# Presentation: 376965

## Comparing Coal IGCC with CCS and Wind-CAES Baseload Power Options in a Carbon-Constrained World 

- Samir Succar, Princeton University

**Comparing Coal IGCC with CCS and ****Wind-CAES Baseload Power Options in ****a Carbon-Constrained World **

## Outline

- Wind and Coal Comparison
- Strategies for Baseload Wind
- Dispatch Cost and Capacity Factor
- Generation Costs of Coal and Wind

## Coal vs. Wind?

## Coal vs. Wind?

- Baseloading Wind
- Backup:Natural Gas (SC/CC)
- Low Capital Cost
- Fast Ramping
- Storage: CAES
- Low Cost Bulk Storage
- Potential for Widespread Availability
- Large Scale

## Compressed Air Energy Storage (CAES)

- 1) Excess Power is Used
- To Compress Air

- 2) Air is Pumped Underground
- And Stored

- 3) When electricity is needed, stored air is utilized to run a gas-fired expander

## Compressed Air Energy Storage

- Compressor train

- Expander/generator train

- Fuel (e.g. natural gas)

- Intercoolers

- Heat recuperator

**P****C**

**P****E**

- Air

- Exhaust

- Air
- Storage

- Aquifer,
- salt cavern,
- or hard mine

- Gas turbine

- Round-trip
- efficiency:
- ~80%

## Basic Assumptions

- 15% Levelized Capital Charge Rate
- 85% Capacity Factor for All Systems
- IGCC Costs, GE Entrained Flow Quench Gasifier (FWE 2003)
- IGCC-V: OCC $1135/kW, LHV Eff 38%
- IGCC-C: OCC $1428/kW, LHV Eff 31.5%
- Wind/CAES Costs
- $923/kW Wind, $453/kW, $1.75/kWh CAES
- Gas Turbine Costs
- $234/kW SC, $571/kW CC
- Fuel Costs, $2002 (EIA 2006) and Emissions (GREET)
- Natural Gas $5.05/GJ HHV, 18 gCe/kWh
- Coal $1.31/GJ HHV, 25 gCe/kWh

## Generation Costs for Baseload Options

## Generation Costs for Baseload Options

** ****No valuation of GHG emissions**
** ****No Transmission Costs**

## Generation Costs for Baseload Options

**237 gC/kWh**

**53 gC/kWh**

**23 gC/kWh**

**62 gC/kWh**

## Generation Costs for Baseload Options

## Generation Costs for Baseload Options

**Highlighting Dispatch Costs**

## Dispatch Cost Concerns

**Dispatch Cost**: fuel + variable operations and maintenance + greenhouse gas emissions price + CO2 transport + storage (short-run marginal cost)
- Actual capacity factors determined in economic dispatch
- Systems called on based on dispatch cost
- Baseload viability requires competitive dispatch costs to sustain large capacity factors

## Variable Dispatch Cost

## Variable Dispatch Cost: Wind/Gas

## Variable Dispatch Cost: Wind/CAES

## Dispatch Cost for Baseload Options

## Generation Costs Revisited

- 100km CO2 Pipeline - $6.82/tCO2 Transport and Storage

- 200km CO2 Pipeline - $11.1/tCO2 Transport and Storage

## Generation Costs Revisited

- Class 5 Winds, 1.9¢/kWh Wind Production Tax Credit (PTC), $923/kW Wind

- 0 km ∆Transmission

- 500 km ∆Transmission

## Generation Costs: Current vs. Projected 

**Current Conditions**
- Class 5 Winds, Production Tax Credit (PTC),
- Current Capital Costs

**Projected**
- Class 4 Winds, no Production Tax Credit (PTC),
- Capital Cost Reductions for Wind and CAES

## Conclusions

- Backup enables wind to participate in baseload
- High dispatch cost makes wind/gas unviable
- Wind/CAES has the potential to compete in dispatch and produce electricity at rates comparable to IGCC w/CCS
- Wind resource quality and remoteness as well as GHG emissions price will be critical factors

## Thank You!

## Slide 23

## Energy Storage Options

- _Technology_
**Compressed Air Energy**
**Storage (CAES) (300 MW)**
- Pumped hydroelectric
- Advanced battery (10 MW)
- Flywheel (100 MW)
- Superconductor (100 MW)

- Source: PCAST, 1999 and EPRI/DOE, 2003

- CAES is clear choice for:
-  Several hours (or more) of storage
-  Large capacity (> ~100 MW)

## Geology Suitable for CAES and Class 4+ Wind Resources

- Geology Suitable for CAES and Class 4+ Wind Resources

## Storage volume required

- 500 m
- (50 bar)

- 1 GW x 168 h (1 week)
- = 840,000 tons air
- = 24 x 106 m3 *

- 250 m
- dia. each

- 4 km
- dia.

- 10 m

- Cavern

- Aquifer

- effective porosity = 0.2

- *30 bar overpressure

## Generation Costs - no PTC

- Class 5 Winds, **No Wind Production Tax Credit (PTC),** Current Capital Costs

## Variable Dispatch Cost at $100/tC