03-hydro.ppt
- 1. © Minister of Natural Resources Canada 2001 – 2002. Renewable Energy Project Analysis Course - Module 3 Photo Credit: SNC-Lavalin Small Hydro Project Analysis Run-of-River Small Hydro Project, Canada
- 2. Objectives • Review basics of Small Hydro systems • Illustrate key considerations for Small Hydro project analysis • Introduce RETScreen® Small Hydro Project Model © Minister of Natural Resources Canada 2001 – 2002.
- 3. • Electricity for Central-grids Isolated-grids Remote power supplies …but also… Reliability Very low operating costs Reduced exposure to energy price volatility What do Small Hydro systems provide? Photo Credit: Robin Hughes/ PNS © Minister of Natural Resources Canada 2001 – 2002.
- 4. Small Hydro System Description © Minister of Natural Resources Canada 2001 – 2002.
- 5. • “Small” is not universally defined Size of project related not just to electrical capacity but also to whether low or high head “Small” Hydro Projects Typical Power RETScreen® Flow RETScreen® Runner Diameter Micro < 100 kW < 0.4 m3/s < 0.3 m Mini 100 to 1,000 kW 0.4 to 12.8 m3/s 0.3 to 0.8 m Small 1 to 50 MW > 12.8 m3/s > 0.8 m © Minister of Natural Resources Canada 2001 – 2002.
- 6. Types of Small Hydro Projects • Type of grid Central-grid Isolated-grid or off-grid • Type of civil works Run-of-river No water storage Power varies with flow available from river: lower firm capacity Reservoir Higher firm capacity year round Significant damming usually required Photo Credit: Frontier Technology/ Low Impact Hydropower Institute Photo Credit: PG&E National Energy Group/ Low Impact Hydropower Institute © Minister of Natural Resources Canada 2001 – 2002. 17.6-MW Run-of-River Hydro Project, Massachusetts, USA 4.3-MW Run-of-River Hydro Project, Oregon, USA
- 7. Components: Civil Works • Typically account for 60% of plant initial costs • Diversion dam or weir Low dam of simple construction for run-of-river Concrete, wood, masonry Cost of dam alone can render project unviable • Water passage Intake with trashrack and gate; tailrace at exit Excavated canal, underground tunnel and/or penstock Valves/gates at turbine entrance/exit, for maintenance • Power house Houses turbine, mechanical, and electrical equipment Photo Credit: Ottawa Engineering © Minister of Natural Resources Canada 2001 – 2002.
- 8. Components: Turbine • Scaled-down versions of large-hydro turbines • Efficiency of 90% possible • In run-of-river, flow rate is quite variable Turbine should function well over a range of flow rates or multiple turbines should be used • Reaction: Francis, fixed pitch propeller, Kaplan For low to medium head applications Submerged turbine uses water pressure and kinetic energy • Impulse: Pelton, Turgo, crossflow For high head applications Uses kinetic energy of a high speed jet of water © Minister of Natural Resources Canada 2001 – 2002. Francis Turbine Photo Credit: Ottawa Engineering
- 9. Components: Other electrical equipment • Generator Induction Must be tied to other generators Use to feed electricity onto large grid Synchronous Can function in isolation from other generators For stand-alone and isolated-grid applications • Other equipment Speed increaser to match turbine to generator Valves, electronic controls, protection devices Transformer © Minister of Natural Resources Canada 2001 – 2002. Photo Credit: Ottawa Engineering Pelton Turbine
- 10. World Hydro Resource • More rain falls on continents than evaporates from them • For equilibrium, rain must flow to the oceans in rivers Technical Potential (TWh/year) % Developed Africa 1,150 3 South Asia and Middle East 2,280 8 China 1,920 6 Former Soviet Union 3,830 6 North America 970 55 South America 3,190 11 Central America 350 9 Europe 1,070 45 Australasia 200 19 © Minister of Natural Resources Canada 2001 – 2002. Source: Renewable Energy: Sources for Fuels and Electricity, 1993, Island Press.
