CHP as a carbon reduction tool - what to consider
Justin Wimbush, Senior Mechanical Engineer, Arup
Neil Adcock, Associate Director, Rolton Group
© 2degrees Ltd.
1
CHP and CO2 Reduction
Technical and Commercial Implications
CHP and CO2 Reduction
• Current position: Senior Engineer
at Arup
• Experience:
• 8 years of working on fossil fuelled and
renewable fuelled CHP schemes.
• Project designs.
• Technical feasibility assessments.
• Commercial assessments.
• Planning applications.
CHP and CO2 Reduction – technical and
commercial considerations
Presentation Contents:
• Introduction to CHP
• What is CHP and why is it useful?
• Is CHP the most appropriate way to reduce CO2 emissions?
• Some technical considerations
• CHP and buildings
• CHP and CO2 reductions
• Some commercial considerations
• Cost and payback
• Technology risk
• Electricity market
• Conclusions
Conventional Heat and Power Supply
• Typical UK fossil fuel power stations generate
electricity with an efficiency of about 35%.
• 65% of the energy is wasted to the atmosphere.
• Distribution from out of town power stations to the
consumer results in distribution losses of the order
of 5-10%.
What is CHP?
• Simultaneous production of heat and electricity
(power)
What makes up a CHP system?
• CHP
• Boilers
• Fuel supply
• Thermal Storage
• Electricity distribution
• Hot water distribution
• Pumps
• Sub-stations
• Heat Exchangers (HIUs)
Gas CHP (Combined Heat and Power)
• Provides heat and electricity
• Low CO2 technology but not
renewable
• Stirling engines, fuels cells,
gas engines and gas turbines
• Available from <3kWe to
>3MWe
• Capacity limited by available
heat demand and economics
• Can serve individual buildings
or multiple buildings
Biomass CHP
Four (4) technologies
• wood chip fuel
• steam turbine CHP
• organic rankine cycle turbine
CHP
• gasification CHP
• indirect turbine CHP
Different capacities, heat to power
ratios & commercial maturity
Liquid biofuel CHP
• sustainable?
• commercially viable? Limited by RTFO
Biomass Air Turbine and Gasification CHP
• Air turbine
•
•
•
•
90kWe modules
Moderate elec efficiency (19%)
Suitable for 100 homes +
Single supplier, demo stage
• Gasification CHP
•
•
•
•
250kWe modules
Moderate elec efficiency (21%)
Suitable for 200 homes +
Multiple suppliers, entering
commercialisation
Biomass ORC and Steam Turbine CHP
• ORC turbine
•
•
•
•
400 - 2000kWe
Low elec efficiency (13%)
Suitable for 2000 homes +.
Mature technology
• Steam turbine
• 2,000kWe +
• Low to moderate elec
efficiency (14 - 20%)
• Suitable for 15,000 homes +
• Mature technology
So what sort of CHP is most suitable for your
project?
• Complex range of factors to
consider:
• Why do you want it?
• To provide lower cost heat and
electricity?
• To reduce CO2 emissions?
• Because the Planning
Department look favourably on
it?
So what sort of CHP is most suitable for your
project?
• The capacity of CHP unit depends on your daily and annual
heating profile
50,000
45,000
Jan
Heating demand (kW)
40,000
Feb
35,000
Mar
30,000
Apr
25,000
May
Jun
20,000
Jul
15,000
Aug
10,000
Sep
Oct
5,000
Nov
0
Dec
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Daily project heating profiles
• Producing excess heat should be avoided to maintain Good
Quality CHP status and to minimise costs.
So what sort of CHP is most suitable for your
project?
• CO2 emissions reduction potential?
• Gas CHP will reduce overall CO2 emissions by
between around 8% - 20%.
• Biomass CHP will mitigate 20% to 100% of your
CO2 depending on the technology selected.
CHP feasibility and CO2 reductions
• How dispersed are your heat loads?
• Heat distribution pipe is expensive and costs
around £300/m F&R for plastic and £600+/m for
steel.
• Heat losses even for
the most highly
insulated pipes can be
> 20%.
• Need to check that
CHP will save CO2!
So what sort of CHP is most suitable for your
project?
