Renewable Firewood Stoves; a community approach to

widespread installation and fuelling suitable for future

inclusion in the RHIJeremy Thorp

Cwm Harry28th March 2012

Project Funding and timescales

• This project has been funded through the LEAF project (Local Energy Assessment Fund) set up by DECC and administered through the Energy Saving Trust.

• Funding was confirmed on 7th February, and the project had to be complete by the end of the Financial year (31st March)

Project team

Cwm Harry Project management and direction

Chris Laughton, Rob Gwillim,

Jacinta Macdermot

Stove monitoring techniques

Shareenergy (Jon Halle) & ROCBF

(Mick Brown)

Business and financial modelling

HES (Alison Davies, Dave Luckhurst) User focus groups

Establishing potential demand

Coed Cymru (David Jenkins) Supply options and constraints

Derwas Ltd Stove supply and installations

Why?

• Non-domestic Renewable Heating Incentive (RHI) offers 7.6p/kWh to users of log batch boilers, wood pellet boilers and wood chip boilers but not log stoves.

• Domestic RHI (phase 2) due to be introduced Summer 2013

• Phase 2 expected to exclude wood stoves same as phase 1

Why are log stoves excluded?

1. Difficult to measure heat output2. Difficult to establish sustainability of fuel

supply

1. Difficult to measure heat output• RHI is based on total heat delivered. For pellet

stoves, chip stoves etc, delivered heat would be measured using heat meter in hot water pipes

• Log stoves deliver most heat as radiant – more difficult to measure

• Deemed heat – difficult as log stoves often used as supplementary heating

2. Difficult to establish sustainability of fuel supply

• DECC argue that you cannot ensure that users are not burning coal (or other non-sustainable fuel) on a log stove

Solutions:1. Measurement of heat output

• Is direct measurement possible?• Can we produce a look-up

table to convert between something measurable (e.g. Flue surface temperature) and heat output?

• Experiments have been carried out to investigate this possibility (see separate presentation)

Solutions:1. Measurement of heat output

• Are there alternative ways of measuring heat output?

• Can we deduce from fuel input an assumption on efficiency of burn?

• How could this be set up in an auditable way?

Measuring fuel use

• Set up company (ESCo) which can take out a long term contract with the client

• Volume of wood delivered would be auditable• Demonstrates proof also of the sustainability

of supply (as long as the ESCo can demonstrate it purchases from sustainable sources)

Measuring fuel use• Could either measure at household level or at

ESCo level• At household level – need accurate data on

weight, species, water content, of each batch delivered

• At ESCo level, only need to prove gross weight, species, etc for supplies coming into the ESCo

• ESCo could receive the RHI on behalf of households, and distribute to them

Measuring fuel input

• The household would have to have a new efficient stove installed by the ESCo to qualify

• The ESCo would install the stove, provide training on use, maintain (sweep chimney) once a year and contract to provide wood for 10 year period

What is the price of log fuel?

• What is the price of heat from logs (compared to oil and gas)

• Does it need a subsidy from RHI, and if so, how much?

• What is the price elasticity?• What is the aesthetic value of a log fire? • What is the “nuisance” cost of lighting it?

What price are logs?

• “Farm gate” price of 5p – 8p/kWh (based on 1m3 bag of hardwood at £37.50 and 1m3 softwood at £27.50)• (Assumes overall efficiency of stove of 50%)

• Need approx 7.6p/kWh (to achieve same income per acre as rent from grass keep)

Public acceptance

• Set up user focus groups• Address questions such as:

• Convenience compared to oil/gas• Reliability of fuel supplies (wood and oil/gas)• Storage of wood fuel

• Question? How do we attribute a price to side issues such as the aesthetic attraction, the inconvenience factor, the carbon reduction effect?

Evidence from focus groups• The majority want to use wood for the following reasons:

• cost, personal satisfaction, environmental benefits

• Of particular interest is the agreement that they all felt a sense of satisfaction / a relationship with their stove and wood fuel and enjoyed the process

• Questions to address in the second group: • Options for “firewood club”, (ESCO / Co-op...)• Discuss options for storage at scale• Cost of keeping warm• Barriers to change

• Skills e.g. lighting fires• Rented accommodation• Alternative uses of the heat • Expert advice on installation, fuel and maintenance

Focus group feedback• People want to be actively engaged, not at a distance

as they are with oil and gas where delivery is in someone else's hands leaving the home owner out of control

• Importance of price for wood fuel, • Awareness of how to use wood heating most

effectively, etc

Supply versus demand

• What is the potential volume of wood fuel available for household use in the UK?

