Solar Energy Solar panels give enough stored energy in batteries to provide electricity for appliances, lighting, and electronics. However, solar-powered batteries hold about one-third the charge of energy used in a regular household wired for electricity. This means that people either buy more batteries or intend to use less electricity than a conventional household. Ideally, earthships are built in places where there is an abundance of sunshine year-round.

Floor-to-ceiling windows on an earthship’s south wall also allow plenty of sunlight. It is important that no trees block the light on this side of the house. The sunlight shines directly onto a brick floor, which then absorbs the heat. This provides enough warmth to maintain a comfortable temperature in the house for the rest of the day. This method of heating the home is called passive solar. Most earthships also have either a wood stove or a heater that uses propane, a type of natural gas. These heat sources are useful on cloudy days. During the summer, the combination of the cool temperature of the earth beneath the floor plus the thick walls can keep the house comfortable without the use of air-conditioning.

In the article "Earthships," how does the section "Solar Power" contribute to the development of ideas in the passage?

A. It states the cost savings of using energy from the sun compared to using propane.

B. It gives information about how windows store energy from the sun to power houses.

C. It describes different ways that earthships use clean energy from the sun for power.

D. It explains that earthships must use regular batteries for power on cloudy days.