LED "bulb" cost saving assessment

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“The total minimum savings per 3.6W LED versus 40W incandescent light over the lifespan of the LED is R 875 in incandescent replacements (at todays’ price) & R 993.47 in power costs (at todays’ kWh prices), resulting in a minimum saving of R 1 868-47 per single lamp at todays’ prices over the lifespan of the LED! Multiply this figure per light fitting you replace in your home with a 40W equivalent LED and the sums speak for themselves”.


See below for the rationale:


Using Eskom’s average c/kWh on their url http://www.eskom.co.za/content/priceincrease2011.pdf, (link no longer active)

 it would appear that the rate average for 2012 will be 52.30c/kWh. If a user has a single 40W light switched on from 6 in the evening until midnight each day of the year, the difference between using a 3.6W LED light fitting versus a 40W incandescent fitting will equate to 79.72 kWh per annum. At the 2012 rate this will equate to a saving of R 41-69 in 2012 per light source excluding any costs in replacing incandescent units.


If the average home has 5 light sources switched on during these hours (working on a guestimate average for a four person household), the annual savings equate to R 208-46 per year in 2012. While this may not seem earth shattering, multiply this single household by 17 876 212 households in 2011 and the perspective shifts. (see Unisa’s study on household dynamics at http://www.unisa.ac.za/contents/faculties/ems/docs/Press364.pdf (link no longer active) (where 1996 figures were 9 059 571 and in 2005 12 726 000. We have used a straight line growth of 40.47% to simplify things although population growth cannot occur in a straight line, resulting in conservative figures on my part).


Our figures, as said, are conservative (using Unisa’s data). The figure suddenly becomes meaningful in the form of savings of R 3 726 427 602.80 in 2012. This figure does not include office buildings and street lighting, nor does it include the savings in building and increasing Eskom infrastructure support to the growing number of households and therefore the growing need for power. The words “saving billons” are here somewhere.


In the event that public awareness was increased with figures from an actuarial exercise based on more scientific data to include office/corporate consumption in lighting and South Africa’s street lighting, the savings would be in the low to mid double figure billions of Rand. Again, this is not including the cost to the environment both in Rand value as well as physical damage relating to the disposal of incandescent lamps.


The next argument is that the consumer, to save power in the long term, has to lay out the cost of buying LED lamps to replace their incandescent units. Most information we have been able to glean indicates an average of 1000 hours for and incandescent bulb and 50 000 hours (check the manufacturers claim first) for LED’s. Using Targot’s price of their basic 12V 3.6 W LED at R 119-90 (unbelievably there is a 20% duty on the import of these lamps which makes one wonder about SARS and Eskom attitudes to encouraging LED use and benefits) and Pick ‘n Pays price for their two bulb blister pack at R 17-50 per bulb (December 2011), the following figures become evident. These exclude the indirect costs related to incandescent bulb purchase (fuel, time etc.) and replacement and also  exclude the disposal aspects, as mentioned:


Cost in today’s money of a 3.6W Targot Enterprises LED:   R 119-90

Cost saving in today’s money of 50 x 40W incandescent bulbs:   R 875-00

Cost saving at the 2012 rate c/kWh per annum x 23.83 years the LED will last at 6 hours per day every day:   R 993-47 (ignoring the fact that electricity rates will increase each year over the next 24 years – this figure represents the minimum savings)


Total minimum savings per 3.6W LED versus 40W incandescent light over the lifespan of the LED is then R 875 in incandescent replacements (at todays’ price) & R 993.47 in power costs (at todays prices), resulting in a minimum saving of R 1 868-47. Multiply this figure per light fitting you replace with a 40W equivalent LED in your home and the sums speak for themselves. Should a customer buy a more expensive LED from Targot it is simple to estimate the savings by subtracting the price of our R 119.90 LED and the subtracting the balance from the above overall savings (A R 219.90 LED is R 100 more expensive so the R 100 is deducted from R 1 868-47, giving an overall saving of R 1 768-47).


This minor investigation on our part is by no means scientific as it is not possible to know precisely how many households will have how many lighting sources switched on for a given period. Obviously large households will compensate for small households. Some medium/large homes have 12 x 40W down-lighters in the kitchen alone and probably another 40 elsewhere around the house excluding conventional incandescent bulbs and spotlights. If a user buys an LED lamp, they need to retain possession of the lamp to gain its benefits. If a user installs LED’s in their home, there is no harm in taking these with when the home is sold and replacing the LED’s with incandescent. Eventually South Africa will have no need for LED lamp migrations.


Obvious factors to consider:


1)     The cost of electricity is increasing. The above saving is therefore very conservative over the lifespan of the LED since it is based on 2012 electricity costs.


2)      The cost of incandescent bulbs is increasing annually. The above saving is therefore conservative.


3)      The cost of LED’s is decreasing as the technology becomes more popular and economies of scale take effect from the point of manufacture.


4)      In the not too distant future one might find that incandescent lighting is banned due to the cost to the environment end the roll-on costs to the economy in terms of growing populations and the impact these human numbers have on electrical grids. How much money might be saved in not having to build an entirely new power station?