RESCO
Biomethane for Grid Injection
supply chain workshop
29th Sept 2011
‘The energy view’
Iain Ward BSc. C. Eng. MIGEM
CNG Services Ltd
www.cngservices.co.uk
Summary
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CNG Services Ltd
Making biogas
Biogas clean up and upgrading
Biomethane to grid plant
BtG Projects
Biomethane Utilisation
• Efficiency
• CO2
• Value
• Summary
CNG Services Ltd
• Supporting development of the BtG and CBM markets in
the UK:
• Cleaning bio-gas and injecting biomethane into the gas grid (BtG)
• Creator of the UU Davyhulme BtG and CBM Project
• Developing the Didcot project for Thames Water, SGN and Centrica
• Supporting a further 15 potential BtG Projects in the UK for Water
Companies and AD developers
• Supporting introduction of compressed biomethane (CBM) fuelled
vehicles in the UK
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VW Caddy Ecofuel
MB Sprinter NGT and Econic NGT
Iveco Daily and Eurocargo
MB and Volvo dual fuel tractors
We are independent from all makers of CHP plant, vehicles, clean-up,
compression etc. Our aim is to support biogas producers in exploiting
the biomethane to grid and compressed biomethane for vehicle
opportunities
What is Biomethane?
• Bio-gas from an anaerobic digester contains typically 65% methane,
35% CO2
– Lager shandy
• Natural gas contains around 90% methane, with ethane, propane,
butane, CO2 and nitrogen making up the rest
– Blended whisky - made from dinosaur poo in a prehistoric AD, contaminated over the
millenia
• Biomethane is bio-gas without the CO2, containing around 98%
methane
– Malt whisky, the elixir of life, we all want to drink it
So, we can make biomethane from organic material in an AD (waste
food etc) or from wood in a gasification plant – better than landfill
Anaerobic Digester and Uses for Biogas
Drawing courtesy of the German Renewable Energy Agency
http://www.unendlich-viel-energie.de/en/bioenergie/biogas.html
Gasification and Methanation
Schematic courtesy of the International Gas Union - British Gas used to
do this from coal (plant closed in 1985 when it was clear that UK had a
lot of gas)
UK Biomethane Potential
Netherlands
UK gas production
UK gas – sold at 20 p/therm for power generation…..by 2025, UK gas
production from North Sea and from organic matter will be similar
Biomethane to Grid (BtG)
Widespread consensus that gas grid injection is attractive because
of absence of uses for waste heat where renewable methane is
made. Take the gas to the customers along existing pipelines and
have high efficiency utilisation….
Making Biomethane
From
Anaerobic
Digester
Lots of ways of cleaning up
raw biogas to make
Biomethane with the
technology shown as
a ‘black box’
This shows biomethane going into the
gas grid, with addition of propane (to
increase the calorific value) and
odorant (to give a smell)
Gas
Grid
Water Wash
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99% of biomethane to grid, 1% methane vented
Can recover heat from larger plants (from cooling water)
12 m high – can have planning issues
Removes H2S and siloxanes
Likely to be lowest cost option
Didcot 2010 (Chesterfield Biogas)
Chemical Absorption
• 99.5% of biomethane to grid, <0.5% methane vented
• Needs significant heat to regenerate the chemicals (15 –
20% of biogas)
• Ideal if waste heat already available
Pressure Swing Adsorption
• 92% of biomethane to grid, 8% of methane goes with the CO2
• This gas can be flared or burnt in CHP or boiler (but needs to be
brought back to 33% methane)
• No methane vented
• Small footprint
• Likely for UU Davyhulme 2011
Membrane Separation
• Few membrane plants
• Contamination of the membranes is an issue
• May be a good technology – similar to PSA in that gives a
waste CO2/CH$ stream that should be used to generate
electricity or make heat
BtG Plant
BtG Plant – Biomethane to Grid plant comprises the
following:
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Propane storage and injection
Odorant storage and injection
Gas quality monitoring
Gas CV measurement
Gas flow measurement
Pressure control
Telemetry
The BtG plant is located after the Clean-up and Upgrading
Plant and before the gas grid
Propane Enrichment Plant
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Gas Thermal Energy Regs set a Flow Weighted Average CV for gas
networks, max 1 MJ difference between grid inputs
Typically around 39.5 MJ/m3
Pure CH4 has a CV of around 36 MJ/m3
Accepted that propane addition is the technically best resolution
Accuracy of dosing paramount to meet CV and WI limits
Incurs substantial Opex; “methane value loss”, energy deducted from RHI
entitlement
Control system required to manage
On-site storage, contracts for supply
BtG Plant – Ownership Options
