Lecture 13: Energy Efficiency and Renewable energy sources

Tue, Feb 23, 2010

	1. energy efficiency
	2. fundamental difference between non-renewable and renewable resources
	3. examples of renewable energy
	4. solar energy policy
	5. assignment 2
	6. return quiz

 

1. Energy Efficiency

negawatt - savings from a watt of power that you don't have to produce

 

2. Fundamental difference between non-renewable and renewable resources

def: resource - something that can be depleted

Even renewable energy sources could be depleted or used faster than they are being renewed.

systems diagram for these two

• renewable
• has the potential for steady state
• renewal rate = use rate

• non-renewable
• large stock can only be depleted

energy vs. water

If we covered 1.7% of the US with solar panels that were 10% efficient we could generate 3 terawatts of power which is enough to meet America's energy needs. (Technology Review Aug/Sept 2009 page 94)

But, water is not predicable or reliable - in India 450 million people live off rain fed agriculture and this year's weak monsoon has resulted in a massive shortcoming in food production (Economist Sept 12, 2009 - page 27)

 

3. powerpoint for lect 13

chapter 16 is very useful

4. Some energy policy

Oregonian article about trying to use incentives to promote solar PV generation

Mr Solar - calculations

 

simple accounting for solar panels

• calculate the number of KWatt*hrs produced over a year
• panel rating * number of hours of sun equivalent to the full rating (might be 4 per day)
• panel rating might be 10 panels at 80 watts/panel = 800 watts
• means you'd get 3.2 kwatt*hr per day or 1168 kwatt*hr per year
• at $0.12 per kwatt*hr thats only replacing $140 worth of electricity
• at about $5 per watt of solar panel = $4000 - it'd take a long time to pay back
• not counting all the other stuff needed (grid-tie, inverter, mounting brackets, etc)

 

Oregon incentives, tax breaks, and refund of some sort on the panels

Oregon Energy Trust

go to the calculator and the example payments

 

feed-in tarrif - the price electric companies have to pay you for the power you put into the grid

• suggested at $0.25 to 0.85 per kwatt*hr
• $20,000 for 3 kwatt system (which only produces 3*4hr/day*30day/mo) = 360 kw*hr/mo)
• which would pay back (360 * .25*12) or (360 *.85*12) = $1080 or $3672 per year making
• payback time is equal to about 20 years down to 5 1/2 years.

 

5. Assignment 2: Climate change and action

Consider our dilemma:

research vs. action

Distinction between "objective environmental science and scholarship" and "environmental activism"

• positivism - that facts and norms need to be separated, based in the belief that there a little atoms of truth (atomistic)
• David Orr - paraphrasing - Is it OK to be purely objective but loose the planet you live on?
• investigator/scholar as partipant - how do you do that in a non-biased way?

Perkins' definition of understanding

different types of problems and action that can be taken

A philosophically and intellecutally satisfying approach is offered by Norton (2005)

scientific adaptive management

 

 

 

6. Hand back quiz

comments and questions