This presentation formed part of the Farming Futures workshop 'Focus on: Renewables in the South East'. 11th February 2009

1. Renewable technologies
overview - do they work?
Paul Holmes-Ling CEnv.

2. Introductions
Paul Holmes-Ling CEnv.
• Environmental Consultant for the last 12
years.
• Working primarily with farmer, landowners
and tourism businesses.
• Currently involved with a wide range of
energy related projects.

3. What are we going to cover?
• Solar
• Heat pumps
• Small scale hydro
• Wind
• Biomass
• Biogas

4. Consider… £
Heat
What are your What
Heat and
Efficiencies
energy resources
power first
requirements are available
Power

5. Renewable Energy - Introduction
Heat Power
Combined heat and
Power (CHP)

6. Renewable Energy - Introduction
1 definition - ‘Using natural replenishable
resources to create energy’
• Sunlight
• Water
• Wind
• Biomass
• Biogas
• Heat pumps

7. Renewable Energy - Solar
Introduction
• Energy derived from the sun
• Passive heat – this is heat derived naturally from
the sun and can be taken into account during
building design to reduce heating costs
• Solar thermal – the suns heat is used to provide hot
water
• Photovoltaics (PV) – using the suns energy to
create electricity.

8. Renewable Energy - Solar
Passive heat
• Incorporating features into buildings that
absorb and then slowly release heat
• No mechanical parts!
• For example large windows, stone floors.
• Can save 50% of energy costs within a
new build and often adds nothing to the
capital cost.

9. Renewable Energy - Solar
Passive heat

10. Renewable Energy - Solar
Passive heat – case study – Brighton
Earthship (www.lowcarbon.co.uk)

11. Renewable Energy - Solar
Solar thermal - background
• Available since the 1970s – technology well developed,
proven
• Large choice in the market place
• One of the cheapest renewable options
• Can provide all hot water during the summer and about
60% year round
• Quick carbon payback
• ‘normally’ considered permitted development
• 30 – 40 % efficient

12. Renewable Energy - Solar
Solar thermal – what do you need?

13. Renewable Energy - Solar
Solar thermal – case study
Dairy Farm – Oxfordshire
• 130 dairy cows
• Main electricity use is heating a 300 litre water storage
tank – used for twice daily cleaning = 70% of energy
use
• Electricity also used for cooling milk (and lighting etc.)
• Electricity use is 40,000 kWh day rate units and
20,000 kWh night rate units = 462kWh per cow
• Annual electricity spend = £5400

14. Renewable Energy - Solar
Solar thermal – case study
Dairy Farm – Oxfordshire
• 2 roof mounted solar panels (2.4m2)
• 300 litre dual coil storage system
• Controller unit
• Pump
• TOTAL cost £4000

15. Renewable Energy - Solar
Solar thermal – case study
Dairy Farm – Oxfordshire
• Annual energy savings of 50% of water heating costs
= £1890
• Payback = 2.5 years or 47% return!

16. Renewable Energy - Solar
Solar thermal – typical costs
• Costs vary depending on the technology used
however the sizing is usually worked out on the size
of the ‘buffer’ tank required.
• 200 litre tank and 2.2m2 of evacuated tubes - £3,000
• 500 litre tank and 5.4m2 of evacuated tubes - £5,000
• Flat plate collectors tend to be cheaper than
evacuated tube systems, but are less efficient
particularly in the winter months when the heat is
needed!
• Important to consider the length of guarantee offered

17. Renewable Energy - Solar
Photovoltaics (PV) – How does it work?
• 1 or 2 layers of a semi conducting material
(usually silicon)
• Light shines on the cell and creates an
electric field across the layers
• The greater the intensity of light the greater
the flow of electricity.
• Efficiency is 12 – 17% depending on
materials used.

