Parameter study for dimensioning of a PV optimized hydrogen supply plant

Green hydrogen produced from intermittent renewable energy sources is a key component on the way to a carbon neutral planet. In order to achieve the most sustainable, efficient and cost-effective solutions, it is necessary to match the dimensioning of the renewable energy source, the capacity of the hydrogen production and the size of the hydrogen storage to the hydrogen demand of the application.For optimized dimensioning of a PV powered hydrogen production system, fulfilling a specific hydrogen demand, a detailed plant simulation model has been developed. In this study the model was used to conduct a parameter study to optimize a plant that should serve 5 hydrogen fuel cell buses with a daily hydrogen demand of 90 kg overall with photovoltaics (PV) as renewable energy source. Furthermore, the influence of the parameters PV system size, electrolyser capacity and hydrogen storage size on the hydrogen production costs and other key indicators is investigated. The plant primarily uses the PV produced energy but can also use grid energy for production.The results show that the most cost-efficient design primarily depends on the grid electricity price that is available to supplement the PV system if necessary. Higher grid electricity prices make it economically sensible to invest into higher hydrogen production and storage capacity. For a grid electricity price of 200 €/MWh the most cost-efficient design was found to be a plant with a 2000 kWp PV system, an electrolyser with 360 kW capacity and a hydrogen storage of 575 kg.     

A techno-economic analysis of tidal energy technology

The choice of which type of electrical power generation technology to adopt is driven by a number of factors including: cost of generated electricity; responsiveness of generating plant to demand; security of supply/resource availability; environmental impact; and execution risk. Within these, tidal energy is unique as a renewable technology since it has the capability of providing predictable, firm power contributing to security of supply. This predictability gives tidal energy additional value in a future electricity market. Especially one where stochastic renewable technologies contribute to a sizable component of the power supplied; and where reserve capacity is required to maintain supply during periods of non-availability. In the shorter term, in order for tidal energy to gain commercial acceptance, tidal technologies under development need to produce electricity at a competitive price. This paper examines the drivers influencing electricity pricing; current tidal energy developments, aimed at reducing capital costs; and bench-mark these against offshore wind.     

Regulatory potential for increasing small scale grid connected photovoltaic (PV) deployment in Australia

The last decade has seen significant innovation and change in regulatory incentives to support photovoltaic deployment globally. With high fossil fuel dependency and abundant solar resource availability in Australia, grid connected photovoltaics are a viable low carbon technology option in existing electricity grids. Drawing on international examples, the potential to increase grid PV deployment through government response and regulation is explored. For each renewable energy certificate (REC) earned by small scale photovoltaics until 2012, the market provides four additional certificates under the current banded renewable targets. Our analysis indicates that REC eligibility is not accurately estimated currently, and an energy model is developed to calculate the variance. The energy model estimates as much as 26% additional REC’s to be obtained by a 3 kWp PV system, when compared to the currently used regulatory method. Moreover, the provision of REC’s increases benefits to PV technologies, in the process distorting CO₂ abatement (0.21 tonne/REC) by 68%, when PV displaces peaking natural gas plants. Consideration of the secondary effects of a banded structure on emissions trading market is important in the context of designing a range of initiatives intended to support a transition to a low carbon electricity sector.     

The future role of photovoltaics: A learning curve versus portfolio perspective

The current cost disadvantage of photovoltaics (PV) risks to reduce its relevance in climate policy strategies. Depending on the used assumptions, electricity from PV can become competitive between 2015 and 2040. Cost competitiveness is, however, a conditional criterion and as an alternative to the learning curve perspective, the future role of PV in electricity production is assessed from a portfolio theory or Capital Asset Pricing Model perspective. In this analysis, the focus is on the input price risks. Fossil fuel price volatility can strongly reduce the financial return of conventional generating technologies. From a welfare perspective, energy planners should try to minimise this risk by adding risk-neutral or no-risk technologies to their portfolio. With an analysis for the year 2025, we illustrate how the addition of renewable capacity to an existing portfolio can lower total portfolio risk without a significant reduction of profitability. PV then emerges as an attractive technology, especially once the best locations for wind energy are already developed.     

