Energy collectors gather energy from natural sources. Man has used solar power since prehistory to preserve herbs, vegetables, and meat by drying them in the sun. Today, major installations may use hydroelectric, solar, or geothermal power, but solar power is the most common means of portable energy collection.
In the 19th century (TL5), many farms in windy areas used windmills. They were common in the U.S. Midwest and Great Plains to pump water from deep wells into holding tanks or ponds. At TL6+, a windmill or wind turbine produces electrical power; in a good windy site, it can provide external power to a small household or workshop. Of course, it provides no power on calm days! $10,000, 500 lbs. LC4.
At TL5, waterwheels simply provide mechanical energy to drive millstones, saw blades, trip hammers, bellows, etc. At TL6, however, hydroelectric plants begin to convert mechanical energy into electricity. At TL8, a waterwheel or a small water-powered turbine can provide external power to a single household in an area with a fast-flowing, yearround water source; a small hydroelectric turbine suitable for the purpose is $10,000, 250 lbs. LC4.
Solar panels convert sunlight into electricity. They might power homes here on Earth . . . or satellites and robots on distant planets. Current panels are made of layers of plastics, and are strong, lightweight, and flexible. They can even be incorporated into such items as roofing shingles. They provide power only in sunlight, however. In any environment dim enough to give even a -1 Vision penalty, they produce no power.
Solar Power Array (TL7). A large array of solar panels capable of providing external power to a whole household. It covers a sizable portion of the roof of a family sized dwelling. $25,000, 1,200 lbs. LC4.
Solar Powered-Battery Recharger (TL8). This flexible, portable solar panel can be rolled up like a tarp and stuffed in a backpack. In good sunlight, it can power a hand-held device or recharge a handful of batteries in a few hours. $100, 2 lbs. LC4.