Portfolio Of Energy Technologies Research Articles

Veggies and PV: Optimization of Building-Integrated Agriculture in an Energy Hub

Building-integrated Agriculture (BIA) is the concept of utilizing façade surfaces for crop production. The potential is to reduce land-use and to increase the utility of built-up area. If outdoor building surfaces were to be used for farming, it results in a competition for sunlight between crops, solar renewable energy (such as photovoltaics, PV), and daylight access to illuminate indoor spaces. We therefore propose a coupled BIA and multi-energy systems model that can represent various energy sources (such as sunlight) and their conversion and storage (such as façade based crop production, PV, or electric batteries) in order to optimally meet demands for building energy and food. It is formulated as a mixed integer linear program (MILP) optimization model that describes the energy flows as an annual hourly time series. The model conducts a bi-objective minimization of monetary cost and carbon emissions, resulting in a Pareto front of optimal solutions. The model meets building energy demands for cooling, heating and electricity by an optimized energy technology portfolio, as well as nutritional demands for leafy vegetables of all occupants by either BIA or supermarket purchases. We apply our model to a residential case study in Singapore, which serves as an example for a high density city with already numerous community-driven and practiced BIA initiatives ongoing. Our results show that when minimizing cost, utilizing PV is more cost efficient on highly exposed surfaces such as the roof than BIA. However, for more shaded façade surfaces, crop production can be a cost and environmentally efficient addition to building design, as the annual vegetables demand of all occupants can be covered entirely by self-grown produce.

Designing residential energy systems considering prospective costs and life cycle GHG emissions

Novel energy technologies are typically associated with large investments and environmental impacts generated in the construction phase. In this work, we present a systematic approach to optimally design residential energy systems, considering (prospective) costs and life cycle greenhouse gas (GHG) emissions of a large set of low-carbon energy technologies and sources. To achieve this, an optimization problem has been formulated and is tested on several scenarios considering climate-specific heat and electricity demand as well as scenario-specific conditions, such as the flexibility of grid electricity tariffs and associated GHG intensities. With GHG-intensive grid electricity supply and flexible energy tariffs, we recommend to implement policy measures to encourage the investment in residential solar PV-coupled batteries and heat pumps, especially in the near future. The inclusion of environmental impacts generated from the production of energy technologies cannot be neglected; they should be considered during the design phase of residential energy systems. Current high electricity and natural gas prices result in the installation of low-carbon energy system components. This implies that battery systems are already an effective option to reduce the reliance on carbon-intensive and expensive energy supply. And lastly, the large-scale deployment of residential lithium-ion batteries might be limited by global lithium production. This implies that energy system designers should consider alternative electricity storage technologies in their energy technology portfolio.

Categorizing distributed wind energy installations in the United States to inform research and stakeholder priorities

BackgroundDistributed wind energy adoption in the United States can contribute to the diverse portfolio of energy technologies needed to achieve ambitious decarbonization goals. However, with limited deployment to date, the current distributed wind market must be better understood; these efforts will support the range of stakeholders who will drive successful deployment. This article first distinguishes three categories of distributed wind from existing literature: (1) behind the meter, (2) intended for explicit local load, and (3) physically distributed. A novel methodology to classify individual wind installations into each of these categories is then presented and applied to two data sets of wind installations in the United States to categorize and illuminate distinct segments in the distributed wind market.ResultsPhysically distributed installations, constituted by small to moderately sized projects serving local loads on distribution systems solely because of their proximity to them, account for the highest amount of capacity but the lowest number of installations out of the three categories. The inverse is true for behind-the-meter installations, which are used to serve on-site loads. Installations intended for explicit local load, which are interconnected on the utility side of the distribution system and intentionally built to provide energy to loads on the same distribution system, rank in the middle for both installed capacity and number of installations.ConclusionsDistributed wind energy deployment in the United States is geographically widespread, but the extent to which a single category is developed in each state varies. Policies, wind resources, and broad energy technology trends contribute to these deployment patterns. By identifying the extent to which each category of installations exists, decision-makers are empowered with data necessary to tailor research and development programs and address stakeholder priorities through policy and other means, ultimately supporting future deployment.