Accelerating residential PV expansion: demand analysis for competitive electricity markets

This article quantifies the potential market for grid-connected, residential photovoltaic (PV) electricity integrated into new homes built in the US. It complements an earlier supply-side analysis by the authors that demonstrates the potential to reduce PV module prices below $1.5/W_p by scaling up existing thin-film technology in 100 MW_p/yr manufacturing facilities. The present article demonstrates that, at that price, PV modules may be cost effective in 125,000 new home installations per year (0.5 GW_p/yr). While this market is large enough to support multiple scaled up thin-film PV factories, inefficient energy pricing and demand-side market failures will inhibit prospective PV consumers without strong public policy support. Net metering rules, already implemented in many states to encourage PV market launch, represent a crude but reasonable surrogate for efficient electricity pricing mechanisms that may ultimately emerge to internalize the externality benefits of PV. These public benefits include reduced air pollution damages (estimated costs of damage to human health from fossil fuel power plants are presented in Appendix A), deferral of transmission and distribution capital expenditures, reduced exposure to fossil fuel price risks, and increased electricity system reliability for end users. Thus, net metering for PV ought to be implemented as broadly as possible and sustained until efficient pricing is in place. Complementary PV “buydowns” (e.g., a renewable portfolio standard with a specific PV requirement) are needed to jumpstart regional PV markets.     

Lower electricity prices and greenhouse gas emissions due to rooftop solar: empirical results for Massachusetts

Monthly and hourly correlations among photovoltaic (PV) capacity utilization, electricity prices, electricity consumption, and the thermal efficiency of power plants in Massachusetts reduce electricity prices and carbon emissions beyond average calculations. PV utilization rates are highest when the thermal efficiencies of natural gas fired power plants are lowest, which reduces emissions of CO₂ and CH₄ by 0.3% relative to the annual average emission rate. There is a positive correlation between PV utilization rates and electricity prices, which raises the implied price of PV electricity by up to 10% relative to the annual average price, such that the average MWh reduces electricity prices by $0.26–$1.86 per MWh. These price reductions save Massachusetts rate-payers $184 million between 2010 and 2012. The current and net present values of these savings are greater than the cost of solar renewable energy credits which is the policy instrument that is used to accelerate the installation of PV capacity. Together, these results suggest that rooftop PV is an economically viable source of power in Massachusetts even though it has not reached socket parity.     

Assessment and evaluation of PV based decentralized rural electrification: An overview

The challenges of providing electricity to rural households are manifold. Ever increasing demand–supply gap, crumbling electricity transmission and distribution infrastructure, high cost of delivered electricity are a few of these. Use of renewable energy technologies for meeting basic energy needs of rural communities has been promoted by the Governments world over for many decades. Photovoltaic (PV) technology is one of the first among several renewable energy technologies that was adopted globally as well as in India for meeting basic electricity needs of rural areas that are not connected to the grid. This paper attempts at reviewing and analyzing PV literature pertaining to decentralized rural electrification into two main categories—(1) experiences from rural electrification and technology demonstration programmes covering barriers and challenges in marketing and dissemination; institutional and financing approaches; and productive and economic applications, (2) techno-economic aspects including system design methodologies and approaches; performance evaluation and monitoring; techno-economic comparison of various systems; and environmental implications and life cycle analysis. The paper discusses the emerging trends in its concluding remarks.     

Renewable power for China: Past,present, and future

This paper briefly examines the history, status, policy situation, development issues, and prospects for key renewable power technologies in China. The country has become a global leader in wind turbine and solar photovoltaic (PV) production, and leads the world in total power capacity from renewable energy. Policy frameworks have matured and evolved since the landmark 2005 Renewable Energy Law, updated in 2009. China’s 2020 renewable energy target is similar to that of the EU. However, China continues to face many challenges in technology development, grid-integration, and policy frameworks. These include training, research and development, wind turbine operating experience and performance, transmission constraints, grid interconnection time lags, resource assessments, power grid integration on large scales, and continued policy development and adjustment. Wind and solar PV targets for 2020 will likely be satisfied early, although domestic demand for solar PV remains weak and the pathways toward incorporating distributed and building-integrated solar PV are uncertain. Prospects for biomass power are limited by resource constraints. Other technologies such as concentrating solar thermal power, ocean energy, and electricity storage require greater attention.     

