The Penetration of Micro CHP in Residential Dwellings in Japan
Hirohisa Aki, Ph.D, Member Energy Network Group, Energy Technology Research Institute
Contents Introduction of Micro CHP Gas engine PEM fuel cell Future perspective
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Background information Energy supply business No energy service provider Electricity utilities (giant) vs. gas utilities (small) Electricity: 9 large utilities, dominant in each area Tokyo Electric: 60 TW, 282,000 TWh, 27.2M customers
Gas: 200 utilities by pipeline + 20,000 supplier by Cylinders Kerosene: gas station + retail stores
Energy demand of homes Grid connected (Max. demand: 3–5 kW) Hot water is used only in bath room and kitchen
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Micro CHP Used in residential homes: ≈1kW Input: natural gas/LPG/kerosene Output: electricity + hot water On-grid only No backward flow allowed CHP in home is a realistic option
(Source: Osaka Gas)
(Source: Tokyo Gas)
Gas engine
Fuel cell
Commercialized
Demonstration
(FY2006: 18,000)
(FY2006: 770) 4
Gas engine Used in residential homes: ≈1 kW Manufacturer: Honda
Rated output
Electricity
1.0 kW
Heat
2.8 kW
Efficiency (LHV) Electricity Heat
580mm
Natural gas / LPG
Fuel consumption
4.92 kW
Dimension (mm)
H 880 x W 580 x D 380
Weight
82 kG
880mm
Engine unit
63.0 %
Fuel type
Engine
Hot water tank
22.5 %
Type
4 cycles OHV
Volume
163 cc
Rated speed
1950 rpm
Auxiliary boiller fuel consumptio
42 kW
Hot water tank
150 L at 70 oC
(Source: Osaka Gas)
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Incentive: gas price discount Example case: offered by Osaka Gas Approx. 28 yen/kWh (+ free heat) Basement Gas price
yen/month
Basic contract CGS contract Apr. - Nov. Dec. - Mar.
Meter charge yen/Nm3
yen/MJ
20 – 50 Nm3
1210
127.21
2.827
50 Nm3 –
1376
123.89
2.753
20 Nm3 –
2450
65.21
1.449
20 – 50 Nm3
1210
127.21
2.827
50 Nm3 –
3890
73.61
1.636
yen/kWh
yen/MJ
– 125 kWh
18.13
5.036
120 – 300 kWh
23.32
6.478
300 kWh –
24.65
6.847
Electricity price
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Incentive: subsidy by government Successful penetration Developed by Osaka Gas with Honda “Gas fired water heater with electricity generation”
Government subsidies 170,000 yen/unit Original cost: 700,000 – 800,000 yen/unit Latest gas boiler: 400,000 yen/unit Customers pay 130,000 – 230,000 yen/unit as premium for electricity generation function
Operation result is not disclosed to public
FY
No. of units
2004
9,500
2005
13,400
2006
18,000*
*: estimated, not confirmed
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For further improvement More electricity required Electricity generation efficiency should be improved Hot water production is not large value (Can be made by conventional boiler at efficiency of 80 – 90%)
Partial load operation Present operation mode: full operation, or stop Electricity demand often stays lower than 1 kW Partial load operation improve load factor
Operation result should be disclosed
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Fuel cell Used in residential homes: ≈1 kW Fuel processor is combined Natural gas/LPG/kerosene -> hydrogen
Manufacturer:
Rated output
800mm
Ebara Ballard, Panasonic, Toshiba, Sanyo
Electricity
1.0 kW
Heat
1.3 kW
800mm
Efficiency (LHV) Electricity Heat
Generation unit
Hot water tank
34 % 44 %
Fuel type
Natural gas
Dimension (mm)
H 800 x W 800 x D 58
(Source: Tokyo Gas)
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Fuel cell – system configuration Generation unit + hot water tank
processor
Heat exchanger
Natural gas
Heat H2 Fuel
Aux. boiler
Cell stack
Hot water tank (300–400 L)
PEM fuel cell 40% elect. + 40% heat
Hot water
Fuel reforming (75% H2) η: 80% (rated operation) High temp. (800 ℃)
INV
Electricity 0.7 – 1 kW
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Residential fuel cell deployment program by government Large-Scale Field Test of Residential Fuel Cell System Government funding on deployment Gas/oil utilities pay fuel cell costs Install fuel cells to general homes Result is disclosed to public (symposium & web site) Subsidy
Total budget
(M. yen)
(B. yen)
480
600
2.5
2006
777
450
3.3
2007
930 *
380 *
3.6 *
FY
No. of units
2005
*: planned, not confirmed
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Residential fuel cell deployment program by government Large-Scale Field Test of Residential Fuel Cell System Government
(funding, management)
Gas/oil utilities
(R&D, O&M, monitoring)
Residents PEFC manufacturers (R&D, maintenance)
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Heat recovery efficiency (%, HHV)
(Oct – Dec 2006)
Average 41.1 %
Average 28.0 %
Electricity generation efficiency (%, HHV) 13
Utilized heat / fuel consumption (%, HHV)
(Oct – Dec 2006) Primary energy conservation
Primary energy saving : avg. 13.7 %
Average 36.9 %
Average 25.3 %
Utilized electricity / fuel consumption (%, HHV) 14
For further improvement Cost reduction Present price is far from realistic level
Lifetime 50,000 hours (= 5 years) is minimum requirement
Reliability Response time
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Customer’s voice: Mr. X Experienced both gas engine and fuel cell Gas engine: March 2003 – Jan 2006 FC: Feb 2006 – present
Profile Osaka Pref. (suburb of Osaka City) Electricity and hot water demand is larger than average 3 adults + 2 high school children
Monitored by Osaka Gas (data sent automatically) 24 hour monitoring: obligated for DG Data: used for improvement of learning control algorithm
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Customer’s voice: Mr. X (cont’d) Comments Learning control: well improved Operating hours: almost 24 hours/day, both CHP Is it desirable? FC works longer time than the gas engine
Size: too big for Japanese houses Noise: enough low, FC is preferred Monthly payment: reduced (thanks for reduced tariff) Impression/satisfaction Happy to contribute to CO2 mitigation Satisfied by the two state-of-the-art technologies,
Next: want experience SOFC ! 17
Future perspective Gas engine Continue penetrate as a economy CHP in home
Residential fuel cell system Penetration: unknown Cost & lifetime improvement is absolute requirements Competitors: gas engine/SOFC
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Future options on micro-CHP SOFC (Solid Oxide Fuel Cell) Suitable for apartment building: 10 – 100 kW Micro scale is also available: ≈ 1kW Under demonstration by Osaka Gas Commercialized by early 2009
Direct hydrogen PEMFC system PEMFC can provide higher performance Hydrogen infrastructure is required
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Concluding remarks / CHP penetration Conventional CHP: 7,000 systems, 8.6 GW by 2005 Micro CHP: 40K + systems by 2006 Residential PV: 200K + systems installed for last 5 years Many DGs embedded in grid: real story soon! Solution: Restriction of DG -> wise use/smart use of DG
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