The U.S. Industrial and Building Sectors

• Industrial energy usage = 35 quads; building energy usage = 40 quads(total = 100 quads)

• Building energy consumption split roughly 50:50 between commercial and residential buildings

• These two sectors account for about 70% of total U.S. GHG emissions

• By 2030, 16% growth in U.S. energy consumption, which will require additional 200 GW of electrical capacity (EIA)

• Energy efficiency goals of 25% reduction in energy use by 2030(McKinsey and National Academies Press reports)

1

Impacts of proposed US GHG legislation if enacted in 2007

http://www.wri.org/climate/topic_content.cfm?cid=42652

Cap• Sets a firm limit of CO2 emissions• Government sets initial cap• Cap steadily decreases over time• Only effects large emittersTrade• Emission permits distributed

- Auctioned- Given away

• Excess permits traded/sold• Creates market for emission permits

3

Future GHG Legislation

Other Alternatives

• Carbon Tax- Price Predictability- Could be Revenue Neutral- Apply to all Carbon Sources

• Regulated CO2

- Recent EPA Announcement

4

CO2 Absorption/Stripping of Power Plant Flue Gas

Flue Gas With 90% CO2

RemovalS

tripp

er

Flue Gas In

Rich Solvent

CO2 forTransport& Storage

LP Steam

Ab

sorber

Lean Solvent

Use 30% of power plant output

5

IGCC PROCESS

6

7

Theoretical Limit

Ceramic Vanesand Blades

Ceramic VanesPrecooled Air

ConventionalCooling

Increased Generation Efficiency

• Conventional efficiency: 40-55%• Cogeneration efficiencies: 75-85%

8

9

What is a Smart Grid?

• Delivery of electric power using two-way digital technology and automation with a goal to save energy, reduce cost, and increase reliability.

• Power will be generated and distributed optimally for a wide range of conditions either centrally or at the customer site, with variable energy pricing based on time of day and power supply/demand.

• Permits increased use of intermittent renewable power sources such as solar or wind energy and increases need for energy storage.

10

Utility of theFuture Vision

Bio fuelsPlug-inH2

Zero Energy Home

Distributed Utility

Fossil Fuels

Solar

Nuclear

Wind

i

11

Electricity Demand Varies throughout the Day

Source: ERCOT Reliability/Resource Update 2006 12

Wind and ERCOT daily load

0

0.2

0.4

0.6

0.8

1

1.2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

No

rmal

ized

Hour Ending

Normalized wind

Normailized load

Source: Dispatchable Hybrid Wind/Solar Power Plant, Mark Kapner, P.E 13

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Today’s GridSmart

Grid 1.0

15

Smart Grid 2.0

Tomorrow’s Grid

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Three Types of Utility Pricing

• Time-of-use (TOU) – fixed pricing for set periods of time, such as peak period, off peak, and shoulder

• Critical peak pricing (CPP) – TOU amended to include especially high rates during peak hours on a small number of critical days; alternatively, peak time rebates (PTR) give customers rebates for reducing peak usage on critical days

• Real time pricing (RTP) – retail energy price tied to the wholesale rate, varying throughout the day

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Smart Grid Challenges/Unknowns

• Design of the grid• Power storage• Redundancy and reliability for peak/base loads• Power flow management• Power stability• Cybersecurity• Automation/decentralized control• Distributed power generation (renewables)• Power electronics• AC vs. DC

19

Electrical Energy Storage (EES) Research Needs

• Increase energy/power densities, reduce system cost, and improve battery durability and reliability

• Solve materials challenges and model complex systems

• Obtain fundamental understanding of atomic and molecular processes that govern performance and durability

• Reduce the gap between identification, synthesis and characterization of new EES materials vs. manufacturing and design specs for devices

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Thermal Energy Storage

• Thermal energy storage (TES) systems heat or cool a storage medium and then use that hot or cold medium for heat transfer at a later point in time.

• Using thermal storage can reduce the size and initial cost of heating/cooling systems, lower energy costs, and reduce maintenance costs. If electricity costs more during the day than at night, thermal storage systems can reduce utility bills further.

• Two forms of TES systems are currently used. The first system used a material that changes phase, most commonly steam, water or ice. The second type just changes the temperature of a material, most commonly water.

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TES Economics Are Attractive for

• High utility demand costs

• Utility time-of-use rates (some utilities charge more for energy use during peak periods of day and less during off-peak periods)

• High daily load variations

• Short duration loads

• Infrequent or cyclical loads

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Methods of Thermal Energy Storage

• TES for Space Cooling: produce ice or chilled water at night for air conditioning during the day– Shifts cooling demands to off-peak times (less expensive in areas with

real-time energy pricing)– May be used take advantage of “free” energy produced at night (like

wind energy)

• TES with Concentrated Solar Power: store energy in thermal fluid to use when sunlight is not available– Gives solar concentrating power plants more control over when

electricity is produced

• Seasonal TES– Long term energy storage– Store heat during the summer for use in the winter

• Many other methods

23

UT’s Thermal Storage System

• Acts as chilling station, but with 1/3 of the cost• 4 million gallon capacity• 30,000 ton-hours of cooling (~105 MWh)

– Enough to run A/C for 1500 Austin homes (2500 sq ft) each day 24

TES for Space Cooling: Calmac’s IceBank® Technology

Charge Cycle: At night, a chiller is used to cool a water/glycol solution. This runs to the Ice Bank, where water inside the tank is frozen.

Discharge Cycle: During the day, the glycol solution is cooled by the ice in the tank and then used to cool the air for the building’s AC needs.

http://www.calmac.com/products/icebank.asp25

An Inside View of the IceBank®

• Coolant runs through tubes

• Water in the tank gets frozen by the coolant at night

• The ice is then used to cool the solution during the day for air conditioning

http://www.calmac.com/products/icebank.asp26

Why Use TES for Space Cooling?• Shifts electricity demands to the night to take advantage of

lower rates at night

• Can also be a way to take advantage of wind power, which is more abundant at night

http://www.calmac.com/benefits/27

TES with Concentrated Solar Power (CSP)

• CSP technologies concentrate sunlight to heat a fluid and run a generator

• By coupling CSP with TES, we can better control when the electricity is produced

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TES with Concentrated Solar Power (CSP)• Two-tank direct method

– Two tanks, hot and cold– Heat transfer fluid flows from

the cold tank and is heated by the solar collectors.

– This hot fluid travels to the hot tank, where it is stored.

– As needed, the hot fluid passes through a heat exchanger to make steam for electricity generation.

• Other methods include two-tank indirect (where the heat transfer fluid is different than the storage fluid) and single-tank thermocline (storing heat in a solid material)

http://www1.eere.energy.gov/solar/thermal_storage.html

The two-tank direct method

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Seasonal Thermal Energy StorageDrake Landing Solar Community (Okotoks, Alberta, Canada)

http://www.dlsc.ca/how.htm30

Annual Energy Savings at Drake Landing

http://www.dlsc.ca/brochure.htm31