Efficient pricing and investment in electricity markets with intermittent resources

Facing growing technological and environmental challenges, the electricity industry needs effective pricing mechanism to promote efficient risk management and investment decisions. In a restructured electricity market with competitive wholesale prices and traditionally regulated retail rates, however, there are technical and institutional barriers that prevent dynamic pricing with price responsive demand. In regions with limited energy storage capacity, intermittent renewable resources present special challenges. This could adversely affect the effectiveness of public policies causing inefficient investments in energy technologies. In this paper, we present an updated economic model of pricing and investment in restructured electricity market and use the model in a simulation study for an initial assessment of renewable energy strategy and alternative pricing mechanisms. A key objective of the study is to shed light on the policy issues so that effective decisions can be made to improve efficiency.     

Abuse of dominance and antitrust enforcement in the German electricity market

In 2008, the European Commission investigated E.ON, a large and vertically integrated electricity company, for the alleged abuse of a joint dominant position by strategically withholding generation capacity in the German wholesale electricity market. The case was settled after E.ON agreed to divest 5 GW generation capacity as well as its extra-high voltage network. We analyze the effect of these divestitures on wholesale electricity prices. Our identification strategy is based on the observation that energy suppliers have more market power during peak periods when demand is high. Therefore, a decrease in market power should lead to convergence between peak and off-peak prices, after controlling for different demand and supply conditions as well as the change in generation mix due to the expansion of renewable technologies. Using daily electricity prices for the 2006–2012 period, we find economically and statistically significant convergence effects after the settlement of the case. In a richer specification, we show that the price reductions appear to be mostly due to the divestiture of gas and coal plants, which is consistent with merit-order considerations. Additional cross-country analyses support our results.     

Renewable power for China: Past, present, and future

This paper briefly examines the history, status, policy situation, development issues, and prospects for key renewable power technologies in China. The country has become a global leader in wind turbine and solar photovoltaic (PV) production, and leads the world in total power capacity from renewable energy. Policy frameworks have matured and evolved since the landmark 2005 Renewable Energy Law, updated in 2009. China’s 2020 renewable energy target is similar to that of the EU. However, China continues to face many challenges in technology development, grid-integration, and policy frameworks. These include training, research and development, wind turbine operating experience and performance, transmission constraints, grid interconnection time lags, resource assessments, power grid integration on large scales, and continued policy development and adjustment. Wind and solar PV targets for 2020 will likely be satisfied early, although domestic demand for solar PV remains weak and the pathways toward incorporating distributed and building-integrated solar PV are uncertain. Prospects for biomass power are limited by resource constraints. Other technologies such as concentrating solar thermal power, ocean energy, and electricity storage require greater attention.     

Design and evaluation of hydrogen electricity reconversion pathways in national energy systems using spatially and temporally resolved energy system optimization

For this study, a spatially and temporally resolved optimization model was used to investigate and economically evaluate pathways for using surplus electricity to cover positive residual loads by means of different technologies to reconvert hydrogen into electricity. The associated technology pathways consist of electrolyzers, salt caverns, hydrogen pipelines, power cables, and various technologies for reconversion into electricity. The investigations were conducted based on an energy scenario for 2050 in which surplus electricity from northern Germany is available to cover the electricity grid load in the federal state of North Rhine-Westphalia (NRW).A key finding of the pathway analysis is that NRW's electricity demand can be covered entirely by renewable energy sources in this scenario, which involves CO₂ savings of 44.4 million tons of CO₂/a in comparison to the positive residual load being covered from a conventional power plant fleet. The pathway involving CCGT (combined cycle gas turbines) as hydrogen reconversion option was identified as being the most cost effective (total investment: € 43.1 billion, electricity generation costs of reconversion: € 176/MWh).Large-scale hydrogen storage and reconversion as well as the use of the hydrogen infrastructure built for this purpose can make a meaningful contribution to the expansion of the electricity grid. However, for reasons of efficiency, substituting the electricity grid expansion entirely with hydrogen reconversion systems does not make sense from an economic standpoint. Furthermore, the hydrogen reconversion pathways evaluated, including large-scale storage, significantly contribute to the security of the energy supply and to secured power generation capacities.     