18. Renewable Energy - Solar
Photovoltaics (PV) – Background
• Easy to integrate into new and existing buildings
• Virtually no maintenance
• Rapidly improving technology
• Long life with no moving parts
• Most expensive micro renewable technology – long
paybacks
• Needs large roof space area and aspect between SE and
SW.
• Good for small off grid situations
• Can be combined with other renewable technologies

19. Renewable Energy - Solar
Photovoltaics (PV) – case study 1
Green ‘wedding and function’ venue
• Converted barn
• Used on average twice a week for events
• Annual electricity usage – 4500kwh

20. Renewable Energy - Solar
Photovoltaics (PV) – case study
• Solution a 5.5 kw peak PV system
installed
• 45m2 of roof spaced required
• Meters upgraded
• Potential output (5.5 X 850) =
4675kwh
• Cost £30,000

21. Renewable Energy - Solar
Photovoltaics (PV) – case study
Expenditure £
TOTAL Capital cost 30,000
Annual Income
ROCS 420 4675 *9p (based on 2 ROCS – see energy
income section)
Annual Savings 467.50 Presuming all electricity is used on site.
Energy price of 10p / kWh has been used
TOTAL Income and 887.50
savings
Payback 33 years
• 50% grant achieved through LEADER
• Key benefit is through marketing as a green
venue – PV is highly visible

22. Renewable Energy - Solar
Photovoltaics (PV) – typical costs
A typical system providing half an average families
annual electricity supply, typically covering 10-15m² of
roof space and generating 1.5- 2kWp (kilowatt peak)
would cost between £4000 and £8000 per kWp
depending on the site and materials used.
A typical small off grid system producing 500Wp (with
a 24Vdc, 400Ah battery and 900W inverter and all
wiring) would cost around £5,000. This system would
provide enough power for a small building for example
a shed or equestrian building with 5 20W low energy
bulbs (each on for 5 hours a day)

23. Renewable Energy – Heat pumps
Heat pumps - background
• Heat pumps use the same technology as
refrigerators but in reverse, moving heat from one
place to another. Ground Source (GSHP), Air
Source (ASHP) and water (WSHP)
• Heat pumps can provide space heating, cooling and
water heating.
• Heat pumps are not truly renewable as the working
fluid is driven around the system by an electrically
powered pump
• Very good paybacks achieved
• There is a heat pump to fit most circumstances and
budgets

24. Renewable Energy – Heat pumps
Heat pumps – background
• 3-5 times more efficient than a conventional boiler
• A GSHP can provide up to 100% of a buildings
heating requirement – therefore no back up system
required. ASHP may only provide 60 – 70%
therefore back up system required.
• No planning required in most cases.
• GSHP not easy to retrofit. ASHP are.
• Requires a ‘wet’ heating system ideally under floor
heating
• Reliant on grid electricity (unless attached to
another renewable technology)

25. Renewable Energy – Heat pumps
Ground Source Heat pumps
• In the UK the ground a few feet below our feet
maintains a constant temp. of 11 – 12ºC year round
• GSHP transfer this heat into a building to provide
space heating and occasionally hot water
• For every unit of electricity used to pump the heat 3-
4 units of heat are produced.
• To be 100% renewable you would need to generate
your electricity from a ‘renewable source.

26. Renewable Energy – Heat pumps
Heat pumps work by:
• Refrigerant in the evaporator is colder than the
heat source, therefore heat moves across causing
refrigerant to evaporate.
• The vapour moves to the compressor, where it
reaches a higher temp and pressure.
• The hot vapour enters a condenser and gives off
heat as it condenses – this is transferred to the
heating system.
• The refrigerant then moves to the expansion valve,
where it drops in pressure and temperature and
returns to the evaporator.

