Off Grid Solar Introductory Guide

Download this guide from www.energyoneafrica.com
An Introductory Guide
to Off Grid Solar Power
Prepared by: MathyMpassyIsinki

© MathyMpassyIsinki 2016
Mathy is an accomplished off grid energy solutions business and technical sales professional technically competent
in the applications and installation of off grid photovoltaic systems, as well as in hybrid energy solutions combining
photovoltaics and diesel generators.
In addition to providing solutions design, customers development and project management services to the off grid
solar industry, Mathy contributes to better energy solutions through training, with the vision of building a better future
for under-served communities in off grid locations. Learn more about Mathy’s online training courses by visiting
www.energyoneafrica.com

1. Why off grid solar
Electricity affects all aspects of development: social, economic, and environmental.
Access to electricity can dramatically improve levels of welfare and increase standards of
living.
However, 1.3 billion People, almost 25% of humanity lacks access to electricity; over
90% of those lacking electricity lives in sub-Saharan Africa and SouthAsia.
Lack of access to electricity is a barrier for development of communities deprived of
social and economic opportunities that are common place to those with access.The issue
is known by governments, most of them are setting aggressive targets to increase access,
and many programs are in place to extend the grid to rural communities.
However, high capital cost, complexity of grid extension, commercial viability especially
in remote and low density areas make most of those programs too long term solutions.
There is growing evidence that investments in small- and medium-scale electrification
projects have a positive impact on improving the energy situation of the majority of
population especially in underserved locations.
Decentralized electrification is emerging as the solution to fill the gap left in socio
economic development of those most in need. Decentralized electrification is described
as an approach where electrification is led by non governmental entities such as private
entrepreneurs, NGOs, cooperatives or the communities. Renewable energy is the
preferred source of energyin decentralized projects.
Due to the high consumers interest about solar off grid electricity, whether in rural
communities lacking access to electricity or within communities victim of unplanned
and frequent power outages making the grid unreliable, many are making parallels
between the explosive growth of telecommunication sector in the past decade and the
nascent off grid solar market.
The modularity of solar, giving the possibility of adding or removing panels to scale up
or down a power generation unit, is making two electrification approachesrising:
 Solar home systems allowing the electrification of a single house and,
 Mini-grids, described as an energy solution including power generation, energy
supply and distribution at a community level.

2. Off Grid Solar Basics
Solar electric systems convert the sun's light energy into electricity using photovoltaic
(PV) cells. A solar cell, made from two layers of semi conducting material, usually
silicon, creates an electric field across the layers when light shines on it.The amount of
energy that can be produced is directly dependent on the intensity of the sunshine.
Assemblies of cells are used to make solar panels, also called solar modules. Modules or
panels together constitute photovoltaic arrays.
Solar PV systems can be connected to the grid or can work as isolated systems for the
use of single households or institutions. An isolated solar power system is referred to as
an off grid or stand alone system and, involves the use of storage batteries. The batteries
store the excess energy generated by the PV array and, in it turn; provide electricity to
the connected load when the sun is not available.

Off grid PV systems are more complex than grid connected systems:
 A charge controller is used so that the batteries are not damaged by overcharging
or excessive discharge.
 When the loads are not DC, then, an inverter is used to convert DC power from
the batteries into AC.
In case the sun is not fully available for a string of days or the users draw more power
than what the batteries should provide, the system might go down. To avoid this, an off
grid system is often backed up by a diesel generator to enable continuous charge to the
battery bank.
3. Off grid solar products classification
Based on their usage and power output, off grid solar power products can be classified in
4 groups:
• Lanterns:
Solar lanterns are sold as integrated systems. Each of the systems comes with a panel, a
battery, wiring and one or two lamps. Moreover, today lanterns often have an option for
cell phone charging. They are small, relatively cheap off-the-shelf products with a
maximum power output of around 3W. Due to the low complexity of the product (it is
simple plug-and-play) there is no need of professional installation. Also, the need for
after-sales service is limited as long as the product is of good quality and the client uses
the system under normal conditions. Solar lanterns are affordable to a large share of the
population, including those at the bottom of the pyramid. They are the most popular off
grid product and also the cheapest.
• Micro-systems:
Micro-systems vary in size from 2.5W to around 15W. Although these small solar
systems are still “off the-shelf” products they are a bit more complex than solar lanterns,
they have separate parts and involve wiring of several rooms. Mobile phone charging is
always an option and more than one room can be illuminated. Additionally, small radios
or energy efficient TVs can be powered by these systems. Prices of small solar systems
are proportional to their power output.

