HOW CAN FUTURE UK HOMES GO ZERO CARBON?
HOW CAN FUTURE UK HOMES GO ZERO CARBON?
Oliver Griffiths - CR Consulting
Overview
What is ‘zero carbon’? Domestic energy usage The renewables contribution Building out energy wastage The occupant contribution Conclusions
What is ‘zero carbon’? Construction?
Maintenance?
Operation?
Decommissioning?
Some assumptions
We ignore indirect energy costs: Construction, O&M Embodied in purchased goods/services (the energy used to
make and deliver them)
The grid remains fossil fuel dependent The supply of biomass is not infinite Heat pumps are broadly as fossil-fuel efficient as mains gas We’re considering nett energy usage in everyday operation not going ‘off-grid’
Domestic energy usage
Our challenge:
to reduce energy consumption to the point where demand can be fulfilled using just zero carbon energy
Our common currency:
kWh/m2/yr
A one bar electric fire used for one hour a year per metre2 of floor area Or a unit of energy/m2/yr
Noting the differences between occupational density and usage
A typical UK home
Total usage 23,204 kWh/yr
Domestic Energy Consumption kWh/yr (Office for National Statistics, 2004)
Average home size 19812001 83m2 So very roughly 280kWh/m2/yr
25000
20000
Divided:
Space heating 62%
Water heating 23%
Appliances etc 13%
15000
10000
5000
Cooking 3%
And stubbornly high
0 1971 Space heating
2001 Water heating
Lighting/appliances
Cooking
‘Renewable’ options Wind turbines
Solar thermal Private wire
Solar PV
Biomass
GSHP Gas CHP Source: adapted from ‘The Merton Rule’/ Adrian Howlett LB of Merton
Effectiveness?
Merton Rule ‘renewable’ energy assessments:
London Plan (LSBU 2007) Croydon/Merton (Cotterill 2009)
Assessing usage and effectiveness Data very poor, but clear mismatch:
Most popular are zero carbon (Solar thermal, PV, heatpumps) Most carbon-effective are non-renewables (CHP and CCHP)
Source: LSBU/GLA 2007, Cotterill 2008
Energy from renewables Onsite sources
(kWh/m2/yr)
Solar thermal 17(Viridian) Solar electric 6 (PV-Compare) Wind 2 (Warwick WT) Total 25 = c.9% of requirement
Existing home energy balance (kWh/m2/yr)
Solar thermal PV Wind Balance
Likely maximum for Southern England assuming southerly-facing house with 12m2 of available roof and best in class technology
Building out wastage
‘Build tight ventilate right’ e.g. Passivhaus
Draughtproofed Superinsulated Low energy lighting and appliances Passive solar gain
Even work for retrofits:
Space heating demand
Pre- renovation 192 kWh/m2/yr (UK ave. 174) Post-renovation 14 kWh/m2/yr €640/m2
MFH Schleipfweg / Rankweil 18 flats
How effective is this? Standard UK dwelling (2001) 280kWh/m2/yr
BedZED (2007) 82kWh/m2/yr
Passivhaus standard 120kWh/m2/yr(?)
Hockerton (1998-2002) 26kWh/m2/yr
Hockerton - grid parity
PV on five homes 2 x 5kW wind turbines
But you have to adapt… BedZED winter satisfaction 2007
7%
BedZED summer satisfaction 2007
0% 3%1%
3%0% 10%
6%
44%
39%
Too hot 1 2 3 Just right 4 5 6 Too cold 7
20%
Too hot 1 2 3 Just right 4 5 6 Too cold 7
30%
37%
…behaviour, tolerance etc
Personal comfort vs altruism/economy
Active engagement
Temperature Appliance use E.g. Opening/closing of windows
Avoid the ‘rebound’ effect/Jevons’ Paradox
The occupant contribution BedZED energy consumption 2007 kWh/p/day
BedZED energy consumption 2007 kWh/m2/yr
12
160 140
10
120 8
100 6
80 60
4
40 2
20 0
17
30
3
6
d g) d e g d p be in ie in hi be ag c s s p 2 r a r u u 1 f e e c 1 o n av th oc lh ow or ia er ED c n d n ( Z e d w So d ar O Be be Sh 2
Heat
20 2
d be
14 4
d be
3 3
be
d
18
O
17
Be dZ E
64
D av w er ne ag r Sh e oc 56 ar c up ed i ed ow 26 ne So rs ci hi 2 al be ho p 1 d 5 us (n in or g th 15 -f ac in 2 g) be 5 d 14 12 be d 3 4 be d 3 3 be d 14 1 be d 17
0
Power
Max variance: Heat: 0.4 - 22.2 kWh/p/day Power: 1.1 - 10.9 kWh/p/day
Heat Power
Conclusion
There’s currently a huge challenge The issue is mainly heat wastage Improving the building fabric and systems can eliminate most, but by no means all, of this Onsite renewables can play a small part, behavioural adaptation a greater one It is possible to go genuinely zero carbon now (but only in exceptional circumstances)
THANK YOU
Oliver Griffiths CR Consulting Ltd, 72 Charlotte Street, London W1T 4QQ [email protected]
Oliver Griffiths - CR Consulting
Overview
What is ‘zero carbon’? Domestic energy usage The renewables contribution Building out energy wastage The occupant contribution Conclusions
What is ‘zero carbon’? Construction?
