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<br />,. <br /> <br /> <br />LEGEND <br /> <br />FZZJ > ~ w/m' <br /> <br />Ililll ,; 600 w'm' <br />2000 Km <br />TRANSMISSION <br /> <br />Fig. 2., Reg:l.pua where w:l.ndi>ow:er density at <br />windie~t s~tea exceeds 30Q W/~2. a~ter Reed4 <br /> <br />T .-.-.----..,'---:--- - -.--.--___-..____...~ .---~_:_~. <br /> <br />. i <br /> <br />Figure 2 shows an esti- <br />mate by Reed ~ of windpower den- <br />sity in the atmospheric boundary <br />layer near the ground in W/m2 of <br />area normal to the 'wind direc- <br />tion. The estimates are based on <br />weather stations located mostly <br />at cities and airports, sites <br />not usually selected for their <br />windiness; they are recognized <br />as biased toward 1m" values5 . <br />In addition, certain terrain <br />features, especially long <br />ridgelines and mountain g,aps, <br />are windier than the surrounding <br />area. For the sake of th,e <br />present exercise, it: is assumed, <br />therefore, that comprehensive <br />prospecting will idemtify <br />suitable windfarm sites within <br />2,000 km of Niagara with <br />lNind-energy density at least as <br />high as that of Figure 2. Most <br />of them will be alon.g the windy <br />coastlines of the Northeast and <br />Hudson Bay and at a few places <br />in mountainous or hilly districts <br />of the interior, especially the <br />Laurentian and the Appalachian <br />Highlands. <br /> <br />- -.,I <br /> <br />Once a general site for a windfarm has been identified, the deI1lsity <br />of placement of wind machines within its boundaries and the size of the power <br />harvest will be governed by two kinds of constraints, physical and economic, <br />A physical. constraint arises if one machine creates a disturbance of the wind <br />that imposes. an unacceptable mechanical load on another machine nearby, An <br />economic cons traint arises when the power extracted by the machinles already <br />installed decreases the windspeed so much where the next machine might be <br />placed that the additional machine is no longer cost-effective. Layouts <br />suggested to date (e.g., 6, 7, 8) have been based on virtually complete <br />non-interference between adjacent machines placed 10 rotor-diametl:!rs apart. <br />Optimal placement in response to both physical and economic constraints will <br />probably result in considerably closer spacing. In the present thought-experi- <br />ment, it has been assumed that the actual power harvestable in open areas will <br />exceed by at least a factor of 2 that implied by 10-diameter spacing, and that <br />where the windfartl! extends linearly along a ridge1ine, there need be a gap of <br />only one rotor-diameter between adjacent machines, An estimate has then been <br />made of the total harvest constrained only by a requirement for an average <br />windpower density of at least 300 W/m2 for windfarms within 1,000 km of <br />Niagara and an average windpower density of at least 500 W/m 2 for windfarms <br />between 1,000 and 2,000 km distance from Niagara. This estimate, 150 G1i1 <br />average power harvested from about 400 GW of installed capacity, establishes <br />an upper limit for the generating capacity of the projected windpower complex. <br />