A renewable energy system for a grid
remote village in India
Gavin Walker
Chair in Sustainable Energy
Energy and Sustainability Research Division
Faculty of Engineering
Partners
• University of Nottingham
– Don Giddings, David Grant, Joel Hamilton
• Heriott-Watt (Tapas Mallick)
• Leeds University (Mohamed Pourkashanian)
• IITB (Prakash Ghosh)
• IITM (K Reddy)
• Visva Bharati University, West Bengal (Shibani Chaudhury)
• The Uttar Sehalai villagers
Figure 1: Maps showing the location of the village
Estimated load profile for the village
Health
Education
Enterprise
Lifestyle
Auxiliary
Water pumping
Water purification
Health care centre
Schooling
Learn & earn
Do & earn
Lighting & cooling
Lantern
Entertainment
LPG compressor
Auxiliary load
Duration
Load
(h)
(kW)
5
0.2
5
0.6
24
0.5
Health total
4
0.55
4
0.52
Education total
2
4.5
Enterprise total
4
2.6
4
1
4
0.2
2
1
Lifestyle total
24
0.5-1.5
Auxiliary total
Daily load
(kW.h.day-1)
1
3
12
16
2.2
2.1
4.3
9
9
10.4
4
0.8
2
17.2
18
18
Daily load
(MJ)
3.6
10.8
43.2
57.6
7.9
7.5
15.4
32.4
32.4
37.4
14.4
2.9
7.2
61.9
64.8
64.8
Energy storage
Battery
6
CPV
150
Electrolyser
hydrogen
4.2
METAL
HYDRIDE
STORE
hydrogen
VILLAGE
14.8
16.3
Crop, food,
animal &
human waste
30.2
19.5
methane
Daily energy
kW.h.day-1
75
Generator
Anaerobic digester
Schematic of the BioCPV power plant
Energy generation
Concentrated photovoltaic (CPV)
Electricity
189 [7.5]
Solar radiation
540 [21.4]
Electricity
Solar
tracking
device
Daily energy: MJ.day-1
[Instantaneous energy: kW]
CPV
Usable heat
169.4 [6.7]
60°C
• Concentrate light with a reflective material on to a PV cell.
• Reduces cost per watt as reflective material is cheaper than PV.
• Cogeneration of electricity and heat
Energy generation - Anaerobic digester
Methane 270 [18.75]
Carbon dioxide
Fertiliser
Food waste
Animal waste
Crop waste
MJ.day-1
Daily energy:
[Instantaneous energy: kW]
Anaerobic digester
• Utilises biodegradable waste
• Generates and regulates its own temperature
– Therefore it is not part of the waste heat investigation
Power generation – ICE Generator
Methane
270 [18.75]
Hydrogen
15.3 [0.7]
Daily energy: MJ.day-1
[Instantaneous energy: kW]
Generator
Internal
combustion
engine
Cooling circuit heat
156.9 [10.9]
80°C
Electricity
70.2 [4.9]
• Methane enriched with
hydrogen
• 25% electrical efficiency
Exhaust heat
29.6 [2.1]
350°C
Energy storage - Battery
Electricity
58.7 [2.3]
Electricity
14.8 [1.1]
Daily energy: MJ.day-1
[Instantaneous energy: kW]
• Lead-acid battery (larger version of a car battery)
• Short term energy storage as these batteries self discharge
• No thermal management required
Energy storage – Hydrogen
Oxygen
857 g.day-1
Hydrogen
15.3 [0.7]
108 g.day-1
Water vapour
0.04 g.day-1
Electricity
21.6 [1.0]
Deionised water
956 g.day-1
0.689 bar
Daily energy: MJ.day-1 [Instantaneous energy: kW]
Water vapour
0.04 g.day-1
Molecular
Sieve
Hydrogen
15.3 [0.7]
108 g.day-1
Heat for
regeneration
Metal
hydride
store
Hydrogen
15.3 [0.7]
108 g.day-1
Heat
Load (kW)
Projected generator and load profile
9
8
7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
To battery and electrolyser
Total electrical load
Total CPV
Generation
Surplus
Deficit
0
3
6
9
12
Hour
15
18
21
From generator (H2 + CH4)
From battery
Total daily load = 64.5kW.h.day-1
Waste heat analysis
Generator exergy
flow
Cold reservoir
(environment) 25°C
𝜂𝐶𝑎𝑟𝑛𝑜𝑡 =
𝑇ℎ𝑜𝑡 − 𝑇𝑐𝑜𝑙𝑑
𝑇ℎ𝑜𝑡
𝐸𝑡ℎ = 𝑄 × 𝜂𝐶𝑎𝑟𝑛𝑜𝑡
Heat engine
ηCarnot = 17%
Coolant 26.7 [1.9] (10.1%)
Hot reservoir 80°C
CH4 251.6 [17.5] (95.3%)
Loss 150.8 [10.4]
(57.0%)
H2 12.5 [0.9] (4.7%)
Exhaust 15.7 [1.1]
(5.9%)
Hot reservoir
350°C
Total 264.1 [18.4] (100%)
Daily exergy: MJ.day-1
[Instantaneous exergy: kW]
(% of exergy input)
Heat engine
ηCarnot = 53%
Electricity
70.2 [4.9]
(26.6%)
Cold reservoir
(environment) 25°C
Waste heat analysis
Energy exergy overview
Daily Instantaneous % of
energy
energy
input
(MJ)
(kW)
energy
Daily
exergy
(MJ)
Instantaneous
exergy
(kW)
% of
input
exergy
Methane +
Hydrogen
285.3
19.8
100.0%
264.1
18.34
100.0%
Electricity
70.2
4.9
24.6%
70.2
4.88
26.6%
Exhaust
29.6
2.1
10.4%
15.7
1.09
5.9%
Cooling
156.9
10.9
55.0%
26.7
1.85
10.1%
Other (aux,
pumping,
friction)
28.5
2.0
10.0%
0
-
z
Loss
Included in losses
151.6
10.52
57.4%
Waste heat analysis - Efficiency
Generator
Total daily load = 232.1 MJ.day-1
Generator efficiency analysis
Daily Instantaneous Energy
Daily Instantaneous Rational
energy
energy
efficiency exergy
exergy
efficiency
(MJ)
(kW)
(%)
(MJ)
(kW)
(%)
Electrical
Cogeneration
CPV
exhaust only)
Cogeneration
(exhaust and cooling)
70.2
4.9
24.6%
70.2
4.9
26.6%
99.8
6.9
35.0%
85.9
6.0
32.5%
256.8
17.8
90.0%
112.6
7.8
42.6%
Waste heat opportunity
• There is a large quantity of waste heat energy
• Most of the waste heat has a low exergy as it is at low temperatures
• Waste heat better used for refrigeration as opposed trying to extract work
• This will improve the overall efficiency of the BioCPV energy system.
Thank You
gavin.walker@nottingham.ac.uk