Techno-economic Perspective Research Articles

Techno-economic analysis of a micro-scale biogas plant integrated with microalgae cultivation for the treatment of organic municipal waste

The deployment of small-scale anaerobic digestion (AD) plants for the treatment of the organic fraction of municipal solid waste (OFMSW) and associated production of renewable energy at a local level has recently attracted attention as opposed to full-scale centralized plants. In this work, we evaluate the technical and economic feasibility of an integrated process comprising small-scale AD of OFMSW followed by microalgae cultivation, to valorise the waste streams of the former (off-gases produced by combined heat and power generation and liquid digestate) for the production of valuable biomass to be destined to either the biofertilizers or the biostimulants markets, in agreement with a circular economy perspective. The material and energy balances were obtained by means of process simulation for a plant located in Northern Italy, taken as a reference. The analysis revealed that, although the high turbidity of the digestate strongly hinders biomass production, the process is profitable from a techno-economic perspective, with discounted payback time ranging from 3.3 to 7.1 years, and profitability indexes greater than 1. The low market price of biofertilizers makes it the less profitable choice, even compared to the AD process alone, while selling the biomass for biostimulants applications could strongly increase the process profitability.

Revenue Stacking for BESS: Fast Frequency Regulation and Balancing Market Participation in Italy

Battery energy storage systems (BESS) are considered a relevant flexible resource for supporting the balancing of a RES-penetrated power grid. Since their cost structure is characterized by very high capital costs, it is of utmost importance to ensure efficient and effective operations from a techno-economic perspective. The possibility of services (and revenues) stacking is one of the most discussed optimization solutions. The present work provides a novel approach for BESS modeling, including the stacking of two diverse ancillary services, a dedicated balancing market bidding model, and a state-of-charge management strategy. Fast frequency regulation is proposed as a power-based service, requiring large ramping capability, but asking BESS activation just for a limited amount of time. For the remainder, BESS power can be traded on balancing market (BM): energy-based services, such as tertiary regulation, could be effectively coupled with power-based, fast regulations, increasing the economic attractiveness of investments in BESS. The case of fast reserve (FR), a new high-speed frequency response service proposed by the Italian TSO in Italy, is assessed in this study. FR provision foresees a capacity-based remuneration (k€/MW/year) and requires to ensure 1000 hours per year of availability. After assessing its cost-effectiveness as a stand-alone service, a sequential multiservice strategy is proposed, where BESS provides FR for 1000 hours, while for the rest of the time it is dedicated to the provision of replacement reserve (RR). Performances of BESS are evaluated considering the reliability of the provision, its operational efficiency, and investment’s economics. Performed tests demonstrate how, within the current Italian regulatory framework, the investment’s rate of return improves thanks to the multiservice approach. In particular, while maintaining a proper reliability, the minimum acceptable remuneration from FR yearly auctions decreases by 13%; at the same time, self-dispatching of energy through BM calls reduces the need to purchase energy on day-ahead market and keeps BESS state-of-charge far from saturation regions, thus also increasing its lifetime.

A techno-economic perspective on a microwave extraction process for efficient protein recovery from agri-food wastes

Different agri-food wastes (brewer´s spent grain (BSG), spent coffee ground (SCG) and kale stems) have been proposed as excellent sources of protein-enriched extracts with an antioxidant capacity. The optimization of the microwave-assisted hydrothermal and alkali extraction has been compared in this study. From a technical and economic point of view, the extraction of BSG under optimal conditions (110 ºC, 10 min and 0.5 M NaOH) provided the best extract with a content of 14.6 kg protein/100 kg BSG (dry matter), 13.8 g/L of total sugars and an antioxidant activity (DPPH method) of 17.1 mg trolox equivalents (TE)/g BSG. This extract had the lowest production cost (29.9 €/kg) and a minimum selling price of 51.7 €/kg, estimated for an extraction pilot plant of 15 kg/h of BSG. The microwave-assisted hydrothermal extraction of kale stems, a novel waste in the biorefinery context, also provides bioactive and green extracts of commercial interest. There is a need for specific research studies related to biorefining of agri-food wastes to produce proteins for food, contributing to the development of a future sustainable and climate-neutral agriculture. The proposed techno-economic assessment represents an important advance in research and scaling-up of microwave-assisted extraction processes for protein recovery from agri-food wastes.

