Small-scale wind energy course delivered at Greenworks, Dublin, June 2011. Course content compiled and delivered by Xavier Dubuisson, sustainable energy consultant at XD Consulting. Email: xavier@xdconsulting.eu
10. Micro Generation: Micro generation is classified by ESB Networks as grid connected electricity generation up to a maximum rating of 11kW when connected to the three phase grid (400V). The vast majority of domestic and agricultural customers are connected at single phase (230V) and for these customers to be classified as micro generators the maximum rating permitted is 6kW.
11. Two Types of system Stand Alone: Where generator is used to charge a battery bank. Typically used in remote locations or ‘off-grid’ applications. Grid Tied system: In this type of system, the output of the wind turbine is connected to the existing mains electricity supply to the home via a controller and inverter. Excess electricity generated can be sent onto the grid while electricity can be drawn from the grid when the turbine is not producing enough electricity to meet your needs.
16. Electrical terms Voltage (V) – a measure of the Potential Difference across an electrical circuit measured in Volts. Analogous to water pressure pushing water round a plumbing circuit. Current (I) – the electron flow in a circuit as a result of a PD across the circuit. Measured in Amps. Resistance (R) – the point in an electrical circuit where work is done by ‘resisting’ current flow e.g. electric heater. Measured in Ohms. V = IR (Ohms Law): an electrical circuit with a PD of 1 volt across a resistance of 1 ohm will result in a current of 1 amp Power (P) in an electrical circuit: current x voltage or P = VI (Watts)
25. Power in the wind Turbine Power = ½ ρAV³ ρ= density of Air ( summer warm- low, winter cold- high ) A = Rotor area = πR² Increasing the diameter of the blades by 20% , increase power by 44% ! V= Velocity of wind ; Cube factor doubling the wind speed increases the power 8 times . Higher up , more wind speed ( less ground friction, obstructions, turbulence) Bigger diameter= more swept area; Bigger /higher requires larger towers to accommodate rotor size and access to maximum wind speeds
43. SITE SURVEY Avoid obstructions (turbulence) Check wind speeds Estimate effect of ‘roughness of site’ Distance from buildings and party boundaries Length of cabling (and trenching) Location of plant room
48. Assessing a potential site Site assessment tools; Anemometer and wind vein Sited at the proposed height and location Ideal site; top of gently sloping south westerly hill, little obstructions such as trees/ buildings Windrose; speeds and direction
49. Output from survey 600 hours not fast enough to reach a cut -in speed of 4 m/s; no power produced
50. Roughness of site Impact on wind speed +9% Effect on output +160% +212% - 20% +13% - 32% +17% - 50% +29%
51. Turbulence on site Impact on quality of the wind Source: Centre for Alternative Technology Effect: wrong direction, wrong speed, excessive wear & tear
56. May require a variance or a special use permit20 m 10 m
57. Other considerations Safety: overhead cables, electrocution, fall of parts (& tower), etc. Visibility: look at it from your neighbours’ point-of-view (reflections, shadows, view obstruction, etc.) – be sensitive They do make noise (swish from blades, mechanical hum) Special conservation areas, natural heritage, etc.
75. Discounted cash flow Future cash flows are discounted to present value (time value of money) Net Present Value (NPV): total present value of a time series of cash flows. If NPV>0, then project worth doing. Internal rate of return (IRR): yield on investment (%) – it’s the i that makes NPV = 0.If IRR> i then project worth doing. t - the time of the cash flow; r – the discount rate; Ct - the net cash flow at time t More info on whole life cycle cost http://www.wlcf.org.uk
76. Accelerated Capital Allowance Budget 2009 (consultation till 3 April 09) 100% of the capital cost of eligible equipment in the first year of purchase (equal 12.5% subsidy)
90. Planning exemptions - wind Plus: matt, non reflective finish, no interference with telecom signals Not forward of front wall of the house. No sign, advertisement, etc. Outside Within 5 km (commercial) 1 turbine max within the curtilage of premises/building
96. “The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the Universe to do." Galileo Galilei Get in touch: xavier@xdconsulting.eu
99. Case Study Fenore Co. Clare Annual Electricity Usage 18,000 kw Hrs Site Location avg wind speed 9m/s Excellent Elevated Location with clear views South and West