Live Science: As utility costs mount ever higher, Americans now have real options to take home energy matters into their own hands with “green” systems that can pay for themselves in as little as a few years. Among the choices: wind, solar, geothermal and a “microhydro” option that is potentially cheaper than a year’s tuition at many state colleges. Choosing the do-it-yourself route can offer the freedom of going partially or totally off the grid. And, if the energy generated exceeds your …