Grid connection
Practical Action
Electricity production
Electricity is most commonly produced by converting an energy source into mechanical shaft
power, which in turn drives a generator which produces electricity. The energy source can vary
depending on the available resources. Typical sources include fossil fuels, nuclear fuels (rarely
in the developing world), hydro power (a selection of countries producing a significant proportion
of total electricity from hydro power; Kenya 55%, Nepal 90%, Peru 48%), solar power, wind
power, geothermal, etc.
• Traditional thermal power generation uses oil, coal or gas to produce heat which in turn
is used to create steam which drives a steam turbine. The turbine provides the
mechanical power for the generator.
• Nuclear power generation uses nuclear fuels such as uranium, which undergo a process
known as nuclear fission in a reactor, to provide heat to drive the turbine.
• Hydropower (which is a very popular source of power in regions where the hydrological
and site conditions permit and /or fossil fuels are scarce) uses the stored or potential
energy of water which has a ‘head’ or height above a certain point. The water is dropped
through a turbine which provides shaft power for directly driving a generator.
• Windpower uses a similar principle but the energy is extracted from the wind to drive
the turbine.
• Geothermal energy is heat energy stored in the earth’s crust which can be tapped to
heat water for driving a turbine (Kenya currently has 127MW installed geothermal
power).
• Solar energy for providing electricity can be derived using one of two methods. Heat
from the sun can be concentrated to drive a steam turbine, or the more popular method
uses the photovoltaic principle to convert sunlight directly into electricity.
Solar and wind technologies are increasingly being used for grid power. Wind farms, both on-
shore and off-shore are becomingly increasing common, India has an installed wind power
capacity of 7,114 MW (2007). Roof top solar photovoltaic systems are increasingly being used
to supply the grid in some developed countries, with Germany leading the way 40% of the
world’s PV installations.
The grid can be owned privately or by the state and is not necessarily owned by the electricity
producer.
The type of fuel source which will be used to
provide electricity is dependent upon several
factors.
Figure 1: National Grid pylon and
transmission lines which do not serve the
local village where it is situated, on the
Pokhara road, Nepal. Photo: Steve Fisher /
Practical Action.
These include the following:
• a country’s fossil fuel resources
• cost of importing fossil fuels
• government energy policy
• availability of sites for exploitation of
renewable energy sources e.g. large rivers,
dams or lakes for hydro power; wind
regime for wind power or geothermal
resources
• technical expertise available in country
Cost of grid connection
There are many constraints to rural grid based
electrification. Firstly there is the question of
cost. The cost of grid connection is influenced by
the voltage and proximity of the grid and whether
there is a step down transformer already serving
the area in question. Capital cost of the
distribution system is very high and demand in
rural areas is very low. A 2000 World Bank/UNDP
study on rural electrification programmes placed
the average cost of grid extension per km at
between $8000–10,000, rising to around
2