Home > BOE, Energy > BOE: Improved Estimates for Proven and Optimistic

BOE: Improved Estimates for Proven and Optimistic

2012 May 24

Improved estimates for the Proven and Optimistic scenarios using the BP Statistical Review of World Energy 2011 (xls) as fully as possible. The original source for the optimistic estimates remains opaque. They are both considerably lower than the ‘in-place’ estimates used in WGIII, as they should be. Recoverable reserves are only a fraction of in-place resources.

# COAL: TONNES TO TONNES OF OIL EQUIVALENT
# BP Statistical Review 2011
# 7273 tonnes of coal / yr (2010)
# 3731 tonnes of oil equivalent /yr (2010)
# conversion factor of tonnes coal to ‘tonnes of oil equivalent’
coal_toe_conv = 3731/7273 # .513

# NATURAL GAS: BILLION CUBIC METERS TO GIGATONNES OF OIL EQUIVALENT
# BP Statistical Review 2011
# 3193 billion cubic meters / yr (2010)
# 2.88 gigatonnes of oil equivalent / yr (2010)
# conversion factor of tonnes coal to ‘tonnes of oil equivalent’
ng_toe_conv = 2.88 / 3193 # bcm to gigatonnes

# BP Statistical Review 2011
gt_proven_coal = 861 # gigatonnes of coal
gt_proven_oil = 189 # gigatonnes of oil
bcm_proven_ng = 187000 # billion cubic meters NG

# BP Statistical Review
coal_conv_co2 = 3.96 # tonnes CO2 per tonne of oil equivalent
oil_conv_co2 = 3.07 # tonnes CO2 per tonne of oil equivalent
ng_conv_co2 = 2.35 # tonnes CO2 per tonne of oil equivalent

# BP Statistical Review
co2_proven_coal = gt_proven_coal * coal_conv_co2 * coal_toe_conv
co2_proven_coal # 1749
co2_proven_oil = gt_proven_oil * oil_conv_co2
co2_proven_oil # 580
co2_proven_ng = bcm_proven_ng * ng_conv_co2 * ng_toe_conv
co2_proven_ng # 396

co2_proven_ff = co2_proven_coal + co2_proven_oil + co2_proven_ng
co2_proven_ff # 2725

# Wiki / Oil & Gas Journal
years_optimistic_coal = 417
years_optimistic_oil = 43
years_optimistic_ng = 167

# BP Statistical Review 2011
rate_coal = 7.273 # gigatonnes
rate_oil = 3.914 # gigatonnes
rate_ng = 3193 # bcm

gt_optimistic_coal = years_optimistic_coal * rate_coal
gt_optimistic_oil = years_optimistic_oil * rate_oil
bcm_optimistic_ng = years_optimistic_ng * rate_ng

# converstion factors same as above

co2_optimistic_coal = gt_optimistic_coal * coal_conv_co2 * coal_toe_conv
co2_optimistic_coal # 6161
co2_optimistic_oil = gt_optimistic_oil * oil_conv_co2
co2_optimistic_oil # 517
co2_optimistic_ng = bcm_optimistic_ng * ng_conv_co2 * ng_toe_conv
co2_optimistic_ng # 1130

co2_optimistic_ff = co2_optimistic_coal + co2_optimistic_oil + co2_optimistic_ng
co2_optimistic_ff # 7808

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  1. Nick Stokes
    2012 May 24 at 10:06 pm

    Ron,
    I think I see part of the problem. I think you’re converting coal to oil equivalent on an energy basis. But that is different to a carbon content equivalent. I don’t think your 0.513 factor is appropriate. In fact coal is 70-80% C, oil is a bit over 80%.

  2. Nick Stokes
    2012 May 24 at 10:40 pm

    Ron,
    Here are the factors I think you should be using:
    Coal. WCE 29.3 GJ/ton; WG3-4.2 92.3 kg/GJ CO2
    so 29.3*.0923=2.7 ton CO2/ton coal

    Oil WCE 42 GJ/ton WG3 76.3 kg/GJ CO2
    so 3.2 ton CO2/ton oil

    NG WCE 46.8 GJ/ton WG3 52.4 kg/GJ CO2
    so 24.5 ton CO2/ton NG
    or 36 GJ/1000 m3 1.9 ton CO2/1000 cu m NG

    On that basis, proven, from your figures
    = 861*2.7+189*3.2+187*1.9 = 3284 Gt CO2

  3. Nick Stokes
    2012 May 24 at 10:50 pm

    That should of course be 2.45 ton CO2/ton NG. These factors are pretty much just chemistry.

    Pure C would be 44/12=3.67 CO2/C
    so coal is 73.5% C on these figs
    and oil is close to pure CH2, so 44/14= 3.14 CO2/CH2
    and NG is mostly CH4: 44/16 = 2.75 CO2/CH4
    so I guess NG has some N2 etc

  4. 2012 May 25 at 8:11 am

    I think we are narrowing our difference …

    The energy per ton of coal that you list is for anthracite.
    Bituminus is bit lower
    Lignite is 50% lower.

    Per the BP reserves and Iowa State
    405 Gt are anthracite and bituminus ( ~ .67 TOE)
    456 Gt are sub-bitumenous and lignite (~ .33 TOE)

    So for back of envelope purposes, using your conversions but adjusting for anthracite -v- lignite, we have

    = 405*2.7+456*1.4+189*3.2+187*1.9 = 2692 Gt CO2

    which is just a bit shy of the 2725 I calcuated above

  5. Nick Stokes
    2012 May 25 at 9:37 am

    Well, the big question is whether you should use proven reserves – which means reserves exploitable at current prices with current technology. For this calc thats very very conservative.

    But I disagree with your last point. Again, it’s carbon content that counts, not energy. Lignite has lower energy partly because there is water content to be evaporated. If you burn a ton, you get less energy, but not much less CO2.

    I used the energy figure because it coupled with the WG3 table factors. But for coal the carbon content is shown directly in this wiki table. Lignite is down relative to anthracite, but not half.

  6. 2012 May 25 at 11:41 am

    But I am using the proven reserves as the bottom of the estimate, There is only about a 5% chance that we will use only as much as the proven reserves and a 95% chance that we will use more.

    What is more problematic is how to anchor the high-end of the PDF. The candidates are: probable reserves, possible reserves, and in-ground – with some treatment of oil sands and oil shales. My use of wiki’s OGJ “most optimistic” isn’t well referenced yet. But hopefully good enough for this guesstimation exercise.

  7. Nick Stokes
    2012 May 25 at 2:37 pm

    Here is an Oil Drum post somewhat agreeing with you I think – not much data but a lot of references.

  1. 2012 May 28 at 1:23 pm
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