27. Renewable Energy – heat pumps
GSHP what do you need?

28. Renewable Energy – heat pumps
Air source pumps
• As the temperature variations are greater, the
COP (coefficient of performance) declines with
temperature.
• Therefore more electricity is required.
• Usually can provide 50-75% of heating
requirement (Ground source 75-100%), and
therefore more likely to utilise other heating
sources.
• Shorter life than ground source as more
‘exposed’ parts
• However suitable for many applications

29. Renewable Energy – heat pumps
water source pumps
• Requires a water body!
• Very efficient if groundwater used
• Open water less efficient (greater COP as
greater temp. variation)

30. Renewable Energy – heat pumps
GSHP – case study
• Plumpton College – new science centre
• Requirement for heating (620m2) and hot
water (35-40ºC)
• Field adjacent to building

31. Renewable Energy – heat pumps
GSHP – case study
• Viessman heat pump
• ‘Wet’ under floor heating system
• 200L buffer tank (with immersion heater)
• 300ms of coil in 6 - 50m trenches, 1.8m
deep and 30cm wide with 5 m separation –
total area = 1340m2 = 0.134ha

32. Renewable Energy – heat pumps
GSHP – case study
Heating system Capital cost Economic life 10yr lifetime fuel cost 10 year lifetime cost annual CO2 poduction (Kg)
GSHP 35,000 20 27,190 62,190 195
31kw LPG boiler 6,500 15 133,134 139,634 503
10 year savings 105,944
annual savings 10,594
Payback 3.03 years
Assumptions:
30.7kw heat load
annual energy consupmption 2071kWh/ year
electricity @ 6p kWh
LPG @ 4.5p kWh
GSHP includes £16,000 for ground works
COP (coeficience of performance) of around 4.57 - therefore with electricity at 6p for every 1kwh of thermal energy produced
only 1.31p of electricity will be required

33. Renewable Energy – heat pumps
GSHP – ‘typical costs’
A typical system to heat a 3 bedroom house would
require an 8kW system, which would cost in the range
of £800 - £1400 per kW of peak output with trench
systems being at the lower end of the range. Typical
installed cost of an 8kW system would be between
£8000 and £14000 plus the cost of the distribution
system (ideally underfloor heating).
An equivalent air source system would cost between
£500 - £700 per peak kW output, but has a lower COP
and cannot provide year round heating requirements
meaning more electricity or alternative heating source
will be required.

34. Renewable Energy - Wind
Wind turbines - background
• Converting the power of moving air into rotating
shaft power and electricity
• Power from the wind is proportional to the wind
speed – small variations make a big difference to
output
• Big variations in turbine sizes from a few hundred
watts to 2- 3MW
• Wind turbines create a DC supply. Needs a
‘converter’ to change to AC.

35. Focus on wind
The UK wind resource
• We have 40% of Europe's total wind energy
resource!
• Largely untapped – currently meeting 0.5% of our
electricity requirements
• It is theoretically possible to obtain 1000TWh or
electricity per annum – 3 times the UKs total energy
demand!
• Practically, due to protected areas, residencies, grid
strength and economics we could achieve 50TWh
per annum (on land)

36. Renewable Energy - Wind
Wind turbines – how do they work?

37. Renewable Energy - Wind
Wind turbines – local wind conditions
Wind speed at 10m above ground level (m/s)
5.6 5.6 5.3
5.3 5.7 5.5
5 5.6 5.7
Wind speed at 25m above ground level (m/s)
6.4 6.4 6.2
6.2 6.5 6.3
5.9 6.4 6.5
Wind speed at 45m above ground level (m/s)
6.9 6.9 6.8
6.7 7 6.8
6.5 6.9 6.9
• Available on NOABL wind database –
www.bwea.co.uk

38. Renewable Energy - Wind
Wind turbines – local wind conditions –
what does this mean?
• Power generated is related to wind speed by a
cubic ratio.
• Therefore if you halve wind speed the power goes
down by a factor of 8 (2 X 2 X 2), a quarter of the
windspeed gives you a 64th of the power (4 X 4 X
4).
• Really need an average wind of over 6m / s

39. Focus on wind
Types of turbine
• Big variations in turbine sizes from a few hundred
watts to 3MW
Make / mode Swift 1.5 Proven 2500 Proven 6000 Westwind 20 WinWind 1
rating 1500Wp 2500Wp 6000Wp 20000wp 1MWp
1.5kwp 2.5kwp 6kwp 20kwp
Height (m) 1.75 10m 15m 18 70
Blade diameter 2.1 3.5 5.5 10.4 60
(m)
Expected energy 1031kwh 3164kWh 7805kwh 23,000kwh 1,000,000kwh
production – per
annum
Cost (£) 1,600 10,900 22,000 50,000 350,000
No. of 0.2 0.8 2 6 90
households!

