Renewable Cost Research Articles

Simulating the value of electric-vehicle–grid integration using a behaviourally realistic model

Vehicle–grid integration (VGI) uses the interaction between electric vehicles and the electrical grid to provide benefits that may include reducing the cost of using intermittent renwable electricity or providing a financial incentive for electric vehicle ownerhip. However, studies that estimate the value of VGI benefits have largely ignored how consumer behaviour will affect the magnitude of the impact. Here, we simulate the long-term impact of VGI using behaviourally realistic and empirically derived models of vehicle adoption and charging combined with an electricity system model. We focus on the case where a central entity manages the charging rate and timing for participating electric vehicles. VGI is found not to increase the adoption of electric vehicles, but does have a a small beneficial impact on electricity prices. By 2050, VGI reduces wholesale electricity prices by 0.6–0.7% (0.7 $ MWh–1, 2010 CAD) relative to an equivalent scenario without VGI. Excluding consumer behaviour from the analysis inflates the value of VGI. Vehicle–grid integration may reduce renewable electricity costs and increase electric vehicle ownership. Simulations combining empirically derived models of vehicle adoption and charging with an electricity system model show that excluding consumer behaviour inflates these benefits.

Water and energy self-supply in isolated areas through renewable energies using hydrogen and water as a double storage system

Because of their geographical isolation, many areas depend mainly on imported fossil fuels for their water and energy production. In this context, the Canary Islands are one such remote area. Due to the topography of the islands, there are numerous isolated areas on each of the islands far from the major population centres. These are known as ‘islands within islands’. The main aim of this paper is to determine the feasibility or otherwise of supplying from renewable energy sources both the energy and water needs of the 219 inhabitants of El Risco located in the municipality of Agaete on the island of Gran Canaria (Spain). For this purpose, the potential use of existing renewable resources in this isolated area has been analysed, using hydrogen as energy vector. A reverse osmosis (RO) plant is integrated into the system to ensure water self-sufficiency and, in turn, constitutes a double storage system (hydrogen-water). Based on the results obtained from the study, the technical feasibility of the system is confirmed, with an annual energy production of 1,743,031kWh/year compared to a consumption of 672,314.32kWh/year, as well as a potable water production volume of 46,546.80m3/year obtained from the RO plant. The reliability of the system is confirmed in the economic analysis, obtaining a renewable electricity cost of 0.107€/kWh compared to 0.18€/kWh when using conventional electricity.

Surface activity and safety of deamidated zein peptides

Hydrolysis of food proteins is a convenient and feasible way to produce amphipathic and low cost peptides. In this study, three deamidated zein peptides were produced from zein via 36, 96 and 144 h alkaline hydrolysis reaction at 37 °C. Longer hydrolysis reaction produced smaller peptides with more carboxyl groups. Changing aqueous solution pH from 4.0 to 8.0, the peptides carried more negative charges that reduced the aggregation of the peptides. In vitro cytotoxicity study verified that the peptides were much safer than sodium dodecyl sulfate (SDS). In pH 4.0–8.0 aqueous solutions, the peptides presented better surface activities than SDS. The apparent critical micelle concentration (CMC) values of the peptides were much smaller than the CMC value of SDS, the pC20 values (ability to reduce surface tension of 20 mN/m) of the peptides were much larger than the pC20 value of SDS, and the surface pressure πCMC values of the peptides were similar to the value of SDS. In addition, the peptides had non-foaming property, good emulsifying capacity and emulsion stability at acidic condition. This study demonstrates that renewable, safe, degradable and low cost peptides produced by hydrolysis of food protein have excellent surface activities. Deamidated zein peptides with adjustable hydrophilicity/hydrophobicity are promising alternatives to chemical surfactants in food industry.

