Wind turbines are complex systems that convert the low speed, low kinetic energy of wind into electricity. The current state of the art involves using very large propellers turning at around 20 rpm to turn a 60 times gear increaser and spin a generator at 1200 RPM. From a purely mechatronic standpoint, this is a very difficult approach because there is a huge mechanical disadvantage due to the inertia mass of the generator. The generator resistance to turning is amplified by the gear box as the square of the ratio; 3600 times. So its going to take some really big propeller blades to spin that thing.
This leads to a whole host of other problems. Notwithstanding, there is a multi-billion dollar industry around building and installing these things called horizontal wind turbines. And it doesn’t look like things are going to slow down any time soon. So let’s accept for the moment we are dealing with a technology that has some potential problems and look at recent history.
60 miles north of Germany, in the North Sea, one of the largest wind turbine projects in the world has recently been completed. The Bard 1 project is 80 – 5 MW Bard turbines, a 400MW total nameplate capacity. The history of the project is plagued with delays and problems that are, of course, in proportion to its enormous size.
The project was scheduled to go on line August of 2013, but faulted the transmission line on startup which, in combination with other issues, has taken the last three years to correct. Expenses are estimated at 1-2 million Euro per day, which for 3 years, less 7 months of production time, would be nearly another billion dollars in cost.
The Bard 1 project is reported to have produced 700 GWhr during the period of time it was on line. There is a tendency with some of the renewable technologies to throw around some very large numbers so one will do the math and figure out what’s really going on. 740 gigawatt hours of generation over 10 months translates to 840 GWhrs/year. Germany has the second highest cost of electricity on average at $0.16/kWhr. The annual production from Bard 1 based on actual operation would only be worth $134 million.
The Bard 1 project cost at $134mil/year would take 32 years to recover, even if there were no operating expenses. The Bard 1 nameplate capacity suggests the ability to generate 3.5 Terawatts per year at full speed. This implies that the 840 mWHr output is only 25% of capacity, roughly the same as on shore wind power. Except that offshore wind power cost 2.5X as much.
So the ‘state of the art’ has not gained the incremental performance we hoped for. Billions of dollars late.