欧盟可再生能源发展形势和2020年发展战略目标分析

2010年,欧盟可再生能源发展呈现出新的形势:一方面,风电满足了欧盟5.3%的电力需求,已经开始发挥替代能源的战略作用;另一方面,光伏发电新增装机容量首次超过风电,显示出分布式光伏发电的巨大优势。在欧盟可再生能源"20-20-20"发展目标的基础上,欧盟各成员国相继制定了具有法律效力的国家可再生能源行动方案,规定了各国在不同时期的可再生能源的发展目标和实现路径。     

Advanced mechanisms for the promotion of renewable energy—Models for the future evolution of the German Renewable Energy Act

The German Renewable Energy Act (EEG) has been very successful in promoting the deployment of renewable electricity technologies in Germany. The increasing share of EEG power in the generation portfolio, increasing amounts of fluctuating power generation, and the growing European integration of power markets governed by competition calls for a re-design of the EEG. In particular, a more efficient system integration and commercial integration of the EEG power is needed to, e.g. better matching feed-in to demand and avoiding stress on electricity grids. This article describes three different options to improve the EEG by providing appropriate incentives and more flexibility to the promotion mechanism and the quantitative compensation scheme without jeopardising the fast deployment of renewable energy technologies. In the “Retailer Model”, it becomes the responsibility of the end-use retailers to adapt the EEG power to the actual demand of their respective customers. The “Market Mediator Model” establishes an independent market mediator responsible to market the renewable electricity. This model is the primary choice when new market entrants are regarded as crucial for the better integration of renewable energy and enhanced competition. The “Optional Bonus Model” relies more on functioning markets since power plant operators can alternatively choose to market the generated electricity themselves with a premium on top of the market price instead of a fixed price.     

Potential of Kyoto Protocol Clean Development Mechanism in transfer of clean energy technologies to Small Island Developing States: case study of Cape Verde

The developed countries committed to greenhouse gases reductions under the aegis of the Kyoto Protocol of the United Nations Framework Convention on Climate Change will, in order to reduce the cost of meeting their commitments, depend on cheaper reductions elsewhere. The reductions will be materialised through several mechanisms of the Kyoto Protocol: the Emission Trade, Joint Implementation and Clean Development Mechanisms. The Mechanisms will carry a strong financial incentive for the dissemination of clean energy technologies, including renewable energy technologies and especially technologies that increase the efficiency of energy transformation and consume. This paper concentrates on the case typical of more than 30 Small Island Developing States, that all have a common situation of relatively low carbon intensity and high price of fossil fuel based economies, and on how the Clean Development Mechanism is expected to influence the transfer of clean energy technologies under the aegis of the Kyoto Protocol. The paper shows, by assessing a case of a small island, that although the emission reduction on global scale is small, there is great potential for establishing a strong market presence of renewable energy technologies in developing countries. A typical small island electricity generation is heavily dependent on Diesel engines, expensive and polluting, but still the most appropriate on such a small scale. This paper studies implications of different scenaria of development of electrical energy system on the island of Santiago, Cape Verde. An estimate of electricity demand for the period until 2030 is given. Baseline scenarium based on Diesel capacity is compared to a renewable energy scenario envisaging 30% of the electricity generated by the wind power, and the other supply side efficiency scenario replacing Diesel capacity with combined cycle. The declining price of clean energy technologies is taken into account. The possible influence of the Clean Development Mechanism is assessed. The potential for financing the technology transfer is quantified and its influence on different electricity system planning scenarios estimated.     

Design of an energy hub based on natural gas and renewable energy sources

This paper presents a simulation model for an energy hub consisting of natural gas (NG) turbines as the main sources of energy (including both electricity and heat) and two renewable energy sources—wind turbines (WTs) and photovoltaic (PV) solar cells. The hub also includes water electrolyzers for hydrogen production. The hydrogen serves as an energy storage medium that can be used in some transportation applications, or it can be mixed with the NG feed stream to improve the emission profile of the gas‐turbine unit. The capacity of the designed hub is meant to simulate and replace the coal‐fired Nanticoke Generating Station with a NG‐fired power plant. Therefore, the aim of this work is to develop a simulated model that combines different energy generation technologies, which are evaluated in terms of the total energy produced, the cost per kWh of energy generated, and the amount of emissions produced. The proposed model investigates the benefits, both economic and environmental, the technological barriers, and the challenges of energy hubs by developing several scenarios. The simulation of these scenarios was done using General Algebraic Modeling System (GAMS®). Although the software is strongly known for its optimization capability, the mixed complementary problems solver makes it a strong tool for solving equilibrium problems. Excess energy produced during off‐peak demand by WTs and PV solar cells was used to feed the electrolyzer to produce H₂ and O₂. The proposed approach shows that a significant reduction in energy cost and greenhouse gas emissions were achieved, in addition to the increased overall efficiency of the energy hub. Out of the examined three scenarios, Scenario C appeared to be the most feasible option for a combination of renewable and non‐renewable technologies as it did not only produce hydrogen, but also provided electricity at relatively lower prices. Copyright © 2013 John Wiley & Sons, Ltd.     