Techno-economic scrutiny of HRES through GA and PSO technique

Presented work analyses the feasible sizing of two different hybrid renewable energy systems (HRSE) are PV-wind-biomass hybrid systems and PV-Wind hybrid systems. The proposed system includes battery unit for storage purpose and diesel generator for reliable operation. The electricity price or cost of energy (COE) is minimised as objective function to decide the optimal solution of hybrid system using GA and PSO. The optimal size of HRES is selected based on the lowest value of COE. The optimal solution includes high reliability, maximum value of renewable fraction (RF), less emission and low penalty cost according to minimum COE. The maximum value of loss of power supply probability (LPSP) is assumed 2% in this case study for reliability analysis. This paper's aim is to present the techno-economic feasibility of above mentioned HRES for a remote area of Jamny Ven Village Barwani district, India. The optimisation results are evaluated through load following and cycle charging dispatch strategy furthermore the results are also compared using GA and PSO optimisation techniques. Hence, the main purpose of presented work is to compare the performance results of GA and PSO with minimisation of COE using load following and cycle charging dispatch strategy.

Project Valuation in the Geothermal Power Plant Project: A Comparison of Expected Net Present Value and Static Net Present Value Approaches

Geothermal energy is one of potential energy that needs development to find renewable and lower cost energy. This study aims to obtain better project valuation in the geothermal power plant. Primary data of the geothermal power plant project obtained from geothermal private company and government. Expected Net Present Value (ENPV) method is a technique for valuing a project where several scenarios were generated. The scenarios generations helped the company get the full overview and conditions of the project. Project value calculated based on Net Present Value (NPV). The Monte Carlo Simulation calculate NPV based on discount rate, production volume, and operation and maintenance (O&M) cost. The risk of the project used three scenarios to obtain NPV and calculate Expected Net Present Value (ENPV). This study demonstrates that the ENPV method can reduce wide variance with multiple uncertainties that related to the project, so the company will have the results of valuation more robust and easier to interpret.

Long-Term Endogenous Economic Growth and Energy Transitions

This article builds a bridge between the endogenous economic growth theory, the biophysical economics perspective, and the past and future transitions between renewable and nonrenewable energy forms that economies have had to and will have to accomplish. We provide an endogenous economic growth model subject to the physical limits of the real world, meaning that nonrenewable and renewable energy production costs have functional forms that respect physical constraints, and that technological level is precisely defined as the efficiency of primary-to-useful exergy conversion. The model supports the evidence that historical productions of renewable and nonrenewable energy have greatly influenced past economic growth. Indeed, from an initial almost-renewable-only supply regime we reproduce the increasing reliance on nonrenewable energy that has allowed the global economy to leave the state of economic stagnation that had characterized the largest part of its history. We then study the inevitable transition towards complete renewable energy that human will have to deal with in a not-too-far future since nonrenewable energy comes by definition from a finite stock. Through simulation we study in which circumstances this transition could have negative impacts on economic growth (peak followed by degrowth phase). We show that the implementation of a carbon price can partially smooth such unfortunate dynamics, depending on the ways of use of the income generated by the carbon pricing.

South Australia's power sector: renewables, batteries and the future role of gas

The South Australia experience is noteworthy in a global power mix set to increasingly shift to renewable energy. The rapid growth of renewables raises intermittency challenges and has already changed the power mix with coal phased out and gas utilisation reduced. However, despite this reduction, gas still remains the most important way to ensure uninterrupted power supply. Meanwhile, South Australia is experimenting with numerous new technologies, in addition to reintroducing diesel generation, in an attempt to ensure security of power supply. Currently, these technologies are not economic compared to gas. Looking ahead South Australia is projected to have installed renewable energy capacity exceed its peak demand by 2020. This paper asks what needs to be considered given the increasing role of renewables in the energy mix? Can battery technology combined with renewables offer a commercial solution for replacing either base load or peak load gas plants? What is required for system security to 2035? If renewables and batteries are proven commercial then what are the implications for gas? To answer these questions, this paper will assess the extent to which renewable and battery technology costs will fall in South Australia. We will compare renewable and gas cost projections for 2018, 2025 and 2035. Using proprietary dispatch modelling we will then assess what the growth in renewables means for annually, monthly and daily gas demand. Demand will undoubtedly decline and become more volatile. This poses challenges. We will assess whether and how current gas contracting terms need to change to ensure that gas has a continued role in ensuring system security in South Australia.