Integrating System and Operator Perspectives for the Evaluation of Power-to-Gas Plants in the Future German Energy System

In which way, and in which sectors, will renewable energy be integrated in the German Energy System by 2030, 2040, and 2050? How can the resulting energy system be characterised following a −95% greenhouse gas emission reduction scenario? Which role will hydrogen play? To address these research questions, techno-economic energy system modelling was performed. Evaluation of the resulting operation of energy technologies was carried out from a system and a business point of view. Special consideration of gas technologies, such as hydrogen production, transport, and storage, was taken as a large-scale and long-term energy storage option and key enabler for the decarbonisation of the non-electric sectors. The broad set of results gives insight into the entangled interactions of the future energy technology portfolio and its operation within a coupled energy system. Amongst other energy demands, CO2 emissions, hydrogen production, and future power plant capacities are presented. One main conclusion is that integrating the first elements of a large-scale hydrogen infrastructure into the German energy system, already, by 2030 is necessary for ensuring the supply of upscaling demands across all sectors. Within the regulatory regime of 2020, it seems that this decision may come too late, which jeopardises the achievement of transition targets within the horizon 2050.

Climate Policy Imbalance in the Energy Sector: Time to Focus on the Value of CO2 Utilization

Global warming is an existential threat to humanity and the rapid energy transition, which is required, will be the defining social, political and technical challenge of the 21st century. Practical experience and research results of recent years have showed that our actions to cover the gap between real situation and aims of climate agreements are not enough and that improvements in climate policy are needed, primarily in the energy sector. It is becoming increasingly clear that hydrocarbon resources, which production volume is increasing annually, will remain a significant part of the global fuel balance in the foreseeable future. Taking this into account, the main problem of the current climate policy is a limited portfolio of technologies, focused on replacement of hydrocarbon resources with renewable energy, without proper attention to an alternative ways of decreasing carbon intensity, such as carbon sequestration options. This study shows the need to review the existing climate policy portfolios through reorientation to CO2 utilization and disposal technologies and in terms of forming an appropriate appreciation for the role of hydrocarbon industries as the basis for the development of CO2-based production chains. In this paper we argue that: (1) focusing climate investments on a limited portfolio of energy technologies may become a trap that keeps us from achieving global emissions goals; (2) accounting for greenhouse gas (GHG) emissions losses, without taking into account the potential social effects of utilization, is a barrier to diversifying climate strategies; (3) with regard to hydrocarbon industries, a transition from destructive to creative measures aimed at implementing environmental projects is needed; (4) there are no cheap climate solutions, but the present cost of reducing CO2 emissions exceeds any estimate of the social cost of carbon.

Citizen Participation in Low-Carbon Energy Systems: Energy Communities and Its Impact on the Electricity Demand on Neighborhood and National Level

In this work, the main research question is how a high penetration of energy communities (ECs) affects the national electricity demand in the residential sector. Thus, the existing building stock of three European regions/countries, namely, the Iberian Peninsula, Norway, and Austria, is analyzed and represented by four different model energy communities based on characteristic settlement patterns. A tailor-made, open-source model optimizes the utilization of the local energy technology portfolio, especially small-scale batteries and photovoltaic systems within the ECs. Finally, the results on the national level are achieved by upscaling from the neighborhood level. The findings of different 2030 scenarios (building upon narrative storylines), which consider various socio-economic and techno-economic determinants of possible future energy system development, identify a variety of modification potentials of the electricity demand as a result of EC penetration. The insights achieved in this work highlight the important contributions of ECs to low-carbon energy systems. Future work may focus on the provision of future local energy services, such as increasing cooling demand and/or high shares of electric vehicles, further enhancement of the upscaling to the national level (i.e., considering the distribution network capacities), and further diversification of EC composition beyond the residential sector.