40. Renewable Energy - Wind
Planning
• Usually requires planning permission from
local authority
• Planners will consider visual impact, noise
and conservation.
• Discuss with your planner early!

41. Focus on wind
Case study – 20kwp westwind turbine
• Farm in Chichester – good average winds
of 13 m /s at 15m.
• Large energy requirement for student
accommodation and offices (anemometer)
• Turbine size based on how much they
wanted to spend and paybacks!

42. Focus on wind
Case study – 20kwp westwind turbine

43. Renewable Energy - Wind
Case study – 20kwp turbine
• 15m tower plus 10m blades
• Costs £40,000 + 10,000 for cabling plus
£1,500 annual maintenance.
• Produced 30,000kWh per annum

44. Renewable Energy - Wind
Case study – 20kwp turbine
Expenditure £
TOTAL Capital cost 50,000
Annual Income
ROCS 2,700 30,000 *9p (based on 2
ROCS )
Annual Savings 3,000 Presuming all electricity is
used on site. Energy price
of 10p / kWh has been
used
TOTAL Income and 5,700
savings
Payback 9 years

45. Renewable Energy - Wind
Bigger = better paybacks
Expenditure 20kwp 6kwp
TOTAL Capital cost 50,000 30,000
Annual Income
ROCS 2,700 702
Annual Savings 3,000 780
TOTAL Income and 5,700 1,482
savings
Payback 9 years 20 years
If wind conditions good and you
can use or sell all the energy

46. Renewable Energy - Wind
Case study 2 – large turbine – Westphalia
- Germany
• 7 farmers formed a co – op
• 65m capable of producing 1,000,000kWh per
annum
• Actually produces 600,000 – 700,000 kWh per
annum
• Capital cost E500,000
• Energy is supplied to local village (average
house uses 3000kW per year)

47. Renewable Energy - Wind
Case study 2 – large turbine – Westphalia
– Germany
Income £ Notes
Electricity sales 60,000 1000MW @ £60MW
LECs 4,000 1000MW @ £4MW
ROCs 39,000 1000MW @ 39MW
TOTAL SALES 103,000
Expenditure
Rent 1,000
Maintanence £6,700
Depreciation 17,000
Finance 17,600
Total Over heads 42,300
Net Margin 60,700

48. Renewable Energy - Wind
Case study 3 – Chicken Farm Berkshire
• ‘Off grid’ system
• 500 bird units
• 24 hour lighting required in early
stages of life
• Houses regularly moved
• Cost of grid connection 50K +

49. Renewable Energy - Wind
Case study 3 – Chicken Farm Berkshire

50. Renewable Energy - Wind
Case study 3 – Chicken Farm Berkshire
• Combined wind and solar system
• 270Ah deep cycle battery – (can store 3
days worth of energy)
• Whole system is mobile
• Cost £5000 per chicken house

51. Renewable Energy - Wind
Typical costs
• Including mast, inverters, turbine and
installation would range from £2,000 for a
1kw system average estimated power
output per year to £18,000 for a 6kw
system.
• A 1MW system may cost in excess of
£350k

52. Renewable Energy – small scale
hydro
Small scale hydro - background
• The oldest method of harnessing renewable energy
• Uses the stored ‘kinetic’ energy to turn a turbine
and create electricity
• Allowances need to be made for seasonal
variations
• Efficiency is 50 – 90% depending on system
• Energy source is ‘predictable’

53. Renewable Energy – small scale
hydro
Small scale hydro - background
• Micro hydro refers to systems producing less than
100kWh
• 2 kinds of system
• ‘low’ and ‘high’ head
• ‘Low’ head – old mill sites with weirs and sluices
• ‘high’ head – fast flowing streams (usually upland).

