Courtesy of Solar Cookers International Around the globe, hundreds of millions of people have limited access to cooking fuels [source: SCI]. In most cases, electricity and gas are out of the question; only charcoal and firewood are within reach, and even charcoal can be too expensive. ...
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Active solar power uses arrays of photovoltaic cells to convert sunlight directly into electricity, and it has traditionally been a prohibitively expensive technology. The benefits of residential solar power are obvious: Energy from the sun is endless (at least for the next 5 billion years, give ...
This electricity can then be stored in the cell or directed through wires to where it is needed.Q: Is solar energy expensive? A: Solar energy is cheap because the sun's rays are free. The only cost is the cost of the solar cell.However solar cells need lots of sunlight so they can...
but this greatly increases the cost of creating a solar farm in both real estate and natural resources. From a monetary standpoint, solar used to be one of the most expensive power sources to build in comparison with the energy collected.However, prices have trended downwardin recent years, ...
Energy is usually more expensive during peak hours, like evenings, so credits earned during off-peak times might not offset as much peak-time use. In some areas, the value of solar exports back to the grid is very minimal. By considering battery backup for your system you can store any ...
4.C 提示:推理判断题。 根据最后一段中“Did you know that solar energy is not as expensive as it used to be? In fact, in the last few years, solar panels have become much more affordable for people to use."可知,太阳能不像以前那么贵了,C选项 表述错误。 反馈 收藏 ...
builders in the western United States resurrected rammed earth. These homes increasingly can be found in Arizona, New Mexico, California and Colorado [source: Fatsis]. Rammed earth construction also is extremely popular in Australia, where wood for construction is limited and expensive. About 20 pe...
More expensive lights may offer a combination of an LED and a small halogen flashlight bulb. The LED is on all the time, and the light bulb turns on for a minute or two when a motion sensor detects movement. For more information on solar yard lights and related topics, check out the ...
根据最后一段中的"Did you know that solar energy is not as expensive as it used to be? In fact, in the last few years, solar panels have become much more affordable for people to use"可知,选项C是错误的描述。 反馈 收藏