Resources and Needs

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Resources and Needs

• What to do with what ?
• Duncan Kerridge

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Aims what do you want to achieve ?

• Local energy self-sufficiency
• Carbon reduction
• Increased awareness
• Better energy efficiency
• Lower bills - fuel poverty
• Community (re-) generation
• Income generation

3
Resources

• Ambient sun, wind, water, biomass
• Human skills, enthusiasm, cohesion
• Financial grants, sponsors, investors

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Needs

• Global carbon reduction
• Local pollution, social cohesion, regeneration
• Personal fuel poverty, improved conditions,
  doing your bit, taking control

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Approach

• Energy efficiency - reducing demand and costs
• Energy production
• Energy supply (group purchase)

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Carbon footprint
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Resource assessment

• Solar maps
• Wind NOABL, met stations
• Hydro catchment and rainfall, Hydra
• Biomass local production of wood, crops, slurry
• GSHP space / water / holes
• Web - RETScreen, etc

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Scale

• Grid-connected electricity
• large turbines small PV
• Heat buildings, district heating
• Stand-alone electricity

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Energy efficiency

• Loft insulation
• Compact fluorescent lights
• Draught proofing
• Advisory services (e.g. AAT)
• Many grants available
• Very cost effective but less glamorous
• Focus on fuel poverty and vulnerable residents

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Wind power

• Most cost effective RE generation
• Main difficulty is perceived visual impact
• Grid connected turbines sell power to electricity
  supply companies
• ROCs gt premium price
• 500 kW turbine, 35m high could supply 400 homes
• Power sales 75,000 p.a.
• Capital cost 300k

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Wind resource

• Site specific
• Power increase with cube of the wind speed
• UK has best European resource
• NOABL database (BWEA website)

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Small Scale Wind

• Excellent for remote area supplies
• Very site specific
• Intermittent supply
• Require batteries for electricity storage, or
  grid connect
• Typical output range 50W-15kW
• Grid connection possible

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Medium wind turbine
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Solar

• Natural day lighting
• Passive solar heating
• Conservatories
• Solar water heating
• Photovoltaics
• Plenty of sun energy 60 of that at equator

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Annual Solar Resource
UK annual average solar radiation 2.5 kW/h per m2
per day on horizontal surface Very season
dependent
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Grid Connected Photovoltaics

• Grid acts as battery - buy and sell through
• Average household - 4,000kWh /year
• 4 kWp photovoltaics 25 m2
• Could cost around 15,000 - 20,000
• Energy Payback - 2 to 5 years
• Financial payback - very slow!
• CO2 saved - around 1 tonne?

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Solar Thermal (Hot Water)

• Provides up to 60 of domestic hot water supply
  in UK conditions (100 summer, 15 winter)
• Over 50,000 in UK
• Many different types to suit most applications
  and sites
• Domestic systems 2000 - 4000 installed

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Heat pumps

• Stored solar energy
• 1kW electricity in 3 - 4 kW heat out
• (may be able to use hydro to direct drive
  compressor)
• Fossil fuel power stations - typically 30
  efficient - 3kW heat in 1kW electricity out
• Only worthwhile with green electricity

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Micro Hydro

• Very site specific
• Good source if available
• Power (watts) flow (l/s) x head (m) x 5
• Abstraction licence
• Cost 1/3 turbine, 1/3 civil works, 1/3 electrical
• 6,000 for 1kW battery charging turbine to 250k
  for 120 kW (costs very variable)

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Biomass

• Includes timber, straw, corn, animal wastes etc.
• Woodchip, logs or pellets can be used for heating
  
• Virtually carbon neutral
• Local resource
• Individual or district heat
• Larger scale CHP
• Supplier co-ops or ESCos

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Small scale biomass

• Log stoves
• Log boilers
• Pellet stoves
• Pellet boilers

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Woodchip boilers

• 30 kW - 2 MW
• Able to tolerate higher moisture content
• Chip quality important
• Bulky fuel storage required
• Automatic

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Biomass District Heating

• 500 kW wood chip boiler
• local fuel supply
• primary school and community centre
• 20 - 40 local houses

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Anaerobic digestion

• Biological conversion of bio-matter into gas
• Suitable for farm slurry
• On farm or centralised plant
• Heating or power generation
• Possibility for sewage works
• High costs - need to sell power, heat and
  co-products for viability

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Anaerobic digestion

• Centralised AD plant - Holsworthy
• 30 farms within 5 mile radius
• 150,000 t/yr slurry, pasteurised
• 2 x 1 MW gas engines produce 14,000 MWh/yr
• Heat main
• 7.7 million, 50 EU funding
• 1.1 m annual turnover, 450 k expenses

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Energy from waste

• Renewable ?
• Incineration unpopular
• Gasification overcomes emissions problems
• Technology still developing
• Small modular units driving CHP

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Costs of small-scale renewable energy
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Green electricity supply

• Cheaper to buy than produce your own
• Green supply vs green fund
• Accreditation, Certificates of Origin
• 5 10 cost premium

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Energy Clubs

• Group purchase schemes in fuel poverty areas
• Commission returned to club for use in efficiency
  improvements and bill support
• Green electric group purchase

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Transport

• 30 of primary energy use
• Need an integrated strategy
• Encourage alternatives walking, cycling, car
  share
• Improve public transport
• Alternative fuels LPG, biodiesel, hydrogen

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Conclusions

• Cheaper to save power than generate it
• Efficiency, transport and local food schemes very
  carbon effective
• Large scale power production is more cost
  effective
• Solar, biomass and GSHP evenly spread resource
• Wind and hydro very site specific
• What are you hoping to achieve ?