More than two years ago (WPE&D, October, 2012) this magazine identified ten wind industry grand challenges. To be truthful, we invented them for kicks. It’s a well known secret of the universe that proclaiming a particular task difficult to accomplish is a good way to stimulate its development. Case in point: Recently I remarked to a colleague that a 10-MW turbine may be impossible. Three days later, Siemens announced a 10-MW design in Europe, one with a 210m rotor. Once again, scoffing preceded a breakthrough.
For a little background, grand challenges are significant developments that finer minds, usually influential organizations want to have happen. The man-powered flight across the English Channel was a grand challenge.
In any case, here are the Wind Industry Grand Challenges we defined from two years ago and how they are progressing. We rank outcomes as Hits, Near hits, and Still waiting..
10. More efficient high-voltage electrical equipment. By one estimate, power transmission wastes 7% of generated power so even a 0.5% improvement can save millions.
RESULT: HIT. ABB had already developed HVDC lines, 500 kV and more, but more recently found a way to take power from an HVDC line at intermediate locations. Other recently developed high-efficiency transformers and equipment also meet the challenge.
9. A manufacturable 10 MW, land based, wind turbine. Offshore turbines will be twice the cost of land based units and besides, the U.S. has plenty of untapped land.
RESULT: NEAR HIT. Vestas has launched an 8 MW behemoth in Europe and taken orders for a few more. The Siemens unit mentioned earlier has not been built.
8 A turbine design that produces power at a cost lower than that generated with natural gas. This would allow dispensing with a Production Tax Credit and other government grants. Wind critics would have to pay homage to such an awesome industry.
RESULT: HIT. Xcel Energy says its recent turbines allow negotiating power purchase agreements around $0.04/kWh. This is significant because the cost of natural gas remains remarkably low, $3.98/million BTUs on 10/3/14.
7. A gearbox that works for 20 years with only routine maintenance.
RESULT: STILL WAITING. However, many incremental improvements are letting gearboxes work longer periods between overhauls, but the real 20-year gearbox is still only a concept.
6. A lightweight, 5-MW generator capable of direct drive and scalable to 10+ MW.
RESULT: HIT. Boulder Wind Power says its low-speed PM generator is capable of 12.8 MW. Blades sufficiently long may be the hold-up. A rotor of 160-m diameter in 11 m/s wind would yield about 9.2 MW at the Betz limit.
5. A cost-effective battery capable of megawatt-hour performance.
RESULT: NEAR HIT. Flow batteries show promise as do lithium-based versions that power recent electric vehicles.
4. Materials that would allow longer, lighter blades and give them a 20-year life.
RESULT: NEAR HIT. Carbon fiber works but it’s costly. High-strength fiberglass may be the better bet, and recent activated graphene, if not too expensive, will be useful.
3. Self-erecting towers capable of 130m height that could say goodbye to $50,000/day cranes.
RESULT: STILL WAITING
2. Active surfaces for more precise blade control. Current independent pitch controls require near constant adjustments to a large-mass blades with each rotation. Flaps, tabs, or some other method would be advantageous.
RESULT: NEAR HIT: None are in production that we know of, but several firms are working on prototype blades. One in the lab uses electrical plasma to influence airflow. Honorable mention goes to vortex generators.
1. Mass produced, less-expensive superconducting materials.
RESULT: NEAR HIT. SuperPower Inc. says its AP wire superconducts at 77°K and is suited for in-magnetic field applications. GE says it’s making headway and others report progress. Search on “superconducting” on the WPE&D site.
After just two years, one can conclude from the update that there has been significant progress from a relatively small industry. WPE
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