Responding to the Challenge

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Code for Sustainable Homes May 1st 2008
Where we are now?
Responding to the Challenge
Recipient of James Watt Gold Medal
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Where we are now?

• Introduction to Current Energy Issues
• The twin Challenges facing us
• Climate Change
• Energy Security
• Review of historic trends in Building Regulations
  and associated energy use in domestic buildings.
• In Part 2 The opportunities facing us

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Issue of Fuel Choice

• Carbon factors for each unit of fuel consumed
  at point of use.
• The following include the transmission/
  distribution losses
• e.g. electricity 8.5
• energy generated locally is effectively worth
  more than nationally supplied energy
• Gas 0.19 kg/kWh
• Oil 0.277 kg/kWh
• Coal 0.33 kg/kWh
• Electricity
• varies depending on mix of power stations. Was
  over 0.65 kg/kWh in 1990 but fell to 0.46 kg/kWh
  in 1999, but as since risen with closing of
  nuclear and less gas being burnt. Currently
  0.52
• For identical situation oil boiler will cause
  emission of around 40 more CO2 than for gas

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The Hard Choices Facing Us

• Climate Change Issues
• Carbon emissions in electricity generation will
  increase in next 5 years even if demand is held
  constant
• - Each unit generated by coal
  1000 g / kWh
• 
  gas 400 g/ kWh
• 
  nuclear 10 20 g/kWh
• Reducing demand for electricity in homes is
  important
• Need to reduce carbon emissions by 60 by 2050

Emissions from electricity generation will rise
in short term even if we order new nuclear.
Deployment of renewables is barely keeping pace
with increased demand yet alone replacement of
nuclear
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The Hard Choices Facing Us

• Energy Security Issues
• Since 2004 UK has been importer of gas
• 70 of coal is now imported
• UK is no longer self sufficient in Energy
• Importance of Energy Conservation
• not merely energy efficiency, but overall
  reduction in energy use
• Still have major coal resources, but only
  viable with Carbon Capture and Sequestration
  because of high carbon factor
• Prospects of CCS?
• Hydrogen/Fuel Cells?
• Only really viable when electricity generation
  has been decarbonised
• CCS routinely available
• Increase in
  Renewable/Nuclear Generation
• CCS Unlikely except for demonstration schemes
  before 2020 - 2025

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A Pathway to a Low Carbon Future ???????
1. ?????? Awareness Information Packs
2. ???????? Technical Solutions to conserve
energy Low energy lighting/better insulation etc
3. ??????? Renewable Energy
4. ????? Offsetting
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Energy Consumption and CO2 Emissions in Domestic
Sector
Carbon Intensity has improved by 8.6 - but
absolute emissions are important
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Energy Consumption Comparison of Sectors
The Domestic Sector is a critical area to tackle
climate change
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Responding to the Challenge Technical
Solutions The Heat Pump
A heat pump delivers 3, 4, or even 5 times as
much heat as electricity put in. Working with
thermodynamics not against it.
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Issue of Fuel Choice

• Example
• Heat house with condensing gas boiler 90
  efficient
• For each unit (kWh) of heat provided.
• 1/0.9 1.11 units of gas must be supplied
• Carbon associated with this 0.21 kg
• Direct electric heating 0.52 kg
• Heat Pump with Coefficient of Performance of 4
• Carbon emission associated 0.52/4 0.13
• A 38 saving over gas.
• Note some people claim higher savings based on
  incorrect DEFRA carbon factor of 0.43
• Improved performance of heat pumps is possible
  with under floor heating

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Changes in the Heating Standards of Houses

• First introduced as Part L in 1976
• Basic Statement largely following what was then
  common practice
• e.g. cavity walls brick cavity block with no
  insulation - no insulation in floor, minimal
  insulation in loft.
• 1994 First attempt to address overall annual
  energy consumption, although elemental method of
  compliance was still permitted
• 2002 Carbon Index introduced
• 2006 Target Emission Rate and Dwelling Emission
  Rate introduced.

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How has the performance of a typical house
changed over the years?
Bungalow in South West Norwich built in mid 1950s
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Changing Energy Requirements of House
In all years dimensions of house remain same
just insulation standards change As houses have
long replacement times, legacy of former
regulations will affect ability to reduce carbon
emissions in future
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Changing Energy Requirements of House
Improvements to existing properties are limited
because of in built structural issues e.g. No
floor insulation in example shown. House designed
to conform the Target Emission Rate (TER) as
specified in Building Regulations 2006 and SAP
2005.
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Changing Carbon Dioxide Emissions
Code 5 Zero Carbon House for Heating/Hot Water
and Lighting Code 6 Zero Carbon House overall
but in reality is this
achievable
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The Behavioural Dimension

• Analysis of 114 houses in Norwich using Gas
  Heating
• Predicted consumption from SAP was within 1.9 of
  actual energy consumption for Space Heating/ Hot
  Water and Gas Cooking.
• Plot shows variation from predicted for each
  house
• Little variation with household size
• Consumption varies by up to a factor of 9 for any
  given household size.
• Education/Awareness is important.

provide INFORMATION PACKS
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The Behavioural Dimension

• Household size has little impact on electricity
  consumption.
• Consumption varies by up to a factor of 9 for any
  given household size.
• Allowing for Income still shows a range of 6 or
  more.
• Education/Awareness is important.