• How much will it cost?
• For an asset that generates both heat and electricity the project whole
life costs should be considered.
• For many projects the whole life costs, including an allowance for
plant replacement, will be lower than the up front capital investment.
Gas & Biomass CHP ESCo NPV Curve
£3.0M
• Whether a CHP scheme will pay
for itself depends primarily on:
£2.5M
£2.0M
£1.5M
• Whether a retail electricity
tariff can be negotiated or
the electricity can be used
on your site.
£1.0M
NPV
• The heat density of the site
£0.5M
£0.0M
-£0.5M
1
3
5
7
9
11 13 15 17 19 21 23 25 27 29 31 33 35
-£1.0M
-£1.5M
-£2.0M
Years
So what sort of CHP is most suitable for your
project?
• How much does CHP cost?
• There are a number of procurement and operation
possibilities:
• Capital purchase – owner operated
• Capital purchase – operated and maintained by FM
company
• ESCo operation
• For new developments cost of
heat distribution is subsidised
by not installing gas network
Summary of Costs / Revenues to be
Considered
• Project capital cost
•
•
•
•
•
•
CHP
District heating pipework
Thermal storage
Heat exchangers
Energy Centre
Procurement of an ESCo
• Operational costs
•
•
•
•
•
Gas
Biofuels
Maintenance
Management
Billing
• Revenues
• Sale of heat
• Sale of electricity
• Sale of renewable obligation
certificates (ROCs)
• CRC savings
Selling electricity – retail or wholesale?
• Pre 2008 unlicensed “private wire” operation allowed for
sale of electricity to residential networks < 1MVA.
• June 2008 Citiworks ruling by European Court of Justice
questioned legitimacy of private wire.
• Now - private wire still permitted, for new schemes
access must be given to other suppliers, for existing
schemes access must be given where practicable i.e. a
private wire market is in most cases no longer captive.
• Business models usually now assume all electricity
exported is sold at wholesale rates.
CRC and CHP
• Organisations operating CHPs are responsible for the
CO2 emissions associated with the fuel consumed –
electricity generation credits can be claimed.
• Organisations purchasing CHP generated electricity
should rate it at the grid CO2 rate.
• Heat supplied from CHP is zero rated for CO2.
• ROCs or FiTs cannot be claimed if CRC benefit is
claimed.
Cost of Reducing CO2
Indicative Costs of Reducing CO2 Emissions
£200
£150
Cost (£/t CO2)
£100
£50
£0
CRC
-£50
3MW wind
turbine
100kW wind
turbine
Biomass
Biomass
3MWe gas
boiler
boiler
CHP (no dh)
(compared to (compared to
oil)
gas)
-£100
* no allowance made for ROCs, FiTs or RHI revenue
3MWe gas
400kW
CHP (13km biomass ORC
dh)
CHP (13km
dh)
Feed-in Tariffs and Renewable Heat Incentive
• No FiTs for CHP.
• Renewable CHP can still claim ROC certificates.
• RHI proposes to fund useful heat (including process
heat) supplied.
• RHI may provide a district heating tariff - tbc.
Gas CHP Rules of Thumb
• Minimum recommended housing density > 50
dwellings per hectare.
• Installed cost for CHP is £450 – 1500 /kWe (not
including the network).
• Installed cost of CHP + heating network is approx
£3000 to £8000 per dwelling served.
• Minimum economically viable operating hours 3,500
– 4,000/year.
Proportion of primary fuel turned into useful
energy
Source: CHPA
Conclusions
• CHP can reduce CO2 emissions and costs
• The extent depends on the energy load density and the
technology selected.
• The denser the load, the greater the benefit.
• Real economies of scale can be realised.
• Cash flows are complex.
• Network economics and regulation are critical.
• A number of procurement options exist but the
ESCo market is immature and risk averse.
The End
Any Questions?
