Regulation-aware optimization for bi-valent industrial processes

This study focused on the effects of variable renewable electricity (VRE) on full load hours and energy efficiency of fossil-fired power generation in the European Union from 1990-2014. Member states were aggregated into three groups based on the level of VRE penetration. Average full load hours are found to be decreasing since 2006 for all groups. The decrease is most in the group with the highest VRE penetration level with a 53% decline from 2005 to 2014 (while VRE penetration increased from 8% to 25%). For VRE-medium the decrease was 34% from 2007 to 2014 (while VRE increased from 3% to 13%) and for VRE-low 32% (with 1% to 5% VRE penetration increase). Both the financial crisis and the share of VRE show strong correlations with full load hours. Both can explain the developments for VRE-high. For VRE-medium no significant relation with the recession was found and for VRE-low both factors were not significant. For energy efficiency, the commissioning year shows a strong correlation for natural gas and less for coal. Significant impacts are found for average commissioning year and full load hours on the energy efficiency of natural gas-fired power generation but not for coal.

The energy mix of Baden-Wurttemberg – one of the most wooded regions of Germany – could be diversified through the optimal valorisation of the existing free potentials of wood resources. Circa 17 PJ of forest residues and landscape wood raw material grow annually over the territory of this federal state. For this reason, an optimisation of the corresponding value chain for power purposes is accomplished in order to identify the most cost-efficient utilisation pathways. Firstly, each unexploited potential of wood resources for up to ten different types of wood chips is estimated at district level. Next, the stages of felling, extraction, debranching, moving and chipping of wood resources are modelled into four specific logistic chains on the basis of the size of forest ownership, the steepness of slope and the variety of tree. Moreover, specific unit costs based on different cost allocation procedures are assigned to the ten identified types of chipped wood resources. Besides the modelling of the transport sector, an array of all feasible technologies for conversion of wood resources into bio-based power are compared to each other in terms of costs. A singular conclusion is drawn according to which, for each particular capacity under the same operation conditions, gasification is more cost-efficient than combustion – except for co-firing. Hence, the fluidised bed gasification coupled to a gas engine or a combined cycle as well as the direct co-firing of wood resources at a 10% co-fire rate are preselected for the intended analysis on account of their higher cost-effectiveness. Lastly, a new MILP model called BioESyMO (Bioenergy System Model for Operation Optimisation) is created for the optimisation of the value chain of wood resources. This optimising tool includes a unique mathematical constraint aiming at assuring profitability of investments within each utilisation pathway. A scenario-based analysis is first developed for remunerations modelled with a high enough value above the breakeven point. Thereby, a combined heat and power cogeneration process consisting of a fluidised bed gasifier coupled to a gas engine of 20 MWe renders electricity production costs of 10.1-13.8 €cent/kWhe for an annual amount of 7,500 full load hours. The co-firing option for the existing coal-fired power plants with bio-based capacities up to 84.3 MWe generates lower electricity production costs of 6.6-11.7 €cent/kWhe, when the facilities are yearly operated for 3,000 full load hours. If a fluidised bed gasifier is connected to a combined cycle of 210/340 MWe (7,500 full load hours per year), this technology turns out to be the most cost-efficient with electricity production costs in the order of 5.6-7.1 €cent/kWhe. These costs ranges can be reduced by progressively decreasing remunerations below each resulting breakeven point. As for the option of co-firing, cheaper bioenergy configurations arise on the basis of cheaper wood resources that enable lower production costs of up to 5.6 €cent/kWhe for 4,000 hours per year at full load. In conclusion, the low incremental capital costs of co-firing as well as the high efficiencies of fluidised bed gasification-based combined cycles together with the valorisation of the more economical deciduous fractions of wood resources might reduce electricity production costs to a rather low range between 4.5 and 9.5 €cent/kWhe. Leveraging such cost reductions, the introduction of appropriate energy policy instruments for the promotion of carbon-neutral baseload power generation is strongly recommended in view of restrictions induced by Germany’s nuclear and coal phase-outs. Although the quality of the results of this study is mainly conditioned by uncertainty and the high spatial aggregation level of the spatial unit, the implemented methodology as well as the performed optimisation analysis represents an interesting breakthrough that may contribute to the initiated energy transition in Baden-Wurttemberg and the whole of Germany.

