Energy supply with hydropower

Transcription

1 Energy supply with hydropower University of Kassel, Department of Hydraulic Engineering g and Water Resources Management Prof. Dr.-Ing. Stephan Theobald in La Paz, Bolivia

2 Contents Introduction Global electricity and hydropower Types of hydropower plants Types of turbine Environmental aspects Ongoing challenges and approaches Conclusions 2

3 Hydropower how did it start: flour, saw, irrigation, mining... Direct mechanical energy derived from water Ref.: Ref.: Ref.: Ref.: de.yoocorp.com 3

4 Global electricity generation (2014) coal 38.9% others 4.7% renewable hydropower energy Oil 4.8% 23.5% 16.8% gas 22% nuclear energy 10.8% Biomass and Waste Source: The World Bank 2% 4

5 Hydropower in the world Africa Asia Australia Europe North- Southamerica /Centralamerica economic potential [TWh/a] generated electricity [TWh/a] teaching material, modified 5

6 Germany: Regenerative Energy and Electricity Full load hours: Biomass ~ 6,400 h/a Wind energy ~ 1,500 h/a Hydropower ~ 4,000 h/a Photovoltaics~ 820 h/a Quelle: BMU,

7 Hydropower Sizes Wide range and individuality (small hydropower plants: P < 1 MW) Technical specifications Discharge : m³/s Head: 6091m 6,0-9,1 Power: 100 MW Annual output: MWh/a Technical specifications Discharge: 18 m³/s Head: 29m 2,9 Power: 320 kw Annual output: MWh/a Technical specifications Discharge : 0,15 Head: 30m 3,0 Power: 3,7 kw Annual output: 15 MWh/a teaching material, modified 7

8 Region-specific use of Hydropower: Example Hesse / Germany Subject of Analysis Federal state of Hesse 21,000 km², 6.1 Mio. population, approx. 25,000 km of streams Hydropower in Hesse location-related analysis of the 621 hydropower plants in Hesse 609 small hydropower plants (P < 1 MW) teaching material, modified 8

9 Calculation of the performance of hydropower plants P ges g h f Q A 0,75 0,90 ges E t 0 P(t)dt Explanation: P power [W] E energy production [Wh] ρ density [kg/m³] = kg/m³ g gravity [m/s²] = 9,81 m/s² h f f drop height [m] design flow [m³/s] Q A η efficiency (complete, turbine, generator) [-] teaching material, modified 9

10 Electricity consumption Annual per capita rate of electricity consumption (including industry ) Year Bolivia Germany USA China Eritrea World kwh kwh kwh 282 kwh kwh kwh kwh kwh kwh 62 kwh kwh Annual per four-person household rate of electricity consumption Germany: kwh ( kwh per person) Ref.: Data.worldbank.org Examples of energy production by hydropower with h/a: a) Q = 1 m³/s, h f = 1 m, η = 0,8 P = 8 kw E = kwh b) Q = 0,2 m³/s, h f = 30 m, η = 08 0,8 P = 48 kw E = kwh 10

11 Required fossil fuels to generate kwh of electricity energy of water ~ 123 kg hard coal Q=1m³/s m³/s, h f = 10 m, time = 10 h ~ 63 kg oil ~ 100 m³ natural gas ~ 240 kg lignite (brown coal) ~ 105 l diesel ~ 240 kg beech wood 11

12 Layout of a Run-of-river power plant teaching material, modified 12

13 Run-of-river power plant natural discharge only immediate and continuous use without major storage base load teaching material, modified Ref.: Energiedienst Holding AG 13

14 Storage power plant natural discharge only & significant reservoir operation day-, week-, month-, or year-storage of discharge energy storage mean or peak load Kaprun reservoir Principle of a Storage power plant teaching material, modified 14

