A wind farm here, along the River Trent, cranks out enough clean electricity to power as many as 57,000 homes. Monitored remotely, the windmills, 34 turbines each about 400 feet high, require little attention or maintenance and are expected to produce electricity for decades to come. “They’re very well behaved,” said Sam Cunningham, the wind farm’s manager, as she drove around the almost three-square-mile site. The owner of the wind farm, the British electricity company SSE, has been betting big on turbines as well as other renewables for years, with multibillion-dollar investments that have made the utility the country’s leading provider of clean power. In theory, last year’s United Nations climate accord in Paris should have been a global validation of the company’s business strategy. […]