Combined heat and power (CHP) plants are efficient regarding fuel, costs, and emissions compared to the separate generation of heat and electricity. Sinking revenues from sales of electricity due to sinking market prices endanger the economically viable operation of the plants. The integration of heat pumps (HP) and thermal energy storages (TESs) represents an option to increase the flexibility of CHP plants so that electricity can be produced only when the market conditions are favorable. The investigated district heating system is located in Germany, where the electricity market is influenced by a high share of renewable energies. The price-based unit-commitment and dispatch problem is modeled as a mixed integer linear program (MILP) with a temporal resolution of 1 h and a planning horizon of 1 yr. This paper presents the optimal operation of a TES unit and a HP in combination with CHP plants as well as synergies or competitions between them. Coal and gas-fired CHP plants with back pressure or extraction condensing steam turbines (STs) are considered, and their results are compared to each other.

References

1.
Claudius
,
J.
,
Hermann
,
H.
,
Matthes
,
F. C.
, and
Graichen
,
V.
,
2014
, “
The Merit Order Effect of Wind and Photovoltaic Electricity Generation in Germany 2008-2016: Estimation and Distributional Implications
,”
Energy Econ.
,
44
, pp.
302
313
.
2.
Hirth
,
L.
,
2013
, “
The Market Value of Variable Renewables—The Effect of Solar Wind Power Variability on Their Relative Price
,”
Energy Econ.
,
38
, pp.
218
236
.
3.
Koytsoumpa
,
E.-I.
,
Bergins
,
C.
,
Buddenberg
,
T.
, Wu, S., Sigurbjörnsson, Ó., Tran, K. C., and Kakaras, E.,
2015
, “
The Challenge of Energy Storage in Europe: Focus on Power to Fuel
,”
ASME J. Energy Resour. Technol.
,
138
(
4
), p.
042002
.
4.
Stein-Brzozowska
,
G.
,
Bergins
,
C.
,
Kukoski
,
A.
, Wu, S., Agraniotis, M., and Kakaras, E.,
2016
, “
The Current Trends in Conventional Power Plant Technology on Two Continents From the Perspective of Engineering, Procurement, and Construction Contractor and Original Equipment Manufacturer
,”
ASME J. Energy Resour. Technol.
,
138
(
4
), p.
044501
.
5.
IEA
,
2014
, “
Linking Heat and Electricity Systems: Co-Generation and District Heating and Cooling Solutions for a Clean Energy Future
,” International Energy Agency, Paris, France,
Report
.
6.
Andrews
,
D.
,
Riekkola
,
A. K.
,
Tzimas
,
E.
, Serpa, J., Carlsson, J., Pardo-Garcia, N., and Papaioannou, I.,
2012
, “
Background Report on EU-27 District Heating and Cooling Potentials, Barriers, Best Practice and Measures of Promotion
,” EU Joint Research Center, Petten, The Netherlands, Report No.
EUR 25289 EN
.
7.
Federal Ministry for Economic Affairs and Energy
,
2015
, “
An Electricity Market for Germany's Energy Transition
,” Federal Ministry for Economic Affairs and Energy, Berlin,
Report
.
8.
Cogen Europe
,
2013
, “
European Cogeneration Review—A Series of Country Reports on Cogeneration in European Countries—Germany
,” Cogen Europe, Brussels, Belgium,
Report
.
9.
Nielsen
,
J. R.
,
Quicklund
,
H.
,
Roynstrand
,
J.
, Stang, J., and Sundberg, V.,
2005
, “
Two-Step Decision and Optimization Model for Centralized or Decentralized Thermal Storage in DH&C Systems
,” International Energy Agency, Sittard, The Netherlands, Report No. 8DHC-05.02.
10.
Wigbels
,
M.
,
Bøhm
,
B.
, and
Sipilae
,
K.
,
2005
, “
Dynamic Heat Storage Optimization and Demand Side Management
,” Frauenhofer Institut Umwelt-, Sicherheits-, Energietechnik UMSICHT, Oberhausen, Germany, Report No. 2005:8DHC-05.06.
11.
Pfeiffer
,
R.
, and
Verstege
,
J.
,
1996
, “
Committing and Dispatching Power Units and Storage Devices in Cogeneration Systems With Renewable Energy Sources
,”
Fourth International Conference on Power System Control and Management
, London, Apr. 16–18, pp. 21–25.
12.
Ito
,
K.
,
Yokoyama
,
R.
, and
Shiba
,
T.
,
1992
, “
Optimal Operation of a Diesel Engine Cogeneration Plant Including a Heat Storage Tank
,”
ASME J. Eng. Gas Turbines Power
,
114
(4), pp.
687
694
.
13.
Rech
,
S.
,
Toffolo
,
A.
, and
Lazzaretto
,
A.
,
2012
, “
TSO-STO: A Two-Step Approach to the Optimal Operation of Heat Storage Systems With Variable Temperature Tanks
,”
Energy
,
45
(1), pp. 366–374.
