This paper presents the analysis of electricity transmitted and demand on Nigeria's electricity grid system from the year 2018 to 2020 to give the present progress of the electricity system in Nigeria. The daily electricity generated and transmitted data, daily distribution companies (DISCOs) electricity demand and consumption data, and data of transmission lines connected to other neighbouring countries (international lines) within the year 2018 and 2020 were used for the analysis. Also, the extrapolation of the monthly energy of each of the data obtained was computed. The analysis was done and graphs and results obtained showed that daily average electricity day-ahead demand by DISCOs varied majorly between 3.5GW to 4GW with a corresponding increase above 4GW and the total daily day-ahead electricity demand by DISCOs varied majorly between 80GW and 90GW from 2018 to 2020. But despite this demand, the study showed that distribution companies did not at any time pick up to their declared load demand despite being the major electricity stakeholder in electricity delivery to consumers. Also, some generating station units were not generating to their capacity due to fault and gas constraints and some generating stations were connected to the grid without using free governor mode (control required for the generating units to respond to the state of electricity demand on the grid in real-time). The study recommends that the government should ensure proper monitoring and impose necessary sanctions if needs be on any electricity stakeholders and participants who violate the Nigeria Electricity Supply Market Rules for effective and the Nigeria grid code created for efficient power delivery. The government should, as a matter of urgency, start the expansion of her generating stations as well as developing new ones considering other sources for power generation such as wind and solar which are predominately abundant in the northern part of the country.