Renewable energy Alternatives to fossil fuels

Which countries consume the most energy? think: How much more energy do Americans use than Chinese?

Alternative energy sources Solar Wind Geothermal Nuclear Tidal Hydroelectric Biofuel We are searching for other sources of energy Renewable resources will not run out Environmental impacts could be much less

Solar power Turning light energy into electricity Sun produces 10,000 x the amount of energy needed to power the world Adv: Free, non-pollution Dis: Expensive to build and install the panels & don’t work at night/ cloudy

Wind Wind is the movement of air caused by the uneven heating of the Earth’s atmosphere. Pros: non polluting, renewable Cons: unreliable, many birds have be killed by turbines, loud

Geothermal Heat generated by the Earth’s core water is pumped deep into the Earth crust where it turns into steam that turns a turbine generating electricity Pros: renewable, nonpolluting Cons: not available everywhere, can use up water reserves (unless reclaimed water is used)

Nuclear Energy Nuclear fission: splitting large atoms releases energy Adv: plenty of fuel, no greenhouse gasses, existing technology Dis: radioactive waste which causes cancer

Tidal power Think: how could tidal power harm sea life? Building a dam in a bay or estuary to use the tides to turn turbines Adv: non polluting, renewable Dis: only available in limited areas, could harm sea life

Hydro-electric Moving water turns turbines to Most rivers are already dammed Causes problems for fish, downstream habitats

Biofuel Organic matter: food scrap, manure, corn ethanol, algae… Pros: can be “carbon neutral” or decrease greenhouse gasses, can be a reuse of waste products, renewable Cons: can increase food prices, may use up too much land or not generate enough energy to be cost effective

Reducing energy waste All forms of energy generation waste energy Power plants are only 35% efficient We need to reduce our energy use and energy waste 157 mpg car Think: of 3 ways you can save energy.

Summary Review How much energy does the US use compared to the world average? Make a chart of the alternative energy sources listed in this lecture of: what they are, how they are ‘harvested’, and the pros and cons of each.