SAF production from cameline oil hydrotreatment: A technoeconomic assessment of alternative process configurations

In the recent years, the increasing demand of air transportation, the concern about the fossil resources depletion and the global warming caused by greenhouse-gas emissions have increased the interest for the viability of sustainable aviation fuel (SAF). The hydrotreatment of vegetable oils can be considered a technologically-feasible alternative to produce SAF compatible with the current aviation technology. This process also generates by-products suitable to be valorized through different pathways to obtain hydrogen and/or power, required in the process, which shall be assessed to find the most feasible solution. With this aim, this work proposes and evaluates different process configurations for kerosene-range hydrocarbon production based on camelina oil hydrotreatment and alternative scenarios for the valorization of the co-produced light-gases. These alternatives, comprising steam reforming, autothermal reforming and power generation, are assessed from a technoeconomic perspective. The results indicate operational costs dominated by the camelina oil price and strongly influenced by hydrogen and electricity prices. The levelized cost of fuel estimated ranges between 0.57 and 0.64 € per kilogram of fuel, depending on the studied scenario, which demonstrate the techno-economic feasibility of the proposed systems.

One piece of the puzzle towards 100 Positive Energy Districts (PEDs) across Europe by 2025: An open-source approach to unveil favourable locations of PV-based PEDs from a techno-economic perspective

To reduce CO2 emissions, the European Commission aims at having 100 Positive Energy Districts (PEDs) planned, developed or established by 2025. A PED annually exports more energy than it imports from the local grid. Because of Europe's diversity, this study aims to indicate where in the EU and under which tariff circumstances an electrified PED will likely thrive most. To do so, the work uses a tailor-made, mixed-integer linear programming model to optimise electrified PED solutions and compare them to the respective status quo for various representative zone-tariff parameter combinations. Results indicate that the optimal potential for PEDs is in southern Europe, with a dynamic electricity tariff and where previously no district heating was used. Under those circumstances, the PED concept could save around 84% of carbon emissions, while being more economical over the project horizon. Pricing of CO2 emissions of energy services additionally nudges towards PED implementation. By limiting the power exchange of the PED with the grid, some of the negative grid impacts can be reduced. This study provides an essential insight into where in Europe a PED could be a sensible addition compared to where other decarbonisation approaches might be more beneficial.

Pilot scale extraction of protein from cold and hot-pressed rapeseed cake: Preliminary studies on the effect of upstream mechanical processing

It is important from a techno-economic perspective to understand the challenges associated with developing scalable processes to extract functional proteins from rapeseed cake for applications as functional food ingredients. One of these challenges is to develop a better understanding of the link between upstream mechanical processing of the rapeseed cake and the yield of extracted protein. An initial trial with cold pressed rapeseed cake (CPR) indicated that wet milling had no impact on protein yield. Measurement of protein yields with the Bradford assay indicated that 14% would be recovered. The total protein recovered (5.4% by Kjeldahl analysis) contained a glucosinolate and phytate content that was similar to the rapeseed cake at the start of the process. The fate of the protein extraction was followed during a pilot scale trial with hot-pressed rapeseed cake (HPR), using only stirring followed by sieving, revealing an increase in protein yields, as determined by the Bradford assay, from 8.0% at the start to 22.6% at the end of processing. In addition, only 16% of HPR was solubilized. A similar pilot scale trial with HPR using wet milling and stirring followed by decanting also showed an increase in protein concentration from 15.3% at the start to 23.7% at the end of processing. In addition, 38% of HPR was solubilized. This study provides an insight into what the effect of upstream mechanical processing (wet milling) has in releasing protein from rapeseed cake in order to improve process efficiency. This could have important consequences for upscaling and commercial extraction of rapeseed cake protein.

Techno-economic analysis of battery electricity storage towards self-sufficient buildings

Effective electricity storage solutions that decouple energy use and production are central to the green energy transition. In particular, in the residential sector, the implementation of such solutions should boost the potential of nearly zero energy buildings to reduce the primary energy consumption and greenhouse gases emission and towards a greater energy self-sufficiency.The aim of this paper is to assess a climate independent scaling law for the introduction of a battery energy storage in a residential environment. To this end, we evaluate the environmental and economic impact of the integration of a lithium-ion battery in a real existing residential building, for different climates and for different battery capacities. The building is made of 13 apartments and features a reversible heat pump, a photovoltaic system, and a lithium-ion battery. We model all the elements and the energy consumption of the building and validate results against measured data.The results show that sizing the lithium-ion battery based on the variation of the self-consumed renewable energy yields a sustainable investment for all climates. Moreover, from a techno-economic perspective, lithium-ion batteries are better suited for daily energy storage rather than seasonal storage. In fact, they efficiently fill the time lag between demand and production on a daily time scale. On the other hand, lithium-ion battery costs gathers unsustainable investments for seasonal storage also considering any foreseeable battery cost reduction. Optimized building-level battery storage cannot fill completely the temporal mismatch between production and usage. As a consequence, different technologies (e.g. electric mobility) should be also considered to locally consume all the energy produced by the photovoltaic.

