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 m 2 heat pipe evacuated tube (30 tubes) or 4 m 2 flat plate collectors Control sub-system that dispensed hot water demand profile and controled auxiliary heating cycle T 1 T 8 Solenoid valve Pulse flow meter Hot water out to demand Solar controller Hot water tank Thermostat Hot water demand & auxiliary heating control system T 3 T 6 Solar fluid Pump Pulse flow meter T 4 T 5 Solar coil T 2 Immersion heater Pulse flow meter T 7 Cold water in Conceptual design of the solar water heating systems
Field trial installations
Energy performance Comparative field performance Item description FPC (4 m 2 ) HP-ETC (3 m 2 ) In-plane solar insolation (kwh/m 2 /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/m 2 /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.
Net present value ( ) Simple payback period (years) Economic performance Auxiliary heater type 0-500 Condensing gas boiler Oil boiler Electric immersion heater -10-409 -574 50 45 40 43.9 48.2 FPC ETC FPC (with grant) ETC (with grant) 38.9-1,000-1,500-2,000-2,500-3,000-1,738-2,365-2,738-987 -1,409-1,950-1,010-1,537 35 30 25 20 15 10 5 33.9 27.3 29.9 21.1 24.1 13.2 14.5 10.2 11.7-3,500-3,328 FPC (with grant) ETC (with grant) FPC ETC 0 Condensing gas boiler Oil boiler Electric immersion heater Auxiliary heater type NPVs for SWHSs with different auxiliary heaters in 2010 SPP for SWHS with different auxiliary heaters in 2010 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 Type Specification 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 %/ o C Module area 1.25m 2 No. of modules 8 NOCT 47±2 o C
Field performance International comparison Location PV type Energy output (kwh/kw p ) Final yield (kwh/kw p - 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, MC-Si 616.9 1.7 7.5-10.0 6.0-9.0 87 60-62 [10] Northern Ireland Warsaw, Poland A-Si 830 2.3 4.5-5.5 4.0-5.0 92-93 60-80 [25] Castile & Leon, MC-Si 1180 1.4-4.8 13.7 12.2 89.5 69.8 [26] Spain 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 Economic parameters Financial model NPV, paybacks for large samples of Irish houses Optimised PV sizes for individual households Electricity smart metering data ( ~ 3900 households)
PV FIT design for Ireland NPV = R t C t R t n N n1 α n AIβTG γ n EX C t C mt C BOS C BOSrep C v NPV = net present value ( ) C t = total life cycle cost ( ) R t = 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) α n = electricity import tariff in year n ( /kwh) β = generation based reward or FIT ( /kwh) γ n = electricity export tariff in year n ( /kwh) N = PV system useful life (years) C mt present value of cost associated with PV module ( ) C BOS present value of cost associated with the initial investment on BOS ( ) C BOSrep present value of BOS replacement cost ( ) C v present value of total variable cost ( )
Cumulative frequency (%) Cumulative frequency (%) Cumulative frequency (%) PV FIT design for Ireland 0.47 kwp 1.41 kwp 1.72 kwp 2.82 kwp 4.23 kwp 5.64 kwp 120 100 80 60 40 0.47 kwp 1.41 kwp 1.72 kwp 2.82 kwp 4.23 kwp 5.64 kwp 110 100 90 80 70 60 50 40 30 20 0-1,000 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 NPV ( ) Cumulative frequency of NPVs for different PV system capacities in 2011 (0.45 /kwh FIT) 0-5,000-4,000-3,000-2,000-1,000 0 1,000 2,000 NPV ( ) Cumulative frequency of NPVs for different PV system capacities in 2011 (0.31 /kwh FIT) 20 10 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) 110 100 90 80 70 60 50 40 30 20 10 0-1,500-1,000-500 0 500 1,000 1,500 2,000 2,500 3,000 3,500 Net present value ( ) Cumulative frequency of NPV for different PV system sizes and recommended FIT to achieve 8% IRR and at least 50% market penetration
Percentage on-site electricity use (%) PV design chart 100 0.47 kwp 1.41 kwp 1.72 kwp 2.82 kwp 4.23 kwp 5.64 kwp 90 80 Low exporter 70 60 50 40 30 Typical user High exporter 20 10 0 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 Average annual electricity demand (kwh) Percentage on-site household electricity use against average annual electricity demand
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 Levelised energy generation cost ( /kwh) Levelised energy generation cost 0.9 0.8 0.7 0.6 PV: 0.61-0.85 (2010) to 0.22-0.31 (2030) ETC (Electric immersion) FPC (oil boiler) 0.47 kwp PV system 2.82 kwp PV system SWH: 0.20-0.34 (2010) to 0.16-0.27 (2030) 0.5 0.4 0.3 0.2 0.1 0.0 Year of installation Levelised energy generation costs for domestic scale PV and SWHSs between 2010 and 2030
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 Marginal abatement cost ( /tco 2 ) Marginal abatement cost 1,000 0.47 kwp (reference scenario) 1.72 kwp (reference scenario) PV: 651.3-915.8 (2010) to 0.0-136.2 (2030) FPC (electric immersion heater) ETC (condensing gas boiler) SWH: 66-408 (2010) to -9-35 (2030) 800 600 400 200 0-200 Year of Installation Marginal abatement costs for domestic scale solar water heating systems and grid connected PV systems (2011 to 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 Technology Cost ( ) Payback period Awareness (% )* (years) Actual + Median willingness to Actual Average accepted* Aware Not aware pay* PV system 9,500 14,500 4,254 > 25 8.5 80 20 Solar water 4,400-5,000 2,591 10.2-48 13 75 25 heating system + Typical prices 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.
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/m 2 /yr HP-ETC generated 681 kwh/m 2 /yr Level of subsidies for SWHSs 1,000 to 2,750 for 4 m 2 FPC 1,500 to 3,300 for 3 m 2 HP-ETC
Conclusion PV system generated 885 kwh/kw p 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
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