6.8 Solar energy

Passive vs Active solar energy

Passive solar: absorbing or blocking heat from the sun, w/out use of mechanical equipment

Active solar: use of mechanical equipment to capture suns heat or convert light rays to electricity

Photovoltaic cells

Aka “solar panels” contain semiconductor that emits low voltage electrical current when exposed to sun

negatives: intermittency (solar energy can only be used during day)

Solution: cheaper, large batteries (arn’t cost effective yet)

Concentrated solar thermal

Heliostats (mirrors) reflect suns rays onto water tower → to heat water to produce steam to a turbine → electricity

Community (solar farm) vs rooftop solar

Large scale solar “farms”: generate electricity & take land up → habitat loss/ fragmentation

Rooftop solar: doesn’t take up land, produces little electricity

solar energy pros & cons

Pros:

-no air pollutants released to generate electricity

-renewable

-no mining

Cons:

Semiconductor metals still need to be mined → disrupt habitat & pollutes water

-silicone is a limited resource