Techno-economic feasibility analysis of Renewable-fed Power-to-Power (P2P) systems for small French islands

In this paper, the feasibility analysis of H2 and Battery based Power-to-Power (P2P) systems are presented from a techno-economic perspective. For this study, 21 small islands of France based in Europe are selected, being naturally endowed with renewable energy sources (RES) of solar and wind. For each island, three distinct energy storage options, i.e., hydrogen storage, battery storage and hydrogen + battery combined storage are discussed and explored. Optimum sizing of RES and P2P systems are achieved through employing particle swarm optimization (PSO) algorithm, keeping Levelized Cost of Energy (LCOE) as an objective function. The hydrogen and battery storage combination with an average LCOE value of 420Euro/MWh was found to be the most suitable option for all 21 reference islands. The associated Net Present Cost (NPC) was EUR564,388,050 which was lower than that for the other two storage options. The hybrid storage selection necessitated installation of 41 MW of photovoltaic (PV) modules and 122MW of wind turbines at these islands. The required storage capacity comprised of 7700MWh of hydrogen and 7MWh of battery storage combined with the auxiliaries. A considerable emphasis is also laid on highlighting the annual reduction of greenhouse gases (GHGs) and other air pollutants through the adoption of the proposed RES-P2P integrated systems. The annual carbon dioxide equivalent measure (CO2,e) of all islands was computed to be around 99507.52tons. It was revealed that more than 99 thousand tons of CO2 emissions can be prevented by avoiding consumption of more than 34 million liters of diesel per year.

Integrated approaches to mitigate threats from emerging potentially toxic elements: A way forward for sustainable environmental management

Potentially toxic elements (PTEs) such as toxic metal (loid)s and other emerging hazardous contaminants, exist in the environment and poses a serious threat. A large amount of wastewater containing PTEs such as cadmium, chromium, copper, nickel, arsenic, lead, zinc, etc. Release from industries during production process. Besides these, chemical-based fertilizers used in soils during crop production have become one of the crucial sources of PTEs. Various techniques are being employed for the mitigation of PTEs like chemical precipitation, ion exchange, coagulation, activated carbon, adsorption, membrane filtration, and bioremediation. Among these mitigation strategies, biological processes such as bioremediation, phytoremediation etc. Are extensively used, as they are economic have high-efficiency rate and are eco-friendly. This review intends to provide information on PTEs contamination through various sources; along with the toxicity of metal (loid)s with respect to their patterns of transmission and risks in the changing environment. Various remediation methods for the management of these pollutants along with their techno-economic perspective are also summarized in this review.

Sustainable processes for treatment and management of seafood solid waste

Seafood processing is an important economical activity worldwide and is an integral part of the food chain system. However, their processing results in solid waste generation whose disposal and management is a serious concern. Proteins, amino acids, lipids with high amounts of polyunsaturated fatty acids (PUFA), carotenoids, and minerals are abundant in the discards, effluents, and by-catch of seafood processing waste. As a result, it causes nutritional loss and poses major environmental risks. To solve the issues, it is critical that the waste be exposed to secondary processing and valorization for recovery of value added products. Although chemical waste treatment technologies are available, the majority of these procedures have inherent flaws. Biological solutions, on the other hand, are safe, efficacious, and ecologically friendly while maintaining the intrinsic bioactivities after waste conversion. Microbial fermentation or the actions of exogenously introduced enzymes on waste components are used in most bioconversion processes. Algal biotechnology has recently developed unique technologies for biotransformation of nutrients, which may be employed as a feedstock for the recovery of important chemicals as well as biofuel. Bioconversion methods combined with a bio-refinery strategy offer the potential to enable environmentally-friendly and cost-effective seafood waste management. The refinement of these wastes through sustainable bioprocessing interventions can give rise to various circular bioeconomies within the seafood processing sector. Moreover, a techno-economic perspective on the developed solid waste processing lines and its subsequent environmental impact could facilitate commercialization. This review aims to provide a comprehensive view and critical analysis of the recent updates in seafood waste processing in terms of bioconversion processes and byproduct development. Various case studies on circular bioeconomy formulated on seafood processing waste along with techno-economic feasibility for the possible development of sustainable seafood biorefineries have also been discussed.

