A review at the role of storage in energy systems with a focus on Power to Gas and long-term storage

A review of more than 60 studies (plus more than 65 studies on P2G) on power and energy models based on simulation and optimization was done. Based on these, for power systems with up to 95% renewables, the electricity storage size is found to be below 1.5% of the annual demand (in energy terms). While for 100% renewables energy systems (power, heat, mobility), it can remain below 6% of the annual energy demand. Combination of sectors and diverting the electricity to another sector can play a large role in reducing the storage size. From the potential alternatives to satisfy this demand, pumped hydro storage (PHS) globalpotential is not enough and new technologies with a higher energy density are needed. Hydrogen, with more than 250 times the energy density of PHS is a potential option to satisfy the storage need. However, changes needed in infrastructure to deal with high hydrogen content and the suitability of salt caverns for its storage can pose limitations for this technology. Power to Gas (P2G) arises as possible alternative overcoming both the facilities and the energy density issues. The global storage requirement would represent only 2% of the global annual natural gas production or 10% of the gas storage facilities (in energy equivalent). The more options considered to deal with intermittent sources, the lower the storage requirement will be. Therefore, future studiesaiming to quantify storage needs should focus on the entire energy system including technology vectors (e.g. Power to Heat, Liquid, Gas, Chemicals) to avoid overestimating the amount of storage needed

Improving the analytical framework for quantifying technological progress in energy technologies

This article reviews experience curve applications in energy technology studies to illustrate best practices in analyzing technological learning. Findings are then applied to evaluate future performance projections of three emerging offshore energy technologies, namely, offshore wind, wave & tidal, and biofuel production from seaweed. Key insights from the review are: First, the experience curve approach provides a strong analytical construct to describe and project technology cost developments. However, disaggregating the influences of individual learning mechanisms on observed cost developments demands extensive data requirements, e.g., R&D expenditures, component level cost information, which are often not publicly available/readily accessible. Second, in an experience curve analysis, the LR estimate of the technology is highly sensitive towards the changes in model specifications and data assumptions.. Future studies should evaluate the impact of these variations and inform the uncertainties associated with using the observed learning rates. Third, the review of the literature relevant to offshore energy technology developments revealed that experience curve studies have commonly applied single-factor experience curve model to derive technology cost projections. This has led to an overview of the role of distinct learning mechanisms (e.g., learning-by-doing, scale effects), and factors (site-specific parameters) influencing their developments. To overcome these limitations, we propose a coherent framework based on the findings of this review. The framework disaggregates the technological development process into multiple stages and maps the expected data availability, characteristics, and methodological options to quantify the learning effects. The evaluation of the framework using three offshore energy technologies signals that the data limitations that restrict the process of disaggregating the learning process and identifying cost drivers can be overcome by utilizing detailed bottom-up engineering cost modeling and technology diffusion curves; with experience curve models

Comprehensive review of current natural gas liquefaction processes on technical and economic performance

This paper provides a quantitative technical and economic overview of the status of natural-gas liquefaction (LNG) processes. Data is based on industrial practices in technical reports and optimization results in academic literature, which are harmonized to primary energy input and production cost. The LNG processes reviewed are classified into three categories: onshore large-scale, onshore small-scale and offshore. These categories each have a different optimization focus in academic literature. Besides minimizing energy consumption, the focus is also on: coproduction for large-scale; simplicity and ease of operation for small-scale; and low space requirement, safety and insensitivity to motion for offshore. The review on academic literature also indicated that optimization for lowest energy consumption may not lead to the lowest production cost. The review on technical reports shows that the mixed-refrigerant process dominates the LNG industry, but has competitions from the cascade process in large-scale applications and from the expander-based process in small-scale and offshore applications. This study also found that there is a potential improvement in adopting new optimization algorithms for efficiently solving complex optimization problems. The technical performance overview shows that the primary energy input for large-scale processes (0.031–0.102 GJ/GJ LNG) is lower than for small-scale processes (0.049–0.362 GJ/GJ LNG). However, the primary energy input for identical processes do not necessarily decrease with increasing capacity and the performance of major equipment shows low correlation with scale. The economic performance overview shows specific capital costs varying significantly from 124 to 2255 $/TPA LNG. The variation could be, among others, caused by the different complexities of the facility and different local circumstances. Production cost, excluding feed costs, varies between 0.69 and 4.10$/GJ LNG, with capital costs being the dominant contributor. The feed cost itself could be 1.51–4.01 $/GJ LNG, depending on the location. Lastly, the quantitative harmonization results on technical and economic performance in this study can function as a baseline for the purpose of comparison

