Exploring The Gaps In Renewable Energy Integration To Grid

ArticleThe continued integration of diverse renewable energy sources into the power grid has led to a significant decrease in power system inertia, thus resulting in several challenges in the electric power system such as frequency instability and sharp rise in rate of change of frequency (rocof). In order to combat these challenges, several technologies such as the use of energy storage systems, hybrid energy storages system and hybrid systems have been used to provide fast frequency response and regulation. This paper gives a comprehensive review of these technologies thus highlighting their applications, merits and demerits for frequency regulation in renewable energy sourced grid. Furthermore, the research reveals that hybridized system provides better characteristics than singly sourced renewable energy system, therefore the best suited hybrid system can be formed based on the desired power grid characteristics and specific power requirement. Finally, it was revealed that FESS, SMES and SCES have similar characteristics, nonetheless, their characteristics is complimentary to that of BESS, CAES and PHES technology, and so a hybrid combination comprising of BESS and SCES could be best suited for fast frequency response in renewable energy sourced grid

Optimization of an Expanded Nigeria Electricity Grid System using Economic Load Dispatch

The objective of an economical and reliable power system is to ensure that customer’s load requirements are met at a reduced cost of generation. Economic Load Dispatch (ELD) determines the power output of each thermal power plant, which minimizes the overall cost of fuel needed to serve the entire system load. This study carried out an optimization analysis on the economical distribution of loads on the existing and expanded thermal plants. The optimization analysis was carried out by formulating ELD problem using MATLAB software packages. This was with a view of developing a dynamic load scheduling between the aforementioned, in order to reduce cost, enhance overall performance and reliability of the system. The obtained result shows it is efficient and costeffective to operate and generate power in the expanded grid. Correspondingly, the expansion of the grid to include new thermal plants of Olorunsogo, Omotoso and Geregu eased the load stress on the old plants of Afam, Egbin, Sapele and Ughelli: thereby mitigating the effect of power transmission loss and offsetting the total cost of generation

Assessing the role of hybrid energy storage in generation expansion planning for enhanced frequency stability

As the power grid transforms towards a renewable energy dominant grid, which are associated with frequency stability challenges, it is important to combat these challenges through proper power system planning. This paper therefore investigates the impact of hybrid energy storage (HES) in enhancing the frequency stability of the modern grid. The optimization problem is formulated as a mixed integer quadratic constrained programming model to minimize the system cost, while maximizing system inertia. The proposed model is then implemented on an IEEE 6-bus system, and solved using CPLEX solver in GAMS, with its performance evaluated using two study cases. Case 1 considers only the economic objective (cost), while case 2 considers both the economic objective (cost) and the technical objective (system inertia). The result show that the incorporation of HES in the generation planning model improved the overall system inertia of the system by 11% (from 6.199s in case 1, to 6.901s in case 2), however the total system cost increased by 3% (from 218M$in case 1 to 2.25M$ in case 2)