Critical Legal issues in the Nigerian Gas to Power Contractual Arrangements

The natural gas and power sectors are pivotal sectors of the Nigerian economy with reflective effect on its gross domestic product. The Federal Government in its gas revolution agenda is taking giant strides to reposition the sector to more adequately harness its abundant natural gas resources and ensure availability of natural gas to the domestic market with the gas supply to the power sector being regulated to build base load volumes to ensure stable electricity supply to its citizens. The synergic connection of the gas and power sectors can only validly exist upon legitimate contractual arrangements such as the gas sale and purchase agreement, the gas transport agreement and the gas sale aggregation agreement which is unique to Nigerian domestic gas industry. Out of these arrangements flow pertinent legal issues which define clearly the relations between the parties. This paper therefore throws more light on some of these salient issues which arise pursuant to the respective agreements. It is hoped that this discourse would guide and further facilitate a deeper understanding of these critical terms.

Neural Network-Based Control for Hybrid PV and Ternary Pumped-Storage Hydro Plants

The growth in renewable energy integration over the past few years, primarily fueled by the drop in capital cost, has revealed the requirement for more sustainable methods of integration. This paper presents a collocated hybrid plant consisting of solar photovoltaic (PV) and Ternary pumped-storage hydro (TPSH) and designs controls that integrate the PV plant such that the behavior and the controllability of the hybrid plant are similar to those of a conventional plant within operational constraints. The PV array control and hybrid plant control implement a neural–network-based framework to coordinate the response, de-loading, and curtailment of multiple arrays with the response of the TPSH. With the help of the designed controls, a symbiotic relationship is developed between the two energy resources, where the PV compensates for the TPSH nonlinearities and provides required speed of response, while the TPSH firms the PV system and allows the PV to be integrated using its existing infrastructure. Simulations demonstrate that the designed controls enable the PV system to track references, while the TPSH’s firming and shifting transforms the PV system into a base load plant for most of the day and extends its hours of operation.

Turn-Down Capability of Ansaldo Energia’s GT26

The operational flexibility of heavy-duty gas turbines is of increasing importance in today’s power generation market. Fast start-up, fast loading, grid frequency support, fuel flexibility and turn-down capability are only some of the keywords that describe the challenges for GT manufacturers. This paper reports Ansaldo Energia’s activities to further reduce the Minimum Environmental Load (MEL) of the GT26. The difficulties related to operation at very low loads and the solutions that were developed are explained. Furthermore, the results of engine validation tests of the new extended Low Load Operation (eLLO) and extended Low Part Load (eLPL) operation concepts are presented. The enhancement of the operational flexibility of the GT26 is in the focus of Ansaldo’s development activities since many years. Its sequential combustion system is a very good basis for flexible and emission compliant operation down to very low loads. Ansaldo Energia’s Low Part Load (LPL) and Low Load Operation (LLO) concepts are standard products in the GT26 flexibility portfolio and established in the market for many years. Low Part Load (LPL) operation extends the standard operating range down to low loads by switching off individual burners in the second combustor (SEV combustor). The compressor mass flow can be varied between idle and base load levels. Low Load Operation is characterized by a combination of idle compressor mass flow and base load temperatures in the first Combustor (EV combustor). The SEV combustor is switched off. LLO is intended to be a “parking point”, where the plant can operate in combined cycle mode during times of low electricity demand. Ansaldo Energia has conducted a development project in the past two years in order to further reduce the minimum simple cycle and combined cycle loads. The extension of the LLO and LPL operating ranges and their combination into one single feature are the main targets of the project.

Pandemic and bills: The impact of COVID-19 on energy usage of schools in South Africa

The COVID-19 pandemic continues to wreak havoc on global operations and economies. Inadvertently, lock-downs and working from home have reduced the daily carbon footprints of transport and office buildings. A beneficial consequence of these reductions is the ability to measure the differential demand of occupants, to benchmark the base load of these buildings, and identify opportunities for efficiency improvements. In this paper we evaluate the change in energy demand in five public schools in South Africa with changes in occupancy due to the COVID-19-imposed lockdowns.

Multi-State Reliability Assessment Model of Base-Load Cyber-Physical Energy Systems (CPES) during Flexible Operation Considering the Aging of Cyber Components

Cyber-Physical Energy Systems (CPESs) are energy systems which rely on cyber components for energy production, transmission and distribution control, and other functions. With the penetration of Renewable Energy Sources (RESs), CPESs are required to provide flexible operation (e.g., load-following, frequency regulation) to respond to any sudden imbalance of the power grid, due to the variability in power generation by RESs. This raises concerns on the reliability of CPESs traditionally used as base-load facilities, such as Nuclear Power Plants (NPPs), which were not designed for flexible operation, and more so, since traditionally only hardware components aging and stochastic failures have been considered for the reliability assessment, whereas the contribution of the degradation and aging of the cyber components of CPSs has been neglected. In this paper, we propose a multi-state model that integrates the hardware components stochastic failures with the aging of cyber components, and quantify the unreliability of CPES in load-following operations under normal/emergency conditions. To show the application of the reliability assessment model, we consider the case of the Control Rod System (CRS) of a NPP typically used for a base-load energy supply.