Integration of prosumer peer-to-peer trading decisions into energy community modelling

Peer-to-peer (P2P) exchange of renewable energy is an attractive option to empower citizens to actively participate in the energy transition. Whereas previous research has assessed P2P communities primarily from a techno-economic perspective, little is yet known about prosumer preferences for solar power trading. Importantly, impacts of community members’ trading decisions on key performance indicators, such as individual electricity bills, community autarky and grid stress, remain unknown. Here, we assess P2P trading decisions of German homeowners on the basis of an online experimental study, and simulate how various decision-making strategies impact the performance of P2P communities. The findings suggest that community autarky is slightly higher when prosumers are enabled to trade energy compared to when they merely aim to maximize their self-consumption. Our analysis, moreover, shows that P2P energy trading based on human decision-making may lead to financial benefits for prosumers and traditional consumers, and reduced stress for the grid.

Techno-economic perspective of a floating solar PV deployment over urban lakes: A case study of NUST lake Islamabad

Water bodies like small lakes, canals, and rivers in urban areas serve to be a way forward to deploy photovoltaic technology with no constraints to involve land procurement. This article aims to estimate the potential deployment of a floating photovoltaic system on an urban lake site to assess its scope and compare it with a similar specification on-ground photovoltaic system. System Advisor Model (SAM) has been used for techno-economic analysis of a site in Pakistan. The technical analysis involves observing the effect of real time temperature drop and calculation of water reduction efficiency for FPV systems. The economic parameters like net present value (NPV) and payback period are used to judge the economic feasibility of the floating photovoltaic deployment project. The floating photovoltaic deployment in an urban area is subject to soiling as the water reservoir being used exists in an area close to or within the city boundaries. The required cleaning water costs a one-time extraction rate of $1435, while for a floating photovoltaic system, the extraction cost is estimated to be $1.35. Under standard temperature conditions (STC) one-year capacity factor turns out to be 0.70% more, producing an additional energy yield of 64 kWh/kW for lake scenarios when a 10 °C temperature drop is considered. The total power potential for the entire NUST Lake turns out to be 4.47 MW. A 1 MW FPV system in NUST lake would result in a water reduction efficiency of 11.6%/year. Under standard temperature conditions, the net present value for the on-ground system becomes negative while it remains optimistic for the floating photovoltaic system as no land costs are required. Similarly, once the land cost is included in the feasibility analysis, the payback period for the on-ground system goes beyond 15 years which is only 5.37 years for a floating photovoltaic system signifying the economic feasibility of the floating photovoltaic project.

Study of Hybrid System for Optimization of Energy Source in Ut Island, Maluku

Eastern side of Indonesia has a group of scattered Islands and have a great distance from the main Island. Fossil fuels are the main option for meeting the needs of electrical energy in the outer Islands. But the availability of fossil fuels is very dependent on the weather and modes of transportation. In addition, fossil energy also causes emissions and environmental pollution, so efforts to diversify alternative energy by utilizing renewable energy are needed to meet energy needs. Ut Island, Maluku is one of the Islands which is not yet powered by utilities. In this paper, the HOMER software is used to determine the optimal hybrid power plant configuration from a techno-economic perspective by utilizing energy resources available on the Island. From the simulations that have been carried out wind speed has a significant influence on the optimal configuration of the PLH system. Load value affects the amount of NPC and COE. The greater the load is fulfilled, the higher the NPC. But contrary to NPC, COE value will decrease.

Deep decarbonization and the supergrid – Prospects for electricity transmission between Europe and China

Long distance transmission within continents has been shown to be one of the most effective variation management strategies to reduce the cost of renewable energy systems. In this paper, we test whether the system cost further decreases when transmission is extended to intercontinental connections. We analyze a Eurasian interconnection between China, Mid-Asia and Europe, using a capacity expansion model with hourly time resolution. Our modelling results suggestthat a supergrid option decreases total system cost by a maximum of 5%, compared to continental grid integration. The maximum cost reductionis achieved when (i) the generation is constrained to be made up almost entirely by renewables, (ii) the land available for VRE farms is relatively limited and the demand is relatively high and (iii) the cost for solar PV and storage is high. This is explained by that a super grid allows for harnessing of remote wind-, solar- and hydro resources demand centers. As for low-cost storage, it represents a competing variation management option, and may substitute part of the role of the supergrid, which is to manage variations through long-distance trade. We conclude that the benefits of a supergrid from a techno-economic perspective are in most cases negligible, or modest at best.

