Wednesday, April 19, 2017

Relooking at the numbers of Singapore's water supply: 3 very interesting deductions (part 2)

This post is a follow-up from part 1.

While we are looking at the topic of water and its associated heated debate on the 30% price hike over 2017 & 2018, we may as well also link up with the other hot potato from 2013 - The Population White Paper (PWP). Its key pain point with many people was the recommendation to increase the population in SG to 6.5-6.9 million by 2030 to sustain our economy and way of life.

What we know from PUB figures
  1. Current (2017) water demand in SG = 430MGD (Imperial mega gallons per day)
  2. 45% of the current demand is for the domestic sector.
  3. Water demand is projected to hit twice the no. in 2060 = 860MGD
  4. The projected domestic demand in 2060 is 30%.
  5. 2030 as given as another milestone in terms of % contributions from Newater and desalination but no mention of the total projected demand in 2030.
  6. There is however a projected domestic demand in 2030 at 40%.
  7. "Singapore's per capita domestic water consumption was reduced from 165 litres per day in 2003 to the current 148 litres. The target is to lower it to 147 litres by 2020 and 140 litres by 2030." No mention of the target for 2060 though.

Time to play with the figures
  1. Using 2017 water demand of 430MGD and 2060 demand of 860MGD, we can linearly interpolate to obtain a total demand of 570MGD in 2030. A linear interpolation in the span of years is reasonable since we are not expecting the demand (domestic or otherwise) to change abruptly.
    (Updated by author on 13/6/17: I have found a PUB diagram that states the water demand in 2030 to 125% of 430MGD. This translates to 540MGD which is not far off from 570MGD. I have added this diagram at the bottom of this post though I can't seem to find it on PUB's website anymore.)
  2. Based on 40% domestic demand, this translates to 228MGD.
  3. Dividing by 140L/d/cap, we are talking about providing water to a population of 7.4M in 2030!!!
  4. This figure is even higher than the max of 6.9M given in the PWP.
    To be fair, the difference is possibly an issue of oversizing the water production capacity. Since water is so important to survival, I would prefer a capacity to supply to more people than being just nice or worse, less than the actual number of people.
    Nevertheless, upping the population to 6.9M is not just on paper. It is implemented in our infrastructure too.
  5. But let's work further towards 2060.
  6. Assume the per capita consumption to remain the same at 140L/d/cap in 2060. (This is not likely since I personally expect to see a further reduction in personal consumption through better technology and education. Other countries e.g. India, can have a lower consumption (less than 140L/d) NOW so why not SG in 2060?)
  7. Based on 30% domestic demand from a total of 860MGD, this translates to 258MGD.
  8. Dividing by 140L/d/cap, our population will have increased to 8.4M in 2060!!!
  9. Is this the long term goal in our population growth? Are we heading towards 10M as envisioned by ex-HDB chief, Liu Thai Ker?
Do take some time to let the above sink in... Good day!

I will wrap up this series with 1 more deduction in the next post. Cheers!

Figure: (Source: PUB though it seems not available on their website anymore) Comparing now (2016) and 2030

Figure: (source: More people expected in SG?

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