Essential Environment: The Science behind the Stories (3rd Edition)

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 21 Testing Your Comprehension 1 Renewable sources account for 12.7% of the world’s primary energy supply. Of that 12.7%, fuelwood is most prevalent, but hydropower produces nearly 90% of renewable electricity generation. 2 The renewable market share is expanding because of fear of diminishing fossil fuel supplies, because of technological advances, and because of growing demand. Wind energy is growing the fastest, at 48% per year over the past three decades. 3 Passive solar heating works by designing buildings to maximize their direct absorption of sunlight in winter while keeping the interior cool during the summer. In an active solar heating system, the sun’s energy is trapped and stored in a form that can be easily circulated throughout the house (e.g., electricity from solar photovoltaic panels). 4 The photoelectric effect occurs when light strikes specially made metal plates, causing the release of electrons that can be channeled into a current or stored in batteries. Photovoltaic cells are made primarily of the semiconductor silicon, enriched on one side with boron, and on the other with phosphorus. These PV cells are often mounted together on rooftops to generate electricity for that building. 5
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 2

EOC_ch21 - Chapter 21 Testing Your Comprehension 1...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online