Maintenance?
Operation?
Decommissioning?
Some assumptions
We ignore indirect energy costs: Construction, O&M Embodied in purchased goods/services (the energy used to
make and deliver them)
The grid remains fossil fuel dependent The supply of biomass is not infinite Heat pumps are broadly as fossil-fuel efficient as mains gas We’re considering nett energy usage in everyday operation not going ‘off-grid’
Domestic energy usage
Our challenge:
to reduce energy consumption to the point where demand can be fulfilled using just zero carbon energy
Our common currency:
kWh/m2/yr
A one bar electric fire used for one hour a year per metre2 of floor area Or a unit of energy/m2/yr
Noting the differences between occupational density and usage
A typical UK home
Total usage 23,204 kWh/yr
Domestic Energy Consumption kWh/yr (Office for National Statistics, 2004)
Average home size 19812001 83m2 So very roughly 280kWh/m2/yr
25000
20000
Divided:
Space heating 62%
Water heating 23%
Appliances etc 13%
15000
10000
5000
Cooking 3%
And stubbornly high
0 1971 Space heating
2001 Water heating
Lighting/appliances
Cooking
‘Renewable’ options Wind turbines
Solar thermal Private wire
Solar PV
Biomass
GSHP Gas CHP Source: adapted from ‘The Merton Rule’/ Adrian Howlett LB of Merton
Effectiveness?
Merton Rule ‘renewable’ energy assessments:
London Plan (LSBU 2007) Croydon/Merton (Cotterill 2009)
Assessing usage and effectiveness Data very poor, but clear mismatch:
Most popular are zero carbon (Solar thermal, PV, heatpumps) Most carbon-effective are non-renewables (CHP and CCHP)
Source: LSBU/GLA 2007, Cotterill 2008
Energy from renewables Onsite sources
(kWh/m2/yr)
Solar thermal 17(Viridian) Solar electric 6 (PV-Compare) Wind 2 (Warwick WT) Total 25 = c.9% of requirement
Existing home energy balance (kWh/m2/yr)
Solar thermal PV Wind Balance
Likely maximum for Southern England assuming southerly-facing house with 12m2 of available roof and best in class technology
Building out wastage
‘Build tight ventilate right’ e.g. Passivhaus
Draughtproofed Superinsulated Low energy lighting and appliances Passive solar gain
Even work for retrofits:
Space heating demand
Pre- renovation 192 kWh/m2/yr (UK ave. 174) Post-renovation 14 kWh/m2/yr €640/m2
MFH Schleipfweg / Rankweil 18 flats
How effective is this? Standard UK dwelling (2001) 280kWh/m2/yr
BedZED (2007) 82kWh/m2/yr
Passivhaus standard 120kWh/m2/yr(?)
Hockerton (1998-2002) 26kWh/m2/yr
Hockerton - grid parity
PV on five homes 2 x 5kW wind turbines
But you have to adapt… BedZED winter satisfaction 2007
7%
BedZED summer satisfaction 2007
0% 3%1%
3%0% 10%
6%
44%
39%
Too hot 1 2 3 Just right 4 5 6 Too cold 7
20%
Too hot 1 2 3 Just right 4 5 6 Too cold 7
30%
37%
…behaviour, tolerance etc
Personal comfort vs altruism/economy
Active engagement
Temperature Appliance use E.g. Opening/closing of windows
Avoid the ‘rebound’ effect/Jevons’ Paradox
The occupant contribution BedZED energy consumption 2007 kWh/p/day
BedZED energy consumption 2007 kWh/m2/yr
12
160 140
10
120 8
100 6
80 60
4
40 2
20 0
17
30
3
6
d g) d e g d p be in ie in hi be ag c s s p 2 r a r u u 1 f e e c 1 o n av th oc lh ow or ia er ED c n d n ( Z e d w So d ar O Be be Sh 2
Heat
20 2
d be
14 4
d be
3 3
be
d
18
O
17
Be dZ E
64
D av w er ne ag r Sh e oc 56 ar c up ed i ed ow 26 ne So rs ci hi 2 al be ho p 1 d 5 us (n in or g th 15 -f ac in 2 g) be 5 d 14 12 be d 3 4 be d 3 3 be d 14 1 be d 17
0
Power
Max variance: Heat: 0.4 - 22.2 kWh/p/day Power: 1.1 - 10.9 kWh/p/day
Heat Power
Conclusion
There’s currently a huge challenge The issue is mainly heat wastage Improving the building fabric and systems can eliminate most, but by no means all, of this Onsite renewables can play a small part, behavioural adaptation a greater one It is possible to go genuinely zero carbon now (but only in exceptional circumstances)
THANK YOU
Oliver Griffiths CR Consulting Ltd, 72 Charlotte Street, London W1T 4QQ [email protected]