Adsorptive removal of metformin on specially designed algae-lignocellulosic biochar mix and techno-economic feasibility assessment

Batch sorption of metformin hydrochloride (MET) onto a specially designed biochar mix consisting of both macro (MAC) and micro (MIC) algae, rice husk and pine sawdust was conducted. Pyrolysis of both MAC and MIC algae mixture was done followed by chemical activation with hydrogen-peroxide. Additionally, sorption of MET under the influence of pH was separately investigated. Batch studies of isotherms were well described by Freundlich model with high non-linearity and Freundlich exponent values ranged anywhere from 0.12 to 1.54. Heterogeneity of MET adsorption to the bonding sites was attributed to the surface functional groups of the modified biochar. Amongst the four biochars, the activated macroalgae biochar (MACAC) and microalgae biochar (MICAC) depicted favourable adsorption of MET with maximum adsorption at pH 7. Up to 76% of MET removal from the environment was obatained using the MACAC biochar. Scanning electron micrographs coupled with energy dispersive X-ray, as well as elemental analyses confirmed formation of oxygen containing surface functional groups due to activation strengthening chemisorption as the main sorption mechanism. Further, Fourier transform infra-red spectroscopy and other surface functional group analyses along with Zeta potential measurements reinforced our proposed sorption mechanism. Lowest zeta potential observed at pH 7 enhanced the electrostatic force of attraction for both the biochars. Negative zeta potential value of the biochars under different pH indicated potential of the biochars to adsorb other positively charged contaminants. From a techno-economic perspective, capital expenditure cost is not readily available, however, it is envisaged that production of pyrolyzed biochar from algal biomass could make the process economically attractive especially when the biochar could be utilised for high-end applications.

Lignocellulosic biomass based biorefinery: A successful platform towards circular bioeconomy

Biorefining of second-generation feedstock gains more attention to improve the living standards and promote circular bioeconomy. The biorefinery concept made an effort to make the environmentally sustainable and economical products. Lignocellulosic biomass is widely available and extensively tested feedstock to produce biofuels, bioenergy and different value- products. By the integration of process to fractionate the lignin, cellulose and hemicellulose can add more values in the process chain that required integration and optimized technologies followed by life cycle analysis and economic assessment. The life cycle and economic analysis together assess the impacts on environment, economic and all the impacts which are involved indirectly throughout the product stages from cradle to grave. The improvement and integration of the current biorefinery process recommends the newer and sustainable bio-economy and will replace the fossil fuels with the renewable reserve. In techno-economic perspective, the optimization of integrated technologies for the production of biofuels and other bioproducts have still to be optimized for efficient production. The proper adoption of pretreatment methods increases the economic value in biorefinery process. The main aim of this review is to summarize the three key research areas that required more attentions, they are; (a) valorization of lignin, cellulose, hemicellulose into value added products, (b) integrated biorefinery approach and process optimization; and (c) circular bioeconomy and its future perspective. This review concludes that the lignocellulosic integrated biorefinery approach is feasible to support the circular bioeconomy, through which number of value products could be derived.

SCO2 power plants for waste heat recovery: design optimization and part-load operation strategies

