In order to have any kind of rational and meaningful conversation about energy generation, energy supplies, energy shortages, we must quantitatively understand the units of Energy.

Most of you are familiar with Power and you frequently confuse that with energy.

For instance, if you have a 100 Watt light bulb and you plug it in, that light bulb radiates 100 Watts of Power . Power is instantaneous or, in other words, at any given time while the light bulb is on, it radiates 100 Watts of Power.

However, what we care about is Energy and

ENERGY = POWER * TIME (of use)

Thus if we use our 100 watt light bulb for 1 hour we have used the equivalent of 100 watts * 1 hour = 100 watt hours of ENERGY.

For residential, commercial and industrial energy use, the standard metered rate used by all electrical utilites in the US is the KiloWatt Hour (KWH)

If we use our 100 Watt light bulb for 10 hours then that is 100 watts x 10 hours = 1000 watt hours = 1KWH.

Your electricity rate is charge at some number of cents per KWH.

The current snapshot of residential rates for the US is shown below:

2007 Snapshot

2010 Snapshot

Notes:

• There are no longer strong state to state variations in the cost of electricity as existed in the past (15 years ago or so)

• Regionally, the Northeast Pays almost double what the national average is so energy costs are a significant political and social concern there.

• The Pacific Northwest no longer has a sole monopoly on cheap electricity. Some of this is related to long term climate change which is causing a significantly reduced snow pack.

Residential Power Requirements:

Supposed you lived in a space, let's call it the Joe Six Pack pad, that had the following:

• 4 100 watt light bulbs for lightning
• a 450 watt fridge for cold beer
• a 150 watt TV
• a 1500 watt space heater

That's it.

So we can easily sum this up to determine that a Joe Six Pack pad has a total maximum power requirement of 2500 Watts or 2.5 KW, if all of the applicances are turned on.

So this is Joe's PEAK POWER REQUIREMENT

Now we know that, at Joe's Place, the fridge and the TV are on ALL OF THE TIME so thats 600 W of continuous power.

Now let's suppose that, averaged over one day, the light bulbs are on for 12 hours and the heater is on for 4 hours per day.

Thus, on an average 24 hour day, Joe's power requirements are

• 600 W (for continuous TV + cold beer)
• 200 W (for lights - 1/2 the day they are not turned on)
• 250 W (for heat - heater is only on 1/6 of the time)

Thus Joe's AVERAGE POWER REQUIREMENT is 600+200+250 = 1050 watts = 1.05 KW.

The next step in this story is to form the Joe Six Pack Electrical Utility Company.

Our company is located in Joe Sixpackville and there are 1000 Joes that live in the pad du Joe.

What do we know?

Well we know that our power plant rating (usually called nameplate capacity) needs to be at least 1000 KW or 1 Megawatt (MW).

Why - because we got 1000 average Joes each using 1 KW.

If we built our plant to handle the peak capacity that would require a 2.5 MW facility, which would cost 2.5ⁿ more. This is not cost effective and as a result, Power Plants are built to handle average loads, not peak loads, since peak loads are a very rare occurence.

When they do happen tho, the industry now has a difficult time accomodating them. More on this later.

Now let's return to Joe and is average montly electricity bill. For simplicity let's assume the electricity rate is 10 cents per KWH. We can now easily compute Joe's average monthly bill:

Bill = 1 KW x 24 hours x 30 days x 10 cents per KWH = 72$

Now in the real world, a typical family house has an average power requirement of 2 KW these days, although indivudal houses may vary from 1 to 8 on this scale.

This means the following and this is how we scale things in this class:

A typical power plant has a nameplate capacity of 1000 MW (1 billion watts) This serves, on average , 500,000 homes.

The City of Eugene, for instance, as an average power requirement of 350 MW which is provided through EWEB:

• 75,000 residential customers
• Peak Demand was 627 MW (Dec 23, 1998)
• 38 Substations in Eugene Area
• 12% of Power EWEB Owned
• 56% purchased from BPA
• 32% purchased from other sources

The University of Oregon has an average electrial power requirement of about 8 MW. But that will increase to 12-15 MW due to the builiding of the Alumni Center, Acadmic Services for Student Athletes, and the Phil Knight Palatial Arena of Roundball.

A typical substation in a neighborhood serves about 500 houses and therefore must distribute about 1 MW of power.

Get to know and understand these various scaling relations.

Visual Summary of EWEB Infrastructure and its evolution from 2003 to 2008:

274 Name Plate in 2009

Name Plate in 2011 = 721 -440 = 281

Small Net gain - there are some losses in Steam Co-gen balanced by gains in Wind farm share

Current Situation

Peak vs Average Forecase

But this is Bullshit

Why so little wind?

Note that half of EWEB's expenses go to Purchased Power. This is significant and leads to voodoo economics to be discussed later.