Answers and solutions
Energy Efficiency- Key Sectors27/04/2011
Electricity production and distribution, industry, and transportation - improving energy efficiency affects all fields of activity. In the last few decades, we have improved energy use and now consume less. These trends have accelerated since the 1990s, made possible by innovative industrial technologies and approaches such as environmentally friendly design.
© Total / Labelle Michel
Electricity - Optimizing Production and Distribution
Electricity companies have to meet consumer (industry, services, and individuals) demand for energy while limiting waste. To do this, they improve the energy efficiency of electricity production and distribution.
It is easy to store a little electricity for later use according to need, for example in mobile telephone batteries. However, it is not possible to store large amounts of electrical energy for later use- the electricity produced by power plants is fed into the grid to meet immediate demand.
This is why companies in the energy sector anticipate demand to adapt production. Despite these precautions, unused surplus energy can remain or there may not be enough energy available at peak times, which can result in power cuts. To prevent this type of situation, electricity companies use various techniques, such as:
• Smart grids help improve electricity consumption management with savings of 5-10%1. These grids have smart meters that use advanced technology to communicate information about the grid to consumers. For example, when global electricity demand falls, individuals receive a message suggesting that this is a good time to run the dishwasher. Thus, surplus energy can be used in real time.
• Pumped-storage plants (PSPs) are hydroelectric power plants that use surplus electricity from the grid. These plants have two reservoirs containing water at different altitudes. At times of peak energy demand, the water in the upper reservoir is released back into the lower reservoir through turbines. The turbines start to rotate, producing electricity. During times of low electrical demand, electric pumps driven by excess energy on the grid pump the water up to the higher reservoir.
• This pumped storage system is also used during periods of heavy rain or ice-melt. During these periods, dams cannot retain all the water swelling the rivers and instead they are left open to evacuate the water. The turbines work at full capacity and electrical production increases. When consumers do not require additional electricity, the system is used to operate the pumps that bring the water back upstream of the dam.
Electricity distributors also seek to reduce energy losses while the electrical current is being transmitted. These losses are related to the Joule effect- when a current is transmitted through a conducting cable, it circulates by making its way through the atoms of the material from which electrical wires are made, and it hits them. The effect of this impact is that part of the electrical energy is converted into heat energy and the wires heat up. The electrical energy lost represents an average of 2.5% of the electricity delivered.
To reduce this loss, the networks' stucture and operations are constantly being improved, and electrical cables are made out of copper or aluminum. These materials are good conductors and make it easier for electricity to circulate in the wires, thus reducing losses caused by the Joule effect.
The Industrial Sector, an Example to Be Followed
After the 1973 oil crisis, the industrial sector reduced its energy consumption to sustain its development. With fossil fuels becoming increasingly rare and costly, it received almost continual government support. In 1974, France established the Energy Savings Agency (AEE), the forerunner of ADEME (the Environment and Energy Management Agency), set up in 1990.
Thus, in just a few short decades, this sector has led the way in terms of saving energy.
• It halved its worldwide oil consumption between 1973 and 20072.
• Between 1997 and 2007, in the 27 EU member states, the industrial sector made final energy savings of 1.8% per year3- final energy being the energy delivered to consumers. So the share of final energy consumed by this field of activity fell from 45% in 1971 to 28% in 2007.
To obtain these results, the industrial sector invested in equipment and processes adapted to the scale of its activities. In fact, a number of technical innovations provide large energy savings in an industrial context, while others are for purely individual use. Thus, industry has invested massively in:
• High-yield, less energy-intensive facilities, combined with improved insulation of industrial buildings
• Improving the management and design of industrial plants
• Building cogeneration thermal power plants- spurred on by a 2004 European directive (in 1997, France introduced pro-cogeneration regulations, but the conditions for their application have since become much less favorable). As with conventional thermal plants, these plants are operated by natural gas combustion. Water is heated until it is converted into steam that drives electrical turbines. However, in cogeneration plants, electricity production is minimized to favor the use of local residual heat in the industrial plant.
... Consuming Better
To improve energy performance even more, the industrial sector is exploring new approaches, such as:
• Thermal integration involves designing production lines where the unused heat energy of one part of the line can be transferred to another part for reuse. For example, the heat from wastewater can be recovered to heat another liquid. In this way, the calories in the water can be put to use.
