relevant, recent, rigorous, original, and complete assessments so that the dynamics of their greenhouse gas (GHG) emissions profiles can be determined. When viewed in a holistic manner, including initial materials extraction, manufacturing, use and disposal/decommissioning, these 41 studies show that both wind and solar systems are directly tied to and responsible for GHG emissions. They are thus not actually emissions free technologies. Moreover, by spotlighting the lifecycle stages and physical characteristics of these technologies that are most responsible for emissions, improvements can be made to lower their carbon footprint. As such, through in-depth examination of the results of these studies and the variations therein, this article uncovers best practices in wind and solar design and deployment that can better inform climate change mitigation efforts in the electricity sector.     

Analysis of hydrogen production from combined photovoltaics, wind energy and secondary hydroelectricity supply in Brazil

In this work, the technical and economical feasibility for implementing a hypothetical electrolytic hydrogen production plant, powered by electrical energy generated by alternative renewable power sources, wind and solar, and conventional hydroelectricity, was studied mainly trough the analysis of the wind and solar energy potentials for the northeast of Brazil. The hydrogen produced would be exported to countries which do not presently have significant renewable energy sources, but are willing to introduce those sources in their energy system. Hydrogen production was evaluated to be around 56.26 × 10⁶ m³ H₂/yr at a cost of 10.3 US$/kg.     

Wind energy and assessment of wind energy potential in Turkey

In this study, the potential of wind energy and assessment of wind energy systems in Turkey were studied. The main purpose of this study is to investigate the wind energy potential and future wind conversion systems project in Turkey. The wind energy potential of various regions was investigated; and the exploitation of the wind energy in Turkey was discussed. Various regions were analyzed taking into account the wind data measured as hourly time series in the windy locations. The wind data used in this study were taken from Electrical Power Resources Survey and Development Administration (EIEI) for the year 2010. This paper reviews the assessment of wind energy in Turkey as of the end of May 2010 including wind energy applications. Turkey's total theoretically available potential for wind power is around 131,756.40 MW and sea wind power 17,393.20 MW annually, according to TUREB (TWEA). When Turkey has 1.5 MW nominal installed wind energy capacity in 1998, then this capacity has increased to 1522.20 MW in 2010. Wind power plant with a total capacity of 1522.20 MW will be commissioned 2166.65 MW in December 2011.     

Solar and wind energy potential and utilization in Pakistan

Pakistan needs substantial amount of energy to develop its industry and to increase the agricultural productivity. The available indigenous energy resources are limited. The only option which the country has to pursue is renewable energy. This paper identifies the potentials of solar and wind energy. The prime sites for wind are coastal area, arid zone and hill terrains. Solar energy is abundant over most part of the country, maximum being received over Quetta valley.     

Industrial emergy evaluation for hydrogen production systems from biomass and natural gas

Fossil fuel resources are the main source for hydrogen production, and hydrogen production by renewable energy, such as biomass, is under development. To compare the performance in natural resource utilization for different hydrogen production systems, in this paper, two laboratorial hydrogen production systems from biomass and one industrial hydrogen production system from natural gas are analyzed by using industrial emergy evaluation indices. One of the laboratorial systems is a continuous supercritical water gasification system from glucose, and the other is a batch supercritical water gasification system from sawdust. The industrial system adopts American Brown technology. The evaluation results show that although the industrial emergy efficiency (IEE) of the industrial system from natural gas is higher than that of the laboratorial systems from biomass, the industrial emergy index of sustainability (IEIS) of the two laboratorial systems are higher than that of the industrial system. To make the laboratorial biomass system become an industrial system, the system should improve its yield, and reduce its capital investment.     

Flexible production of green hydrogen and ammonia from variable solar and wind energy: Case study of Chile and Argentina

We report a techno-economic modelling for the flexible production of hydrogen and ammonia from water and optimally combined solar and wind energy. We use hourly data in four locations with world-class solar in the Atacama desert and wind in Patagonia steppes. We find that hybridization of wind and solar can reduce hydrogen production costs by a few percents, when the effect of increasing the load factor on the electrolyser overweighs the electricity cost increase. For ammonia production, the gains by hybridization can be substantially larger, because it reduces the power variability, which is costly, due to the need for intermediate storage of hydrogen between the flexible electrolyser and the less flexible ammonia synthesis unit. Our modelling reveals the crucial role in the synthesis of flexibility, which cuts the cost of variability, especially for the more variable wind power. Our estimated near-term production costs for green hydrogen, around 2 USD/kg, and green ammonia, below 500 USD/t, are encouragingly close to competitiveness against fossil-fuel alternatives.