Planning for Energy Usage

## Choose one or more of the Following Energy Sources:

• 1. Solar PV Arrays (needs storage)
• 2 .Magic Hydro Power that doesn't kill salmon (does not need storage)
• 3. Wind Power (needs storage)
• 4. Environmentally Friendly Coal Burning (doesn't need storage)
• 5. Biomass Burning (doesn't need storage)

## Choose of the of the Following means of Energy Storage:

• Hydrogen burning
• Batteries
• Flywheels

Each storage facility that I describe below has a capacity of 200 Megawatts but variable durations over which that power can be delivered.

You need to realistically calculate the capital costs of building the facility, how much land it will utilize, and what the operating costs are. I will give you all the relevant numbers for this.

The way efficiency works is as follows:

If I have some energy storage system which is only 10% efficient, then that means I have to deliver 2000 Megawatts of energy to that system in order to store 200 Megawatts. In this case, since 500 Megawatts was the original goal, I would have to build 4 more 500 Megawatt units just to have energy storage. Obviously this is silly, but the point is that you must factor this in.

## Specifications for 200 MegaWatt Storage Facilities

1. Hydrogen: Efficiency = 25%. Energy storage = 40 kilowatt hours per gram. Hydrogen is separated from water via electrolysis and when burned recombines with oxygen to form water. Approximately 10% of the mass of water is in the form of hydrogen. A 10,000 liter facility (about 2500 gallons) that stores the hydrogen in cryogenic form, costs 2 million dollars to build and 0.5 cents per KWH to operate. Each 10,000 liter facility can produce energy for a period of 8 hours. The facility can be recharged in another 8 hour period.

Sodium-Sulfate Batteries: Efficinecy = 50%. Energy storage = 100 Watt hours per kilogram. Battery life is 72 hours. Charging period is 12 hours. The batteries cost 10 dollars per kilogram to manufacture. The operating costs for a 200 Megawatt facility are 1 cent per KWH.

Fused-Silica Flywheels: Each flywheel has a mass of 600 kg and a radius of 100 centimeters. Efficiency = 80%. Energy storage capacity per flywheel is 500 Watt hours. Each flywheel costs \$10,000 to manufacture. Each flywheel can deliver energy continuously for 30 days before it needs to be recharged. The recharge period is 72 hours per flywheel. A 200 Megawatt facility would have an operating cost of 0.1 cents per KWH.

## Specifications for the Energy Generating Plant:

1. Solar PV Facility:

• Location: Eastern Oregon
• Incident solar radiation: 1000 Watts per sq. meter in summer and 300 Watts per sq. meter in winter
• Efficiency: 10%
• Panels cost 150\$ per sq. meter to make
• Failure rate is 5% per year (1 out of 20 panels fails each year)
• Operating costs are expected to be 0.1 cents per KWH

2. Salmon Friendly Hydro Power:

• Location: New dam on columbia river
• Efficiency of turbines: 90%
• Height of spillway: 10 meters
• 4 thousand gallons per second of flow generates 1.5 MW of power
• Dam costs \$2,000 per gallon per second of flow
• Friendly fish navigation devices \$2,000 per gallon per second to build
• Operating costs are 0.75 cents per KWH (0.25 of it for salmon maintenance)

3. Wind Power:

• Location: Headlands of Oregon Coast
• Average wind speed = 10 miles per hour
• Power generated by this wind = 250 Watts per square meter
• Power goes as the cube of the wind velocity. Assume 50 days per year when the average wind speeed is 30 miles per hour.
• Windmill manufacturing costs are 500 dollars per square meter.
• There are no operating costs
• Failure rate of windmills is 1% per year

4. Coal Burning

• Location: Not in My Backyard
• Costs are the following:

• 200 Million Dollars for basic 500 MW plant with no pollution control
• operating costs are 4 cents per KWH (this includes cost of delivery of coal)
• Add 200 million dollars in capital costs and 2 cents per KWH in operating costs for each 50% reduction of emissions.
• Eugene city council demands a "low emission" plant (interpret that however you want but take it to mean there must be at least some pollution control)

5. Biomass Burning Facility

• Location: Willamette Valley
• Current crop yield is 2 Kilowatts (KW) per acre
• To plant, grow, harvest and transport crops to the burning facility is \$1000 per acre each year
• After each harvest there is some nutrient loss to the soil which results in 5% reduction in annual yield each year

Okay that's it. I have tried to be fairly realistic with the above numbers in order to reflect what the current costs are. You are to build an energy model from this array of power generating facilities and energy storage that you will be sustainable and deliver energy at a reasonable cost to the consumer. Your report should emphasize the four points outlined above.

Good luck.

PS:

Don't forget to factor in over-capacity as required for energy storage. That is, your generating power for immediate demand but also to be used at later times (like when the sun isn't up or when the wind isn't blowing)