World energy supply and consumption
Current consumption
The worldwide energy consumption of the human race in 2004 was estimated as 15 TW (TW=1012 Watt) [1] by the United States Energy Information Administration. This is equivalent to 0.5 ZJ (ZJ =1021J) per year. There is at least 10% uncertainty in this number because the underlying data is continuously changing and not all of the world’s economies track their energy consumption with the same rigor.
Eighty-seven percent of the world’s energy is supplied by fossil fuel. The 15 TW total energy consumption is divided as follows:
| Oil | 5.6 | TW | =1012 Watt |
| Gas | 3.5 | TW | |
| Coal | 3.8 | TW | |
| Hydroelectric | 920 | GW | =109 Watt |
| Nuclear | 918 | GW | |
| Geothermal, Wind, Solar, Wood | 132 | GW |
Currently renewable energy supplies around 7% of the world’s energy consumption. Most (87%) of the renewable energy is hydroelectric power. Solar and wind power provide 4[2] and 65 GW (GW=109 Watt) respectively.
Energy consumption broadly tracks with gross national product although there is a significant difference between Japan and Germany with consumption levels of 6 KW and the US with 11.4 KW per person. In developing countries such as India the per person energy use is 0.5 KW.
Ever since the advent of the industrial revolution, the worldwide energy consumption has been growing steadily. Between 1980 and 2004 the worldwide annual growth rate has been 2%. The most significant growth of energy consumption is currently taking place in China which has been growing at 5.5% over the last 25 years. Its 1.3 billion people are currently consuming energy at a rate of 2 KW per person.
Transportation, industry, residential and commercial (offices & shops) each consume approximately equal shares of the total 15 TW.
In 2005 the world produced electricity at a rate of 2 TW. The energy consumed to generate the 2 TW of electricity is approximately 5 TW as the efficiency of a typical existing power plant is around 38%.[3] The new generation of gas fired plants reaches a substantially higher efficiency of 55%. Coal is the most popular fuel for the world’s electricity plants.
Available Energy Resources
Despite several voices[4] predicting the imminent decline of fossil fuels, there are still significant reserves of all the traditional energy components.
Remaining reserves of conventional fossil fuels are estimated[5] [6] as:
| Coal | 290 ZJ | |
| Oil | 45 ZJ | |
| Gas | 30 ZJ |
Again significant uncertainty exists for these numbers. For example the estimations for oil reserves vary from low estimate of 8 ZJ, [7] consisting of currently proven and recoverable reserves, to a maximum of 110 ZJ[6] consisting of available, but not necessary recoverable reserves. Both estimates provide oil for the foreseeable future at current consumption rates. Coal is especially abundant and by itself can sustain the current energy consumption of the entire planet for the next 600 years.
Political and/or environmental[8] considerations might move the world’s energy consumption away from fossil fuels. Renewable energy sources are even larger than the traditional fossil fuels and in theory can easily supply our energy needs.
There is 89,000 TW[9] of solar energy available at the planet’s surface. In other words; we need to capture less than 0.02% of the available solar energy to meet all our energy needs.
The available wind energy range from 300[9] to 370 TW. [6] Using the lower estimate, just 5% of the available wind energy would supply the worldwide energy needs. Most of this wind energy is available over open ocean. Not only does the ocean cover 71% of the planet, wind also tends to blow stronger over open water because there are less obstructions.
The above percentages for solar and wind energy ignore the formidable challenges of energy distribution and storage that need to be solved to overcome the intermittent and seasonal variations of these energy sources. The numbers do however illustrate that it is technically possible to move away from fossil fuels should society decide to make the necessary investment. The required investment to change energy sources is enormous. It is estimated that the cost to replace the global infrastructure for liquid transportation fuels alone is $3-5 trillion. [9].
Whether a significant investment in renewable energy is a wise or not, is currently the subject of much debate. Trials are taking place in several countries; Japan and Germany have started to make some investments in solar energy, making them the largest consumers of photovoltaic cells in the world despite their unfavorable geographic location. Denmark and Germany have installed 3 GW and 17 GW of wind power respectively. Wind generates 16% of all the electricity in Demark. Brazil has made a significant investment in ethanol fuel which supplies a significant part of the transportation fuel in that country. In the second half of last century France and Japan made large investments in nuclear power and to this date most their electricity in these two countries comes from their nuclear plants. In the 21st century some of these different energy paths might become more mainstream and start replacing the ubiquitous fossil fuels.
External Links
- Official Energy Statistics from the US government
- United States Geological Survey
- Exergy: Energy and the Second Law by Wes Hermann
- BP 2006 review of World Energy
References
- ^ "Energy Information Administration".
{{cite web}}: Unknown parameter|access date=ignored (|access-date=suggested) (help) - ^ "National Renewable Energy Laboratory" (PDF).
{{cite web}}: Unknown parameter|access date=ignored (|access-date=suggested) (help) - ^ "Article by group of ten leading electricity companies".
{{cite web}}: Unknown parameter|access date=ignored (|access-date=suggested) (help) - ^ Peak oil
- ^ "USGS World Energy Assessment Team".
{{cite web}}: Unknown parameter|access date=ignored (|access-date=suggested) (help) - ^ a b c Wes Herman, Global Climate and Energy Project at Stanford University
- ^ Energy Information Administration
- ^ Global Warming
- ^ a b c “Sustainable Energy” 2005 The MIT Press by Jefferson W. Tester et al