A qualitative-computational cataloguing of the EU-level public research and innovation portfolio of clean energy technologies (2014–2020)

To better allocate funds in the new EU research framework programme Horizon Europe, an assessment of current and past efforts is crucial. In this paper we develop and apply a multi-method qualitative and computational approach to provide a catalogue of climate crisis mitigation technologies on the EU level between 2014 and 2020. Using the approach, we observed no public EU-level funding for multiple technologies prioritised by the EU, such as low-carbon production and use of cement and chemicals, electric battery, and a number of industrial decarbonisation processes. We observed a rising trend in the funding of solar power and onshore wind, the adjacent to them power-to-X technology, as well as recycling. At the same time, the shares of funding into fuel cell, biofuel, demand-side energy management, microgrids, and waste management show a decline trend. With note of the exploratory character of the present paper, we propose that the EU Horizon 2020 funding of clean technologies only partially reflected the expectations of key institutionalised EU actors due to the existence of many non-funded prioritised technologies.

Explaining successful and failed investments in U.S. carbon capture and storage using empirical and expert assessments

Most studies of deep decarbonization find that a diverse portfolio of low-carbon energy technologies will be required, including carbon capture and storage (CCS) that mitigates emissions from fossil fuel power plants and industrial sources. While many projects essential to commercializing the technology have been proposed, most (>80%) end in failure. Here we analyze the full universe of CCS projects attempted in the U.S. that have sufficient documentation (N=39)—the largest sample ever studied systematically. We quantify 12 project attributes that the literature has identified as possible determinants of project outcome. In addition to costs and technological readiness, which prior research has emphasized, we develop metrics for attributes that are widely thought to be important yet have eluded systematic measurement, such as the credibility of project revenues and policy incentives, and the role of regulatory complexity and public opposition. We build three models—two statistical and one derived through the elicitation of expert judgment—to evaluate the relative influence of these 12 attributes in explaining project outcome. Across models, we find the credibility of revenues and incentives to be among the most important attributes, along with capital cost and technological readiness. We therefore develop and elicit experts’ judgment of 14 types of policy incentives that could alter these attributes and improve the prospects for investment in CCS. Knowing which attributes have been most responsible for past successes and failures allows developers to avoid past mistakes and identify clusters of near-term CCS projects that are more likely to succeed.

Open-source modeling of a low-carbon urban neighborhood with high shares of local renewable generation

The main research question of this work is how an urban neighborhood can optimally exploit its local renewable generation potential to cover its electricity, heat and cooling demand. Various cost-minimizing energy technology portfolio studies are examined for an energy community in Vienna, Austria. The method applied is a tailor-made extension of the existing open-source model urbs. Additional functionalities and energy services have been implemented. The results of three scenarios identify a variety of different trade-offs between energy technology utilization, local supply within the community and external supply from outside. The introduced performance indicators reveal the respective strengths/weaknesses of the different energy supply options. In this context, the economic efficiency of geothermal sources and the connection to the district cooling network are highlighted, which have so far received little attention. The insights achieved in this work directly support sustainable urban energy planning. Future work may focus on mapping higher spatial resolution, further enhancement of the performance indicators and implementation of operational energy scheduling and dispatch into the open-source modeling approach.

We choose what we like – Affect as a driver of electricity portfolio choice

Numerous countries are restructuring their electricity systems. Transitioning to electricity systems that are considered acceptable by the public requires that the public's preferences be taken into account. In this study, we investigate the type of energy technology portfolio that people prefer for Switzerland, and why they prefer it, when they are faced with two realistic constraints: (i) the limited domestic potential for the expansion of power plants and (ii) the requirement to not dismantle existing infrastructure. We find that the affect evoked by particular energy technologies is consistently the most important driver of the proportion of those technologies included in an energy portfolio. The regression models for the investigated technologies explain between 14% and 54% of the variance, providing strong support for the affect heuristic. We further find that concerns regarding environmental impacts, costs or climate change play an additional role for portfolio preferences. This is reflected in four different clusters we identified for the German-speaking Swiss population who potentially hold opposing views as to what they consider the best electricity mix. For policymakers, our findings suggest that positive affective reactions towards energy technologies are necessary, although concerns must also be considered if the implementation is to be widely accepted.

