CONECT conference presentation

1. pp.kk.aaaa
HEAT PUMP USAGE IN ESTONIAN RURAL
DISTRICT HEATING NETWORKS
Kertu Lepiksaar, PhD student, junior researcher
Kiur Kalme, Andres Siirde, Anna Volkova
Faculty of Engineering / Department of Energy Technology
Tallinn University of Technology
12.05.2021

2. TALLINNA TEHNIKAÜLIKOOL
HEAT PUMPS IN DISTRICT HEATING
Recently interest in using heat pumps in district heating has increased:
 Developments in heat pump technology
 Ammonia and CO2 as refrigerant
 Possibility to use industrial excess heat and natural heat sources
 Electrification of heat sector
 Power-to-heat
 District cooling possibilities
 Renewable energy sources integration to energy system
2/10 12.05.2021

3. TALLINNA TEHNIKAÜLIKOOL
DISTRICT HEATING VIABILITY IN RURAL AREAS
 The main problems with rural district heating networks
 Low heat consumption density
 Decreasing consumption
 Decreasing population
 Increase of buildings energy efficiency
 Warming climate conditions
 Why heat pumps are good solution in rural areas?
 Lots of free space for heat pump installations
 Manages well fluctuating load
3/10 12.05.2021

4. TALLINNA TEHNIKAÜLIKOOL
ESTONIAN RURAL DISTRICT HEATING NETWORKS
 In Estonia there are about 240 DH networks and 140 of them have annual consumption
below 16 GWh – these 140 DH networks were considered as rural DH networks
 Rural DH networks were divided into 7 groups and were analysed by their characteristics and
heat demand profile
Characteristic Group 1 Group2 Group 3 Group 4 Group 5 Group 6 Group 7
Average annual heat
consumption, MWh
681 1914 3956 6235 7812 10393 14192
Number of
consumers in
DH Network
3 6 15 25 37 52 70
Average DH price,
EUR/MWh
70,3 67,4 64,5 61,7 56,7 64,4 57,1
Average supply
temperature, °C
80 80 80 85 90 100 110
Number of DH
networks in the
group
23 58 24 8 8 9 5

5. TALLINNA TEHNIKAÜLIKOOL
HEAT DEMAND PROFILE
 For analysis heat demand profile was created for each group based on Estonian average
ambient temperature and annual heat demand
 The shape of the profile is same for each group
5/12 12.05.2021
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 1000 2000 3000 4000 5000 6000 7000 8000
Heat
demand,
MW
Hours
Group 1
Group 2
Group 3
Group 4
Group 5
Group 6
Group 7

6. TALLINNA TEHNIKAÜLIKOOL
PROPOSED OPTIONS
 Heat sources in DH networks were examined
 Average existing solution for all groups was estimated
 Two alternatives for new heat sources were proposed
6/10 12.05.2021
+
Biomass
boiler
Heat
pump
Heat pump
only
-Groundsource
-Surface water
-Sewage water
Possible consumer price
(ECA method):
• Annual heat
consumption
• Allowed profit:
• Variable costs
• Operation and
maintenance costs
• Capital costs
• Weighted average
cost of capital
(5,7%)

7. TALLINNA TEHNIKAÜLIKOOL
CAPACITY ESTIMATIONS
 Base load boiler capacity:
 Min. load 50% of
nominal
 Max.load 110% of
nominal
 HP thermal capity was
assumed according to
maximum heat load value
 HP electric capacity was
estimated using COP
values for each type of
heat pump
 In case of all rural DH
networks electrification
Estonian peak electricity
consumption would
increase 10% 0
1
2
3
4
5
6
7
8
9
Existing
boilers
Boiler+HP
HP
Existing
boilers
Boiler+HP
HP
Existing
boilers
Boiler+HP
HP
Existing
boilers
Boiler+HP
HP
Existing
boilers
Boiler+HP
HP
Existing
boilers
Boiler+HP
HP
Existing
boilers
Boiler+HP
HP
Group 1 Group 2 Group 3 Group 4 Group 5 Group 6 Group 7
MW
HP Peak boiler Base load boiler

8. TALLINNA TEHNIKAÜLIKOOL
PRICE AND COSTS
0
20
40
60
80
100
120
Biomass
+ HP
HP Biomass
+ HP
HP Biomass
+ HP
HP Biomass
+ HP
HP Biomass
+ HP
HP Biomass
+ HP
HP Biomass
+ HP
HP
1 2 3 4 5 6 7
DH
consumer
price,
EUR/Mwh
WACC
capital costs HP
capital costs biomass
O&M
water and sewerage
environmental fees
fuel
Existing price
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 Fuel and O&M costs are smaller when only HP is used
 Water and severage costs are the same for both cases
 Capital costs (investments) are bigger when only HP is used
 HP capital costs make 11-47% of the consumer price in case of biomass boiler + HP
 HP capital costs make 22-58% of consumer price in case of only HP
 INVESTMENT SUPPORTS!

9. TALLINNA TEHNIKAÜLIKOOL
CONCULSIONS AND DISCUSSION
 Smaller DH networks need investment support to keep DH price low
 With help of investment support DH price can be lowered up to 31%
 In case of bigger DH networks investment support can reduce consumer price up to 8%
 Difference between different types of HP in terms of consumer price is not remarkable
 In case of smaller DH networks ground source HP would be more cost-effective
 The situation for very small DH networks is difficult and considerable solutions would be
 Induvidual heating – that could not be always the best solution, as investments are still
big and fuel costs per consumer remain the same
 Investment support
 Add new consumers to the network
9/10 12.05.2021

10. Kertu Lepiksaar, kertu.lepiksaar@taltech.ee
TalTech Research Group of Smart District Heating
TALLINN UNIVERSITY OF TECHNOLOGY
Ehitajate tee 5, 19086 Tallinn
taltech.ee
10/10 12.05.2021