wind

Question 2

History of wind

Answer 2

before fossil fuels, wind used a lot for transport, pumping water; wind later used in rural areas; fossil fuels and transmission caused decline in rural wind

Question 3

PURPA and wind

Answer 3

provided 25% investment tax credit for wind power

Question 4

1992 Energy Policy Act and wind

Answer 4

production tax credit for wind generatred electricity–will expire at end of 2012!! =debate

Question 5

wind & electricty, US & world

Answer 5

1.6% of world elec, 2.9% of US elec

Question 6

wind growth rate

Answer 6

20%/year over last ten years!

Question 7

typical power rating

Answer 7

current ones 10kW - 3000kW; turbines being built now: 1.6-3 MW

Question 8

cut in, cut out speeds

Answer 8

cut in: 4-7mph, cut out: 50-65 mph

Question 9

availability

Answer 9

percent of time turbine operating when wind is available: >95%

Question 10

capacity factor

Answer 10

historically 30-40%, some now approaching 60%

Question 11

efficiency

Answer 11

theoretical from wind: 60%; mech/elec: 80%; site: 90%; net:35-40%

Question 12

turbine types by axis, location

Answer 12

horizontal axis, vertical axis, upwind, downwind

Question 13

turbine by axis

Answer 13

horizontal: dominated production; vertical: gearbox/gen low to ground for easy axcess, but low wind speeds a problem

Question 14

turbine by location

Answer 14

upwind: controls keep turbines constantly in optimal direction for max production; downwind: follow wind, tower/nacelle shadow causes stress and noise

Question 15

wind farm

Answer 15

collection of wind turbines erected on concrete foundtations–>makes electricity!

Question 16

wind farm components

Answer 16

nacelle, tower, generator, gearbox, rotor, blades, hub

Question 17

wind farm schematic

Answer 17

turbineds are connected by underground cables, have axcess roads, substation and transmission lines

Question 18

how long does wind farm construction take

Answer 18

6-12 months, but don_t forget about enlisting the support of community!

Question 19

how do wind turbines spin?

Answer 19

shape of blades causes lift on one side, duh (bernoullis)

Question 20

power of the wind

Answer 20

P = (1/2)rhoareavelocity^3

Question 21

cut in speed

Answer 21

speed below which power can’t be generated

Question 22

rated wind speed

Answer 22

speed at which power out 100% of rated (often 25mph)

Question 23

cut out speed

Answer 23

speed at which turbine may shut down to protect rotor and drive train from damage

Question 24

turbine improvements (5)

Answer 24

modern blades designed to capture more energy from wind, latest rotor hub designs are flexible, innovative direct drive low speed generator and power train designs, improved tower designs/construction materials, advanced power control systems

Question 25

are turbine sizes growing?

Answer 25

yes.

Question 26

offshore wind advantages

Answer 26

high winds, low surface roughness, low turbulence = more power production; also, there may be fewer aesthetic concerns because further away

Question 27

offshore wind disadvantages

Answer 27

expensive (100-400% higher than shore)

Question 28

wind farm econ

Answer 28

production and capacity factor are critical to making sure power price is competitive; also, wind speeds really matter.

Question 29

where is all of the US wind?

Answer 29

in the center of the US–like IOWA, south dakota, nebraska

Question 30

meteorological masts

Answer 30

towers use to prdict project energy, understand variation, reduce spatial uncertainty

Question 31

key wind development criteria

Answer 31

wind data forecasting; power purchase agreement; equipment; interconnection; construction plan; permits; ops & maint; economics

Question 32

wind cost summary

Answer 32

LC is most competitive new-build elec generation, cheaper than some exisiting generation

Question 33

why is wind cost info mostly crappy?

Answer 33

rapid declines in turbine prices; no obvious marketplace for turbine prices; rapid improvement in technology; debt bubble of 2006-8; inability to look forward

Question 34

production tax credit variability impacts project development in US

Answer 34

that’s all

Question 35

wind versus natural gas

Answer 35

wind: low op cost, high cap cost, non dispatchable, no fuel supply/cost risk, no emissions__NG: high op cost, low cap cost, dispatchable, fuel supply/cost risk, bunches of emissions

Question 36

wind power advantages

Answer 36

free!, high availability, renewavle, no emissions, predictable fuel; modular; cost competitive where wind and market exist; windy times coincide with peak demand; small land use; benefit rural economy

Question 37

wind power disadvantages

Answer 37

high capital cost; intermittent; non-dispatchable; transmission access not always available; noise/birds/sight; NIMBY; political association with democrats (what!how is this last one a thing?)

Question 38

wind power land use

Answer 38

small because most of the land can still be used for farming–so net land use is lower than maybe everything but NG

Question 39

us market trends

Answer 39

wind has become a mainstream generating tech; grid operators are working on dispatch problems and pricing

Question 40

global wind drivers

Answer 40

Kyoto/GHG mitigation; fuel security (minimizing imports); domestic jobs; minimal social costs; flexible, modular

Question 41

global wind trends

Answer 41

turbine size increasing; offshore wind developing; transmission networks developed; incentives guarantee purchase; improving turbine tech

Question 42

US wind players

Answer 42

developers(diverse group), owners(lower risk now = lots of people making plays), offtakers, manufacturers (GE dominates)

Question 43

US wind drivers

Answer 43

RPS; good investment returns + PTC; demand for green gen; difficult permitting for coal; all-in cost (combining social/environ costs in prod price)