• DN funds the plant, owns it, receives a return and takes
appropriate liabilities
• Customer funds, DN owns and maintains, no return to DN,
DN takes liabilities for plant performance
• 350 m3/hr plant = 1 million th/annum = approx £5k per day gas
value
• Customer funds and owns, having to meet DN’s
specification
• This is the National Grid NTS Model
• Customer has GT Licence, they fund, own, operate BtG
plant and pipeline with the DN network a connected system
No consensus on which of these, may be that each DN will adopt a
different approach related to their appetite for investment and risk
Network Entry Agreement
• Needs to address capacity (NTS NEA has no relevance
to capacity which is covered in UNC)
• May need to address liabilities if the DNO provides some
services such as odorant addition or gas quality
monitoring
• ie from Options 1 and 2
• NTS NEA has concept of Daily Flow Notifications were
NTS informed continuously of flow forecasts
• For biomethane likely to be unmanned sites
• Key is that the DNO network is not impacted if biomethane flows stop
• The biomethane system flows must be monitored by computer with no
need for manual intervention
• Links to Biomethane Sales - the gas purchaser also
requires forecasts to allow them to stay in balance
• Materiality point as flows very low
Didcot Project
CNG Services as designer and project manager
Up to 7 days
Up to 18 days
Initial
separation
Sludge
From
Summer
2010 gas
is saved
for
treatment
and
beneficial
use
Fertiliser
Cake
Clean
Water
Odorant
Clean
Biomethane
to
consumers
via existing
network
Anaerobic
Digesters
Gas
Analysis
Safety Pressure
shut off control
valve
Dedicated plant to
apply safety controls at
gas network entry
BioGas
is
currently
wasted
New plant to
remove impurities
in BioGas
Efficiency - Converting Sunlight Falling On A
Hectare Of Land Into Vehicle Fuel
Biomethane always wins……..graph courtesy of German Energy
Agency (dena) “Biogas Partnership,”
initiative http://www.biogaspartner.de/
Carbon Trust Shows Best Use is Transportation
CBM is environmentally very attractive but the worst in terms of
economics for the biogas producer
CBM Vehicles
Vehicle use makes sense for depot based vehicles
Electricity Feed In Tariff
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Biogas that generates electricity can an electricity
Feed In Tariff (FIT)
FIT worth 9 p/kwh on top of the normal electricity
price
UK makes a lot of biogas at present, water companies, it all goes to
make electricity, limited use for waste heat....in long term, post 2020,
this will not be a good idea as the UK electricity grid is being decarbonised (wind, nuclear, CCS)
Renewable Heat Incentive (RHI)
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Worth approx £1.96/therm in 2011, indexed
Earned on the net energy exported to grid, heat raised by
non-renewable sources is deducted
Paid to the Biomethane producer
Economically comparable to CHP with advantage in favour
unless CHP has very high efficiency
Particularly good if Biogas plant already exists e.g. Water
Co.
Gas Transporters keen to facilitate, Ofgem may allow
incentive return to stimulate further
Injection into gas grid strongly supported by UK gas grid owners
Green Gas Certificates
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Enables injection of Biomethane in one place and by
displacement usage at another, regardless of relative
locations.
Supports all BtG projects and also gas a transport fuel.
Scheme arranged by REA and now active
At the present time, more value from making electricity or injecting gas into
the gas grid. UK CBM is highest taxed CBM in EU – in most places it is
duty free – UK CBM tax is more than double the tax on Fossil CNG in
Germany...
Biomethane Conclusions
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Biogas should only generate electricity when all the heat can be used
UK has advanced gas grid and the full support of UK gas distribution
network owners and energy suppliers
UK gas production is declining and we need to find new gas
resources to supply domestic customers and improve security of
supply
Biomethane injection into gas grid is widespread in Europe, no
material technical issues (it is just processing gas on a small scale)
We have commercial vehicles made by OEMs such as VW, MB and
Iveco – new dual fuel diesel-CBM tractors very good
Put all this together and we can create a thriving domestic BtG and
CBM industry that is able to make a very material contribution
towards the UK’s 2020 targets
There are no material technical issues or barriers, the BtG premium has
been set at an appropriate level so that we can get on with it. We also
need promotion of CBM as a vehicle fuel for depot based commercial
vehicles (and lower CBM fuel duty please)