Modern wind turbines also drives a generator. Kaine supports the development of solar energy and offshore wind turbines. This makes HVDC preferable for siting wind turbines very far offshore. Modern large wind turbines are variable-speed machines. Installation of new wind turbines can be controversial. Bergey Windpower is a supplier of small wind turbines. There are different size classes of wind turbines. Germany is a leading producer of wind turbines and solar-power technology. Vertical-axis wind turbines (or VAWTs) have the main rotor shaft arranged vertically. The production of permanent magnets used in some wind turbines makes use of neodymium. The water is too deep for fixed wind turbines. Near Sweetwater, an EF2 tornado damaged or destroyed several wind turbines. It is the location of the Dagenham wind turbines. Electricity generation was powered by three 12 MW Rolls Royce Avon gas turbines. The "Sverdlov"s had 6 boilers providing steam to two shaft geared steam turbines generating .