Microgeneration Technology

Performance in the Irish Housing

Stock

Dublin Institute of Technology

Dr. A. Duffy

Dr. L.M. Ayompe

SERVE Conference November 18, 2011

Tipperary Institute of Technology

Overview

Introduction

Solar water heating systems

Grid-connected PV systems

Behavioural studies

Policy analysis

Conclusions

Introduction

The aim of the four-year inter-disciplinary study was to identify

which domestic-scale, retrofit microgeneration technologies are

most economically viable in the Irish housing stock and should

be favoured by policy makers in the medium to long term (10-

30) years.

The technologies which were considered in the study are: solar

thermal water heating systems; grid-connected photovoltaic

systems; wood pellet boilers; ground source heat pumps; micro

wind turbines; and micro-CHP.

Solar results are the focus of this presentation.

Introduction

The objectives of the project were to address the following questions:

what technologies will become economically attractive to individual investors over the period and what subsidies are required to make them viable?

what are the household characteristics which favour microgeneration uptake?

what would be the associated cost to the exchequer for each technology, does this represent value for money and which technologies should be most favoured?

what are the main non-economic barriers to the uptake of microgeneration technologies?

which economic and non-economic policies would facilitate the uptake of the most favoured technologies?

Introduction

The methodological approach comprised three main areas:

modelling the investment viability of technologies at an individual building level using transient net energy balance models which combine demand and microgeneration supply data;

assessing the non-economic barriers to the uptake of microgeneration technologies using a national market survey; and

aggregating the above economic and non-economic data to establish technology deployment potential, cost to the exchequer and cost of carbon abated under a number of different future policy scenarios.

System design Forced circulation

300 litres stainless steel tank

3 m2 heat pipe evacuated tube (30 tubes) or 4 m2 flat plate collectors

Conceptual design of the solar water heating systems

Pump

Hot water out to demand

Hot watertank

Immersion heater

Solar coil

Solar controller

Solar fluid

Cold water in

Pulse flow meter

Pulse flow meter

T6

T1

T2

T3

T8

T7

T4

T5

Hot water demand &

auxiliary heating control systemThermostat

Pulse flow meter

Solenoid valve

Control sub-system that dispensed hot water demand profile and controled auxiliary heating cycle

Field trial installations

Energy performance

Item description FPC

(4 m2)

HP-ETC

(3 m2)

In-plane solar insolation (kWh/m2/d) 1,087 1,087

Energy collected (kWh/yr) 1,984 2,056

Energy delivered (kWh/yr) 1,639 1,699

Energy collected per unit area (kWh/m2/yr) 496 681

Supply pipe losses (kWh/yr) (15 m) 326 (16.4%) 366 (17.8%)

Solar fraction (%) 38.6 40.2

Collector efficiency (%) 46.1 60.7

System efficiency (%) 37.9 50.3

System cost (€2010) 4,400 5,000

Simple payback period (yrs) (Electric immersion heater) 13.2 14.5

Net present value (€) (@ 8%) -1,010 -1,537

Net present value (€) (@ 8%) with grant aid -10 -574

L.M. Ayompe, A. Duffy, M. Mc Keever, M. Conlon and S.J. McCormack. Comparative field performance study of flat plate and heat pipe evacuated tube collectors for domestic water heating systems in a temperate climate. Energy (2011): 36; 5, 3370-3378.

Comparative field performance

-1,738

-409

-10

-2,365

-987

-574

-2,738

-1,409

-1,010

-3,328

-1,950

-1,537

-3,500

-3,000

-2,500

-2,000

-1,500

-1,000

-500

0

Condensing gas boiler Oil boiler Electric immersion heater

Net

pre

sen

t v

alu

e (€

)

Auxiliary heater type

FPC (with grant) ETC (with grant) FPC ETC

NPVs for SWHSs with different auxiliary heaters in 2010

43.9

27.3

13.2

48.2

29.9

14.5

33.9

21.1

10.2

38.9

24.1

11.7

0

5

10

15

20

25

30

35

40

45

50

Condensing gas boiler Oil boiler Electric immersion heaterS

imp

le p

ay

ba

ck

perio

d (y

ea

rs)

Auxiliary heater type

FPC ETC FPC (with grant) ETC (with grant)

SPP for SWHS with different auxiliary heaters in 2010

Economic performance

L.M. Ayompe, A. Duffy, M. Mc Keever, M. Conlon and S.J. McCormack. Comparative field performance study of flat plate and heat pipe evacuated tube collectors for domestic water heating systems in a temperate climate. Energy (2011): 36; 5, 3370-3378.

