IEEE Electrification Magazine - June 2016 - 17

Per Day Cost

captured from the homes validate the simulation results
presented in Table 6 for solar-dc systems.

Economics of On-Grid Homes Without Load Shedding
Finally, consider power costs for the two kinds of homes
on the grid with zero load shedding. Table 7 shows that
a dc home scores significantly again in terms of power
costs. The monthly power bill would come down from
about ₹500 for the current ac homes to less than ₹200
for a dc home. This is huge for low- and midincome
homes as they are often unable to power their homes
because of the lack of affordability. Direct current
homes, therefore, will go a long way in enabling them to
afford power. Midincome homes can now also afford to
consume more and add more dc appliances.

System 1
System 2
System 3

5.00
10.00
15.00 20.00
Duration of Load Shed h

Figure 8. The variation in cost of power per day with the load shed
duration for different types of homes. System 1: an ac home, system 2:
an ac home with ac-powered dc appliances, and system 3: a dc home.

batteries can be less, or better quality of service could be
provided to each home by keeping the size the same.
A multihome microgrid deployment requires the
energy consumption of each home (from different
sources) to be billed appropriately. The Inverterless-500
system, shown in Figure 11, is equipped with an
inverterless remote unit (IRU) deployed at each home,
which measures energy consumption and enables cutting off the supply in case the consumption exceeds the
(configurable) threshold power consumption after generating a suitable warning signal. This system, however,
measures only the total energy consumed by a home
and does not separate the energy used from different
sources (solar panel, grid, and battery). The Inverterless-2500 system, on the other hand, performs these
measurements. These systems have a normal line and
an emergency (low-load) line at each home. At the time
when the grid and the solar panel are not feeding power

Expanding the Solar-dc
microgrid for multihomes
So far, we have discussed how a solar-dc microgrid
deployment within a home is highly beneficial in terms
of energy savings and savings in power costs. It becomes
imperative to analyze the impact when such a solar-dc
microgrid is scaled to a cluster of homes. One of the
advantages would come from the fact that the most
expensive elements of a solar-dc system, that is, solar
panels (power sources) and backup storage, would now
be shared. The Inverterless-500 system has been designed
to power a cluster of four homes using common solar
panels and batteries on a 48-V dc power line. Similarly,
the Inverterless-2500 system uses common solar panels
and batteries and extends the dc microgrid to a cluster of
12/24 homes. As it is unlikely that each home will use the
peak load at the same time, the system can be designed
for average loads rather than peak loads; in other words,
such shared systems can benefit from the different energy-usage patterns of individual homes by what is known
as the law of averages. This also enables one home to
draw more power when needed while other homes are
not consuming much. Thus, in comparison to the sum of
the sizing of the solar panels and batteries needed to
power each home, the size of shared solar panels and

(a)

60.00
50.00
40.00
30.00
20.00
10.00
0.00
0.00

TABLE 7. Per day cost of power in grid-connected

ac and dc homes with no load shedding.

(b)

Type of
Home

Load/Day
(W H)

Cost/Per
Day (₹)

Efficiency
(%)

ac home

3,266.00

16.3

100.00

dc home

1,212.00

6.45

94

(c)

Figure 9. A deployment at Tirmal, Odisha. (a) A school running on dc power supplied by a solar-dc inverterless system, (b) a cluster of homes
powered by a solar-dc inverterless system, and (c) a home in Tirmal, Orissa, with dc appliances powered by a solar-dc inverterless system.
(Photos taken with permission of the family that owns the system.)
IEEE Electrific ation Magazine / j unE 2 0 1 6

17



Table of Contents for the Digital Edition of IEEE Electrification Magazine - June 2016

