Temps de lecture :3 minutes
Electricity represents 25% of the total demand for energy. 39% comes from coal, 19% from renewable energy, 15% nuclear, 20% from gas, and 7% from petrol.
In 2006, the production of electricity in the world was around 18 000 TWh, compared with 5 217 TWh in 1971. Between 1990 and 2004, the average annual growth rose to 2.9% per year and reached 3.5% in 2005. The greatest increases were in Asia-Pacific (+5.5%), Africa (+4.3%) and the Middle East (+4.7%).
If the demand for and production of electricity continues to average 2.5% per year, levels will double by 2030. Most of this future need for electricity will come from developing countries.
The current issue is finding a mixture of sources for optimal production in order to feed the growth in demand while taking into account the accessibility and price of resources, the sustainability of the materials supplied, and CO2 emissions.
Multiple Production Sources
In 2006, nuclear power represented 15% of the electricity produced in the world, an increase of 1.3% from 2005.
However, on the whole, it is the production of fossil fuel energy that is profiting the most from the growth of developing countries. In 2005, the fossil fuels used for electricity production were coal (60%), natural gas (30%), and petrol (10%). Coal is the main fuel used for electricity production throughout the world, but its combustion emits more carbon dioxide per heat unit than the other combustible fuels. The Massachusetts Institute of Technology (MIT) published a report of the future of coal in March 2007, concluding that trapping and storing carbon gas in geological formations could allow a reduction in carbon has emissions while responding to global needs.
Natural gas emits two times less carbon dioxide than the highest performing coal power stations and does not contain sulphur. But the rise in gas prices is not without impact on demand: it has caused certain operators to favour coal, giving an advantage to new coal power stations. In the last ten years, the electricity sector has become the driving force behind the increase in the use of natural gas in the world, and by 2020, this sector will use 35% of commercial gas each year. Finally, oil forms the smallest part of the fossil fuels and is used mainly for heating oil.
89% of renewable electricity comes from hydroelectricity, 5.7% from biomass (solid or liquid biomass, biogas and renewable household waste), and 3.5% from wind energy. A further 1.7% is from geothermal energy, 0.2% from solar energy (solar or thermal power stations, photovoltaic power stations), and 0.02% from marine energy. Since 2004, the growth of renewable energy has exceeded that of traditional energy production, reaching 18.6% in 2006. A large part of this growth in acceleration in renewable energy is due to the introduction of new capacities of hydroelectricity production and better discharge rates, especially in Asia and South America.
Production Adapted to Demand
The capacity of these new sources has sparked interest in developing countries without their own carbon-based resources, worried about rising fossil fuel prices. This is encouraging a move towards renewable solutions, whether through a centralised plan involving the development of a large hydroelectric plant, or a decentralised one involving autonomous systems. It is more economically profitable to develop electricity infrastructure in places with higher consumption and increase the installation of autonomous generators in villages far from the network, and where demand is less.
A study carried out on ten countries involved in decentralised rural electrification revealed that more than 1.5 million homes in these countries had their electricity supplied by autonomous photovoltaic systems. Further, the growing liberalisation of the energy market will increase the interdependence of the electricity markets. The electricity market is becoming more and more regional which requires interconnection of supplementary capacities between electricity networks to increase efficiency.
In 2005, 2 billion people had no electricity access, and 2.5 billion living in developing countries, mainly in rural areas, had only limited access to commercial electricity networks.