Field trial Installation

PV module/array Specification

Type Monocrystalline

silicon

Cell efficiency 19.3%

Module efficiency 17.2%

Maximum power (Pmax) 215 W

Maximum power voltage (Vpm) 42.0 V

Maximum power current (Ipm) 5.13A

Open circuit voltage (Voc) 51.6 V

Short circuit current (Isc) 5.61 A

Warranted minimum power (Pmin) 204.3 W

Output power tolerance +10/-5 %

Maximum system voltage (Vdc) 1000

Temperature coefficient of Pmax -0.3 %/oC

Module area 1.25m2

No. of modules 8

NOCT 47±2oC

Field performance – International comparison

Location PV type Energy output

(kWh/kWp)

Final yield

(kWh/kWp-

day)

PV module

efficiency

(%)

System

efficiency

(%)

Inverter

efficiency

(%)

Performance

ratio (%)

Reference

Crete, Greece PC-Si 1336.4 2.0-5.1 - - - 67.4 [8]

Germany 680 1.9 - - - 66.5 [13]

Málaga, Spain 1339 3.7 8.8-10.3 6.1-8.0 85-88 64.5 [21]

Jaén, Spain 892.1 2.4 8.9 7.8 88.1 62.7 [22]

Algeria MC-Si 10.1 9.3 80.7 - [23]

Calabria, Italy PC-Si 1230 3.4 7.6 - 84.8 - [24]

Germany 700-1000 1.9-2.7 - - - - [15]

Ballymena,

Northern Ireland

MC-Si 616.9 1.7 7.5-10.0 6.0-9.0 87 60-62 [10]

Warsaw, Poland A-Si 830 2.3 4.5-5.5 4.0-5.0 92-93 60-80 [25]

Castile & Leon,

Spain

MC-Si 1180 1.4-4.8 13.7 12.2 89.5 69.8 [26]

Umbertide, Italy PC-Si - - 4.0-7.0 6.2-6.7 - - [27]

UK 744 - - - - 69 [9]

Liverpool, UK Tiles 777 - - - - 72 [9]

Dublin, Ireland MC-Si 885.1 2.4 14.9 12.6 89.2 72.4 Present

study

UK A-Si - - 3.7 3.2 64.5 42.0 [10]

UK PC-Si - - - 7.5 - 68.0 [10]

UK - - - - 8.4 90-91 59-61 [10]

Italy A-Si - - - - - 66 [10]

Germany - - - - - - 50-81 [10]

Brazil A-Si - - - 5 91 - [10]

Thailand - - 2.9-4.0 - - 92-98 70-90 [28]

PC-Si: poly-crystalline silicon, MC-Si: mono-crystalline silicon, A-Si: amorphous silicon

L.M. Ayompe, A. Duffy, S.J. McCormack and M. Conlon. Measured performance of a 1.72 kilowatt rooftop grid connected photovoltaic system in Ireland. Energy Conversion and Management (2011): 52; 2, 816-825.

PV Financial Model

PV electricity output model

Electricity smart metering data

( ~ 3900 households)

Financial model

NPV, paybacks for large samples

of Irish houses

Optimised PV sizes for individual

households

Economic parameters

PV FIT design for Ireland

NPV = Rt – Ct

Nn

1n

nnt EXγβTGAIαR

NPV = net present value (€)

Ct = total life cycle cost (€)

Rt = total revenue (€)

AI = avoided import as a fraction of total electricity generated (kWh)

EX = electricity export as a fraction of total electricity generated (kWh)

TG = total generation (kWh)

αn = electricity import tariff in year “n” (€/kWh)

β = generation based reward or FIT (€/kWh)

γn = electricity export tariff in year “n” (€/kWh)

N = PV system useful life (years)

Cmt present value of cost associated with PV module (€) CBOS present value of cost associated with the initial investment on BOS (€) CBOSrep present value of BOS replacement cost (€) Cv present value of total variable cost (€)

vBOSrepBOSmtt CCCCC

PV FIT design for Ireland

Cumulative frequency of NPVs for different PV system capacities in 2011 (0.45 €/kWh FIT)

0

20

40

60

80

100

120

-1,000 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000

Cu

mu

lati

ve

freq

uen

cy (%

)

NPV (€)

0.47 kWp 1.41 kWp 1.72 kWp 2.82 kWp 4.23 kWp 5.64 kWp

0

10

20

30

40

50

60

70

80

90

100

110

-5,000 -4,000 -3,000 -2,000 -1,000 0 1,000 2,000

Cu

mu

lati

ve fr

equ

ency

(%)

NPV (€)

0.47 kWp 1.41 kWp 1.72 kWp 2.82 kWp 4.23 kWp 5.64 kWp

Cumulative frequency of NPVs for different PV system capacities in 2011 (0.31 €/kWh FIT)