Adsorption Behavior of PGM-Free Catalysts By Near-Ambient Pressure X-Ray Photoelectron Spectroscopy

Polymer Electrolyte Membrane Fuel Cells (PEMFCs) are an important component in the portfolio of renewable energy technologies that are important for our society. While being green technology, PEMFCs rely on precious metals to catalyze the oxygen reduction reaction (ORR) on the cathode side. Several approaches have been explored in order to reduce the amount of precious metals, including core-shell structures, extended thin films, and various alloys with non-precious metals. Potential solutions also include PGM-free catalysts made with earth abundant, inexpensive elements. One promising area of PGM-free catalyst development is the integration of nitrogen and iron into high surface area carbon nanostructures.1,2 These materials have significantly improved in activities over the past decade, yet their heterogeneous nature motivates further study into the nature of the active sites, with the goal of improving activity, active site density, and stability. Multi-technique, multi-scale characterization of these materials, under ex situ and in situ conditions, provides opportunity to better understand surfaces of the materials under relevant conditions and to optimize various interfaces in these systems for optimum performance. In this work near-ambient pressure x-ray photoelectron spectroscopy (nAP-XPS) is used to investigate adsorption and desorption behavior of a diverse set of catalysts and supports, which contain nitrogen and iron sites of interest. Challenges associated with analysis of nAP-XPS data from adsorption and desorption studies include: i) presence of different types of potential sites and the multitude of binding energy shifts that could be happening upon adsorption on these various sites, ii) subtle changes in the spectra associated with adsorption/desorption due to low number of potential sites for adsorption, and iii) sampling depth limitations of the technique.3 To overcome these challenges, we explore less conventional approaches to analysis of the XPS N 1s and O 1s spectra, and complemented XPS with other in situ techniques such as diffuse reflectance infrared fourier transform spectroscopy (DRIFTS). Figure 1. XPS N1s difference spectra comparing adsorption and desorption processes on a PGM-free FeNC material. Jaouen, F., Proietti, E., Lefèvre, M., Chenitz, R., Dodelet, J.P., Wu, G., Chung, H.T., Johnston, C.M., and Zelenay, P., Energy Environ. Sci. 4, 114 (2011).Wood, K. N., O’Hayre, R., and Pylypenko, S. Energy Environ. Sci. 7, 1212 (2014).Matanovic, I., Artyushkova, K.; Strand, M. B., Dzara, M. J., Pylypenko, S., Atanassov, P., Core Level Shifts of Hydrogenated Pyridinic and Pyrrolic Nitrogen in the Nitrogen-Containing Graphene-Based Electrocatalysts: In-Plane vs Edge Defects. J. Phys. Chem. C 120, 51 (2016) Figure 1

The optimal research and development portfolio of low-carbon energy technologies: A study of China

To support decision-making for an optimal portfolio strategy for low-carbon energy technology research and development (R&D), this study proposes a dynamic two-stage stochastic programming model, taking into account both the uncertainty of technological change and damages of climate change. Based on China's economic and technology level and expert elicitation, an R&D investment portfolio strategy looking at three low-carbon technologies (carbon capture and storage [CCS], solar photovoltaic [PV], and nuclear), including nine projects, is investigated through the proposed model. The optimized results show that the optimal R&D technology portfolio is robust to different levels of risk in climate damage. However, the total social costs for the optimal R&D technology portfolio is lowest in the medium risk of climate damage scenario. Under different opportunity costs, the composition of the optimal R&D portfolio varies. However, projects for each of the three technologies always constitute the optimal R&D portfolio. Furthermore, the implication is that a technology synergistic R&D strategy is conducive to enhancing the level of CO2 abatement and reducing the total social cost.

