Transcript Slide 1

CSP
Grid Value of Energy Storage
and LCOE Implications
26 August 2013
Overview
• Background
• Presentation based on a study done for Eskom’s Solar 1 CSP plant to be
constructed near Upington
• Study focused on the economic value of CSP Storage to the system
• Considers capacity and energy value to supply demand and reserves
• Detailed enough to analyse hourly profiles
• Content
• Methodology
• Assumptions
• Study
• Results
2015/07/20
2
Methodology
Conversion of Solar Data
• By System Advisor Model (SAM) of NREL
SAM
Receiver Thermal Energy Output
(to Plexos)
2015/07/20
4
Modelling of CSP Generator
• In Plexos, include CSP Generator as part of Supply System
Receiver Thermal Energy Output
(from SAM)
Spill(a)
representing
“de-focusing” of
Heliostat Field
when
Solar Energy >
(Generation
Capability and
Storage is full)
Storage
Spill(b)
representing
storage heat
losses =
f(storage)
Energy to Generating Plant
(normal Plexos modelling)
2015/07/20
5
System Modelling (Transmission not included)
“Demand side”
“Boundary conditions”
Emission
Constraints
Scenarios
TWh
600
400
200
Scenarios
Demand Forecast
Demandside
interventio
ns (DSM)
400
Adequacy
Criteria
Ensure match
of supply and
demand instantaneously
•
Mt CO2
200
0
2010
2020
Policy
Objectives
Jobs
Localisation
Local industry
…
•
•
•
•
2030
0
2010 2015 2020 2025 2030
Iterative
Energy & Capacity
Shortfalls
600
f
400
TWh
80 GW
•
60
40
200
•
20
Least-cost
optimisation model
One result per
scenario
Plans as
decision
basis for
DoE
0
0
2010 2020 2030 2010 2020 2030
0
2010 2015
2020 2025 2030
6
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
…
Scenarios
20
CSP
40
PV
CAPEX
x
x
OPEX
Fuel costs x
Load factor x
Oper. regimex
…
60
Wind
GW
Nuclear
80
“Supply side”
Capacity Options
Coal
Committed New Builds &
Decommissioning
Analysis
• Economic Analysis
• CSP amount of Storage
Incrementally increase hours of storage
(StoreHoursi, i = 1 to n)
• Determine total system cost for each increment (Plexos)
[With CSP costs = 0]
(SystemCostsi, i = 1 to n)
• Determine total CSP cost for each increment (SAM)
[CSP Cost = Capital Cost + O&M Cost + Running Cost (water)]
(CSPCostsi, i = 1 to n)
• Determine:
Valuei+1 = SystemCostsi - SystemCostsi +1
Costsi+1 = CSPCostsi+1 - CSPCostsi
• If Valuei+1 > Costsi+1
Increase in storage is economic
• System Costs include capital, fixed and variable operating and maintenance and fuel
costs incurred in meeting demand and reserves.
Environmental costs are not internalised. A cap is placed on the annual amount of CO2.
2015/07/20
7
Assumptions
Input Data
• As per IRP2010 (updated where required)
• Demand Forecast
• Eskom and CSIR
• Reserves Requirements
• Eskom System Operator
• New build options
• EPRI
• CSP plant (Solar 1)
• Owner’s Engineer, SAM and EPRI
• Station commercial from 2022
• Existing Plant
• Eskom
• DSM
• Eskom IDM
2015/07/20
9
Integrated Resource Plan 2010 (IRP 2010)
centrally defines the generation mix until 2030
Installed capacity
Energy mix
Total installed
Capacity in GW
Electricity supplied
in TWh per year
90
450
86
PV
80
Wind
60
42
40
Nuclear
255
OCGT (Diesel)
250
CCGT (Gas)
200
30
OCGT (Diesel)
CCGT (Gas)
150
Coal
20
50
0
0
2010
2015
2020
2025
2030
Share renewables
~ 95%
??%CO
Coal
100
10
2
intensity
Renewable
TWh's in
2030
(14%)
Hydro
300
Nuclear
50
Wind
350
Hydro
PV
CSP
400
CSP
70
436
2010
2015
2020
2025
2030
5%
14%
912 g/kWh
600 g/kWh
Notes: Pumped storage capacity of 1,4 GW in 2010 and 2,7 GW in 2030 is not included since it is a net energy user
Source: Integrated Resource Plan 2010, as promulgated in 2011; Eskom EPMD
-34%
Carbon
free
TWh's
in 2030
(34%)
Study
Models
• Models: SAM and Plexos
• SAM
Convert solar irradiation
to thermal energy available
from Receiver
(on an hourly basis)
• Plexos
System optimisation by minimising total cost subject to constraints.
Hourly chronological modeling.
Monte Carlo approach for uncertainties.
2015/07/20
12
Options
• CSP parameters
• Solar Multiple (SM) – 1,0 to 3,5
• CSP Storage – 1 to 12 hours
• System Parameters
• IRP2010 Policy Adjusted Plan
• Most significant impact for this analysis will be system adequacy
• Excess supply will decrease optimal CSP storage
• Supply shortage will increase optimal CSP storage
• Only IRP2010 Plan studied = adequate system
2015/07/20
13
Results
Load Factor (Capacity Factor)
CSP : Load Factor vs. Storage
Load Factor =
Energy Sent-out in period (year) / (Sent-out Capacity x Hours in period (year))
Sent-out means as measured on the HV-side of the generator transformer (entry into the
HV substation)
2015/07/20
15
Incremental Value and Cost
Incremental Value or Incremental Cost vs. Incremental Storage
2015/07/20
16
Total System Cost
Total System Cost vs. Storage
2015/07/20
17
Levelised Cost of Energy (LCOE)
• LCOE calculated from:
•
Plant CAPEX, O&M and Running costs used in the study
•
Optimal storage, with associated annual generation, as determined in the study
2015/07/20
18
Hourly Profiles
Summer (four days)
2015/07/20
19
Hourly Profiles
Winter (four days)
2015/07/20
20
Conclusions
• A CSP Load Factor of > 60% can only be reached at Solar Multiples > 3,0 and
storage in excess of 8 hours.
• CSP’s optimum storage capability, when using as value the benefit gained
from forming part of the South African system, has been determined as:
SM
1,0
1,5
2,0
2,5
3,0
3,5
Optimal
Storage
(hours)
3
5
7,5
11
>12
>12
• Based on the system analysis of SM up to 3,5 and number of Storage hours up
to 12 the system optimal is reached at SM between 2,5 and 3,0 and Storage of
between 9 and 12 hours.
• The CSP LCOE can be reduced to 65% of the LCOE at a base of SM = 1,
when developed and operated at the system optimal point.
• The increased daily summer solar energy (compared to winter) dovetails well
with the higher load factor requirement in summer due to the flatter system
demand profile in summer.
2015/07/20
21
Thank you