An Anglo-Dutch consortium plans to build the world’s tallest pair of offshore wind turbines this summer, in the North Sea one kilometer off England’s northeast coast. The partners, which include oil giant Royal/Dutch Shell, hope the pilot project will pave the way for a potential $9.6 billion investment in the area, considered to be Europe’s richest potential source of wind power. But the project’s planners complained yesterday that the energy plans unveiled by the UK government earlier this week didn’t include as much funding for renewable energy as had been expected. At present, just 2.3 percent of Britain’s energy comes from renewable sources, though it aims to increase that to 10 percent by 2010.