Test-Rig Simulation on Hybrid Thermal Barrier Coating Assisted with Cooling Air System for Advanced Gas Turbine under Prolonged Exposures—A Review

Thermal barrier coating (TBC) and cooling air systems are among the technologies that have been introduced and applied in pursuing the extensive development of advanced gas turbine. TBC is used to protect the gas turbine components from the higher operating temperature of advanced gas turbine, whereas cooling air systems are applied to assist TBC in lowering the temperature exposure of protected surfaces. Generally, a gas turbine operates in three main operational modes, which are base load, peak load, and part peak load. TBC performance under these three operational modes has become essential to be studied, as it will provide the gas turbine owners not only with the behaviors and damage mechanism of TBC but also a TBC life prediction in a particular operating condition. For TBC under base load or so called steady-state condition, a number of studies have been reviewed and discussed. However, it has been found that most of the studies have been conducted without the assistance of a cooling air system, which does not simulate the TBC in advanced gas turbine completely. From this review, the studies on TBC-assisted cooling air system to simulate the advanced gas turbine operating conditions have also been summarized, which are limited to test rig simulations under thermal cyclic mode where thermal cyclic represents peak and part peak load conditions. The equipment used to simulate the gas turbine operating condition, test temperatures, and durations are parameters that have been taken into consideration under this review. Finally, a test rig that is capable of simulating both TBC and cooling air effects at a high operating temperature of advanced gas turbines for prolonged exposure under steady-state condition has been proposed to be developed.

A Resource and Policy Driven Assessment of the Geothermal Energy Potential Across the Islands of St. Vincent and the Grenadines

The energy security of each Caribbean Community (CARICOM) member state is a key issue specifically addressed based on the energy demands of each nation. St. Vincent and the Grenadines (SVG) has the potential to strengthen its energy sector through the exploitation of immense untapped natural geothermal resources. Currently, SVG is planning to integrate base load power through a 10 Megawatt-electric (MWe) geothermal power plant (GPP1). The paper aims to highlight a detailed resource assessment profile of the renewables across SVG and the projected benefits of the proposed 10 MWe geothermal power potential, such as the positive economic development (displacing 149,000 bbls of crude oil), and the transition to a more climate-sensitive nation (displacing an estimated 0.172 million tCO2e/year). In addition, a volumetric method (Monte Carlo simulations) has been applied to reveal that the geothermal reservoir can sustain a minimum of 31 MWe, 34 MWe and 92 MWe over the lifespan of 25–30 years, for well 1 (SVG01), well 2 (SVG02) and well 3 (SVG03) respectively. Given the findings of the assessment and simulations, several policy approaches are identified as potential means of enhancing geothermal resource development and leveraging the resource for the islands’ sustainable energy demands. These include incentivization for public-private partnerships, information certainty, regulatory processes, and strengthened institutions.

An Approach to the Operation Modes and Strategies for Integrated Hybrid Parabolic Trough and Photovoltaic Solar Systems

Concentrated solar power (CSP) and photovoltaic (PV) solar systems can be hybridized, creating synergies: on one hand procuring dispatchability by storing thermal energy, and on the other hand generating electricity at a highly competitive prize. In this paper, we present an approach to the operation strategies and modes for integrated hybrid CSP + PV systems. We focus on parabolic trough (PT) solar plants, especially those operating in the south of Spain. Our study consists in the definition of suitable states for each of the subsystems that constitute a hybrid solar plant. We then propose modes from the combination of suitable states and establish the conditions for the transition between modes depending on the operation strategy. We propose two operation strategies: demand coverage and base load production. The results of this paper can be used in decision making for hybrid solar system simulation programs.

Formation Mechanism of the Perfect Inverted V-Shape CO2 Emission Amount Environmental Kuznets Curve (EKC) at the Country Level: Taking Taiwan as an Example

The reduction of carbon emissions (such as CO2) is important to slow down global warming. The direct emissions of CO2 in Taiwan are contributed from the power generation sector. This research thus analyzes the effect of fuel used in the past years and finds that the summarized percentage of coal and natural gas used is the key factor in the amount of CO2 emissions. Results show that the CO2 emission amount exhibits a perfect inverted V-shape environmental Kuznets curve (EKC) from 1998 to 2014 in Taiwan. We attribute this to there being a disproportion process of transferring residual load powering to base-load powering for coal and natural gas energies and the increase in electric generation amount every year. This disproportion process means the co-existence of all technical generation in power plants.