Science Energy Hybrid Rooftop Wind and Solar Generator Now Available in U.S. For Early Adopters By Derek Markham Derek Markham Twitter Writer Derek Markham is a green living expert who started writing for Treehugger in 2012. Learn about our editorial process Updated October 11, 2018 ©. WindStream Share Twitter Pinterest Email Energy Renewable Energy Fossil Fuels The SolarMill, a 1.2 kW combination wind and solar energy system, will be sold in the U.S. for about $3000. WindStream Technologies' hybrid rooftop energy system, which combines solar panels and vertical axis wind turbines in a single modular unit, was originally intended to be used in regions of the world with high energy costs or an unreliable grid (or no grid whatsoever), but interest in the devices from U.S. residents over the last few years has resulted in the company now making the product available in this country. The 1.2 kW SolarMill SM1-3P, with three 300W solar panels and three Savonius wind turbines, measures 10' wide by 10' deep by 7' high (3m x 3m x 2.1m) and weighs in at 375 lbs.(170 kg), and is designed to be mounted on a roof, where it is claimed to be capable of producing up to 135 kWh per month under optimal conditions. According to WindStream, the SolarMill unit offers "very high" renewable energy density, and because it incorporates both wind turbines and solar panels, can continue to produce clean electricity after the sun goes down, with power generation at wind speeds as low as 4.5mph (2m/s). The units come with a micro-inverter, and the company offers an optional online energy monitoring service for the entire system, allowing owners to keep tabs on the performance of the SolarMill. WindStream has the SM1-3P available for sale on its website for US$3,130 (not including shipping), and the company is offering a $200 "factory installation credit" voucher for early adopters in the U.S.