The mighty winds that blow through Texas, Oklahoma and elsewhere in the United States aren’t as mighty or as consistent as the gusts out in the oceans. But 13 years after the nation’s first offshore wind park was envisioned in Nantucket Sound, this plentiful source of renewable energy has yet to produce a kilowatt of utility power. Now a Seattle company hopes to join that race by harnessing some of the fiercest winds off the Pacific Coast.