Microgrid as a Cost-Effective Alternative to Rural Network Underground Cabling for Adequate Reliability

Abstract

Microgrids can be used for securing the supply of power during network outages. Underground cabling of distribution networks is another effective but conventional and expensive alternative to enhance the reliability of the power supply. This paper first presents an analysis method for the determination of microgrid power supply adequacy during islanded operation and, second, presents a comparison method for the overall cost calculation of microgrids versus underground cabling. The microgrid power adequacy during a rather long network outage is required in order to indicate high level of reliability of the supply. The overall cost calculation considers the economic benefits and costs incurred, combined for both the distribution network company and the consumer. Whereas the microgrid setup determines the islanded-operation power adequacy and thus the reliability of the supply, the economic feasibility results from the normal operations and services. The methods are illustrated by two typical, and even critical, case studies in rural distribution networks: an electric-heated detached house and a dairy farm. These case studies show that even in the case of a single consumer, a microgrid option could be more economical than network renovation by underground cabling of a branch in order to increase the reliability.The profitability possibilities of residential microgrids as an aggregator-based solution to the perspective of different stakeholders, for example, utilities, aggregators, and prosumers, were analyzed in [6]. The feasibility and profitability of microgrids participating in the primary frequency control reserve (FCR) market through an aggregator were assessed in [7]. Furthermore, battery energy storage system (BESS) usage on the frequency regulation market was analyzed in [8].According to [9], underground cabling of the network is an effective way for distribution system operators (DSOs) to increase the reliability of power supply. However, underground cabling is expensive.Today, farming is highly automated and electricity-dependent [10], and even short power interruptions are very detrimental. Farming is an energy-intensive industry [11], and thus farmers value the reliability of the electricity supply more so than most of the other customer groups.Farms are located naturally in rural areas, possibly on the long distribution network radial branches with low electricity customer density. The majority of farmers have backup generators (e.g., [11]). Farmers having their own power production to cover a portion of their electricity need is gaining popularity.Several recent studies have focused on microgrid islanded-mode operation, microgrid energy management systems, and power supply adequacy and forecasting (e.g., [12][13][14]). The power supply capability in islanded-mode operation was assessed in [12] over a few hours by using a simulation maximum time step of 1 min. Electro-technical aspects of an unexpected microgrid islanded operation were also analyzed in [14] while considering optimal energy management of...

Sensitivity Assessment of Microgrid Investment Options to Guarantee Reliability of Power Supply in Rural Networks as an Alternative to Underground Cabling

“…As seen in the results presented in [11], an electric heated detached house with a battery storage and solar PV production only, would not be a reasonable solution alternative for a microgrid as a means to increase the reliability of supply. In order to enable a relatively long capability of power supply for un-reduced power demand during the network outage and microgrid islanded operation, a PV-BESS combination only, would be a very expensive option if all the equipment was paid by the prosumer.…”

“…The method used in this paper has been presented in [11]. Normal grid-connected operation of the microgrid is calculated for each hour of the year.…”

“…As in [11], the costs of an underground investment and microgrid investment are calculated and compared. The method is used here for demonstrating different cost-sharing strategies for the microgrid investment alternative, as well as assessing the influence of uncertainty and variability of the study case parameters through a sensitivity analysis.…”

“…For the case study, hourly data for a full year is used. As in [11], this time resolution is considered adequate for the purpose of the analysis method.…”

“…This study applies the method presented in [11] for a microgrid consisting of a single electricity consumer in a detached house with own partially controllable power production. A full year of hourly data is analysed in order to assess the capability for a suddenly occurring islanded operation during network outage.…”