• We optimized five sCO 2 cycle configurations for waste heat recovery application. • Optimal plants reach efficiency higher than ORC (>27%) with similar specific cost (2000$/kW) • Simple recuperative cycle with bypass (SRBC) is selected as the optimal configuration. • We studied the different part-load strategies for this optimal configuration (SRBC) • Variable inventory part load strategy is more efficient than constant inventory strategy. This paper focuses on the potential of supercritical carbon dioxide closed cycle for waste heat recovery applications. The valorization of waste heat released from glass, steel and cement production facilities is recognized as one of the most effective solutions for the reduction of carbon footprint of the industrial sector. Common solutions rely on steam Rankine cycles and organic Rankine cycles while only few sCO 2 power plants have been manufactured and operated so far as this technology has not yet reached the technical and commercial maturity. In spite of the large interest on sCO 2 power plant from industry, institutions and academia, the role of this solution in future waste heat recovery applications is still unclear, highlighting the need of research studies focused on the performance assessment of these novel systems in both design and off-design conditions. This paper aims at bridging the gap between preliminary numerical studies and the design of real power systems by focusing on different aspects scarcely investigated in literature. The first section of this study deals with cycle design and provides a full description of the numerical complexity related to sCO 2 power plant optimization, with a detailed description of the assumptions and the models implemented for the design of cycle components. Five different cycle configurations for the exploitation of a heat source consisting of a 50 kg/s stream of flue gas at 550 °C have been analyzed and optimized: results are presented with a set of sensitivity analyses and the most promising configurations are analyzed from both a thermodynamic and a techno-economic perspective. Simple recuperative cycle, simple recuperative cycle with recuperator bypass and turbine split flow configurations are compared in detail proving that sCO 2 technology can reach overall efficiencies up to 27.5%, a value higher than ORC for the same power output (around 6 MW el ), and with a similar specific cost (2000 $/kW). Simple recuperative cycle with recuperator bypass is selected as the most promising configuration and it is further studied in off design conditions in the second section of the paper. Five different part-load strategies have been implemented allowing to assess the part-load performance of the selected cycle, considering both variable CO 2 inventory and constant CO 2 inventory systems. Results highlight that sCO 2 recuperative cycles equipped with a CO 2 storage vessel present a very high and almost constant efficiency down to 50% of the normalized flue gases mass flow rate, while a lower efficiency is expected for constant inventory systems. Both solutions can be operated down to 30% load with no difficulties on system components and with a minimum plant efficiency still competitive against ORC technology.

Techno-economic analysis of methanol production units coupling solid oxide cells and thermochemical biomass conversion via the TwoStage gasifier

Energy dense liquid biofuels are needed where direct electrification is infeasible, such as the heavy-transports sector. A novel flexible methanol production unit with highly integrated solid oxide cells, characterized by five operating modes, is compared with two non-flexible units from a techno-economic perspective. The aim is to investigate whether a more complex flexible methanol production facility that is able to both store and produce electricity could be cost-competitive with single-mode solutions, by ensuring a higher capacity factor. The flexible solution has the highest capital cost (620 M$2019), followed by the so-called electricity storage single-mode unit (490 M$2019) and the conventional unit (390 M$2019). Decomposition of the methanol production costs shows that electricity and biomass are the major cost factors. The minimum fuel selling price is generally lowest for the conventional unit (92–117 $/MWhth), followed by the electricity storage single-mode unit (87–127 $/MWhth), and the flexible system (93–125 $/MWhth). Flexibility is generally not a key-strength for the flexible unit, as the increased investment cost associated to a major complexity represents a disadvantage. However, flexibility becomes relevant when imposing constraints on the use of electricity produced from fossil fuels to produce methanol, since it ensures higher capacity factor and methanol yield.

Techno-Economic Assessment of Flexibility Options Versus Grid Expansion in Distribution Grids

In this paper five different flexibility options are analysed from a techno-economic perspective as alternatives to traditional grid expansion for a specific distribution grid in Germany. The options are: two reactive power control strategies with photovoltaic inverters (as a function of the power feed-in, or of the voltage at the connection point), one residential and two large scale battery storage applications (primary control reserve with autonomous reactive power control or self consumption maximisation strategy with autonomous reactive power control). For the pilot grid located in Southern Germany a photovoltaic expansion pathway is determined. The main goal of this work is to quantify the grid expansion actions that can be avoided by applying these five flexibility options for the assumed expansion pathway, focusing on large scale battery storages. It is shown that the five flexibility options increase the hosting capacity for PV systems, compared to a scenario without, by up to 45%. Furthermore, the results of the economic assessment indicate that the analysed flexibility options might be a viable alternative to traditional grid expansion as all of them show a cost reduction potential for the pilot region. These results could encourage DSOs to consider the integration of additional PV and battery storage systems not as a problem which triggers grid expansion, but as part of the solution reducing future grid expansion costs.

A Techno-Economic Perspective on Natural Gas and Its Value Chain

We describe the elements and actors in the global natural gas value chains with an emphasis on characteristics relevant for large-scale energy system and market modeling. We give backgrounds on natural gas as a hydrocarbon to provide a rationale and understanding for what functional representations in mathematical programming models aim to represent. Simply taking the most advanced and detailed functional forms for all value chain characteristics and activities will typically result in numerical intractability. One should carefully determine what is needed to address a research question or analyze a business case. Recent advances in mathematical programming do allow solving large models with adequate detail for many types of analysis. We discuss which functional forms and modeling approaches can be appropriate for representing various characteristics in different types of analysis and provide a succinct and general mathematical programming formulation reflecting the optimization problems for different types of actors in the value chain. We provide an implementation for a stylized network using GAMS.