Forecasting renewable hydrogen production technology shares under cost uncertainty

This analysis applies a novel learning-curve methodology with uncertainty through Monte Carlo simulation to forecast market share of competing renewable fuel production technologies from 2025 through 2050. The analysis incorporates uncertainty in technology learning rate within Wright's Law, market rate of growth, and project-specific bidding to develop build-out scenarios for renewable hydrogen production capacity to serve the global market through 2050 with California as a proxy. Two major hydrogen production technologies are included: electrolyzers (with proton exchange membrane electrolytic cells as proxies) and thermochemical devices (with gasifiers as proxies). The method provides a quantitative foundation to forecasting technology shares in emerging sectors, overcomes the weakness of point estimates of relative cost that generally lead to binary behavior, and can support policy development and assessment of community impacts associated with the large-scale facility build-out needed to serve the growing demand for renewable hydrogen in transportation and other applications. Results show that biomass gasifiers are the dominant technology in the early market but the higher learning rate of electrolyzers and long-term trend of price decline for renewable electricity leads to equal shares for new installations by the mid-term and eventually to electrolyzers having the dominant share of new facilities. Electricity, biomass, and initial gasifier technology costs are the three primary factors impacting 2050 renewable hydrogen market composition.     

Comparative impacts of wind and photovoltaic generation on energy storage for small islanded electricity systems

This paper addresses the annual energy storage requirements of small islanded electricity systems with wind and photovoltaic (PV) generation, using hourly demand and resource data for a range of locations in New Zealand. Normalised storage capacities with respect to annual demand for six locations with winter-peaking demand profiles were lower for wind generation than for PV generation, with an average PV:wind storage ratio of 1.768:1. For two summer-peaking demand profiles, normalised storage capacities were lower for PV generation, with storage ratios of 0.613:1 and 0.455:1. When the sensitivity of storage was modelled for winter-peaking demand profiles, average storage ratios were reduced. Hybrid wind/PV systems had lower storage capacity requirements than for wind generation alone for two locations. Peak power for storage charging was generally greater with PV generation than with wind generation, and peak charging power increased for the hybrid systems. The results are compared with those for country-scale electricity systems, and measures for minimising storage capacity are discussed. It is proposed that modelling of storage capacity requirements should be included in the design process at the earliest possible stage, and that new policy settings may be required to facilitate a transition to energy storage in fully renewable electricity systems.     

Evaluating the potential of small-scale renewable energy options to meet rural livelihoods needs: A GIS- and lifecycle cost-based assessment of Western China's options

The economics and livelihoods impacts of stand-alone, small-scale (less than 2 kW) renewable energy technologies for rural electrification are assessed using a representative sample of 531 rural households in three provinces of Western China. Over 20 small wind, photovoltaic (PV) and wind–PV hybrid configurations were evaluated for their potential to meet local electricity needs. The assessment integrates lifecycle costing and geographic information system (GIS) methods in order to provide a comprehensive resource, economic, technological and livelihoods assessment. The results of the analysis indicate that off-grid renewable energy technologies can provide cost-effective and reliable alternatives to conventional generator sets in addressing rural livelihoods energy requirements. Findings also demonstrate the existence of a sizeable market potential for stand-alone renewable energy systems in Western China. In support of market development for these technologies, policy recommendations are provided.     

The merit-order effect: A detailed analysis of the price effect of renewable electricity generation on spot market prices in Germany

The German feed-in support of electricity generation from renewable energy sources has led to high growth rates of the supported technologies. Critics state that the costs for consumers are too high. An important aspect to be considered in the discussion is the price effect created by renewable electricity generation. This paper seeks to analyse the impact of privileged renewable electricity generation on the electricity market in Germany. The central aspect to be analysed is the impact of renewable electricity generation on spot market prices. The results generated by an agent-based simulation platform indicate that the financial volume of the price reduction is considerable. In the short run, this gives rise to a distributional effect which creates savings for the demand side by reducing generator profits. In the case of the year 2006, the volume of the merit-order effect exceeds the volume of the net support payments for renewable electricity generation which have to be paid by consumers.