Flexibility options of CHP:
bringing together renewable
energies and efficiency
(German example)
Adi Golbach
1
The question
• Growing share of fluctuating wind and solar
power is changing the generation
requirements
• How does cogeneration fit into these
requirenments?
2
Development of RES supply share in Germany
Electricity
Final Energy
Heat
Car fuels
3
RES objectives of the German „Energiewende“
RES-share in electricity consumption
Historical development and targets
90%
80%
70%
60%
50%
Historisch
EEG12
40%
EEG14 oberer Wert
EEG14 unterer Wert
30%
20%
10%
0%
4
Trend aktueller Plan
Growing „needles“ call for flexibility
20 % Wind & Solar
Load/ Capacity
[GW]
40 % Wind & Solar
80 % Wind & Solar
red
Elt. Load
green
Generation
Wind & Solar
Source: Prof. Dr.-Ing. habil. Ingo
Stadler/ Westfalen Wind GmbH
5
Perspectives
2030 expected Residual loads
(blue)
79 % RES-Generation (scenario RES association)
GW
Szenario 2030
120
100
80
60
40
20
(20)
1
352
703
1054
1405
1756
2107
2458
2809
3160
3511
3862
4213
4564
4915
5266
5617
5968
6319
6670
7021
7372
7723
8074
8425
-
(40)
(60)
Last
Erzeugung Wind, PV & Laufwasser
Residuallast
Source: Norbert Krzikalla et al. (BET): Möglichkeiten zum Ausgleich fluktuierender Einspeisungen aus Erneuerbaren Energien, April 2013
Folie 6
Does cogeneration fit into these new
requirenments?
7
CHP load in GW
Outdoor temperature
Example CHP load in 2005
Hours on one year
Source: FfE, CO2-Verminderung in Deutschland, 2009
8
Electricity and heat demand over the year
Office building 12,000 m³
Load in kW
Electricity
Heat
Source: Transferstelle Bingen
9
Electricity demand over one day
¼ hour load kW el
Example appartment house
Quelle: Transferstelle Bingen
10
Load curve of a District heating system
100%
80%
60%
40%
20%
0%
0
730
1460
2190
2920
3650
4380
5110
5840
6570
Source: Prognos
11
7300
8030
8760
Sorted annual heat load curve district heating
CHP design & operation without heat storagge
Boiler
CHP
h
12
Sorted annual heat load curve district heating
CHP design & operation with heat storage
Boiler
CHP
h
13
Market as control center :
EPEX-Prices indicate the relative scarcity
Example.
Week 12-19.8.14
Power exchange prices
give incentives to switch
CHP on or out
Convent. PP
solar
Wind
Hydropower
Bioenergy
Power load
Electr. demand
€/MWh
Negative Prices:
unflexible „must-run“power plants overburden
the export market
-- power price EPEX-Spot
Source:
Example CHP plant flexible operation
•
•
•
420 kW existing + 1.562 kW additional
Schedule winter week: many operating hours
Due to higher capacity more CHP heat production  higher overall efficiency
EPEX
price
demand-oriented
operation:
tranquility for the
low price time
Power
production
Heat
production
Heat storage
recharging and
discharging in the daily
rhythm
Spring Week: low number of operating hours
Bedarfsorientierter
Operation at high
Betrieb möglichst zur
price hours only
Hochpreiszeit
Heat storage:
bridging rest together
with small CHP
16
Example of a Danish CHP with heat stoarag
(Ringkøbing)
17
Heat oriented CHP design & operation
62.5
Heat load MW
50.0
Sorted annual heat load
37.5
Boiler
25.0
12.5
CHP
0.0
Days of the year
18
Power oriented CHP & operation
62.5 62.5
Jahresdauerlinie des Wärmebedarfs
Heat load MW
50.0 50.0
Sorted annual heat
load
Heizkessel
37.5 37.5
BHKW
25.0 25.0
12.5 12.5
0.0
CHP
0.0
Jahrestage
Days
of the year(d)
Jahresdauerlinie des Wärmebedarfs
19
Monvalent design
62.5 62.5
BHKW
Wärmeleistung MW
Heat load MW
50.0 50.0
37.5 37.5
CHP
25.0 25.0
12.5 12.5
0.0 0.0
Jahrestage
(d)
Days
of the year
20
District heat production in % of maximum
Low Correlation between CHP and solar power
In cold and very cold hours
PV generation is low.
PV generation in % of maximum
Source: Prognos AG
21
Correlation between DH CHP and wind power
District heat production in % of
maximum
In cold and very cold hours
wind power generation is
low.
High wind power generation
in the transition period.
Wind power generation in % of maximum
Source: Prognos AG
22
CHP Roadmap compatible with RES
development?
Business level
economic
potential
Reference Scenario
Target Scenario
Socioeconomic
potential
185 TWh/a
CODE2
CHP
Roadmap
CHP potential
CHP compatible power generation
The heat view
• CHP is not only the most efficient way of power
production but also the most efficient way of
heat production.
• As heat will be needed for room heating and
industrial processes also on the long run in the
future, the electricity produced as a by-product
to heat (i.e. in cogeneration) has the same
ecological value as wind or solar power, because
not using this electricity source would mean
squandering it.
•  “Saving energy is the best energy source.”
24
Some more aspects
• CHP can very well interact with
– electrical heat pumps
• CHP generate electricity in high price hours
• HP use electricity in low price hours
– Power-to-heat systems
• CHP can also use „wind gas“ from „power-togas“-systems
Some pictures
Modern CHP with a heat storage
27
Biogas CHP with gas storage
1,500 m³ biogas storage
28
• 1200 kW el
• 1224 kW th
• CO2 saving 7,000
ton per year
2 medium sized CHP plants in
Denmark with heat storage tanks
29
The future
30
Cogeneration for the people
31
The future of electricity production
will be decentralized
today
tomorrow:
Cleaner, cheaper, more
reliable
32
Summary
•
•
•
•
With growing shares of fluctuation power production from wind and solar more and more flexible
production technologies are needed to cover the residual loads.
Modern CHP technologies are flexible and – different to electricity only power plants – also high
efficient. The CHP electricity will be produced in times with low wind and solar power production
and high electricity prices, which indicate the relative scarcity on the market. By use of
appropriate heat storage tanks the heat produced in cogeneration with electricity can be used later,
as heat demand pattern is different from the residual electricity demand pattern.
With CHP the residual electricity demand can be completely covered and thus security of supply be
ensured without power-only-plants, i.e. without any compromise regarding energy efficiency. So
we do not need new power only plants in future, neither for energy efficiency nor for security of
supply.
A growing CHP share means an intelligent and cost effective interaction between covering
electricity supply and heat supply – considering all objectives
–
–
–
–
33
security of supply,
economy,
decarbonisation
using limited energy resources as efficient as possible.
Thank you for your kind attention
more Information and connection:
adi.golbach@kwkkommt.de
www.kwkkommt.de (German)
Linkedin: Adi Golbach (English)
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