1. Wind Energy Storage Options GREG BELL WARRINGTON EGGLESTON SARAH HARDING

2. Background Information  Unlike coal or other energy sources, the amount of energy produced by wind cannot be controlled.  A large wind farm’s generating capacity can drop from gigawatts to zero watts in just seconds.  Electrical energy cannot be stored directly, so supply must meet demand and this balance has cost implications.  If a turbine’s energy is moved directly to the grid, energy in excess of the grid’s demand must be dumped.

3. Storage Options  Pumped Hydroelectric Storage (PHS) [Gravitational Potential Energy]  Battery Storage (Chemical Energy)  Compressed Air Energy Storage (Potential Energy)  Flywheels (Kinetic Energy)  Must be efficient in storage and provide power in a timely manner to meet demand.

4. Pumped Hydroelectric Storage  Most mature and most used form of storage (127 GW worldwide storage capacity).  Electricity is used to pump water uphill where it is stored as gravitational potential energy.  Low energy density – large area required.  Constrained by elevation and water availability.  Pumped hydro systems round trip efficiency is between 75 and 78 percent.

5. Compressed Air Energy Storage (CAES)  Use electricity to power an air compressor  The energy is converted back to electricity by mixing pressurized air with fuel and using it to power a combustion engine  Efficiency estimates vary significantly depending on the specific CAES technology and geologic features, but is usually between 73 and 89 percent  Risk of explosion

6. Flywheel Energy Storage (FES)  Converts electricity to kinetic energy in the form of rotational momentum of a mass  Converted back into electricity by letting the spinning mass power a motor  About an hour of stored energy, but can be released instantaneously  Constrained by rotor material strength, weight, and cost, as well as motor-generator size and technology  Can cause noise pollution

7. Electrochemical Batteries  Lead acid  Very low cost, low specific energy and power, short life cycle, high maintenance requirements and toxicity  Nickel cadmium  Relative low cost, high energy density, high power delivery capabilities, hardiness, reliability, high life expectancy and toxicity  Lithium Ion  High cost, high energy density, are less mature, low standby losses and cycling tolerance, low expected lifetime at full discharge, used in consumer electronics

8. Comparison of Options

10. Installed Revenue Opportunity

11. Comparison of Options

13. Works Cited  http://www.purdue.edu/discoverypark/energy/assets/pdfs/SUFG/p ublications/SUFG%20Energy%20Storage%20Report.pdf http://www.purdue.edu/discoverypark/energy/assets/pdfs/SUFG/p ublications/SUFG%20Energy%20Storage%20Report.pdf  http://spectrum.ieee.org/energywise/energy/renewables/an- energystoring-wind-turbine-would-provide-power-247 http://spectrum.ieee.org/energywise/energy/renewables/an- energystoring-wind-turbine-would-provide-power-247  https://upcommons.upc.edu/e- prints/bitstream/2117/11473/1/Mu%C3%B1oz4.pdf https://upcommons.upc.edu/e- prints/bitstream/2117/11473/1/Mu%C3%B1oz4.pdf  https://www.wind-watch.org/faq-electricity.php https://www.wind-watch.org/faq-electricity.php  http://www.mpoweruk.com/electricity_demand.htm http://www.mpoweruk.com/electricity_demand.htm