Electrical energy demand
The demand for electrical energy , also the demand for electricity, is the amount of electrical energy that electrical devices need to operate. The actual implementation in operation during a defined period of time is referred to as power consumption or power consumption .
Physical definition
The converted electrical energy W (from English work = work) is measured in watt seconds or kilowatt hours . It is the total electrical work that flows during the period t under consideration with the power consumption P under consideration . If the demand remains the same, the converted energy is the product of the electrical power P and the elapsed time t :
Example: A hair dryer consumes 2000 watts (2 kW) of electrical power . If the hair dryer is operated for half an hour (0.5 h), the electrical energy requirement is 2 kW · 0.5 h = 1 kWh (one kilowatt hour).
Temporal progression of the demand for electrical energy
The demand for electrical energy is subject to both time of day and seasonal fluctuations. In terms of time of day, there are peaks in demand between 7 a.m. and 2 p.m. and in the evening hours. The need reaches a minimum in the late hours of the night. In winter, due to the shorter time of day (increased lighting requirements) on the one hand and the lower temperatures (electric heating) on the other hand, there is a higher demand for electrical energy. As a result of climate change , there has been a second peak in consumption in warmer countries in the last few years due to the consumption of air conditioning systems . This effect is expected to increase in the future.
In order to permanently cover the demand, it is necessary to be able to safely handle the peaks in demand in addition to the basic demand. In this context, one speaks of base load , medium load and peak load .
Power plants that supply the base load are types that work inexpensively all year round, apart from overhaul times (coal, nuclear, run-of-river power plants). In Austria run-of-river power plants and storage power plants mainly take on this task. In the Central European average, these types cover around 30% of the energy requirement.
The medium-load power plants include hard coal, oil, gas and storage power plants. A characteristic of this type is the ability to be able to react flexibly to large-scale fluctuations in demand. They cover around 40% of the electrical energy requirement.
However, in order to be able to compensate for fluctuations in demand, it is necessary to operate peak load power plants such as gas turbine, oil, storage and pumped storage power plants. Such systems are usually put into operation for a few hours at short notice in order to satisfy the short-term high energy demand.
In this context, pump storage plants allow the most effective adaptation to the increased demand for electrical energy, as pump turbines can be converted from pump operation to turbine operation within a few seconds.
To ensure a continuous and even power supply , automation systems are operated in the power plants or this is done by integrating the systems into a supra-regional network.
Demand statistics
Germany
In 2011, the gross annual electricity consumption in Germany was 606.8 billion kWh with gross electricity generation of 613.1 billion kWh. The contribution of renewable energies to this was over 20%. The following table gives an overview of the development of gross electricity consumption and the share of renewable energies since 1991:
| year | Gross electricity consumption | Primary energy consumption | ||
| all in all | including: renewable energy sources |
all in all | including: renewable energy sources |
|
|---|---|---|---|---|
| [TWh] | [%] | [PJ] | [%] | |
| 1991 | 539.6 | 3.2 | 14,610 | 1.3 |
| 1992 | 532.9 | 3.8 | 14,319 | 1.4 |
| 1993 | 528.0 | 4.0 | 14.309 | 1.6 |
| 1994 | 530.8 | 4.6 | 14,185 | 1.8 |
| 1995 | 541.6 | 4.9 | 14,269 | 1.9 |
| 1996 | 547.4 | 4.4 | 14,746 | 1.8 |
| 1997 | 550.0 | 4.7 | 14,614 | 2.4 |
| 1998 | 556.6 | 5.0 | 14,521 | 2.6 |
| 1999 | 557.3 | 5.7 | 14,323 | 2.8 |
| 2000 | 579.6 | 6.6 | 14,401 | 2.9 |
| 2001 | 585.1 | 6.7 | 14,679 | 2.9 |
| 2002 | 587.4 | 7.8 | 14,427 | 3.2 |
| 2003 | 600.7 | 7.6 | 14,600 | 3.8 |
| 2004 | 610.2 | 9.3 | 14,591 | 4.5 |
| 2005 | 614.1 | 10.2 | 14,558 | 5.3 |
| 2006 | 619.8 | 11.6 | 14,837 | 6.3 |
| 2007 | 621.5 | 14.2 | 14,197 | 7.9 |
| 2008 | 618.2 | 15.1 | 14,380 | 8.0 |
| 2009 | 581.3 | 16.3 | 13,531 | 8.9 |
| 2010 | 615.4 | 17.0 | 14,217 | 9.9 |
| 2011 | 606.8 | 20.4 | 13,599 | 10.8 |
| 2012 | 607.1 | 23.7 | 13,447 | 10.3 |
| 2013 | 604.9 | 25.2 | 13,822 | 10.8 |
| 2014 | 592.2 | 25.9 | 13,158 | 11.5 |
| 2015 (1) | 600.0 | 32.6 | 13.306 | 12.5 |
The following shares were accounted for by the individual areas of net electricity consumption in 2014 (524.0 TWh):
- Industry: 46.6% (244.4 TWh)
- Households: 24.8% (129.7 TWh)
- Trade & Commerce: 14.7% (77.0 TWh)
- Public institutions: 9.9% (51.8 TWh)
- Transport: 2.2% (11.6 TWh)
- Agriculture: 1.8% (9.5 TWh)
According to calculations by the Federal Environment Agency , electrical energy sales rose by eleven percent between 1995 and 2000. After that, it fell by about seven percent by 2005.