IEEE Electrification Magazine - June 2016 - Cover1
IEEE Electrification Magazine - June 2016 - Cover2
IEEE Electrification Magazine - June 2016 - 1
IEEE Electrification Magazine - June 2016 - 2
IEEE Electrification Magazine - June 2016 - 3
IEEE Electrification Magazine - June 2016 - 4
IEEE Electrification Magazine - June 2016 - 5
IEEE Electrification Magazine - June 2016 - 6
IEEE Electrification Magazine - June 2016 - 7
IEEE Electrification Magazine - June 2016 - 8
IEEE Electrification Magazine - June 2016 - 9
IEEE Electrification Magazine - June 2016 - 10
IEEE Electrification Magazine - June 2016 - 11
IEEE Electrification Magazine - June 2016 - 12
IEEE Electrification Magazine - June 2016 - 13
IEEE Electrification Magazine - June 2016 - 14
IEEE Electrification Magazine - June 2016 - 15
IEEE Electrification Magazine - June 2016 - 16
IEEE Electrification Magazine - June 2016 - 17
IEEE Electrification Magazine - June 2016 - 18
IEEE Electrification Magazine - June 2016 - 19
IEEE Electrification Magazine - June 2016 - 20
IEEE Electrification Magazine - June 2016 - 21
IEEE Electrification Magazine - June 2016 - 22
IEEE Electrification Magazine - June 2016 - 23
IEEE Electrification Magazine - June 2016 - 24
IEEE Electrification Magazine - June 2016 - 25
IEEE Electrification Magazine - June 2016 - 26
IEEE Electrification Magazine - June 2016 - 27
IEEE Electrification Magazine - June 2016 - 28
IEEE Electrification Magazine - June 2016 - 29
IEEE Electrification Magazine - June 2016 - 30
IEEE Electrification Magazine - June 2016 - 31
IEEE Electrification Magazine - June 2016 - 32
IEEE Electrification Magazine - June 2016 - 33
IEEE Electrification Magazine - June 2016 - 34
IEEE Electrification Magazine - June 2016 - 35
IEEE Electrification Magazine - June 2016 - 36
IEEE Electrification Magazine - June 2016 - 37
IEEE Electrification Magazine - June 2016 - 38
IEEE Electrification Magazine - June 2016 - 39
IEEE Electrification Magazine - June 2016 - 40
IEEE Electrification Magazine - June 2016 - 41
IEEE Electrification Magazine - June 2016 - 42
IEEE Electrification Magazine - June 2016 - 43
IEEE Electrification Magazine - June 2016 - 44
IEEE Electrification Magazine - June 2016 - 45
IEEE Electrification Magazine - June 2016 - 46
IEEE Electrification Magazine - June 2016 - 47
IEEE Electrification Magazine - June 2016 - 48
IEEE Electrification Magazine - June 2016 - 49
IEEE Electrification Magazine - June 2016 - 50
IEEE Electrification Magazine - June 2016 - 51
IEEE Electrification Magazine - June 2016 - 52
IEEE Electrification Magazine - June 2016 - 53
IEEE Electrification Magazine - June 2016 - 54
IEEE Electrification Magazine - June 2016 - 55
IEEE Electrification Magazine - June 2016 - 56
IEEE Electrification Magazine - June 2016 - 57
IEEE Electrification Magazine - June 2016 - 58
IEEE Electrification Magazine - June 2016 - 59
IEEE Electrification Magazine - June 2016 - 60
IEEE Electrification Magazine - June 2016 - 61
IEEE Electrification Magazine - June 2016 - 62
IEEE Electrification Magazine - June 2016 - 63
IEEE Electrification Magazine - June 2016 - 64
IEEE Electrification Magazine - June 2016 - 65
IEEE Electrification Magazine - June 2016 - 66
IEEE Electrification Magazine - June 2016 - 67
IEEE Electrification Magazine - June 2016 - 68
IEEE Electrification Magazine - June 2016 - 69
IEEE Electrification Magazine - June 2016 - 70
IEEE Electrification Magazine - June 2016 - 71
IEEE Electrification Magazine - June 2016 - 72
IEEE Electrification Magazine - June 2016 - Cover3
IEEE Electrification Magazine - June 2016 - Cover4
http://www.nxtbook.com/nxtbooks/pes/electrification_december2019
http://www.nxtbook.com/nxtbooks/pes/electrification_september2019
http://www.nxtbook.com/nxtbooks/pes/electrification_june2019
http://www.nxtbook.com/nxtbooks/pes/electrification_march2019
http://www.nxtbook.com/nxtbooks/pes/electrification_december2018
http://www.nxtbook.com/nxtbooks/pes/electrification_september2018
http://www.nxtbook.com/nxtbooks/pes/electrification_june2018
http://www.nxtbook.com/nxtbooks/pes/electrification_december2017
http://www.nxtbook.com/nxtbooks/pes/electrification_september2017
http://www.nxtbook.com/nxtbooks/pes/electrification_march2018
http://www.nxtbook.com/nxtbooks/pes/electrification_june2017
http://www.nxtbook.com/nxtbooks/pes/electrification_march2017
http://www.nxtbook.com/nxtbooks/pes/electrification_june2016
http://www.nxtbook.com/nxtbooks/pes/electrification_december2016
http://www.nxtbook.com/nxtbooks/pes/electrification_september2016
http://www.nxtbook.com/nxtbooks/pes/electrification_december2015
http://www.nxtbook.com/nxtbooks/pes/electrification_march2016
http://www.nxtbook.com/nxtbooks/pes/electrification_march2015
http://www.nxtbook.com/nxtbooks/pes/electrification_june2015
http://www.nxtbook.com/nxtbooks/pes/electrification_september2015
http://www.nxtbook.com/nxtbooks/pes/electrification_march2014
http://www.nxtbook.com/nxtbooks/pes/electrification_june2014
http://www.nxtbook.com/nxtbooks/pes/electrification_september2014
http://www.nxtbook.com/nxtbooks/pes/electrification_december2014
http://www.nxtbook.com/nxtbooks/pes/electrification_december2013
http://www.nxtbook.com/nxtbooks/pes/electrification_september2013
http://www.nxtbookMEDIA.com