Small Hydro Project Analysis Renewable Energy Project Analysis

Small Hydro Project Analysis Renewable Energy Project Analysis Course - Module 3 Run-of-River Small Hydro Project, Canada Photo Credit: SNC-Lavalin © Minister of Natural Resources Canada 2001 – 2002.

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.

What do Small Hydro systems provide? • Electricity for 4 Central-grids 4 Isolated-grids 4 Remote power supplies …but also… 4 Reliability 4 Very low operating costs 4 Reduced exposure to energy price volatility Photo Credit: Robin Hughes/ PNS © Minister of Natural Resources Canada 2001 – 2002.

Small Hydro System Description © Minister of Natural Resources Canada 2001 – 2002.

“Small” Hydro Projects • “Small” is not universally defined 4 Micro Mini Small Size of project related not just to electrical capacity but also to whether low or high head Typical Power RETScreen® Flow RETScreen® Runner Diameter < 100 k. W < 0. 4 m 3/s < 0. 3 m 100 to 1, 000 k. W 0. 4 to 12. 8 m 3/s 0. 3 to 0. 8 m 1 to 50 MW > 12. 8 m 3/s > 0. 8 m © Minister of Natural Resources Canada 2001 – 2002.

Types of Small Hydro Projects • Type of grid 4 Central-grid 4 Isolated-grid or off-grid 17. 6 -MW Run-of-River Hydro Project, Massachusetts, USA • Type of civil works 4 4 Run-of-river § No water storage § Power varies with flow available from river: lower firm capacity Photo Credit: PG&E National Energy Group/ Low Impact Hydropower Institute 4. 3 -MW Run-of-River Hydro Project, Oregon, USA Reservoir § Higher firm capacity year round § Significant damming usually required Photo Credit: Frontier Technology/ Low Impact Hydropower Institute © Minister of Natural Resources Canada 2001 – 2002.

Components: Civil Works • Typically account for 60% of plant initial costs • Diversion dam or weir 4 Low dam of simple construction for run-of-river 4 Concrete, wood, masonry 4 Cost of dam alone can render project unviable • Water passage 4 Intake with trashrack and gate; tailrace at exit 4 Excavated canal, underground tunnel and/or penstock 4 Valves/gates at turbine entrance/exit, for maintenance • Power house 4 Photo Credit: Ottawa Engineering Houses turbine, mechanical, and electrical equipment © Minister of Natural Resources Canada 2001 – 2002.

Components: Turbine • Scaled-down versions of large-hydro turbines • Efficiency of 90% possible • In run-of-river, flow rate is quite variable 4 Turbine should function well over a range of flow rates or multiple turbines should be used • Reaction: Francis, fixed pitch propeller, Kaplan 4 For low to medium head applications 4 Submerged turbine uses water pressure and kinetic energy Francis Turbine • Impulse: Pelton, Turgo, crossflow 4 For high head applications 4 Uses kinetic energy of a high speed jet of water Photo Credit: Ottawa Engineering © Minister of Natural Resources Canada 2001 – 2002.

Components: Other electrical equipment • Generator 4 4 Pelton Turbine 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 Photo Credit: Ottawa Engineering • Other equipment 4 Speed increaser to match turbine to generator 4 Valves, electronic controls, protection devices 4 Transformer © Minister of Natural Resources Canada 2001 – 2002.

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 1, 070 45 200 19 Europe Australasia Source: Renewable Energy: Sources for Fuels and Electricity, 1993, Island Press. © Minister of Natural Resources Canada 2001 – 2002.

Site Hydro Resource • Very site specific: an exploitable river is needed! 4 Change in elevation over a relatively short distance (head) 4 Acceptable variation in flow rate over time: flow duration curve § Residual flow reduces flow available for power • Estimate flow duration curve based on 4 Measurements of flow over time 4 Size of drainage above site, specific run-off, and shape of flow duration curve © Minister of Natural Resources Canada 2001 – 2002.

Small Hydro System Costs • 75% of costs are site specific • High initial costs 4 But civil works and equipment can last >50 years Photo Credit: Ottawa Engineering • Very low operating and maintenance costs 4 One part-time operator is usually sufficient 4 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 k. W © Minister of Natural Resources Canada 2001 – 2002.

Small Hydro Project Considerations • Keep costs down with simple design and practical, easilyconstructed civil structures • Existing dams and civil structures can be used • Development time of 2 to 5 years 4 Resource and environmental studies: approvals • Four phases for engineering work: 4 Reconnaissance surveys/hydraulic studies 4 Pre-feasibility study 4 Feasibility study 4 System planning and project engineering Photo Credit: Ottawa Engineering © Minister of Natural Resources Canada 2001 – 2002.

Small Hydro Environmental Considerations • Small hydro development can change 4 Fish habitat 4 Site aesthetics 4 Recreational/navigational uses • Impacts and environmental assessment requirements depend on site & type of project: 4 Run-of-river at existing dam: relatively minor 4 Run-of-river at undeveloped site: dam/weir/diversion construction 4 Water storage developments: larger impacts that increase with scale of project © Minister of Natural Resources Canada 2001 – 2002.

Example: Slovakia, Canada, and USA Central-Grid Small Hydro Systems • Run-of-river projects will feed grid when Small Hydro Development, Southeastern, USA flow available • Utility-owned or independent power producer with long-term PPA Photo Credit: CHI Energy 2. 3 -MW, 2 Turbine, Jasenie, Slovakia Photo Credit: Emil Bedi (Foundation for Alternative Energy)/ Inforse Small Hydro Development, Newfoundland, Canada Photo Credit: CHI Energy © Minister of Natural Resources Canada 2001 – 2002.

Example: USA and China Isolated-Grid Small Hydro Systems Small Hydro Generators, China • Remote communities • Remote residences & industry Photo Credit: International Network on Small Hydro Power • Higher price paid for electricity • Run-of-river projects typically King Cove 800 k. W Small Hydro System, Town of 700 People Photo Credit: Duane Hippe/ NREL Pix need supplemental capacity and may have flow in excess of demand © Minister of Natural Resources Canada 2001 – 2002.

RETScreen® Small Hydro Project Model • World-wide analysis of energy production, life-cycle costs and greenhouse gas emissions reductions 4 Central-grid and isolated-grid 4 Single turbine micro hydro to multi-turbine small hydro 4 “Formula” costing method • Currently not covered: 4 Seasonal variations in isolated-grid load 4 Variations in head in storage projects (user must supply average value) © Minister of Natural Resources Canada 2001 – 2002.

RETScreen® Small Hydro Energy Calculation See e-Textbook Renewable Energy Project Analysis: RETScreen® Engineering and Cases Chapter 3: Small Hydro Project Analysis © Minister of Natural Resources Canada 2001 – 2002.

Example Validation of the RETScreen® Small Hydro Project Model • Turbine efficiency 4 Compared with manufacturer’s data for an installed 6 MW GEC Alsthom Francis turbine • Plant capacity & output 4 Compared with Hydr. A for a Scottish site 4 All results within 6. 5% • Formula costing method 4 Compared with RETScreen®, within 11% of a detailed cost estimate for a 6 MW project in Newfoundland © Minister of Natural Resources Canada 2001 – 2002.

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: 4 Lower cost & lower environmental impacts 4 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.

Questions? Run-of-River Small Hydro Project, Canada Photo Credit: SNC-Lavalin www. retscreen. net © Minister of Natural Resources Canada 2001 – 2002.