IEEE Electrification Magazine - March 2015 - 19

Most of these challenges mentioned apply to the rural
off-grid power systems as well. There, the power quality
and reliability issues are even more pronounced because
of the lack of sophistication in system planning and operation. While most of the discussions in this and the following sections are based on the U.S. electric power
system, the general principles also apply to other countries and other types of electric power systems.

Sustainable rural Electric
Infrastructures-a New Era
The challenges facing today's centralized electric power
system are the results of the over 100 years of legacy. They
also reflect the lack of viable alternative solutions up until
now. Today, the entire energy industry, of which rural electrification is an integral part, is undergoing a transformation that only happens once in a lifetime. Numerous
breakthroughs are happening in renewable generation, the
smart grid, energy storage, electric vehicles, and energy
efficiency that will fundamentally change the way we
generate, store, deliver, and consume
electricity. The convergence of energy
and information technologies (or OT
and IT) is also a signature of this
transformation. There is already a
critical mass to integrate these technologies into a new, affordable, and
sustainable energy system-rural
electrification included.
I propose a model rural electric
system, where the ingredients of this
model system include mostly local
renewable generation (solar, wind,
and biomass), a local power-delivery
network (no transmission or substation), an optimal amount of energy storage, energy-efficient
and flexible loads, and operation management to self-balance the local generation and demand. The size of this
model system can range from a few kilowatts to several
megawatts, powering anywhere from a single home to an
entire rural community.
This model elegantly addresses the many challenges
discussed earlier. Using local renewable resources brings
generation closer to the load and eliminates the need for
building long transmission and distribution lines. Selfbalancing at a smaller footprint makes system planning
and operation simpler and more resilient. By dynamically
managing the flexible load, it is possible to optimize the
supply and demand curve at the same time. It is worth
pointing out that market mechanisms and business models need a paradigm change as well to go local and
distributed. Deregulated retail energy services, nontraditional utilities, prosumers (i.e., producer and consumer),
transactive energy, cooperatives, peer-to-peer energy sharing, and other ideas have shown promises. There is no
one-size-fits-all solution. This is a fertile ground for inno-

vation as the energy transformation unfolds. The following sections will discuss the proposed model rural electric
system in more detail.

Local Renewable Generation
The advancement in renewable generation technologies and
the rapid decline in costs have become game changers for
the electric industry, and rural electrification is no exception.
The vast area covered by rural communities used to be a disadvantage, but it now becomes a huge advantage because
renewable generation, which is the distributed energy
resource, needs a lot of land space. In ideal cases, the rural
areas will be net electricity exporters because their wind,
water, and solar resources exceed what can be consumed
locally. David Mackay well articulated this point by plotting
the per capita energy consumption (i.e., energy consumption
intensity) for most of the countries in the world alongside
the available renewable energy resources per square meter.
Note that this is the total energy consumed for transportation, heating, and electricity. (The average energy consumption in the United States is the equivalent of 250 kWh/day per person.) It can
be seen from Figure 1 that in most of
the world (including the United
States), the average energy intensity is
below the 0.5-W/m2 line. Comparing
this to the wind power line of 2.5 W/m2
and the PV solar line of 10 W/m2, it is
reasonable to conclude that in most
places, local wind, solar, and other
renewable resources are sufficient to
meet the demand with acceptable
land use ratio. Other studies have
reached similar conclusions.
We can extend this analysis to
rural areas using the same methodology and U.S. census
and Energy Information Administration data. Figure 2
shows a plot of some representative samples of state- and
city-level electricity consumption versus the population
density. On average, the per capita electricity consumption
is about one-third of the total energy consumption. Without
any surprise, we found that there is a wide distribution of
population density and per capital electricity consumption
among the states and major cities. We carefully researched
and plotted the "United States Rural" data point, which is
calculated using data from the National Rural Electric Coorperative Association (NRECA) fact sheets, and the "Tri-State"
data point, which is calculated from the annual report of
the Tri-State cooperative utility in the western region. These
indicate that the average rural energy consumption per
person is much lower than the U.S. average. Regardless of
urban or rural, the per capita electricity consumption
across the United States is quite high (close to 100 kWh/
day/person).
Almost all of the states and cities plotted (except for the
densely populated areas of New Jersey, New York City, and

The current natural
gas production boom
and low price have
made gas-fired
power plants more
competitive.

IEEE Electrific ation Magazine / marC h 2 0 1 5

Table of Contents for the Digital Edition of IEEE Electrification Magazine - March 2015