0

10

20

30

40

50

60

70

80

90

100

110

-1,500 -1,000 -500 0 500 1,000 1,500 2,000 2,500 3,000 3,500

Cu

mu

lati

ve fr

equ

ency

(%)

Net present value (€)

0.47 kWp (0.45 €/kWh) 1.41 kWp (0.39 €/kWh) 1.72 kWp (0.32 €/kWh)

2.82 kWp (0.31 €/kWh) 4.23 kWp (0.34 €/kWh) 5.64 kWp (0.38 €/kWh)

Cumulative frequency of NPV for different PV system sizes and recommended FIT to achieve 8% IRR and at least 50% market penetration

PV design chart

0

10

20

30

40

50

60

70

80

90

100

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

Per

cen

tag

e o

n-s

ite

elec

tric

ity

use

(%

)

Average annual electricity demand (kWh)

0.47 kWp 1.41 kWp 1.72 kWp 2.82 kWp 4.23 kWp 5.64 kWp

Low exporter

Typical user

High exporter

Percentage on-site household electricity use against average annual electricity demand

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

20

10

20

11

20

12

20

13

20

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20

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20

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20

27

20

28

20

29

20

30

Lev

elis

ed e

ner

gy

gen

era

tio

n c

ost

(€

/kW

h)

Year of installation

ETC (Electric immersion) FPC (oil boiler)

0.47 kWp PV system 2.82 kWp PV system

Levelised energy generation cost

Levelised energy generation costs for domestic scale PV and SWHSs between 2010 and 2030

PV: 0.61-0.85 (2010) to 0.22- 0.31 (2030)

SWH: 0.20-0.34 (2010) to 0.16 - 0.27 (2030)

Marginal abatement cost

-200

0

200

400

600

800

1,000

20

11

20

12

20

13

20

14

20

15

20

16

20

17

20

18

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25

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20

27

20

28

20

29

20

30M

arg

ina

l a

ba

tem

en

t co

st (€

/tC

O2)

Year of Installation

0.47 kWp (reference scenario) 1.72 kWp (reference scenario)

FPC (electric immersion heater) ETC (condensing gas boiler)

Marginal abatement costs for domestic scale solar water heating systems and grid connected PV systems (2011 to 2030)

PV: 651.3-915.8 (2010) to 0.0-136.2 (2030)

SWH: 66-408 (2010) to -9-35 (2030)

Active Resistance

Sample size = 1010

Computer Assisted Telephone Interviews administered by professional market-research company.

Consumers willing to purchase within 12 months (~ 8%)

Consumers’ postponing decision (~ 42%) Positive attitudes, perceive high relative advantage

Motives: high cost, functional risk, low social pressure

Consumers’ rejecting adoption (~ 50%) Motives: low relative advantage, incompatibility with habits and

values, functional risk, no social pressure

(Claudy et al.)

Awareness and Willingness to pay

Men higher awareness

Younger and older people have a lower awareness

People with internet access have higher level of awareness of microgeneration technologies.

People in rural areas more aware

No significant differences between social classes or household sizes

*M.C. Claudy, C. Michelsen, A. O’Driscoll, M.R. Mullen. Consumer awareness in the adoption of microgeneration technologies An empirical investigation in the Republic of Ireland. Renewable and Sustainable Energy Reviews (2010): 14; 2154-2160.

Technology Cost (€) Payback period

(years)

Awareness (% )*

Actual+

Median

willingness to

pay*

Actual Average

accepted*

Aware Not

aware

PV system 9,500 – 14,500 4,254 > 25 8.5 80 20

Solar water

heating system

4,400 - 5,000 2,591 10.2 - 48 13 75 25

+ Typical prices

Conclusions There exists a wide range of performances for solar

technologies for domestic application

Policy makers have to be careful in designing support policies

Both SWHS and grid-connected PV systems not yet

economically viable

Both technologies would however become viable in the future

if global support policies are sustained

FPC generated 496 kWh/m2/yr

HP-ETC generated 681 kWh/m2/yr

Level of subsidies for SWHSs

1,000 to 2,750 for 4 m2 FPC

1,500 to 3,300 for 3 m2 HP-ETC

Conclusion

PV system generated 885 kWh/kWp

Parity between PV generated electricity and grid and wholesale

electricity prices occurs soonest in 2020 and 2025

New FIT design required since current tariff not suitable

Required FITs range between 31-45 euro cents/kWh

Single FIT not suitable for domestic scale PV systems

MAC for ST is significantly lower that for PV until 2030

More sensible to subsidize ST at present because it has a closer

payback period

Thank you!

Any Questions?