Титульні сторінки

Transition to a bio-based economy will create new demand for biomass, e.g. the increasing use of bioenergy, but the impacts on existing markets are unclear. Furthermore, there is a growing public concern on the sustainability of biomass. This study proposes a methodological framework for mapping national biomass flows based on domestic production-consumption and cross-border trade, and respective share of sustainably-certified biomass. A case study was performed on the Netherlands for 2010-2011, focusing on three categories: (i) woody biomass, (ii) oils and fats, and (iii) carbohydrates. Between 2010-2011 few major shifts were found, besides the increasing biofuel production. The share of sustainably-certified feedstock is growing in many categories. Woody biomass used for energy amounted to 3.45 MT, including 1.3 MT imported wood pellets (>85% certified). About 0.6 MT of oils and fats and 1.2 MT (estimation) of carbohydrates were used for biofuel production. It is assumed that only certified materials were used for biofuel production. For non-energy purpose, more than 50% of woody biomass used was either certified or derived from recycled streams. Certified oils has entered the Dutch food sector since 2011, accounted for 7% of total vegetable oils consumption. It is expected that carbohydrates will also be certified in the near future. Methodological challenges encountered are: inconsistency in data definitions, lack of coherent cross-sectorial reporting systems, low reliability of bilateral trade statistics, lack of transparency in biomass supply chains, and disparity in sustainability requirements. The methodology may be expanded for future projection in different scenarios

Regionalized cost supply potential of bioenergy crops and residues in Colombia:A hybrid statistical balance and land suitability allocation scenario analysis

The Colombian agricultural sector has the capacity and ambition to reduce its land use and GHG emissions through sustainable intensification of livestock production. However, the impact of such pathway on the availability of land for bioenergy crops production has not been thoroughly investigated. Moreover, previous assessments of the role bioenergy in Colombia have mostly focused on residues, in isolation of land use policies. To address this gap, we propose a hybrid statistical land balancing and suitability allocation approach to estimate long term projections of the cost–supply potential of bioenergy crops and residues. Regionalized to the 32 Colombian departments (administrative divisions), this approach could provide higher resolution than global assessments, while avoiding the complexity of spatially explicit methods. We investigated three scenarios covering the uncertainty of socioeconomic drivers and agricultural and livestock productivity factors. Our results suggest that pursuing progressive land use policies (SSP1 scenario) could release up to 14 Mha of land by 2050, which could be available to produce perennial bioenergy crops. The cumulative potential of crops in SSP1 could reach up to 2200 PJ, where about half of this potential could be attained at 7 $ GJ 1 or less. Potential supply centers could be identified in Orinoquía, Andean, and Caribbean regions for energy crops and the Pacific region for residues. Our findings indicate that there could be an opportunity to create synergy between the low carbon development strategies of the land use and energy sectors in Colombia

Білоруська соціал-демократична громада Чернігівщини

У статті аналізується документ, в якому вперше згадується про існування білоруської секції Революційної української партії.В статье анализируется документ, в котором впервые упоминается о существовании белорусской секции Революционной украинской партии.This article analyzes the document, in which the existence of the Belarusian section of the Revolutionary Ukrainian Party was first mentioned

Potential of Power-to-Methane in the EU energy transition to a low carbon system using cost optimization

Power-to-Methane (PtM) can provide flexibility to the electricity grid while aiding decarbonization of other sectors. This study focuses specifically on the methanation component of PtM in 2050. Scenarios with 80–95% CO2 reduction by 2050 (vs. 1990) are analyzed and barriers and drivers for methanation are identified. PtM arises for scenarios with 95% CO2 reduction, no CO2 underground storage and low CAPEX (75 €/kW only for methanation). Capacity deployed across EU is 40 GW (8% of gas demand) for these conditions, which increases to 122 GW when liquefied methane gas (LMG) is used for marine transport. The simultaneous occurrence of all positive drivers for PtM, which include limited biomass potential, low Power-to-Liquid performance, use of PtM waste heat, among others, can increase this capacity to 546 GW (75% of gas demand). Gas demand is reduced to between 3.8 and 14 EJ (compared to ∼20 EJ for 2015) with lower values corresponding to scenarios that are more restricted. Annual costs for PtM are between 2.5 and 10 bln€/year with EU28’s GDP being 15.3 trillion €/year (2017). Results indicate that direct subsidy of the technology is more effective and specific than taxing the fossil alternative (natural gas) if the objective is to promote the technology. Studies with higher spatial resolution should be done to identify specific local conditions that could make PtM more attractive compared to an EU scale

Technical and economic optimization of expander-based small-scale natural gas liquefaction processes with absorption precooling cycle

The objective of this study is to investigate potential technical and economic performance improvement for expander-based natural gas liquefaction processes in small-scale applications. Four expander-based processes were optimized and compared in this study, including conventional single nitrogen expansion process without (SN) and with ammonia absorption precooling (SNA), and single methane expansion process without (SM) and with ammonia absorption precooling (SMA). A two-phase expander is utilized in the methane expansion process to enable liquid generation at the expander outlet. The optimization was done with two objective functions: minimization of specific energy consumption and minimization of production cost. The energy and cost analyses were performed for the four processes by comparing optimization results. Lastly, exergy losses in the main equipment were analyzed. The results show that the ammonia precooling cycle reduces energy consumption and production cost by 26–35% and 13–17%, respectively. The single methane process with precooling is the most promising process, which has 28–48% lower energy consumption and 13–43% lower production cost compared to those of the other three processes. Results also indicate that the best techno-economic performance is obtained with objective of minimizing production cost and not with the commonly used energy-related objective