54. Renewable Energy – small scale
hydro
Small scale hydro – how do they work?
• An intake
• A penstock pipe
• A powerhouse
• An outflow
• Cables to transmit elec.

55. Renewable Energy – small scale
hydro
Small scale hydro – permissions
• Planning
• An abstraction license

56. Renewable Energy – small scale
hydro
case study 1 – the mill at Sonning
• Existing mill with race and wheel
• High energy use for cinema and attractions
during the day
• Low use and export at night

57. Renewable Energy – small scale
hydro
case study 1 – the mill at Sonning
• 18.5kW Propeller and turbine fitted
• EA permissions granted, no abstraction
license as ‘Millers rights’
• Project cost £54,000
• Generates about 153MW/year

58. Renewable Energy – small scale
hydro
case study 1 – the mill at Sonning
2006 / 2007
Income £s Notes
Energy sales 2,280 76MW * £30 (3p / kW)
ROCs 5,967 153MW*39
LECS 612 153MW*4
Total income 8,859
Savings 4,408 76MW * £58 (5.8p kW)
Total 13,267

59. Renewable Energy – small scale
hydro
case study 1 – the mill at Sonning
2008/ 2009
Income £s Notes
Energy sales 3,876 76MW * £51 (5.1p / kW)
ROCs 5,967 153MW*39
LECS 612 153MW*4
Total income 10,455
Savings 7,828 76MW * £103 (10.3p kW)
Total 18,283

60. Renewable Energy – small scale
hydro
case study 1 – the mill at Sonning
• Seasonal variation – trash rack fills in the
autumn and needs regular cleaning
• No good in floods as no head!
• Potential to expand and double the power!

61. Renewable Energy – small scale
hydro
Small scale hydro – further information
• www.britishhydro.org.uk
• www.flowline.co.uk
• www.segen.co.uk/hydro
• www.hydrogeneration.co.uk
• www.environmentagency.org.uk

62. Renewable energy – biomass
• Focus on woodchip

63. Woodland Cover in SE England:
Ancient Woodland
Other Woodland

64. The Resource
Woodland Cover in South East England
% Ancient & Plantations Total
County: Woodland Woodland Total Land semi- on ancient ancient
Area Cover Area natural woodland woodland
woodland sites
(as per Figures comprise all land which featured
2002 on the Provisional Ancient Woodland
Inventory & Inventory and in the 2,000 Inventory
inc. all
woods >
0.1 ha)
Berkshire 18,308 14.5 125,880 3,600 1,770 5,370
Buckinghamshire 17,573 9.4 187,675 4,885 3,910 8,795
Oxfordshire 18,235 7.0 260,595 5,075 2,650 7,725
Surrey 37,564 22.4 167,715 6,640 2,640 9,280
Hampshire 66,939 17.7 377,870 18,680 9,290 27,970
Isle of Wight 4,549 12.0 38,015 800 710 1,510
West Sussex 37,507 18.9 198,810 9,530 7,300 16,830
East Sussex 29,924 16.7 179,540 12,055 6,135 18,190
Kent 39,487 10.6 373,500 18,780 8,280 27,060
TOTALS: 270,084 14.0 1,909,600 80,045 42,685 122,730

65. What might this provide?
• Conservatively all woodland in SEE is growing
at, at least, 4m3 per ha per year = > 1,000,000m3
• Of this perhaps 25% may be readily available for
the wood fuel market = 200,000 dry (30% mc)
tonnes = 70 million litres of oil
• Could be much more but is price dependent

66. Fuel costs
per kWh

67. Value of Coppice used for Fuel
15 year old sweet chestnut yields 70-80 tonnes/acre Standing Value
75 tonnes/acre (180t / ha)
If you can sell worth £100-200 say £150 £150.00
Sell as fuel 60t @ £50 / t £3,000
Cost of producing woodchip
For woodchip - 1 acre felling £10 / t - £750 £750
Chipping £10 / t £600
Delivery £10 / t £600
Sundries £5 / t £300
£2,250 £750.00
NB 75 t green @ 50% moisture content
air seasoned to reduce MC to 30%
Weight reduces to 60 tonnes
1t woodchip@30%mc is approx equal to 400 litres of heating oil
60 t is approx' 24,000 litres
Woodchip can reduce heating costs
Increase income for woodland owner
Improve Woodland management - grants etc
Sell the best chip the rest!

