Power Supply vs. Demand

A couple of days ago Delhi consumed more power in a single day than ever before. 

According to reports from the State Load Dispatch Centre (SLDC), the national capital recorded its highest ever peak power demand on Tuesday (29 June 2022) noon when it crossed 7,695MW. In the coming days this is expected to cross 8000MW - this is quite a jump from the previous recored of 7,409MW on 2 July, 2019.

The spike in demand has been attributed to the really hot and and humid summer this year with the city's Heat Index (HI) or 'real feel' temperature climbing up to 53C.

While such high temperatures are par for the course for summers in North India, what surprised many of us is near absence of power outages this year. Not once did an extended power cut knock out the inverters leaving us sleepless on sweltering, sweat-soaked bedsheets, seeking refuge on balconies teeming with mosquitos.

What explains this? 

A part of the answer comes from an oped written earlier this month by RK Singh, the current cabinet minister for power and renewable energy. Writing for the Hindustan Times, he presented some interesting numbers:

• India's capacity to generate power was 248,554 MW in 2014. in the last 8 years this has increased by 169,110MW, taking the total power generation capacity to over 400GW
• Maximum demand this year - 215 GW
• The country now has the world's largest integrated grid. Inter-regional transfer capacity has increased from 37,950MW to 112,250MW.
• At COP-21 India pledged to increase power generated from renewable energy sources to 40% by 2030. This goal has already been achieved in November 2021

What is puzzling here is the big gap between capacity and demand. Why are we ramping up power generation capacity when the actual demand is far less? 

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REFERENCES & LINKS

* SinghRK(2022): The Growth of the Energy Sector is Unparalleled, HT, 16Jun22 - https://www.business-standard.com/article/economy-policy/no-power-crisis-in-india-generation-capacity-more-than-peak-demand-govt-122031500831_1.html

* PTI (2022): No Power Crisis in India, Business Standard (15 Mar., 2022) - https://www.business-standard.com/article/economy-policy/no-power-crisis-in-india-generation-capacity-more-than-peak-demand-govt-122031500831_1.html

* GoI - Ministry for Power and Renewable Energy - https://powermin.gov.in/en/content/honble-cabinet-minister-power-new-renewable-energy

Dam Good!

One thing that strikes you as you travel to Kugti is the number of hydro-electric projects that have sprung up all over the Chamba Valley.

From the moment you leave the Punjab plains and enter Himachal Pradesh, you see power projects of assorted shapes and sizes all along the route. Many of them are the conventional, small-scale run-of-the-river projects where you have a small dam blocking the river and the resulting resorvoir being used to generate electricity. Others are a lot more complex, and the only sign of their existence is the tunnels that have been bored through the mountains, to divert waters into long pipes that feed hidden turbines.

It may not make the river look cleaner or prettier but it certainly helps the local population access one thing that makes the winter months more bearable: electricity. Thanks to projects like these, Himachal Pradesh is able to generate more than 8500MW of electricity which it is able sell to states located downstream.

Perhaps the largest player in this valley is the National Hydro Power Corp (NHPC), a central public-sector enterprise that has set up some of the largest power plants on the Ravi river, such as the Chamera-I and Chamera-II projects. Having decided to settle down for a long haul, NHPC has numerous office/staff/residential complexes all along the Chamba valley, commanding some of the best views in this district!

Private players are not too far behind. GMR and Lanco too have a growing presence here with the former represented by deep green container-box offices set up all along the road up to Holi.

Now, which are the small HEPs located along the road to Kugti? 

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REFERENCES & LINKS

* NHPC -- http://www.nhpcindia.com/projects-overview.htm

- presently has an installation base of 6667 MW from 21 hydropower stations on ownership basis including projects taken up in Joint Venture.

* GMR - http://www.gmrgroup.in/energy-gmr-bajoli-power-project.aspx

- Bajoli-Holi 180MW project on Ravi - to be commissioned in 2018

* Lanco Budhil Project -- http://www.lancogroup.com/DynTestForm.aspx?PageID=29

- 70 MW plant commissioned in 2012

- Village Thalla, P.O. Ghared, Tehsil Bharmour, District Chamba 

* Hydro-Electric Power in Himachal Pradesh - https://en.wikipedia.org/wiki/Hydroelectric_power_in_Himachal_Pradesh

- 8,418 MW is harnessed so far

* Hydro Electric Projects in HP - http://india-wris.nrsc.gov.in/wrpinfo/index.php?title=Hydro_Electric_Projects_in_Himachal_Pradesh

* Himachal Pradesh Power Corp - http://www.hppcl.in/page/hydro.aspx

Let There Be Light

Are high pressure sodium vapour lamps more efficient than LEDs?

The key to answering this question is "Luminous Efficacy", a measure of how well a light source a Watt of electricity into Lumens, a measure of light intensity visible to the human eye.

Today, while clearing some litter at a nearby park, I came across this box -

It was lying on the grass, right below a high-mast lamp. Even though I knew that these sodium vapor lamps consumed a lot of electricity, what struck me was the quantum of light produced by these bulbs. A 400W bulb produces more than 44,000 lumens!

If this makes little sense, just compare it to the standard LED lamps being distributed by the government, in its efforts to being down household electricity  consumption -

In terms of luminous efficacy, one would have thought that the LED lamps are a lot more efficient that any incandescent, power-guzzling bulb. However, in terms of light output (lumens), the sodium vapour lamp produces 110 lumens/W while the LED lights prouduce 114 lumens/W, which is hardly any difference.

If there is not much difference in the efficiency of LED bulbs and sodium-vapour lamps, is there a big difference in cost? The sodium-vapour lamp costs INR 675 per unit while an (unsubsidized) LED lamp costs anywhere between INR 150 and 250. This means that the cost of luminous efficacy is INR 0.16 lm/W/INR for the sodium-vapour lamp and 0.57 lm/W/INR for LEDs.  

This simply means that you are getting 3.5 times more bang for your buck with LEDs, compared to sodium-vapour lamps. So it does make sense to switch to LEDs.

Now, what is the difference is cost between LEDs meantand SVs for high-mast lamps? That would berhaps perhaps be a better comparison of oranges with oranges!

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LINKS

* Energy efficiency of LEDs - http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/led_energy_efficiency.pdf

* https://en.wikipedia.org/wiki/Luminous_efficacy

* 2009 - Toshiba releases 93 lm/W bulbs - http://ledsreview.com/news/367/