Dawn Smith

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Sheffields CHP District Energy Scheme
Presented by Peter Mildenstein Onyx Sheffield Ltd
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Presentation Sequence

• Background information
• The Product - District Heating
• Air Quality
• Developing Sheffield

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Background Information

• Industrial City 530,000 1 of UK Population
• 230,000 Homes
• 260,000 tonnes of Domestic Waste per Year
• Limited Landfill Space Available
• Positive Attitude towards the Environment
• Waste to Energy - Preferred Option

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Background Information

• Built by Sheffield City Council
• Commissioned 1976
• Two Municipal Waste Streams
• Two Clinical Waste Streams - from 1991
• Flue Gas Treatment System - dry system
• District Heating
• Electrical Power Generation Plant

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The Product - District Heating District Heating

• Water
• Temperature up to 120C
• Pressure up to 16 bar
• Distributed by pumps
• Backed up by 85MW of boilers
• Computer controlled for maximum efficiency

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The Product - District Heating The District
Heating Customer

• Over 1,500 Flats and Houses.
• 119 Large Buildings.
• Unit Energy Charge linked to other fuels
• Standing Charge
• Connection Fee
• Competitive in the Market Place.
• Flexible Heat Tariff Structure.
• Customer Care

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The Product - District Heating Technical Overview

• Heat Sources
• Pumping
• Pipework
• Control
• Heat Exchanger Technology
• Specific System Parameters

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The Product - District Heating Technical Overview
- Heat Sources

• Incinerator Throughput lt10 t/h
• Annual Throughput 150,000 t.
• Average Gross Calorific Value 9,935 kJ/kg
• Steam Production 65 t/h
• Thermal Output 36 MW
• Availability 90

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The Product - District Heating Technical Overview
- Heat Sources

• 9 Boilers
• Sizes from 4.0 - 14.6 MW
• 37.2 MW Fired by Oil
• 47.2 MW Fired by Gas
• ALL Burners have Duel Fuel Capability
• Boilers Located in 3 Different Positions
• Total Back-up 84.4 MW

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The Product - District Heating Technical Overview
- Pumping

• 15 Circulating Pumps over 2 Networks
• Centrifugal Pumps
• Every Set Duty/Standby/Double Mode
• Pumps Arranged in Parallel/Series
• Total Water Deliverable gt 700 kg/s

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The Product - District Heating Technical Overview
- Pipework

• Construction
• Insulatitive Properties
• Protection in Ground
• Leak Detection
• System Integrity 99.9

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The Product - District Heating Technical Overview
- Control

• Two On-line PLCs
• PLCs Backed up by 20 Single Loop Controllers
• Manually Operable
• System Linked by Open Communication Channels

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The Product - District Heating Technical Overview
- Heat Exchangers

• Modular Construction
• Brazed Plate Heat Exchanger
• Small Water Volume
• High Temperature Gradient
• Control Valves
• Sensors
• Moving parts - Control Valve Water !
• Space 80-90
• Mass 75-95
• Cost 65-80
• Cost of Maintenance 75-90
• Provision of Flue

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The Product - District Heating Technical Overview
- Heat Exchangers

• Steel plate heat exchanger allows transfer of DH
  network to Consumers system.
• Electronic heat meters allow consumer to be
  charged in Megawatt hours of heat energy used.
• Electronic controls allow flexibility.

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The Product - District Heating A City Wide Scheme
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Infilling Projects Include-

• University

• Sheffield College

• Housing

• Heart of the City

• Cultural Industries Quarter

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The Product - District Heating Customer Profile -
Network I

• Developed from existing small scheme

• Identified initial load and installed pipe

• 1988 first load - 2003 latest connection

• Currently 12 km of pipe

• Delivering approximately 31,000 MWh / annum

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The Product - District Heating Customer Profile -
Network II

• Developed from 1989 and continuing

• Secured Key Clients - Public Sector Commercial
  
• Town Hall / Ponds Forge - Fountain Precinct
• Weston Park Hospital - University of Sheffield

• 30 km of pipe installed

• Delivering approximately 82,000 MWh/annum

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Air Quality Issues
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Air Quality Issues
CO2 Concentration in 1987 - prior to widespread
use of District Heating in the City
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Air Quality Issues
CO2 Concentration in 1997 - after the expansion
of the District Heating scheme.
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Air Quality Issues
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Developing EfW in Sheffield

• New 225kt pa
• Providing 72 MW thermal energy as
• 61MW District Heating or
• 39 MW DH 11 MW Electricity or
• 0 MW DH 19 MW Electricity

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Developing EfW in Sheffield
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Sheffields CHP District Energy Scheme
www.greenenergy.co.uk www.onyxgroup.co.uk
Presented by Peter Mildenstein Onyx Sheffield Ltd