Solar energy utilization patterns for different district typologies using multi-objective optimization: A comparative study in China

Abstract Currently, solar energy technologies are in the stage of intensive development. With booming solar industry, there is a challenge to seek for appropriate solar energy solutions for different district typologies. This paper presents a comparative study on solar energy utilization patterns for different types of districts located in Kunming, China. Four district typologies are investigated: residential district (RD), official district (OD), commercial district (CD) and industrial district (ID). For each district, the objective is to identify such solar energy utilization patterns that result in an optimal design and operation of solar energy system. The optimum system is defined and obtained through minimizing life cycle CO 2 emissions and costs as well as maximizing exergy efficiency. To that end, a multi-objective optimization approach based on Genetic Algorithm is proposed. The results of the case study suggest that solar energy is to represent 3.7%, 5.9%, 7.9% and 21.4% of annual energy consumption for RD, OD, CD and ID, respectively. For each district, the portfolio of solar energy technologies is different. Solar power systems factually contribute to the energy supply of ID only. The final work aims at investigating the effects of different solar energy parameters on the solar utilization patterns for these districts.

Evaluation of a proposal for reliable low-cost grid power with 100% wind, water, and solar

A number of analyses, meta-analyses, and assessments, including those performed by the Intergovernmental Panel on Climate Change, the National Oceanic and Atmospheric Administration, the National Renewable Energy Laboratory, and the International Energy Agency, have concluded that deployment of a diverse portfolio of clean energy technologies makes a transition to a low-carbon-emission energy system both more feasible and less costly than other pathways. In contrast, Jacobson et al. [Jacobson MZ, Delucchi MA, Cameron MA, Frew BA (2015) Proc Natl Acad Sci USA 112(49):15060–15065] argue that it is feasible to provide “low-cost solutions to the grid reliability problem with 100% penetration of WWS [wind, water and solar power] across all energy sectors in the continental United States between 2050 and 2055”, with only electricity and hydrogen as energy carriers. In this paper, we evaluate that study and find significant shortcomings in the analysis. In particular, we point out that this work used invalid modeling tools, contained modeling errors, and made implausible and inadequately supported assumptions. Policy makers should treat with caution any visions of a rapid, reliable, and low-cost transition to entire energy systems that relies almost exclusively on wind, solar, and hydroelectric power.

CO2 capture and storage (CCS) cost reduction via infrastructure right-sizing

Carbon capture and storage (CCS) will be a critical component of a portfolio of low-carbon energy technologies required to combat climate change (IEA-GHG, 2013). As such, an extensive transportation infrastructure will be required to transport captured CO2 from different sources to the available sinks. Several studies in the literature suggest that shared oversized pipeline networks may be the most efficient long term option compared to single source to sink pipelines, based on increased CCS deployment over the years and therefore increased CO2 flowrate to the transport network. However, what is neglected in this vision is that the deployment of intermittent renewable energy tends to displace thermal power generation. This directly reduces the amount of fossil fuel burned, CO2 produced, captured and transported through the network. This paper presents an optimisation methodology to “right-size” CO2 transport infrastructure, explicitly accounting for the transient flow of CO2 arising from the co-deployment of intermittent renewable energy generators. By application of this methodology, we demonstrate that capital cost reductions of up to 28% are possible relative to a business-as-usual design case.

Community energy system planning: a case study on technology selection and operation optimization

Community energy planning has attracted wide attention in China as the implementation of China’s low-carbon city policies. Meanwhile the rapid development of energy science and technology has shifted buildings and communities from energy consumers to prosumers, which lead to more difficulties in configuring the energy technology portfolio. This study es-tablishes an optimal decision-making model for community energy planning and develops an online tool called District EnErgy Planning(DEEP). Based on DEEP, the impact of energy price and equipment cost on optimization results, and the corresponding operational strategies are discussed through case study and scenario analysis. The results show that, when natural gas price exceeds 2yuan/m3 the gas-based solutions become economically uncompetitive. The technologies are propitious when equipment prices are reduced by 50%, 50%, 80% for CHP facilities, PV panels and electric battery, respectively.

