Optimising Low and Zero Carbon Technologies in the NHS

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Optimising Low and Zero Carbon Technologies in
the NHS

• Chris Hall
• Environmental Advisor
• Sustainable Development

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Contents

• Meeting the zero carbon challenge
• Review of low and zero carbon technologies (LZCT)
• Solar Thermal - ST
• Photovoltaic's - PV
• Combined Heat and power - CHP
• Ground source heat pumps - GSHP
• Biomass (wood to heat)
• Wind.
• Application to the NHS
• Rules of thumb

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Steps to zero carbon

• 1. Conservation
• Fabric, HVAC, Lighting, Intellegent Controls,
  Behaviour
• Often cheap to apply - gives fast payback
• Requires smallest change in consumer attitudes
• 2. LZCT
• Solar, Wind, Hydro, Biomass, Heat Pumps, CHP
• More investment required -gt slower payback
• Requires larger shift in attitudes
• Changes in economics
• 3. Community schemes
• 4. Carbon trading

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Issues to consider

• Passive opportunities maximised
• Services should be correctly sized and integrated
  so that servicing will be minimised.
• Identification of need for cooling energy on site
  and how this may be best achieved
• Use of energy simulation techniques for each
  building on site to inform site energy strategy.
• Consideration of the use and integration of
  renewables
• Whole life costing/ payback
• Carbon intensity of displaced mains electricity

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Carbon outcomes from modelling the NHS estate

• Performance of existing buildings
  145KgCO2/m2
• Best practice outcome existing estate
  110KgCO2/m2
• New buildings compliant with UK Building
• Regulations (Part L) 95KgCO2/m2
• New build Best practice building scenario
  70KgCO2/m2
• Best possible case including LZCT
  50KgCO2/m2

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Solar Insolation Map - annual kWh/m2
Annual solar energy on horizontal plane kWh/m2
Ubbink Nederland
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Active solar thermal technology check

• A typical system comprises
• Collector
• Fluid (water with anti-freeze)
• Heat exchanger
• Control system (temperature sensor and electric
  pump)

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Solar thermal technology check
There are two types of collectors..

• Evacuated tube
• Flat plate
• evacuated tube collectors have
• greater efficiency (up to 65).
• flat plate collectors are cheaper
• of the two (typically 2,500 for a
• 4m2 panel)
• Should comply with BS EN12975

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Potential for Solar thermal

• Up to 50 of NHS DHW demand could be met by ST
• Results show 1/5th of NHS would meet NHS DHW
  needs
• Typical costs 800 /m2, this equates to around
  880m across the NHS Estate

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Photovoltaic applications

• Mounted on roofs or walls
• Roof tiles
• Integrated into blinds or glazing
• Independent of the building
• Street furniture

PV / ST The relative energy output of PV to
ST for any given area of collector can be around
2.5 to 6 less resulting in a 1/3 of the CO2
saving from PVs than from ST
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Photovoltaic technologies

• Crystalline Silicon (mono- and poly- types )
• Amorphous Silicon (thin film)

• Rating
• In Watts Peak (Wp)
• Crystalline approx 100Wp/m2
• Amorphous - approx 60Wp/m2

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Photo voltaic assumptions and carbon savings

• Yield 850 kWh/kWp
• Grid displaced electricity factor 0.568 kgCO2/kWh
  
• The relative energy output of PV to ST for any
  given area of collector can be around 2.5 to 6
  times smaller saving 1/3 of the CO2 savings from
  ST
• Typical PV costs 850 /m2.
• Cost to NHS 1,732.5m

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Norfolk NHS Acute Adult Units

• Solar hot water collectors
• Saving by solar 14 20
• Equivalent to 6.38 tonnes of CO2 emissions saved
• Photovoltaics
• South facing arrays 200m2 each unit
• Supply about 25 of each buildings electricity
  demand

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CHP technology check

• A revenue creating device
• To be cost effective CHP requires
• the plant to operate for long hours gt 4500hrs/a
  to achieve economic pay back.
• A significant difference between fossil fuel and
  electricity costs/ kWh.
• Cost 750/kWe
• Gas reciprocating engines likely to provide the
  most robust solution
• Maximise heat loads available to the CHP
• Dont oversize - do the energy efficiency
  measures first
• Maximise the hours run
• Maintain it
• Consider finance options

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Potential for CHP in the NHS based on 2006/7 NHS
ERIC energy returns

• Current CHP installed capacity 100MWe
• Potential for CHP 70 MWe
• CHP potential is equivalent to 1.85 of all NHS
  CO2 emissions equivalent to 65,000 tonnes of CO2
  annually
• 4000 tonnes of CO2 could be saved by improving
  the performance of existing CHP.
• 6 of the NHS CHP was achieving 78 efficiency
• CO2 savings only became apparent at CHP
  efficiencies of around 65
• 72 efficiency with around 4 CO2
• 78 efficiency with around 8 CO2 savings