Are Renewables Profitable in 2030? A Comparison between Wind and Solar Across Europe

The European Union has set ambitious targets for emission reduction and the penetration of renewable energy, including the electricity generation sector as one of the major emitters of CO2. After a period of subsidy-driven investments, the costs of renewables decreased strongly making investments more attractive. Since European countries differ strongly in terms of natural resources, we analyse the profitability of wind onshore and offshore and solar PV across Europe to determine where it is optimal to invest in the future and to understand which factors drive the profitability of the investments. We use a power systems model to simulate the whole European electricity market in 2030. Using the renewable revenues determined by the model, we calculate the internal rate of return to analyse how profitable each technology is in each country. We find that investments in the considered technologies are not homogeneously profitable across Europe. This suggests that cooperation between European countries can be expected to achieve the overall targets at lower costs than nationally-driven approaches. We also find that in many countries, wind onshore and solar PV are profitable by 2030 in absence of any financial support. Wind offshore does not seem to be profitable without financial support.

Energy Sustainability and Its Impacts on Croatian Tourism

Energy efficiency, renewable energy sources, and environmental protection projects play a pivotal role in tourism. The World Tourism Organization (UNWTO) addresses resource management and energy use as one of the major issues. The main goal of the paper is to present the economic–financial analysis and the assessment of investment projects in the construction of a conventional mid-size hotel using fossil fuels and a mid-size hotel based on sustainable principles and renewable energy sources. Comparative analysis of conventional and energy efficient hotels is used to calculate the key financial indicators in decision making. Case study shows that the introduction of renewable energy sources meets the needs of modern guests and increases the hotel's competitiveness, while the effects of energy sustainability reflect on the environment and reduced CO2 emissions. Based on the results, the paper suggests measures for improving energy sustainability in hotels and other tourism facilities. The paper is intended for those who deal with theoretical and practical issues of energy sustainability in tourism, tourism certificates, renewable energy sources and investment costs―scientists, researchers, PhD candidates and students as a basis for further comparative studies and benchmarking. It can also be useful for a considerably wider circle of users―managers at all levels and other business decision makers, as well as proprietors, investors, and creditors.

Influence of technical failures on the performance of an optimized community-size solar heating system in Nordic conditions

There is a substantial need to accelerate the advancement and implementation of clean energy technologies in order to solve the challenges of the energy crisis and climate change. Solar heating technology is a feasible solution among clean energy technologies. In real conditions such complex systems often suffer from different kinds of technical failures and deviations reducing the system performance. This paper focuses on the challenges of a solar district heating system at high latitudes, proposes an optimized solution and investigates the influence of possible failures in planning, implementation and operation phase. The configuration proposed is a heat pump connected between two tanks, using solar-charged borehole storage to directly charge the lower temperature tank. Dynamic simulations were performed and a multi-objective optimization was carried out. The impact of the considered system solutions on the renewable energy fraction, purchased electricity and investment cost as a function of demand, solar thermal and photovoltaic areas, tanks and borehole volumes have been evaluated. The influence of 10 different technical failures was investigated. The study showed that in the optimized system, the most serious faults were i) de-stratification of the storage tanks (23–35% increase in annual purchased electricity) ii) on-off instead of variable speed control of the solar circulation pump (1–22% increase) and iii) reduction in heat pump performance (7–21%). These numbers of course depend on the initial assumptions, but still they show the magnitude of performance reduction some failures can achieve. Therefore, these parameters need to be considered during the implementation of such a system.

Analysing the impact of renewable energy regulation on retail electricity prices

Retail electricity prices have substantially increased in the last decade in the European Union (EU) as a result of different regulations, raising the concern of policy makers. The growth in the support costs for electricity from renewable energy sources (RES-E) has often been singled out as a main driver of the increase in these prices. The aim of this paper is to analyse the degree of influence of RES-E promotion costs on the evolution of the retail price of electricity in the EU Member States. The analysis is carried out for households as well as for industry, with the help of a panel data econometric model. Our results show that the impact of renewable energy promotion costs on retail electricity prices is positive and statistically significant, although relatively small. Differences across consumer types can be observed. An increase of 1% in those costs induces an average increase of only 0.023% in industrial retail prices and 0.008% in the residential retail prices. This impact on retail prices is mediated by the type of support scheme which is adopted, with price-based support instruments showing a greater effect than quantity-based ones.

