Introduction Flashcards
What is Renewable Energies?
An energy carrier which are:
1) infinite in human terms
2) or fast regenerated
Biomass Historical Overview
- Oldest utilizable energy source
- Ignition: thunderbolts
Reasons for invention of controllable ignition?
- Colonization of northern regions not colonised before;
- Socialization
- Population growth
- Progress
Biomass is predominant energy source for:
- Food preparation
- Heating
- Production of copper, iron, bronze (early energy extensive industries)
Wind Historical Overview
1700 BC - 1st wind wheels for irrigation (Middle East)
650 AD - 1st wind mills (resistance rotor type, West Asia)
1200 AD - 1st wind mills with horizontal rotor axis (North France)
1250 AD - 1st “modern type” tower wind mills (Mediterranean)
17-18 cent. - mathematical optimization of wings by Leibnitz, Bernoulli, Euler –> advanced wind mills designs & techno
1891 - Poul la Cour (Denmark) 1st wind power plant (35 kWel)
1922 - M&A Jacobs (USA) windladder - 1st commercial product
1920s - Darrieus, modern 2&3 wing rotors
Pitch-regulated Wind Turbine (PRWT)
- Usually used for high wind speeds only;
- has an active control systems that can vary the pitch angle (turn the blade around its own axis) of the turbine blades to decrease the torque produced by the blades in a fixed-speed turbine and to decrease the rotational speed in variable speed turbines;
- allows the wind turbine to actively change the angle of attack of the air on the blades;
- preferred over a stall-regulated WT as it enables far greater control of the power output;
- When wind speeds get very high (above rated power), the blades will pitch so that there is less lift and more drag due to increasing flow separation along the blade length (the blades are pitched into stall). This will slow down the turbine’s rotational speed or the torque transferred to the shaft so that the rotational speed or the torque is kept constant below a set threshold;
- pitch regulated turbines see increasing power up until the rated wind speed beyond which it sees constant power up until a cut-out speed when the pitch control is no longer able to limit the rotational speed or aerodynamic torque or where other forces like structural vibrations, turbulence or gusts pose a threat to a rotational turbine.
Stall-regulated WT
- has its blade designed so that when wind speeds are high, the rotational speed or aerodynamic torque, and thus the power production decreases with increasing wind speed above a certain value (usually not the same as the rated wind speed);
- the decrease in power with increasing wind speeds is due to aerodynamic effects on the turbine blades (regions of the blade are stalled, propagating from the hub and outwards with increasing wind speeds);
- the blades are designed so that they will perform worse (in terms of energy extraction) in high wind speeds to protect the WT without the need for active controls;
- the benefit of SR over PR is limited tcapital cost of the turbine, as well as lower maintenance associated with more moving parts;
- has breaks to bring the turbine to a halt in extreme wind speeds
Difference between SRWT and PRWT
- mostly noticeable in high wind speeds;
- SR systems rely on the aerodynamic design of the blades to control the aerodynamic torque or the rotational speed of the turbine in high wind speeds;
- PR systems use an active pitch control for blades. This allows PR systems to have a constant power output above the rated wind speed, while the SR systems are not able to keep a constant power output in high winds.
Hydro Historical Overview
3.000-4.000 years ago - mechanical conversion of running-water power
1.000 - 2.000 BC - 1st waterwheels (China) недоработ.
1500 AD - development of overshot waterwheels (Germany)
Modern turbine design
1827 Development of reaction turbine (Francis
turbine, France)
1850s Development of impulse turbine (Pelton
turbine, Europe)
1838 Axial turbines (Germany)
1913 Propeller turbines (Kaplan turbines,
Germany)
Archimedes Screw for small scale hydro-power
Solar Historical Overview
Ancient world: concave mirrors used for
ignition of firewood
18th century: Horace-Bénédict de Saussure
developed the first solar collector
1881 C.M. Kemp: First solar plant for water
heating
1912: First solar thermal parabolic trough power plant (40 kWel)
Oil crisis, 1973: Enforced installation of large
scale parabolic trough power plants
Solar Historical Overview
Ancient world: concave mirrors used for
ignition of firewood
18th century: Horace-Bénédict de Saussure
developed the first solar collector
1881 C.M. Kemp: First solar plant for water
heating
1912: First solar thermal parabolic trough power plant (40 kWel)
Oil crisis, 1973: Enforced installation of large
scale parabolic trough power plants
Photovoltaics Historical Overview
Alexandre Edmond Becquerel, 1839: Photoelectric effect
Russel Ohl, 1940 (Bell Laboratories): Doping of silica probes
Walter Schottky, 1948: Semiconductor photovoltaics (Schottky-diodes)
First implementation:
Vanguard I satellite, USA, 1957
Terrestrial implementation started with oil
crisis, 1973
Decrease of production cost in recent years:
Massive installation of photovoltaic panels in
small an large scale
Geothermal Energy Historical Overview
Ancient times: thermal springs were used as
water supply for public baths
Larderello, Tuskany, Italy: First geothermal
power plant (1913) Electrical output today:
700 MWel
Iceland: 54% of its primary energy is sourced
from geothermal formations
Storage Systems Historical Overview
Thermal storage systems
• Sensible heat storage
• Latent heat storage
• Thermo-chemical heat storage
18th century: Alessandro Volta and Luigi
Galvani define the basics for electrochemical
energy storage.
1859: First Accumulator was invented by
Gaston Planté (France)
1881: First electric driven vehicles by Trouvé
(France)
1988-1994: Battery-Storage power plant
Berliln-Steglitz (17 MW and 14.4 MWh)
2011: Renaissance of electric driven cars (i3,
Tesla, …)
Accumulators in mobiles, PV-systems,