Techno-economic competitiveness of 50 MW concentrating solar power plants for electricity generation under Kuwait climatic conditions

Production costs for synthetic methane in 2030 and 2050 of an optimized Power-to-Gas plant with intermediate hydrogen storage

Economic Comparison of Electric Fuels Produced at Excellent Locations for Renewable Energies: A Scenario for 2035

Techno-economic assessment of seasonal heat storage in district heating with thermochemical materials

Electricity Load Implications of Space Heating Decarbonization Pathways

In this study, a methodology is developed to evaluate the technical and economic parameters of a grid-connected wind power plant in Syria. The methodology was used for designing a grid-connected wind power plant in the area close to the Al-Sukhnah town (in Homs province), which is one of the most promising areas in Syria to build wind farms. Technical assessment of a 12 MW grid-connected wind power plant, which consists of 8 wind turbines with rated power of 1.5MW for each one, is performed using the WindPRO software. The following tasks are carried out in WindPRO: the microscale numerical modeling of the wind flow of the area with consideration the terrain and roughness, determination of wind resources at wind turbine tower height, selection of suitable wind turbine and definition of energy production. The results of the technical assessment show that the wind power density in the power plant site at wind turbine tower height is 333–459 W/m 2 with average annual wind speed of 6.5–7.7 m/s, energy production is 38391.1 MWh/year with consideration the losses, capacity factor is 36.5% with full load hours of 3199 h/year. Economic assessment of the considered power plant is performed in Excel program. The following economic indicators are calculated in Excel: net present value (NPV), discounted payback period (DPP), internal rate of return (IRR), profitability index (PI), the normalized cost of energy (LCOE). The results of calculations show that the proposed grid-connected wind power plant is completely profitable for conditions in Syria.

Selection of suitable sites for offshore wind farms in the Caspian Sea and choosing the most suitable wind turbine in each area

Life cycle assessment of domestic fuel cell micro combined heat and power generation: Exploring influential factors

<p>As Europe strives for a decarbonization of electricity supply, many countries proclaim ambitious targets for capacity additions of wind and photovoltaic (PV) power. By increasing renewable capacities, countries seek to reduce their dependency on fossil fired electricity generation. For instance, Germany recently announced new capacity targets that mean a triplication of wind and PV power capacities while at the same time aiming for a full coal exit until 2030. However, the potential of renewable energies is not equally distributed over the European continent. Due to higher irradiance levels with decreasing latitude, PV power achieves higher full load hours and thus higher generation per installed capacity in southern Europe.  Wind power reaches higher capacity factors close to shorelines, where near-surface wind speeds are higher.</p><p>In light of the unequal distribution of PV and wind power generation potentials, national capacity targets may not lead to optimal utilization of capacities, i.e. maximum renewable generation. We analyse the effects of such national capacity targets for the case of PV generation. To do so, we compare two scenarios: A scenario with PV generation capacity distributed over Europe according to national political targets and a scenario with a distribution of newly installed capacities chosen such that it optimizes the renewable power potentials. Next to PV generation potentials, our assessment considers the European power grid, because line capacities limit the transmission and hence the trading between different countries. Line limits can have a negative impact on the overall power generation since renewable generation has to be curtailed if power can neither be locally used nor transmitted to another region.  We employ a linear optimization-based electricity market model with inter-European transmission constraints and hourly resolution weather data for 35 historic weather years (1982-2016). We analyse the scenarios if terms of differences in power generation and curtailment, greenhouse gas emissions, and system operational cost. We pay special attention to extreme weather situations and the effects of a sub-optimal PV power allocation on security of supply.</p>