15 Pumped-storage power plant bidirectional artificial i flow (uphill pumping and downhill turbine operation) incl. short-term storage => energy storage covering peak energy demand grid stability (constant voltage, frequency) in case of a power drop 2-3 minutes from inactivity to full load Example Waldeck 2U Upper reservoirs: Volume: Mio. m³ Volume: 4.4 Mio. m³ penstock Power: Waldeck I 140 MW Lower reservoir Waldeck II 480 MW Volume: 7.6 Mio. m³ Ref.: EON Wasserkraft teaching material, modified 15

16 Pelton-Turbine (since 1890) drop heights ( m) high efficiency turbine good regulation regulation of nozzles 16

17 Francis-Turbine (since 1849) drop heights ( m) uniform admission is necessary radial flow regulation of the diffuser 17

18 Kaplan-Turbine (since 1913) drop heights (2-70 m) large discharge low / medium pressure radial or axial flow diffuser / impeller system guide vanes Kaplanturbine RADAG (HB) runner blades Kaplanturbine; Yacyreta ; Voith Siemens 18

19 Crossflow-Turbine drop heights (1-200 m) Q A : 25 l/s until 13 m³/s radial flow partial admission by cells optimized efficiency (80 until 86 %) low speed cheap 19

20 Some turbine types for small hydropower only Technical improvement of small-power-sites: sites: less backwater sensitivity larger discharges larger power Water wheels Hydrodynamic screw Ref.: Hydrowatt Ref.: HNA VLH-turbine Pumps as Turbines (PaT) Ref.: stellba-hydro 20

21 Selection of the ideal type of turbine Pelton-turbine dro op height [m m] Francis-turbine Kaplan-turbine Crossflowturbine Kaplan-bulb-turbine Design flow [m³/s] 21

22 Hydropower: Impacts to aquatic eco-systems The use of hydropower may cause significant environmental impacts e. g. Altered flow pattern which may result in sediment deposition and oxygen depletion Impairment of fish migration Fish injury teaching material, modified Legal constraints: EU, national and federal states regulations (WFD, nature conservation, fishery,...) 22

23 Some current challenges in hydropower Expansion of hydropower in rural regions (rural off-grid electrification and decentralized energy allocation) Development of tools to investigate the hydropower potential (e. g. parameters: economic efficiency, ecology, technology) Compact design and cost-effective solutions Ecological improvement measures at rivers and reservoirs Optimizing of inflow and outflow conditions of hydraulic structures Modernization of machinery & equipment 23

24 Environmental impact mitigation well established Ecological l motivated t requirements to reduce the environmental impacts fish passes for upstream migration ecologically discharge (instream flow) Ref.: ib-gebler.de teaching material, modified 24

25 Environmental impact mitigation ongoing approaches Ecologically motivated approaches to reduce the environmental impacts Downstream connectivity fish bypasses fish protection incl. increased hydraulic performance and electricity production Bed load and reservoir management teaching material, modified Fish bypasses (Ref.: Hassinger) Fish protection rack (Ref.: Hassinger) 25

26 Existing site optimization: Improvement of approaching flow - Flow separation limiting turbine operation - Re-Design in Physical Model & Hydrodynamic Numerical Model (3D) - Investigation of variations of design Initial state Recommended design Flow separation prevented by adjusted geometry of hydraulic structure teaching material, modified 26

27 Existing site optimization: Physical Modelling Initial state velocity [m/s] 68,3 % 31,7 % Recommended design 51,0 % 49,0 % teaching material, modified 27

28 Conclusions Hydropower passed through a long, continuous and experienced development is regenerative, reliable, established, region-specific and site-individual decentralized energy supply reduces the use of non-sustainable energy sources offers additional potential and opportunities at existing dams (e. g. non-powered dams, instream flow turbines) as well as at unexploited sites alters the environment and is by correct use sustainable (ecologically, economically and social) exploitations are supported by appropriate engineering methods is a long-term energy source and may be a consistent investment 28

29 Thank you very much for your attention! Contact: University of Kassel Department of Hydraulic Engineering and Water Resources Management Prof. Dr.-Ing. Stephan Theobald Kurt-Wolters-Str. 3 Germany Kassel Tel.: s.theobald@uni-kassel.de Web: 29