• How many households would a log stove be appropriate for?

What is the potential volume of wood fuel available for household use in the UK?

• How much fuel wood could be obtained from existing sustainable sources?

• Address issues of:• Alternative uses of timber (saw-wood, mdf production)• Need to maximise value obtained from woodland• Use of the waste stream (equal in size to home grown

timber)• Large quantities currently used for dual-firing of coal

fired power station

What is the potential volume of wood fuel available for household use in the UK?

• UK total woodland area 3,078,000 hectares• (870,000 managed by Forestry Commission)• Total harvest 9.5 million green tonnes coniferous, 0.5

million tonnes broadleaf timber• = 3.25 green tonnes /ha/yr• State forest in Wales 7.5 green tonnes /ha/yr• Hence theoretical additional 4.25 green tonnes/ha/yr

from 3,002,000 hectares = 12 million green tonnes per year = 19 million Mwh = 0.6 million homes

Supply• For Powys 75,083 hectares of woodland• Survey indicates woodlands are adequately

but not heavily stocked• Suggest 4.2 m3/yr could be harvested, of

which, 40% is firewood.• Suggest county yield of 80,000 m3 hardwood

and 400,000 m3 softwood suitable for firewood

• Off the mains gas grid• Demographics – (<70 yrs, disabilities etc)• Logistics (can a flue be installed, is there room

for a stove, storage space for fuel, not high-rise flats etc)

• What is the typical carbon saving per household?

How many households would a log stove be appropriate for?

Carbon saving from households

• Estimate of 21% of households not on mains gas grid could benefit from installation of a log stove

• Estimate 5m3 of dry logs used in average dwelling

• Estimate 2.5 tonnes CO2 saving per household

• National potential – 2 million tonnes carbon saving per annum

6 models

1a No RHI, Green Deal funding for stove installation

1b No RHI, private loan fund for stove installation

1c No RHI, log fuel supply only

2a RHI certification obtained on stoves

2b RHI certified log fuel

2c RHI certified co-operative ESCo model

No RHI

With RHI

Model maps

Fuel supplier

Social Enterprise

Heat user

Government

ContractsGoods

Money

1a: No RHI, Green Deal funding for stove installation

Fuel supplier

Social Enterprise

Heat user

Government

Sup

ply

of

sto

ve

Fuel supply

Payments for fuel + Green Deal chargeP

aym

ents

ba

sed

On

fuel

usa

ge

Payments based on fuel usage, passed on

Green deal agreement

ContractsGoods

Money

Gre

en d

eal

agre

eme

nt

Green deal agreement

1b: no RHI, private loan fund for stove installation

Fuel supplier

Social Enterprise

Heat user

Initi

al

loan

Fuel supply

Payments for fuel

Reg

ular

loa

n re

paym

ent

s

Loa

n ag

reem

ent

ContractsGoods

Money

Sup

ply

of

sto

ve

1c: no RHI, fuel supply only

Fuel supplier

Social Enterprise

Heat userFuel supply

Payments for fuel

ContractsGoods

Money

Fuel supply contract

Payments for fuel

2a : RHI certification obtained on stoves

Fuel supplier

Social Enterprise

Heat user

Government

Purchase of stove

Fuel supply

RHI Payments basedon heat usage

Lea

se

ContractsGoods

Money

Stove supplier

Installation of stoveRHI accreditation

Purchase of fuel

RHI registration

2b : RHI certified log fuel

Fuel supplier

Social Enterprise

Heat user

Government

Purchase of stove

Fuel supply

Pur

cha

se o

f fu

el

RHI Payments basedon fuel usage

ContractsGoods

Money

Stove supplier

Installation of stove

RHI registration

Fuel supply contract

RH

I ac

cre

dita

tion

Pos

sibl

e R

HI

accr

edita

tion

2c : RHI certified log fuel ESCo model

Fuel supplier

Social Enterprise

Heat user

Government

Purchase of stove

Fuel supply

Pay

men

ts b

ase

d O

n he

at

usag

e

RHI Payments basedon heat usage

ES

Co

cont

ract

ContractsGoods

Money

Stove supplier

Installation of stove

RHI registration

Purchase of fuel

For each model:

Is it viable - worth pursuing?

What are the barriers/hurdles to pursuing this?

1a No RHI, Green Deal funding for stove installation

1b No RHI, private loan fund for stove installation

1c No RHI, log fuel supply only

2a RHI certification obtained on stoves

2b RHI certified log fuel

2c RHI certified co-operative ESCo model

No RHI

With RHI