Electricity consumption in private households
In private households , according to the International Energy Agency (IEA), the total electrical energy turnover due to new and additional electrical appliances has risen sharply. Although there were declines in washing machines and refrigerators due to improved energy efficiency, the electrical energy consumption from televisions, air conditioning systems and computers rose significantly at the same time. As a result, the percentage share of electrical energy in the total energy consumption of private households rose from 15 to 20 percent between 1990 and 2004.
The distribution of the use of electricity in private households has been determined on the basis of consumption data collected by the North Rhine-Westphalia Energy Agency from 380,370 one to six-person households that participated in the Energy Agency NRW's "Electricity checks for households" advisory program. According to this, the two areas of information and entertainment electronics “office equipment” and “TV / audio” are the most energy-intensive and account for a quarter of the electricity consumed in private households. Four other areas of use each take up around 10%: hot water, cooling, lighting and cooking. The amount of electricity consumption could be determined depending on the size of the household, whereby the type of hot water preparation (with or without electricity) has a clear influence (see table).
| Annual electricity consumption in private households by household size (1) Figures in kWh |
||||
|---|---|---|---|---|
| Household size |
Typical consumption |
with WWB 2 |
without WWB 2 |
Number of records |
| 1-pers. | 2,256 | 2,818 | 1,798 | 72,693 |
| 2-pers. | 3,248 | 3,843 | 2,850 | 143,699 |
| 3-pers. | 4,246 | 5,151 | 3,733 | 72,139 |
| 4-pers. | 5,009 | 6,189 | 4,480 | 67.605 |
| 5-pers. | 5,969 | 7,494 | 5,311 | 18,988 |
| 6-pers. | 6,579 | 8,465 | 5,816 | 5,246 |
The Institute for Energy and Environmental Research Heidelberg calls u. a. the following reasons for the increase in the demand for electrical energy despite increasingly efficient end devices:
- Reservations about new techniques such as B. energy saving lamps
- increasing demands for comfort
- larger average living space
- an increased use of ever larger devices and the steadily falling acquisition costs for household goods and electronics
The increasing use of heat pumps for domestic and building heating as a substitute for fossil-fueled heating systems as well as controlled living space ventilation , in addition to saving fossil primary energy, also leads to an increase in electricity consumption.
European comparison
Note: This table from "Stromvergleich.de" obviously contains an error in Greece: the total consumption is correct, with around ten million inhabitants it results a per capita consumption of 6,011.1 kWh / a.
In a comparison of the EU countries, in addition to the total consumption of electricity, the conversion to residents is also common. This comparative figure indicates the total consumption per capita and must be distinguished from private consumption, which is significantly lower. In terms of total electricity consumption per inhabitant, Finland was by far the front runner among the EU countries with 15,372 kWh / a. The EU average consumed 6201 kWh / a per inhabitant, Germany with 6648 kWh / a was slightly above the average, Italy with 5187 kWh / a significantly below. In Austria, the total electricity consumption per inhabitant in 2011 was 7762 kWh / a, in France 7042 kWh / a and in Poland 3433 kWh / a.