14.
Bach
,
B.
,
Werling
,
J.
,
Ommen
,
T.
, Münster, M., Morales, J. M., and Elmegaard, B.,
2016
, “
Integration of Large-Scale Heat Pumps in the District Heating Systems of Greater Copenhagen
,”
Energy
,
107
, pp.
321
334
.
15.
Averfalk
,
H.
,
Ingvarsson
,
P.
,
Persson
,
U.
, Gong, M., and Werner, S.,
2017
, “
Large Heat Pumps in Swedish District Heating Systems
,”
Renewable Sustainable Energy Rev.
,
79
, pp.
1275
1284
.
16.
Ito
,
K.
,
Shiba
,
T.
, and
Yokoyama
,
R.
,
1994
, “
Optimal Operation of a Cogeneration Plant in Combination With Electric Heat Pumps
,”
ASME J. Energy Resour. Technol.
,
116
(1), pp.
56
64
.
17.
David
,
A.
,
Mathiesen
,
B. V.
,
Averfalk
,
H.
, Werner, S., and Lund, H.,
2017
, “
Heat Roadmap Europe: Large-Scale Electric Heat Pumps in District Heating Systems
,”
Energies
,
10
(
4
), p.
578
.
18.
Christidis
,
A.
,
Koch
,
C.
,
Pottel
,
L.
, and
Tsatsaronis
,
G.
,
2011
, “
Der Beitrag von Wärmespeichern zur kostenoptimalen Bereitstellung von Fernwärme und Strom im Versorgungsgebiet Berlin der Vattenfall Europe AG
,”
Energieeffizienz - Tagungsband des VDI-Expertenforums”Energieeffizienz in den Städten und der Industrie von morgen
,
R.
McKenna
and
W.
Fichtner
, eds.,
KIT Scientific Publishing
, Karlsruhe, Germany, pp.
61
75
.
19.
Christidis
,
A.
,
Koch
,
C.
,
Pottel
,
L.
, and
Tsatsaronis
,
G.
,
2012
, “
The Contribution of Heat Storage to the Profitable Operation of Combined Heat and Power Plants in Liberalized Electricity Markets
,”
Energy
,
41
(
1
), pp.
75
82
.
20.
Mollenhauer
,
E.
,
Christidis
,
A.
, and
Tsatsaronis
,
G.
,
2016
, “
Evaluation of an Energy- and Exergy-Based Generic Modeling Approach of Combined Heat and Power Plants
,”
Int. J. Energy Environ. Eng.
,
7
(
2
), pp.
167
176
.
21.
Christidis
,
A.
,
Mollenhauer
,
E.
,
Tsatsaronis
,
G.
, Schuchardt, G. K., Holler, S., Böttger, D., and Bruckner, T.,
2017
,
EnEff: Wärme—Einsatz von Wärmespeichern und Power-to-Heat-Anlagen in der Fernwärmeerzeugung
, AGFW, Frankfurt am Main, Germany (in German).
22.
Energi-Styrelsen, and Energinet
,
2012
, “
Technology Data for Energy Plants: Generation of Electricity and District Heating, Energy Storage and Energy Carrier Generation and Conversion
,” Danish Energy Agency, Copenhagen, Denmark,
Report
.
23.
Garcia
,
N. P.
,
Vatopoulos
,
K.
,
Riekola
,
A. K.
, Lopez, A. P., and Olsen, L.,
2012
, “
Best Available Technologies for the Heat and Cooling Market in the European Union
,” Technical Report, Publications Office of the European Union, Luxembourg, Report No. EUR 25407 EN.
24.
Agora
,
2014
, “
Power-to-Heat zur Integration von ansonsten abgeregeltem Strom aus Erneuerbaren Energien: Handlungsvorschläge basierend auf einer Analyse von Potenzialen und energiewirtschaftlichen Effekten: Langfassung (in German)
,” Berlin, Report No. 046/09-S-2014/de.
25.
Huhn
,
R.
,
2007
, “
Beitrag zur thermodynamischen Analyse und Bewertung von Wasserwärmespeichern in energieumwandlungsketten
,” Ph.D. thesis, Technische Universität Dresden, Dresden, Germany (in German).
26.
Rühling
,
K.
,
Groß
,
S.
,
Herwig
,
A.
, Heymann, M., Rhein, M., Robbi, S., Rothmann, R., and Felsmann, C.,
2016
,
EnEff: Wärme—Erhaltung der Marktfähigkeit von KWK Anlagen mittels Einbindung von Umweltenergie
, AGFW, Frankfurt am Main, Germany.
27.
Schuchardt
,
G. K.
,
Holler
,
S.
, and
Olbricht
,
M.
,
2014
, “
Energetic Performance of Short Term Thermal Storages in Urban District Heating Networks
,”
14th International Symposium on District Heating and Cooling, Stockholm
, Sweden, Sept. 7–9, pp. 221–232.
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