LEAPFROGGING TO RENEWABLE ENERGY: THE OPPORTUNITY FOR UNMET ELECTRICITY MARKETS

Electricity plays a crucial role in the socio-economic development of any country. Developing countries, however, unlike their developed counterparts, do not have electricity markets that are fully satisfied, nor are they ‘laden’ with large-scale infrastructure that could create inertia about making the transition. The objective of this paper is to identify the potential trajectories for unmet electricity markets in sub-Saharan Africa to leapfrog to renewable energy as they strive to accelerate access to electricity. The following key drivers of renewable energy leapfrogging in unmet electricity markets were identified from the review: the need to achieve sustainability targets; the availability of renewable energy resources on a sufficient scale; growing investment in renewable energy; maturing niche renewable technologies; a weakening renewable energy cost hypothesis; and a growing population and increasing urbanisation. The paper further conceptualised three potential transition paradigms: revolutionary, scattered , and coned pathways. These paradigms were defined by the pace and magnitude of the transition that can be observed, and depend on the intensity of the identified drivers in a specific unmet electricity market. The paper argues that the largely unmet electricity market in sub-Saharan Africa provides an opportunity to leapfrog the fossil-intensive energy regime to adopt a renewable energy regime.

Electricity regulation and economic growth

The main objective of this paper is to analyse the effect of electricity regulation on economic growth. Although the relationship between electricity consumption and economic growth has been extensively analysed in the empirical literature, this framework has not been used to estimate the effect of electricity regulation on economic growth. Understanding this effect is essential for the assessment of regulatory policy. Specifically, we assess the effects of two major areas of regulation, renewable energy promotion costs and network costs, on electricity consumption and growth. A dataset for the period 2007–2013 and 22 European countries was compiled based on CEER reports and EUROSTAT databases. The results of the empirical analysis show that the two regulation instruments have a negative effect on electricity consumption and economic growth and provide estimates of their effects on growth in quantitative terms.

The effect of renewable and nonrenewable electricity generation on economic growth

This note examines the impact of electricity generation on economic growth using data for a panel of 174 countries over the period 1980–2012. The paper makes several contributions. First, contrary to much of the literature, the paper focuses on the effect of electricity generation on economic growth. Because of transmission and distribution losses, and theft, not all the electricity that is generated is eventually consumed, making it necessary to investigate the impact of electricity generation on growth. Second, we disentangle the impact of total electricity generation on growth into renewable and nonrenewable effects. With increasing pursuit of energy security, technological advances, the falling costs of renewables, and the movement to exploit renewable energy sources for electrification, there is need to study not only the impact of traditional sources of electricity but renewable sources, as well. Third, we deviate from previous studies that focus on granger causality and/or cointegration by estimating the effect of electricity generation on growth using the System Generalized Method of Moments (GMM). Given that electricity generation and many of the other regressors in our model may be jointly determined with GDP growth, the System GMM approach is appropriate to deal with these endogeneity issues. Fourth, we provide evidence of a link between electricity loss and economic growth. Our results indicate a strong positive and statistically significant relationship between renewable and nonrenewable electricity generation, and growth.