• Decentralized heat production involves industrial plants producing part of the heat energy they need. This mode of production contributes to energy efficiency: the less energy is transported, the less energy is lost in transmission.
Looking at a Product's Entire Life Cycle
At the same time, industry stakeholders have adopted environmentally friendly design processes. This involves taking environmental issues into account throughout the life cycle of a product or service (production, distribution, use, and end-of-life recovery through recycling in particular). In Europe, the plastics industry was the first to make widespread use of environmentally friendly design in the 1990s.
Environmentally friendly design primarily involves reducing energy consumption and optimizing energy use for less environmental impact. For example, since 2009, the Total group has been developing Total Ecosolutions, a range of 13 products designed with energy efficiency in mind. These include innovative plastics, glues, and lubricants. Less energy is needed to make and use these products. In 2010, Total estimated that the use of these 13 products was already helping to significantly reduce greenhouse gas (GHG) emissions, equivalent to the annual emissions of 160,000 vehicles!
Environmentally friendly design involves reducing the energy used both to manufacture and transport a product. For example, in a truck carrying yogurts in glass pots, the product itself takes up only 64% of the volume available in the truck, while the packaging takes up the remaining 36%. On the other hand, if the yogurt is packaged in plastic pots, much more can be transported in the same vehicle, with 97% of the truck's volume used to transport the product and the plastic packaging taking up just 3% of the volume4. In this way, less energy is used to deliver goods to consumers - plastic packaging helps to save 10 million tons of fuel per year in Europe5.
Significant Improvements in the Transportation and Petroleum Product Industries
Trains and airplanes also use new technologies to reduce their energy consumption.
• Since 2007, high-speed trains designed by Alstom use 10% less electricity7. They are fitted with a system where its kinetic energy - i.e. the energy of the moving train - is recovered each time the train brakes. Instead of being dispersed in the form of heat as in a standard train, this kinetic energy is converted into electricity and used to supply the locomotive and wagons.
• Aircraft manufacturers Airbus and Boeing now use up to 50% composite materials made from carbon fiber-reinforced plastic. Since they are lighter than standard aircraft, these airplanes use 20% less kerosene8.
• Since the 1990s, Michelin has been manufacturing tires that help deliver fuel savings of 1.4 million tons9. Like all tires, they dilate when they come into contact with uneven ground surfaces as the vehicle moves. To regain their initial shape, they use part of the mechanical energy provided by fuel combustion. However, as they are made of silica, they undergo much less distortion than standard tires and thus help save fuel because of their low rolling resistance.
More Efficient Fuels and Engines...
The oil industry is working to improve engine and fuel performance. Researchers have managed to make gasoline molecules more explosive, improving combustion and reducing fuel consumption
Similarly, substances that reduce carbon deposits in engines, a phenomenon that can reduce fuel combustion efficiency, are added to gasoline.
... Designed to Save Energy
To extract, transport, and refine crude oil, manufacturers working in the oil industry use huge amounts of energy. Improving energy efficiency is therefore a key target in this field. It involves extending approaches and techniques to minimize energy consumption and optimize energy use.
• Energy assessments are carried out to identify sites and processes where improvements energy efficiency can be made
• Existing facilities are being upgraded
• New, less energy-intensive facilities are being favored (for example, industrial furnaces where air is preheated to improve yield)
• Heat recovery systems are being installed - these are systems that recover the heat energy available in hot fluids for reuse on-site
• Investment in research programs on energy efficiency is being stepped up
• Training in energy efficiency techniques is being provided to people working in the sector.
The Total oil group pioneered energy efficiency. As far back as the 1970s, it adopted innovative processes and equipment in its oil refineries.
• The Packinox heat exchanger transfers heat energy between two fluids while keeping them separate. It is made of plates that transfer heat more efficiently than conventional tube exchangers, thereby providing energy savings.
• Specific distillation processes used in these refineries also provide energy savings.
• The Donges refinery is currently developing techniques to dry industrial sludge using solar energy trapped by greenhouses combined with energy produced by a heat recovery system. This drying method is less energy-intensive and cheaper than conventional sludge elimination through incineration.
When all these improvements are added together, they provide substantial energy savings.