This document discusses how energy behaviors may change with the adoption of solar panels and battery storage in homes and communities. It presents the results of simulations of individual off-grid homes, grid-lite homes with varying energy equipment configurations, and an energy sharing community. The simulations show improved financial returns with battery storage when prices decrease by 2025. Load shifting and community energy sharing can significantly reduce grid reliance. The role of the grid may evolve to provide generation, storage and links between communities, while dwellers need only minimally manage energy through settings like load scheduling.

1. Energy Behaviour in a Community of Smart Homes
Joris Suppers and Mark Apperley

2. Who am I?
• Joris Suppers
• PhD Student at the University of Waikato
• A Smart Network of Household Electricity Management Systems
• Energy Informatics Group
• ei.cms.waikato.ac.nz

3. This Paper
• How will the energy behaviours involved in a community of
households change with the uptake of solar panels and energy
storage systems?

4. Energy Behaviours
Grid
Household
Community
Dweller

5. Decreasing Costs
Source: Transpower
0
200
400
600
800
1000
1200
1400
1600
1800
2016 2017 2018 2019 2020 2021 2022 2023 2024 2025
COST$AUD/kWh
Storage System Installation Cost: Including Inverter and Battery
15%
Tesla $100
USD/kWh
Battery Target
Costs of solar panels and energy storage systems
are steadily decreasing

6. Simulations
nzspot.cms.waikato.ac.nz ei.cms.waikato.ac.nz/hems
PV simulation Electricity simulation
• 16 households from WEL Networks (2500 to 15000 kWh per year with average 7200kWh/year)

7. Off-Grid
Household

8. Off-Grid: 25 Years
Assumptions
Solar Panel (kW)
Enough to
generate a days
usage in July
Solar Panel degradation (%) 0.8
Storage (kWh)
2 x average day
usage in July
Storage replacement cost
($/kWh)
200
Storage replacement year 12.5
Storage degradation (%) 2
Inverter replacement cost
($/kWh)
0.4
Inverter replacement year 15
Maintenance ($/kW/year) 20
Maintenance escalation (%) 2
Generator on/off (%) 20,50
Petrol cost ($/kWh) 1.125
Upfront cost ($) 68,000
House
Battery
(kWh)
PV
(kW)
Savings/
Grid Cost
Profit
(2016
prices)
Profit
(2025
prices)
Average 44.4 7.4 31908 -154128 -24576.2
10483 26.8 4.47 20311 -91994.8 -13792.99
11334 66 11 30845 -245695 -53118
12114 42 7 36162 -139818 -17269
12707 24 4 21304 -79256 -9228
12817 20.8 3.47 21764 -65401.8 -4706.99
13598 66.6 11.1 43669 -235385 -41057.3
13928 40 6.67 21588 -146025.8 -29308.59
14339 84 14 57131 -294829 -49731
14661 104.6 17.44 65631 -372670.6 -67457.48
14853 63.6 10.6 46201 -220283 -34708.8
16106 35.6 5.94 29802 -119389.6 -15506.98
16423 52 8.67 44818 -173075.8 -21344.59
17611 16 2.67 15215 -51838.8 -5149.59
18638 56.6 9.43 42715 -194425.2 -29279.71
18800 96.4 16 40718 -362922 -81720.4
19189 39.2 6.53 23664 -140570.2 -26195.01

9. But…
Off-Grid can be suitable if:
• There’s a high connection cost
Grid-lite 33

10. But…
Off-Grid can be suitable if:
• There’s a high connection cost
• Battery capacity is reduced
-1500
-1000
-500
0
500
1000
1500
2000
0 6 12 18 24
Load and PV combined
Shift Load

11. But…
Off-Grid can be suitable if:
• There’s a high connection cost
• Battery capacity is reduced
• Heating efficiency is increased

12. Grid-Lite Model

13. Smart-Home
Different households in Grid-Lite model include:
• No PV or storage

14. Smart-Home
Different households in Grid-Lite model include:
• No PV or storage
• PV only

15. Smart-Home
Different households in Grid-Lite model include:
• No PV or storage
• PV only
• PV and storage

16. Smart-Home
Different households in Grid-Lite model include:
• No PV or storage
• PV only
• PV and storage
• Storage only

17. PV and Storage ROI
Average yearly ROI (over 25 years)
PV only PV and storage
System
(kW)
Worst
(%)
Average
(%)
Best
(%)
Worst
(%)
Average
(%)
Best
(%)
Present(2016)
2 -0.4 3.4 5.4 -2.5 -2.1 -2
3 -0.3 3.2 6.2 -2.4 -1.5 -1.4
5 0.09 2.8 6.3 -2.2 -1 -0.2
Future(2025)
2 0.5 5.5 8 0.9 1.4 1.9
3 1.2 5.4 9.3 0.3 2.6 3.1
5 1.2 4.7 9.3 0.5 3.2 5.3
Assumptions
2kWp Solar system price ($)* 6499
3kWp Solar system price ($) 8995
5kWp Solar system ($) 12495
PV degradation (%/year) 0.8
Feed-In tariff (cents/kWh) 8
Peak electricity price (cents/kwh) 30.93
Off peak electricity price
(cents/kwh)
15.79
Shoulder electricity price
(cents/kwh)
26.16
Storage (kWh) 6.4
Storage replacement year 12.5
Storage degradation (%) 2
Inverter replacement cost
($/kWh)
0.4
Inverter replacement year 15
Maintenance ($/kW/year) 20
Maintenance escalation (%) 2
* Real prices from abw electric
** Based on the Genesis "My Time Tariff" for Hamilton

18. Storage Only
*Assumptions: Today’s price $11200 (1750 x 6.4), future price $2483 (388 x 6.4). 1 cycle a day for 10 years with 2% degradation allows
charge of 21,257 kWh, with 15% charge loss we get 18068kWh. 11200 ÷ 18068 = 0.62 cents 2483 ÷ 18068 = 0.14
Todays price of batteries you would need to
make a profit of 62 cents for each kWh to break even.
In the future (2025) this may drop to 14 cents.*
Average yearly ROI (over 10 years)
System 6.4kWh Worst Average Best
Today’s price -8.8 -8.4 -8.2
Future price -4.2 -2.3 -1.2

19. Community
2: Adjust load
3: Peak shaving
1: Share energy
PV size
(kW)
No
sharing
Sharing
16
kWh
16 75% 94% 100%
32 57% 70% 91%

20. Grid
• Provide generation, storage and a link between communities

21. Dweller
The energy management system (EMS) in a Smart Home is an
automatic and autonomous system. As a result, minimal to no energy
behaviour change is needed. What would help:
• Load shifting to peak generation times
• Set next travel time and distance for your EV

22. Summary
• Simulation tools
• Off-Grid
• Grid-lite
• Smart-home
• Community
• Grid
• Dweller