When will fossil fuels
finally run out?
What is the technical potential
for renewable energy resources?
Dr. Stas Burek
School of the Built and Natural Environment
Glasgow Caledonian University
Scotland, UK
1

Fossil Fuels
 What

can historical trends tell us?
Renewable energy
 13,500
times more solar energy than
commercial energy consumption
 Why is there an ‘energy crisis’?
2
First - a puzzle:
is energy expensive?
How much does energy cost?



Cost of electricity (€/kWh)
Cost of gas, oil (€/kWh, €/GJ)
Cost of petrol (€/litre)
0.12 €/kWh
0.05 €/kWh
1.10 €/litre
0.13 €/kWh
How much does personal
energy cost?




Rate of work (W)
Energy used for work
(kWh/time)
Earnings (€/time)
Cost of personal
energy (€/kWh)
200W
0.2 kWh/hour
8kWh/week (40 hours)
5 €/hour (200 €/week)
25 €/kWh
Personal Energy Cost (Euro/kWh)
Cost of Energy (Euro/kWh)
200:1
Global Energy Consumption
10000
Nuclear
8000
Hydro
6000
Gas
Oil
4000
Coal
2000
0
19
65
19
68
19
71
19
74
19
77
19
80
19
83
19
86
19
89
19
92
19
95
19
98
20
01
20
04
20
07
Consumption (Mtoe)
12000
Year
7
Fossil fuels



‘Oil will never run out’?
Reserves-to-production ratio (R/P)
Proved reserves:
 ‘those
quantities that geological and engineering
information indicates with reasonable certainty can be
recovered in the future from known reservoirs under
existing economic and operating conditions’

Ultimately Recoverable Reserves
8
Historical data

Assume exponential growth
Annual energy consumption
an = a0.rn

Cumulative energy consumption

S n  a0
1 r
n 1
1 r
9
Fossil fuel consumption since 1985
Exponential Growth Model
(Equal area under the curve)
Annual increase 1.69%
Actual consumption
9000
8000
7000
07
20
05
20
03
20
01
20
99
19
97
19
95
19
93
19
91
19
89
19
87
19
85
6000
19
Consumption (Mtoe)
10000
Year
10
Future depletion date






Reserves at the start of 1985 667.0 x 103 Mtoe
Consumption in 1985 a0 = 6412 Mtoe
Reserves at the end of 2007 754.6 x 103 Mtoe
Total consumption between 1985 and 2007 (inclusive)
an = 178.5 x 103 Mtoe (n = 22)
Cumulative reserves since the start of 1985
Sn = 933.1 x 103 Mtoe (n = 22)
Reserves ratio (1985 – 2007) 1.40
Reserves
ratio 
Cumulative
Reserves
reserves
since1985
at the start of 1985
11
Depletion date of fossil fuels
2100
0% - annual increase in consumption
2090
1%
Depletion year
2080
2070
2007
2%
2060
2050
1985
3%
2040
2030
2020
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
Reserves ratio w.r.t. 1985
12
Reported Oil Reserves
Prospects for fossil fuels

Reserves-to-production ratios
 Oil
40 years
 Gas
65 years
 Coal
155 years
 ALL fossil fuels


77 years
Need to find 1.3% reserves each year
Within the uncertainty limits of reserves
estimates?
14
Fossil fuels: Current trends

Ultimate depletion date
 ALL


fossil fuels
52 years
Since 2000 annual increase has fallen below 2%
only twice
For 2% annual increase
 Need
to increase cumulative reserves by 3% each
year
 Only two years since 1995 that reported reserves
have risen by more than 2%
15
New reserves

Beware mis-reporting!
 e.g.,
Iran
 ‘Large’ finds are actually quite small

Technological development needed
 e.g.,
Canadian tar sands
 e.g., methane hydrates
16
Alternatives to fossil fuels

Use less energy!
 Energy
efficiency
 Reducing unnecessary activities
 Economic development needs

Nuclear energy
 Heading

for the same crisis in the future?
Renewable energy
17
Earth’s energy flows
Resource
Mtoe per year
Ratio to fossil fuel use
Incident solar energy
1.31 x 108
13452
Direct reflection
3.94 x 107
4036
Entering the atmosphere
9.20 x 107
9416
Conversion to heat
6.13 x 107
6280
Evaporation etc.
3.03 x 107
3106
Wind and waves
2.76 x 105
28.3
Photosynthesis
7.04 x 104
7.21
Tidal energy
2.25 x 103
0.23
Terrestrial energy
2.43 x 104
2.49
Formation of fossil fuels
9.52 x 10-3
9.750 x 10-7
18
Hydropower
Water cycle: 3106 times fossil fuel use
 Total theoretical capacity 3TW

 60%

of fossil fuel consumption
Current contribution 707 Mtoe
 7.2%

of fossil fuel consumption
Maximum economical capacity 0.6TW
 12%
of fossil fuel consumption
19
Current status

Three Gorges Dam
 22,500
MW
 84.7 TWh per year (19.3 Mtoe)
 0.23% of fossil fuel consumption

Need another 430 similar schemes to
replace fossil fuels
20
Wave energy



Up to 1000 kW/m
Assume 50 kW/m potential
Need 100,000 km of wave devices to replace
fossil fuels
 2½

times the Earth’s circumference
750 TWh (170 Mtoe) per year economically
recoverable
 1.73%
of current fossil fuel use
21
Wind energy
93,800 MW installed capacity worldwide
 100m diameter, 5MW rated output
 To replace fossil fuels:

 One
tenth of the Earth’s surface
 Average windspeed 5m/s
 150m diameter turbine every 2.5 km2
22
Solar photovoltaic


Currently 25,000,000m2 (25km2) PV cells
worldwide
In order to replace fossil fuels
of high solar availability (6kWh/m2 per day)
 350,000 km2 required
 4% of the Sahara Desert
 14,000 times current capacity
 Areas

PV manufacture and electricity transmission
issues
23
Biomass
Solar energy to photosynthesis 7 times
annual fossil fuel usage
 To replace fossil fuels:

 14%
of the Earth’s surface
 46% of global land area

Conversion efficiency of plants ~1-2%
24
Conclusions – fossil fuels

R/P ratio for ALL fossil fuels 77 years
 New
reserves needed 1.3% of current reserves each
year

Current trends: ultimate depletion date 52 years
 New
reserves needed 3% each year of current
reserves to maintain 2% annual increase


Uncertainties in estimating reserves
Uncertainties in reported data
25
Conclusions - renewables







Some renewable technologies could replace
fossil fuels ...
... but would need massive and rapid expansion
Potential for new energy giants
Small-scale developments
Mix of technologies
Environmental impacts
NO ‘SILVER BULLET’!
26
Finally...
Glasgow Caledonian University
 MSc Energy and Environmental
Management
 MSc Waste Management
 MSc Sustainable Energy Technology
 www.gcal.ac.uk

27
Thank you
Any Questions?
Dr Stas Burek
School of the Built and Natural Environment
Glasgow Caledonian University
Scotland, UK
28