Iridium Nanowires As Highly Active, Oxygen Evolution Reaction Electrocatalysts

Iridium Nanowires as Highly Active, Oxygen Evolution Reaction Electrocatalysts Shaun M. Alia,1 Sarah Shulda,2 Chilan Ngo,2 Svitlana Pylypenko,2 Bryan S. Pivovar1 1 Chemistry and Nanoscience Center, National Renewable Energy Laboratory, Golden, CO 80401 2 Department of Chemistry, Colorado School of Mines, Golden, CO 80401 shaun.alia@nrel.govIn the United States, 2% of energy used goes through the hydrogen pathway, to produce ammonia in agriculture and upgrade oil in transportation. [1, 2] While most hydrogen is produced by steam methane reformation, electrolysis can become competitive with the use of low-cost renewable power sources. Further reductions in the cost of renewables may increase hydrogen use as an energy intermediate between the electric grid and transportation and industrial processes. [3] Electrolyzers today operate at high capacity and with constant power input. A shift toward intermittent renewables and a focus on hydrogen production cost, however, increases the importance of catalyst thrifting and durability in the oxygen evolution reaction (OER). [2] Iridium or iridium oxide nanoparticles are typically used as OER catalysts, but are limited in activity and durability, particularly at low loading. [4] Iridium-nickel and iridium-cobalt nanowires have been developed as OER electrocatalysts for proton exchange membrane-based electrolyzers. These catalysts use similar templates and synthesis routes previously used in the development of fuel cell oxygen reduction electrocatalysts. [5] A previous comparison between polycrystalline iridium and nanoparticles suggests that extended structures can potentially benefit from higher site-specific activity. [4] Differences between the nanowire templates affect catalyst composition, structure, and OER activity. While these materials exceed the performance of iridium nanoparticles, acid leaching is necessary to minimize template dissolution and improve durability. The acid leached catalysts exceed the half-cell activity of nanoparticles by an order of magnitude, and the half-cell mass activity of any catalyst available in literature by 4 times. In membrane electrode assemblies, the nanowires also outperform traditional iridium catalysts by 4‒5 times in single-cell electrolyzers. Figure caption. Surface areas (ECA, x-axis) and specific OER activity (is, y-axis) of acid leached iridium-nickel (Ir-Ni) nanowires, iridium-cobalt (Ir-Co) nanowires, iridium nanoparticles (Ir), and iridium oxide nanoparticles (IrO2). Solid black lines correspond to constant mass activities of 0.3, 1, and 3 A mgIr ‒1 at 1.55 V. Nanowire compositions are listed as-synthesized (in parentheses) and following acid leaching (immediately following parentheses).

Performance and Durability Baselines in Alkaline Hydrogen and Oxygen Evolution Reactions

In the United States, 2% of energy uses hydrogen as an intermediate, to produce ammonia in agriculture and upgrade oil in transportation. [1, 2] While the majority hydrogen is produced by steam methane reformation, electrolysis can become cost-competitive through the use of renewable power sources. Further reductions in the cost of renewables may increase hydrogen use as an energy intermediate between the electric grid and transportation and industrial processes. [3] Since the cost of electrolysis-produced hydrogen is dominated by electricity cost, electrolyzers typically operate with high catalyst loadings to avoid durability losses. With a shifting focus toward hydrogen production cost, however, catalyst thrifting and durability become critical. [2, 4] The use of anion exchange membrane (AEM) electrolyzers are an attractive option, with potential durability benefits and an ability to use non-platinum group metal (non-PGM) catalysts in place of platinum and iridium. This study presents baseline performance in rotating disk electrode half-cell tests, in the hydrogen evolution and oxygen evolution reactions for alkaline electrolytes. PGM and non-PGM catalysts are evaluated, included polished metal electrodes and commercial nanoparticle catalysts, differentiating between surface area and specific activity as the source of mass activity. This work develops testing protocols, and examines the effect of the electrolyte manufacturer, the electrochemical cell, the counter electrode, and contaminants on performance and durability. Baselined catalysts were also evaluated for durability in alkaline hydrogen and oxygen evolution. While minimal hydroxide evolution losses are expected, durability in the oxygen evolution reaction is critical, to demonstrate a potential benefit to proton exchange membrane-based electrolyzers and to ensure non-PGM stability at elevated anode potentials. The modes of loss under specific testing protocols are presented and evaluated, and compared to performance and durability in single-cell electrolyzers. These types of studies are critical for establishing baseline catalyst performance within the electrocatalysis community. Figure caption. Summary of mass (red) and specific (blue) exchange current densities in the alkaline hydrogen evolution reaction, with platinum (Pt), Pt-ruthenium (Pt-Ru), palladium (Pd), and nickel (Ni) catalysts evaluated. Dashed blue lines corresponding to the specific activities of metal electrodes (Pt, Pd, Ni lines above respective commercial nanoparticles).