Need for individual electrical devices
Below are some examples of the typical needs of household appliances - the electricity costs apply to a working price of 25 cents / kWh.
- A hair dryer with a power consumption of 2000 watts that is used 5 minutes a day requires around 61 kWh of electrical energy for 15 euros a year.
- A flat-screen TV with 150 watt power consumption, which is used two hours a day, requires around 110 kWh of electrical energy per year for 28 euros.
- An electric stove with a power consumption of 4000 watts that is in operation for half an hour a day requires 730 kWh of electrical energy per year, which costs 183 euros.
- A 1200 watt kettle that is used for 10 minutes a day consumes 73 kWh per year and generates electricity costs of 18 euros.
- A washing machine in energy efficiency class A +++ with a capacity of 6 kg requires around 0.9 kWh of electrical energy for a standard wash (cotton, 60 ° C). The electricity for a load of laundry therefore costs a little over 20 cents .
The actual energy consumption values of household appliances sometimes differ greatly from the manufacturer's information. According to a study, many devices consume significantly more energy in practice than indicated. The additional consumption is therefore often 20 to 30 percent, in one extreme case the consumption was even more than twice as high.
Savings potential
See also
Individual evidence
- ↑ a b c d T. Strobl, F. Zunic: Wasserbau, Current Basics-New Developments . Springer-Verlag, Berlin / Heidelberg / New York 2006, ISBN 3-540-22300-2 .
- ↑ Alea Business Software: Assessment of the electricity consumption in Europe for the year 2016 (English), January 5, 2017, accessed on August 19, 2019.
- ↑ Potsdam Institute for Climate Impact Research : Electricity demand in Europe is shifting due to climate change . August 28, 2017. Retrieved August 19, 2019.
- ↑ a b J. Giesecke, E. Mosonyi: Hydropower plants, planning, construction and operation . Springer-Verlag, Berlin / Heidelberg / New York 2005, ISBN 3-540-25505-2 .
- ^ Arbeitsgemeinschaft Energiebilanzen eV: Gross electricity generation in Germany from 1990 to 2013 by energy source. (PDF) December 12, 2013, archived from the original on February 1, 2014 ; accessed on January 23, 2014 .
- ↑ a b Federal Statistical Office: Share of renewable energy sources in gross electricity consumption for Germany. (No longer available online.) March 18, 2016, archived from the original on May 11, 2016 ; accessed on March 22, 2016 .
- ↑ a b Federal Association of Energy and Water Management eV: 3.12 Net electricity consumption in Germany according to consumer groups. November 2015, accessed May 11, 2016 .
- ↑ Study on private households - Germans waste energy. tagesschau.de, November 14, 2006, accessed on September 11, 2007 .
- ↑ Holger Dambeck: Spiegel Online: Electricity consumption by electrical appliances has increased dramatically. September 10, 2007, accessed September 11, 2007 .
- ↑ Energy Agency NRW: Stromcheck - interactive online evaluation , Düsseldorf 2013.
- ↑ Energieagentur NRW: Presentation of the results of the survey "Where does the electricity stay?" , Düsseldorf 2013.
- ↑ a b c Energy Agency NRW: Survey “Where is the electricity?” (PDF; 4.0 MB), Düsseldorf 2011.
- ↑ ifeu: Efficient advisory modules for reducing electricity consumption in private households , chap. 3.5 Factors influencing electricity consumption, PDF, March 2006.
- ↑ Note: In the original table of the source "Stromvergleich.de" there is an obvious typo: The total consumption is correct, at approx. 10 million inhabitants, the per capita consumption is calculated at 6,010 kWh / a. A comparison with an official source, e.g. B. Eurostat , will follow (as of April 2013)
- ↑ Average power consumption in numbers. www.Stromvergleich.de, February 5, 2013, accessed on February 5, 2013 .
- ↑ Calculator, stove and hairdryer and the math of electricity consumption. January 17, 2011, accessed January 20, 2011 .
- ↑ Electricity consumption in the household. Retrieved February 18, 2013 .
- ↑ Power consumption: how much does a wash cost? Retrieved September 16, 2014 .
- ↑ Manufacturers beautiful power consumption of household appliances. June 21, 2017. Retrieved June 21, 2017 .