Justin Wimbush
Arup
Telephone: 020 7755 4196
Email: [email protected]
Engineering the Future
CHP - A Carbon Reduction Tool – Case
Study
Introduction
• Neil Adcock
• 42 year old Chartered Engineer
• BREEAM Assessor
• Over 20 years experience in both
contracting and consulting
• Experience of delivery of projects in the
Industrial, Education, Health and Social
Housing market
CHP – A Carbon Reduction Tool – Case Study
Contents
• Project Background
• Planning Considerations
• Strategic Approach
• Integrating Renewables
• Constructing an Energy Usage Profile
• Selection of CHP
• Commercial Considerations
• Predicted Performance
• Conclusions and Summary
CHP - A Carbon Reduction Tool – Case Study
Project Background
• Client is a Housing Association
• Redevelopment of existing estate within
Kensington & Chelsea
• Providing up to 1100 dwellings, small
amount of commercial offices and retail
• A mixture of social housing & private maximum height is 12 storey
• Over a site of 42518m2, a density of 1 person
per 19m2
CHP – A Carbon Reduction Tool – Case Study
Planning
Considerations
• All dwellings in initial phases
to meet Code 4 Sustainable
homes - in excess of the
London Plan
• Future proofing to Code 6
• Requirements of the London
plan
• Decentralised Energy generation
• 20% renewables
• RBKC Urban Development Plan
and Supplementary Planning
Documents
• Location of plant exhausts and
noise sources
CHP – A Carbon Reduction Tool – Case Study
Strategic Approach
BE LEAN- Increase u values and adopt
passive measure to reduce carbon usage
BE CLEAN- Maximise the efficiency of
engineering systems such as energy
efficient lighting and combined heat and
power to reduce carbon usage further
BE GREEN- Install 20% of appropriate
renewables, i.e. ones that meet the planning
constraints and compliment proposed
engineering systems
CHP – A Carbon Reduction Tool – Case Study
Integrating Renewables
Wind - local wind speeds not
favourable, negative planning impact
Biomass/Biofuel
Space
not
available for site storage, transport of
fuel to site an issue
GSHP - insufficient space available on
site
ASHP - insufficient space on site
negative planning impact on elevations
Solar Thermal - insufficient roof
space available and this technology is
at odds with CHP
Solar PVC - preferred option as the
required area can be found at roof
level & the FIT assists in the meeting
of commercial concerns
CHP – A Carbon Reduction Tool – Case Study
Constructing a energy Usage
Profile
To optimise the size of the CHP we need
to construct an energy profile this was
achieved by:
• Using the clients likely occupancy
patterns based on existing housing
data
• Utilising the BRE`s Domestic Energy
Model
• Modelling the performance of the
buildings with an IES thermal model
• Exploring the opportunities for local
heat network via the GLA`s heat
mapping models
CHP – A Carbon Reduction Tool – Case Study
Selection of CHP
The selection of the optimum size of
CHP was based around the following
considerations:
• The summertime base energy load –
domestic hot water demand
• The opportunities for exporting heat
to local surroundings does not exist
at this time
• The provision of a thermal store is
used to flatten the daily profile and
thus increase viable CHP size
• No Summertime heat dumping is to
be implemented
• The CHP is to have a Quality Index in
excess of 100 as defined by CHPQA
CHP – A Carbon Reduction Tool – Case Study
Commercial Considerations
Given the considerations previously stated the
solution we have arrived at is as follows:
• A 400 kWe /465kWT gas fired CHP
• 150 000 litre Thermal Store split across the site
between central and local storage
• With a district heating system to meet the
heating and hot water needs of the
development
• Phased to match the project procurement
programme and give future possibilities of heat
networking
• Integrating with roof mounted PVC`s to meet
the renewables requirement
• The site generated electricity shall be utilised
for landlord services with any excess being
exported to the grid, thus maximising the
benefit of the FIT
CHP – A Carbon Reduction Tool – Case Study
Green
Clean
Lean
Predicted Performance
• Carbon reduction against Building Regs 2006
• Lean = 7% reduction
• Clean = 38% reduction
• Green= 50% reduction
CHP - A Carbon Reduction Tool – Case Study
Summary
• Project Background
• Planning Considerations
• Strategic Approach
• Integrating Renewables
• Constructing an Energy Usage Profile
• Selection of CHP
• Commercial Considerations
• Predicted Performance
• Conclusions and Summary
CHP - A Carbon Reduction Tool – Case Study
Engineering the Future
Thank you for your time
Any Questions?