- 11. Site Hydro Resource • Very site specific: an exploitable river is needed! Change in elevation over a relatively short distance (head) Acceptable variation in flow rate over time: flow duration curve Residual flow reduces flow available for power • Estimate flow duration curve based on Measurements of flow over time Size of drainage above site, specific run-off, and shape of flow duration curve © Minister of Natural Resources Canada 2001 – 2002. Flow-Duration Curve 0.0 10.0 20.0 30.0 40.0 50.0 0 10 20 30 40 50 60 70 80 90 100 Percent Time Flow Equalled or Exceeded (%) Flow (m³/s)
- 12. Small Hydro System Costs • 75% of costs are site specific • High initial costs But civil works and equipment can last >50 years • Very low operating and maintenance costs One part-time operator is usually sufficient Periodic maintenance of major equipment requires outside contractor • High head developments tend to be less costly • Typical range: $1,200 to $6,000 per installed kW © Minister of Natural Resources Canada 2001 – 2002. Photo Credit: Ottawa Engineering
- 13. Small Hydro Project Considerations • Keep costs down with simple design and practical, easily- constructed civil structures • Existing dams and civil structures can be used • Development time of 2 to 5 years Resource and environmental studies: approvals • Four phases for engineering work: Reconnaissance surveys/hydraulic studies Pre-feasibility study Feasibility study System planning and project engineering Photo Credit: Ottawa Engineering © Minister of Natural Resources Canada 2001 – 2002.
- 14. Small Hydro Environmental Considerations • Small hydro development can change Fish habitat Site aesthetics Recreational/navigational uses • Impacts and environmental assessment requirements depend on site & type of project: Run-of-river at existing dam: relatively minor Run-of-river at undeveloped site: dam/weir/diversion construction Water storage developments: larger impacts that increase with scale of project © Minister of Natural Resources Canada 2001 – 2002.
- 15. Example: Slovakia, Canada, and USA Central-Grid Small Hydro Systems • Run-of-river projects will feed grid when flow available • Utility-owned or independent power producer with long-term PPA Photo Credit: Emil Bedi (Foundation for Alternative Energy)/ Inforse Photo Credit: CHI Energy Photo Credit: CHI Energy © Minister of Natural Resources Canada 2001 – 2002. 2.3-MW, 2 Turbine, Jasenie, Slovakia Small Hydro Development, Newfoundland, Canada Small Hydro Development, Southeastern, USA
- 16. Example: USA and China Isolated-Grid Small Hydro Systems • Remote communities • Remote residences & industry Photo Credit: Duane Hippe/ NREL Pix Photo Credit: International Network on Small Hydro Power © Minister of Natural Resources Canada 2001 – 2002. Small Hydro Generators, China King Cove 800 kW Small Hydro System, Town of 700 People • Higher price paid for electricity • Run-of-river projects typically need supplemental capacity and may have flow in excess of demand
- 17. RETScreen® Small Hydro Project Model • World-wide analysis of energy production, life-cycle costs and greenhouse gas emissions reductions Central-grid and isolated-grid Single turbine micro hydro to multi-turbine small hydro “Formula” costing method • Currently not covered: Seasonal variations in isolated-grid load Variations in head in storage projects (user must supply average value) © Minister of Natural Resources Canada 2001 – 2002.
- 18. RETScreen® Small Hydro Energy Calculation © Minister of Natural Resources Canada 2001 – 2002. See e-Textbook Renewable Energy Project Analysis: RETScreen® Engineering and Cases Chapter 3: Small Hydro Project Analysis Calculation of plant capacity Calculation of turbine efficiency curve Flow duration curve Calculation of energy available Calculation of power duration curve Calculation of energy delivered (central grid) Power duration curve Calculation of energy delivered (isolated grid)
- 19. Example Validation of the RETScreen® Small Hydro Project Model • Turbine efficiency Compared with manufacturer’s data for an installed 6 MW GEC Alsthom Francis turbine • Plant capacity & output Compared with HydrA for a Scottish site All results within 6.5% • Formula costing method Compared with RETScreen ® , within 11% of a detailed cost estimate for a 6 MW project in Newfoundland © Minister of Natural Resources Canada 2001 – 2002. 0% 20% 40% 60% 80% 100% 0% 20% 40% 60% 80% 100% Percent of Rated Flow Efficiency (%) Turbine Efficiency Curves: RETScreen vs. Manufacturer RETScreen Manufacturer
- 20. Conclusions • Small hydro projects (up to 50 MW) can provide electricity for central or isolated-grids and for remote power supplies • Run-of-river projects: Lower cost & lower environmental impacts But need back-up power on isolated grid • Initial costs high and 75% site specific • RETScreen® estimates capacity, firm capacity, output and costs based on site characteristics such as flow duration curve and head • RETScreen® can provide significant preliminary feasibility study cost savings © Minister of Natural Resources Canada 2001 – 2002.
- 21. Questions? www.retscreen.net © Minister of Natural Resources Canada 2001 – 2002. Photo Credit: SNC-Lavalin Run-of-River Small Hydro Project, Canada