A Technology Selection and Operation (TSO) optimisation model for distributed energy systems: Mathematical formulation and case study

This paper presents a model which simultaneously optimises the selection and operation of technologies for distributed energy systems in buildings. The Technology Selection and Operation (TSO) model enables a new approach for the optimal selection and operation of energy system technologies that encompasses whole life costing, carbon emissions as well as real-time energy prices and demands; thus, providing a more comprehensive result than current methods. Utilizing historic metered energy demands, projected energy prices and a portfolio of available technologies, the mathematical model simultaneously solves for an optimal technology selection and operational strategy for a determined building based on a preferred objective: minimizing cost and/or minimizing carbon emissions. The TSO is a comprehensive and novel techno-economic model, capable of providing decision makers an optimal selection from a portfolio of available energy technologies. The current portfolio of available technologies is composed of various combined heat and power (CHP) and organic Rankine cycle (ORC) units. The TSO model framework is data-driven and therefore presents a high level of flexibility with respect to time granularity, period of analysis and the technology portfolio. A case study depicts the capabilities of the model; optimisation results under different temporal arrangements and technology options are showcased. Overall, the TSO model provides meaningful insights that allow stakeholders to make technology investment decisions with greater assurance.

Challenges in assessment of clean energy supply-chains based on byproduct minerals: A case study of tellurium use in thin film photovoltaics

Transitioning to a sustainable energy supply will be critical to meeting future economic and environmental goals. This transition will require optimizing and commercializing a portfolio of new clean energy technologies. However, many promising clean energy technologies are based on materials with inherent risks in their supply; these risks include scarcity, price volatility, criticality, and other potential supply-chain disruptions. Using tellurium use in CdTe photovoltaics as a case study, this paper presents analysis of some of the key challenges associated with modeling byproduct systems (a supply-chain where a key material is actually a byproduct of extraction of another material, copper in the case of tellurium). This work presents a novel modeling approach; the results of the case study are used to identify potential supply risks facing this clean technology, with a unique focus on sensitivity to changes in the preliminary lifecycle stages. Supply-chain sensitivities are connected with direct environmental impacts to frame the implications in a broader sustainability context and to emphasize the future role of recycling. Ultimately, it was shown that if historical supply and demand trends continue, supply gap conditions will emerge before the end of the current decade. However, improvements in byproduct yield, end-use recycling rate, and end-use material intensity exhibit significant leverage to minimize risk in the energy-critical tellurium supply-chain.

Adapting Business of Energy Corporations to Macro-Policies Aiming at a Sustainable Economy. The Case for New Powering of Automobiles

A portfolio of new energy technologies has emerged in the first decade of the 21st Century, and many of them could be used for re-structuring the energy sector towards Sustainable Development. A key subject in this quest is the future of automobile, with possibilities on powering ranging from biofuels to Hydrogen Cars (HC), to Electric Vehicles (EV). In turn, the latter is closely connected with the need to deploy Renewable Energies (RE) for electricity generation. Within such new situation, countries and governments are aware that there are new tools for fighting Global Warming (GW), and new policies could be established for winning this battle against CO2. All these initiatives will affect the future of energy corporations, notably hydrocarbon companies; and it should be noted that it will be difficult for the companies to define long-term strategies if energy policies convey upheavals, sudden changes in promoting alternatives and interruptions on activities. Hence, it is very important to adopt energy policies allowing a smooth evolution of the companies’ activities to the new energy model. After analyzing the alternatives with a forecasting-backcasting methodology, an “eclectic approach” is proposed, with the Plug-in Hybrid car with Flexible Fuel (PiHFF) as the central paradigm in the coming promoting policies.

Assessing renewable energy portfolio futures with multiple perspectives: The case of the northwest US

Renewable energy has become a major driver for the federal and state governments. Many have received funds from recently announced programs. However there have been challenges in determining the optimum portfolio of energy alternatives. Multiple perspectives were operationalized through a prior assessment by the Office of Technology Assessment. Through additional literature review, a model was created to consider all factors and perspectives to be considered in developing a portfolio of renewable energy technologies. A limited demonstration with goal programming and scenarios was included. The case of the state of Oregon was used to demonstrate the approach.