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CO2/ year 0 - 4 tonnes 4 - 6
tonnes 6 - 8 tonnes 8 -
10 tonnes gt 10 tonnes
Variations in Carbon Emissions in existing
houses Analysis courtesy of Karla Alcantar
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The Future Code for Sustainable Homes

• Introduced over next few years to improve
  standards to ultimate zero carbon house
• But objectives of a low carbon future may be
  jeopardised if attention is not also paid to
  sustainable transport associated with new
  dwellings

Data for 1 household with 2 cars
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Code for Sustainable Homes May 1st 2008
Responding to the Challenge
Recipient of James Watt Gold Medal
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Responding to the Challenge

• Improvements on the SAP 2005 standards as
  required by the different code levels can be met
  by
• Improved Fabric performance
• Lower U-values
• Technical Solutions
• Solar Thermal
• Solar Photo-voltaic
• Heat Pumps
• Biomass
• Micro- CHP
• Low Energy Lighting (SAP 2005 already specifies
  30)

• Energy Service Companies may offer a solution
  for financing
• Issues of Carbon Trading

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Responding to the Challenge

• Improved Fabric / standard appliance Performance
• SAP 2005 standard reference

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The Future Code for Sustainable Homes
Improvements in Insulation and boiler performance
Code 1 Code 2 H nearly makes code 3
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Responding to the Challenge Technical
Solutions Solar Thermal Energy
Basic System relying solely on solar energy
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Responding to the Challenge Technical
Solutions Solar Thermal Energy
Solar tank with combi boiler
indirect solar cylinder
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Responding to the Challenge Technical
Solutions Solar Thermal Energy
Dual circuit solar cylinder
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Responding to the Challenge Technical
Solutions Solar Thermal Energy
Solar Collectors installed 27th January 2004
Annual Solar Gain 910 kWh
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Responding to the Challenge Technical
Solutions Solar Thermal Energy
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It is all very well for South East, but what
about the North?
House on Westray, Orkney exploiting passive solar
energy from end of February
House in Lerwick, Shetland Isles with Solar
Panels - less than 15,000 people live north of
this in UK!
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The Future Code for Sustainable Homes
Improvements using solar thermal energy
Code 1 Code 2
Note little extra benefit after 3 panels, but
does depend on size of house
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Responding to the Challenge Technical
Solutions Solar PhotoVoltaic
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The Future Code for Sustainable Homes
Improvements using solar Photovoltaic
Code 1 Code 2 Code 3
Note 2 panels of solar thermal have same benefit
as 5 sqm of PV
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Responding to the Challenge Technical
Solutions The Heat Pump

• Any low grade source of heat may be used
• Coils buried in garden 1 1.5 m deep
• Bore holes
• Lakes/Rivers are ideal
• Air can be used but is not as good
• Best performance is achieved if the temperature
  source between outside source and inside sink is
  as small as possible.

Under floor heating should always be considered
when installing heat pumps in for new build
houses operating temperature is much lower than
radiators. Attention must be paid to provision of
hot water - performance degrades when heating
hot water to 55 60oC Consider boost using off
peak electricity, or occasional Hot Days
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The Future Code for Sustainable Homes
Improvements using Heat Pumps
Code 1 Code 2 Code 3
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The Future Code for Sustainable Buildings
Improvements using Biomass options
Note Biomass with solar thermal are incompatible
options
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Ways to Respond to the Challenge Technical
Solutions

• Micro CHP plant for homes are being trialled.
• Replace the normal boiler
• But there is a problem in summer as there is
  limited demand for heat electrical generation
  will be limited.
• Backup generation is still needed unless
  integrated with solar photovoltaic?
• In community schemes explore opportunity for
  multiple unit provision of hot water in summer,
  but only single unit in winter.

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The Future Code for Sustainable Homes
Various Combinations
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Responding to the Challenge

• How can low carbon homes be provided at an
  affordable cost?
• Energy Service Companies (ESCos)
• Home costs same initial cost as traditional home
• Any additional costs for providing renewable
  energy, better insulation/controls are financed
  by ESCo
• Client pays ESCo for energy used at rate they
  would have done had the house been built to basic
  2005 standards
• ESCo pays utility company at actual energy cost
  (because energy consumption is less)
• Difference in payments services ESCo investment
• When extra capital cost is paid off
• Client sees reduced energy bills
• ESCO has made its money
• Developer has not had to charge any more for
  property
• The Environment wins

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The Future Code for Sustainable Buildings
Conclusions

• Significant Improvements can be achieved
• Better Insulation Standards
• Heat Pumps
• Biomass Boilers
• Solar Thermal
• Solar PV

• But avoid incompatible options
• Too large a Solar thermal Array
• Biomass with solar thermal
• CHP with Solar Thermal

Lao Tzu (604-531 BC) Chinese Artist and Taoist
philosopher
"If you do not change direction, you may end up
where you are heading."
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