Adapting to the Sri Lankan load profile _ Importance in understanding load profile

Battle between drought and electricity demand

“Switch off a light and save for future”. This is not a strange slogan for Sri Lankans as it was regularly being broadcasted through various media channels within the last few months. In recent times, ceylon Electricity Board has been experiencing in a crucial crisis due to the inability to satisfy electricity demand in the country, which adversely impacted on the generation plan and financial estimations. Main reason for this was unexpected drought prevailed. Water levels of all the reservoirs were low and hydro generation was strictly scheduled for a limited time period.

Countries such as Sri Lanka have to inevitably face numerous problems under such weather condition, since generation from hydro sources contributes to a significant portion of total generation in the country. Hydro and other sources weigh 40% and 60% from total generation respectively in a period with average hydrological conditions. Hydro generation came down below 20% during this season and the deficit of electricity demand had to be purchased from independent power producers (IPPs) who generate power using diesel, incurring substantial amount of rupees during the peak time.

DSM as a solution

As an immediate solution to mitigate the problems arises, supply side had to be equipped with demand side management (DSM) tools. As a basic step, supply side tried to control the electricity demand by managing consumer behavior towards energy saving. This was the point where above mentioned slogan came into play through public media like Television, Radio, Newspapers, Social network…etc. All these urged to save electricity by avoiding unnecessary usage.  As night peak hours from 6.30 p.m. to 9.30 p.m. are more critical in this case, their attention was mainly focused on night peak hours. Though morning peak hours from 5.30 am to 6.30 am deliver less impact, as electricity consumers, our attention should be given to that period as well. This campaign was successful to a certain extent with the theme of “Janawiduli balagara”.

But the real situation is, consumers don’t have a proper understanding about these peak hours and the advantages of saving electricity during peak hours.  It might be an easy task to stimulate consumers towards positive attitudes in energy saving, if they have a clear view and understanding regarding the load profile of Sri Lanka.

Behavior of load profile

Load Profile is a chart in which electricity demand is plotted against the time, 24 hours of a day. The shape of this chart is almost same on all five weekdays. But it gets deviated slightly on weekends and holidays. Following graph represents the load profile of a normal weekday.

The above load profile extracted from the energy balance 2010, illustrates the variation of electricity demand for a day within year 2010 with an average hydrological condition. It is apparent that the Sri Lankan load profile is fluctuating significantly between numerous peaks and valleys. Two specific time slot of this graph could easily catch the eyes and those are well-known as the peak hours.

Peak hours are the time periods in which the electricity demand is significantly higher than the average demand level. As per the diagram illustrates, 5.30 a.m. to 6.30 a.m. period is identified as “Morning peak” and period from 6.30 p.m. to 9.30 p.m. is identified as “Night peak”. It is evident that demand is very low during the midnight and early in the morning. The time slot from 2.00 a.m. to 4.00 a.m. reports the lowest demand within a day which could be identified as the “Base load” of the system.

Next article of this series will bring you a comprehensive analysis of load profile, a discussion on the criticality of peak hours and the importance of providing a general understanding about them to the public in the way of effective utilization of electricity.

Terminology

IPP- Independent power producer is an entity which is granted with permission to generate electricity for sale to utilities and end users

Supply side- This includes all the bodies that are responsible for power generation, transmission and distribution

DSM-Demand side management is a method of encouraging the consumers to use energy efficiently and effectively.

Article By: Janaka Lakmewan

Posted in: Utility and Social