68. Carbon Dioxide Emissions From A Single Family Home
Using 18,000kw hours per year
5,000kg
4,140kg 90kg
Fossil CO2
Fossil CO2 Fossil CO2
Oil Gas Wood

69. HOW?
Do you get from the woodland to the boiler?

70. Medium Scale Heat

71. Medium Scale Heat

72. Case Study
Conversion of farm buildings to offices
with communal woodchip heating
system

78. Worten Farm Office Conversion
3 Units – gross internal area 3,200 sq ft
Oil Woodchip
Capital Costs £7,500 £26,000
Annual Fuel £2,150 £600
Cost
Additional Cost of Woodchip System £18,500
Saving £1,500 per annum
12 years to recoup additional cost at current oil
price

79. Annual Fuel Price Comparison
3000
2500
2000
1500 Oil
Woodchip
1000
500
0
Budget Actual
Budget oil costs based on 30p/litre. Actual cost 48p/litre
Woodchip costs based on £50 per tonne

80. Renewable Energy - CHP
Combined Heat and Power

81. Renewable Energy - CHP
Combined Heat and Power – Trial site
• Requires 2.5 tonnes of biomass a day –
forestry waste, straw, woodchip, miscanthus
etc.
• 100kWh of electricity through a micro air
turbine
• 200kWh of hot water
• Cost approx £300,000

82. Renewable Energy – Biogas
Biogas – Anaerobic digestions -
background
• A natural process where bacteria breakdown
organic matter in an environment with little or no
oxygen
• Methane is produced (plus about 40% CO2)
• Methane is burnt in an engine to produce energy
and hot water
• Usually large scale collaborative projects
• A 500Kw plant would cost in excess of £1,000,000

83. Renewable Energy – Biogas
Biogas – Anaerobic digestion
manure
CHP
Agricultural Gas
residues storage
Digestate storage
Imported
organics pasteurisation digester

84. Renewable Energy – Biogas
Biogas – Anaerobic digestions –
background

85. Renewable Energy – Biogas
Case study 2 – 500kWh plant on dairy
farm
• 4 farmer Co – op
• 1.5 ha site (planning a big issue!)
• Plan to digest 20,000m3 of manure and 7,000 m3
of maize
• Expected production 4,000,000kW / year
• Plus 2,000,000kW hot water per year
• Long term plan to move from maize to food ‘waste’

86. Income MWh / year rate Total
Electricity sales 4,000 45 180,000
Hot water sales 2,000 0 5,000
digestate sales 0 0 0
ROCs 4,000 80 320,000
LECs 4,000 4.4 17,600
(gate fees) 0 0 0
Total 522,600
Expenditure
maize 300ha £400 / ha 120,000.00
land rental 300ha £150 45,000.00
cereal -
slurry / manure -
labour 1.00 50,000.00
management costs 10% 5,000.00
water 12,000.00
electricity 12,000.00
fuel 4,000.00
spreading digestant 4,000.00
annual maintanence 16,000.00
maintenance contract -
ROCS mmt. Charges 2,000.00
electricity charges -
fees / charges (legal) 10,000.00
insurance 5,000.00
sundry 5,000.00
accountancy fees 3,000.00
depreciation 157,333.00
interest 88,114.00
Total 538,447.00
Net profit / loss 15,847.00

87. Consider… £
Heat
What are your What
Heat and
Efficiencies
energy resources
power first
requirements are available
Power

88. Paul Holmes-Ling
paul@laurencegould.com
0771 3334821
01444 232822