To achieve the European Union's ambitious climate targets, not only the energy system must be transformed, but also other sectors such as industry or transport. Power-to-X (PtX) technologies enable the production of synthetic chemicals and energy carriers using renewable electricity, thus contributing to defossilization of economy. Additionally, they provide storage capacity for renewable energy. Detailed life cycle assessments (LCA) of PtX is required, to prove the environmental advantages to fossil-based benchmark technologies. An emerging PtX technology for syngas production is the high temperature co-electrolysis (HT-co-electrolysis), which produces syngas. Aim of this LCA is the evaluation of syngas production by HT-co-electrolysis at its early stage of development to derive incentives for further research. For comparison, a small-scale steam methane reforming process (SMR) serves as today’s fossil-based benchmark. The required CO2 is obtained via direct air capture (DAC). The by-far most important input for the HT-co-electrolysis is electricity. Hence, several future electricity mixes are considered, representing two different climate protection targets (CPT80, CPT95) for the energy system in 2050. For each CPT, an additional distinction is made regarding full load hours, which depend on the availability of renewable energy. The results show lower global warming potential (GWP) and fossil fuel depletion for HT-co-electrolysis compared to SMR if mostly renewable power is used. Exclusively renewable operated HT-co- electrolysis even achieve negative net GWPs in cradle-to-gate LCA without considering syngas use. If HT-co-electrolysis shall operate continuously (8760 h) additional fossil electricity production is needed. For CPT80, the share of fossil electricity is too high to achieve negative net GWP in contrast to CPT95. Other environmental impacts such as human toxicity, acidification, particulate matter or metal depletion are worse in comparison to SMR. The share of DAC on the total environmental impacts is quite noticeable. Main reasons are high electricity and heat demands. Although plant construction contributes to a minor extent to most impact categories, a considerable decrease of cell lifetime due to higher degradation caused by flexible operation, would change that. Nevertheless, flexibility is one of the most important factors to apply PtX for defossilization successfully and reinforce detailed research to understand its impacts.

Methodology of determining the optimum performances of future concentrating solar thermal power plants in Algeria

The purpose of this paper is to study and analyse the factors affecting customer decisions in using electricity at peak-load hours (between 17.00 to 22.00 WIB) and their behaviors towards electricity conservation in Indonesian household. The underlying rationale is to influence a reduction in energy consumption by stimulating energy saving behaviors, thereby reducing the impact of energy use on the environment. How is the correlation between the decisions in using electricity during peak load hours with the household customer’s behavior towards saving electricity? The primary data is obtained by distributing questionnaires to customers of PT. PLN Jakarta Raya and Tangerang Distribution from Household segment. The data is analysed using the Structural Equation Model (SEM) and AMOS Software. The research is finding that all factors (Personal, Social, PLN Services, Psychological, and Cultural) are positively influence customer decision in using electricity at peak load hours. There is a correlation between the decisions in using electricity during peak load hours with the household customer’s behavior towards saving electricity.

Deep packet inspection (DPI) technology has conventionally been introduced for traffic monitoring, bandwidth control, bandwidth allocation, access control of specific types of traffic, etc. By installing a DPI equipment at any arbitrary point in a network, it is possible to monitor communications of many servers simply and this could simplify dramatically the conventional work load for system management and reduction of power consumption by servers. As a new potential application of DPI technology, this paper explores the possibility of applying DPI technology to server congestion control and reduction of power consumption by servers, and presents implementation examples of these applications. This paper first proposes an example of server congestion control method, in which the DPI equipment estimates the CPU usage of each server by constantly monitoring the number of live TCP connections established by each server, and moves some of virtual machines on the congested server to other servers through remote control timely. Next, this paper proposes an example of reducing power consumption by servers, in which the DPI equipment constantly monitors the traffic sent or received in each area with multiple servers. Finally, the feasibility of the proposed methods is demonstrated by an evaluation system with a real DPI equipment.