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CHP potential based on the 2006/7 ERIC analysis
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CHP outcomes based on modelling changes to the
NHS estate

• Saving in emissions 4.7 KgCO2/m2.
• As performance of buildings and heating increases
  CHP potential falls

Guy's and St Thomas' NHS Foundation Trust
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Heat pumps

• Extracting low-grade heat from surrounding
  ground, air or water and converting it to higher
  grade heat for buildings
• Electrically powered, but provides more energy as
  heat than it consumes as electricity
• Significant savings in CO2 emissions
• Several types of heat pump technology
• Ground source
• Water source
• Air source

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Potential for ground source heat pumps

• Need ground space so more applicable to non Urban
  sites
• The laws of thermodynamics mean that heat pumps
  are most energy efficient when temperature
  differences between the collector and emitter are
  low.
• Building heating and cooling systems need to be
  designed to work with this fact.
• if seasonal COP drops below 2.5, the use of GSHP
  increases CO2 emissions when compared to
  efficient gas boilers

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GSHP technology check

• If applied 100 of potentially could reduce
  emissions by 3.88kgCO2/m2
• If applied 80 potentially could reduce
  emissions by 3.1kgCO2/m2

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Hellesdon hospital

• 100kW system
• 120 boreholes

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Case study

• Churchill Hospital, Oxford
• Ground source heat pump system
• 250 geothermal heating boreholes
• Twenty internal heat pumps each 100kW to provide
  heating and cooling to the hospital
• Each borehole will be 130mm in diameter and 135
  metres deep
• Polyethylene pipework system externally
• Around 2/3 cost of conventional boiler and
  chiller system
• Around 37 reduction in running costs

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Potential savings from Biomass

• Assumptions
• Rural areas and the edges of urban areas and
  hospitals with large sites
• Leading to an annual consumption of 8000GWh/a
  requiring 4 Mtonnes of wood chips annually

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Biomass

• Wood or crop waste
• Limited supply
• Woodchip cheaper than gas / kWh
• Biomass as lead boiler(s)
• Typically sized for 100DHW
• and 40 space heating
• Costs 300/kW installed
• for larger installations

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Wind Power

• http//www.bwea.com/noabl/download.htm
• Modelled on 1km grid squares
• Scotland, Wales, NI well blessed!
• Always datalog first for large projects
• Power Cube Law 1/2 x Ro x Swept area
• x V3
• Betz limit of 59
• Machine performance usually less
• Check your wind speed!
• Need clearance of 5-10 rotor diameters

• mean annual wind speeds are available for 10, 25
  and 45m above sea level

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Wind power

• Power generated by
• Single turbines
• Small clusters
• Wind farms
• The taller the tower, the greater the power
• Can be stand-alone or grid connected

Estimated annual energy output at wind turbine
hub height (in thousand kWh/yr)
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Assumptions and carbonsavings from wind
generation
Antrim Area Hospital 660kW wind turbine generator
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Case study wind energy
Wind farm feasibility at HMP Haverigg, Cumbria

• Exposed headland, av. wind speed 7.3 m/s
• Loads 120-600 kW, annual energy 2287 MWh
• 850 kW installed wind capacity recommended
  (530k)
• equates to annual average power 295 kW
• annual energy 1516 MWh on site
• export of 1060 MWh to grid predicted
• Net annual benefit to HMP 14.5k
• Existing row of wind turbines on adjacent
  farmland, local planners, etc., have no
  objections

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Grant support /feed in tariffs

• LCBP -www.lowcarbonbuildings.org.uk
• 50 grants
• Feed-in tariffs reward the generation of
  renewable electricity from April 2010 up to 5 MW
  Including
• Wind
• Solar photovoltaics (PV)
• Hydro
• Anaerobic digestion
• Biomass and biomass combined heat and power (CHP)
• Non-renewable micro-CHP.
• Renewable Electivity Financial Incentives
  consultation
• Renewable heat incentive (RHI) rewards the
  generation of renewable heat from 2011.

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Contacts

• Renewable Energy Association www.r-p-a.org.uk
• British Photovoltaic Association
  www.pv-uk.org.uk
• The National Energy Foundation www.nef.org.uk
• Low Carbon buildings programme
  www.lowcarbonbuildings.org.uk
• Energy Saving Trust http//www.energysavingtrust
  .org.uk
• BRE Consultancy www.bre.co.uk
• UK Microgeneration Certification Scheme
  www.ukmicrogeneration.org

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Conclusions

• Its cheaper to save energy than to generate new!
• Technologies are at different stages of
  development, which in turn affects costs.
• Renewable energy should be seen as integral in
  the solution
• Energy efficiency
• Renewable energy
• Efficient fossil fuel use

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More information

• buildingdesignconsultancy_at_bre.co.uk
• 01923 664290
• On the IHEEM Sustainability stand