Separation and Purification Technologies for Lactic Acid – A Brief Review

Lactic acid is an important platform chemical with a wide range of applications. Production of lactic acid by fermentation is advantageous because renewable and low cost raw materials can be used as substrates. After fermentation, the broth needs to be purified to obtain pure lactic acid for further uses. Thus, efficient downstream processes are very important because they account for 50% of the production costs. This review discusses different processes that are currently employed for lactic acid recovery, focusing on precipitation, solvent extraction, and separation with membranes. Advances in such recovery processes and drawbacks that limit the application of these technologies at the industrial level are also presented.

Hydrogen import pathway comparison framework incorporating cost and social preference: Case studies from Australia to Japan

Summary Recent proposals to produce and import hydrogen from Australia to Japan for electricity generation raise questions about how to compare the costs and feasibilities of different hydrogen import pathways. This paper establishes a framework for the comparison of technological, economic, and social costs and feasibility. The framework is then applied to 3 potential production and import case studies. First, a benchmark case study is considered which uses Australian brown coal from the Latrobe Valley combined with carbon capture and sequestration (CCS) technology. The second and third comparative case studies use renewable energy and electrolysis near port facilities in Karratha, Western Australia, using solar power exclusively as the renewable energy source, and Gladstone, Queensland, using a combination of onshore wind and solar-based generation. The study finds that comparative pilot project generation costs for the brown coal pathway are between approximately 5.9 and 15.4 yen/kWh cheaper than for solar and/or wind-based pathways. However, limitations of scaling up CCS, a limited brown coal supply, long-term reducing costs of renewables, and the prospect to develop complementary renewable infrastructure make a strong counterargument for investment in solar and wind pathways as an alternative to brown coal and CCS.

HELOS: Heterogeneous Load Scheduling for Electric Vehicle-Integrated Microgrids

With increasing concerns about worldwide environmental conditions and rapid development of renewable energy technologies, microgrids have been regarded as a promising solution to reduce the burden of infrastructure-based power systems. However, due to the intrinsically intermittent features of existing renewable energy, along with random residential behavior patterns, unpredictable plugged-in or unplugged actions of electric vehicles (EVs) and the time-varying price of electricity, it is challenging for microgrid operators to efficiently perform load scheduling and energy management. In this paper, we propose an online algorithm to conduct cost-aware scheduling of EV loads and energy supplies for microgrids. We formulate this problem into a stochastic optimization problem with the objective of minimizing the time-average cost of a microgrid, including the purchase cost of electricity from the main grid, the cost of charging and discharging batteries, renewable harvesting costs, and life-cycle greenhouse-gas emission costs. To solve this problem, the key idea is to exploit the dynamics of the price of electricity to conduct battery charging and discharging operations, renewable energy harvesting, and schedule EV loads properly. Our method is based on the Lyapunov optimization technique, which has low computational complexity and only requires limited prediction of price information. The theoretical analysis of our algorithm confirms that the proposed strategy can achieve optimality with explicit bound. By conducting extensive real-data driven simulations, we demonstrate that our proposed algorithm can achieve much lower cost and be more eco-friendly than other alternative solutions.

How does Changing the Penetration of Renewables and Flexibility Measures Affect the Economics of CCS Penetration?

In recent years, investment into carbon capture and storage (CCS) technologies has been seemingly sidelined to encourage larger renewable energy generation investment. High initial CCS costs have to compete with decreasing renewable costs and in some scenarios the role of CCS is completely overtaken by renewable energy. However, not recognising the value of a wider variety of low-carbon options in an energy system and committing to a single low-carbon technology can lead to a reduction in flexibility and further down the line even a lock out from successfully adapting the system to new advancements in smart technologies. On the path to a greener British energy system, gas power plants are considered as the transitional technology given the intermittent nature of most renewable generation. CCS can play a crucial role in mitigating the polluting effects of conventional generation. This paper employs real options analysis (ROA) to explore various cost and flexibility states, accounting for various penetrations of CCS and renewables working in cohesion.