• Solar Home Systems:
Solar Home Systems (SHS) are systems bigger than 15W.They are sometimes sold as a
whole plug-and-play systems, but more commonly as separate components, which need
to be installed by a technician. Given the large size of these systems, proper estimation
of the power demand, sizing of the system components and a professional installation
and maintenance are important. Moreover, consumer education is necessary to ensure
proper use of the product. Also, after-sales support may be necessary in case one of the
components breaks down. In addition to lighting and cell phones charging, these
systems are able to power small electrical appliances such as a TV, larger ones also
power fridges and beyond. In case AC appliances are used, an inverter isrequired.
• Solar Mini-grid:
Solar mini-grid involves solar power generation, supply and distribution at community
scale.
4. Benefits of using solar power
A solar power system to produce electricity only needs the free, renewable and clean
energy provided by the sun.Therefore, the use of solar systems generates very little
running cost and helps limiting greenhouse gases emissions and global warming.When
one considers the lifespan of a photovoltaic module which, easily exceed twenty years, it
is easy to imagine the environmental and economic benefits of using solar power
systems.
Investing in solar energy helps not only improving living conditions of local
communities, but it also allows countries to reduce their dependence on fuel imports,
reducing their spending in foreign currencies and increasing their resilience to energy
crises.
Due to their modularity, solar power systems are accessible to anyone based on energy
needs and willingness to pay.
Solar energy is not just for domestic purposes;water pumping and irrigation are good
examples of high impact productive use of solar energy.

Based on the above; we could list:
Sustainability;
Environmental benefit;
Economic growth and;
Energy security among the key benefits of using solar energy.
5. Weaknesses of solar power
High initial investment cost.
Even if solar power running cost is very low, the related initial investment cost might be
high, and, therefore, it raises a barrier for the adoption of solar power products by wide
segments of the population.If lanterns are the best selling off grid solar power product,
this does not mean, in most cases, that users needs are limited to the use of a lamp and
the recharge of a cell phone.The most successful off grid solar power companies always
offer their products together with the financial mechanisms that will make the payment
affordable for all and the products accessible for the majority.
Technical constraint.
In addition to the financial constraint related to user’s budget limitations, products
design is alsoa constraint: an undersized system will not produce what users expect and
an oversized system will cost unnecessarily expensive.
Need of a standby generator.
An off grid solar power system is designed to meet the needs of a specific user. Beyond
the purpose it was designed for, the system might stop. Moreover, the photovoltaic
conversion depends on the intensity of the sunshine. This means that below the
expected sunshine, the system might also stop working.The most reliable systems
integrate a generator to ensure battery charging under allconditions.
6. Energy efficiency
Photovoltaic systems are designed according to specificenergy needs; the bigger the
needs, the bigger the system.So saving energy is an important key for reducing the size
and subsequently the cost of photovoltaic systems.
Energy needs are based on the power demand and usage time of the connected
appliances.Therefore, either reducing demand or usage time both result in energy
saving.Energy efficiency aims to save energy without affecting users comfort.This
involves choosing more efficient equipment anda smarter use.A good example

ofreducing demand is the replacement of halogen spotlights by LED spotlights which
are much more efficient. Reducing usage time could happen for example through the
replacement ofconventional switches by occupancy sensors.Both of them either lamps
or switches replacement resulting on energy saving.
The role of the technician here is to,first, identify and inform users of all the energy
savingopportunities.Then, after the system has been sized and installed, the technician
should educate users in order to instill and maintain the habits of anenergy efficient
use.The user should here understand that small changes in his way of using energy
enabled him to have a smaller and cheaper system;an efficient usage is the only way of
maintaining the system under normal load conditions.
7. Sizing the systems
A stand-alone PV system is the only energy source available for its users: it must
therefore provide enough power to all the connected appliances without any failure.The
major issues arising during its sizing is that:
One side, the demand is not constant all over the day and all over theseasons
And on the on the other side, the energy available from the PV arraychangesall
along the dayand is not constant over the seasons
The periods of low energy yield, rainy season, and overcast for example might
correspond to periods of high demand with as an example, anincreased need of lighting
due to overcast.
When irradiation for a particular location is known, then the equivalent sun hours can
be calculated. Irradiation is defined as the amount of energy delivered by the sun per
unit of surface. Sizing of standalone PV systems should be undertaken based on the
lowest equivalent sun hours. In north hemisphere, this corresponds to winter months
values.
Off grid PV systems are sized in four major steps:
Determinationofenergy needstobe covered
Sizing the PV array
Sizing thebattery bank
Selecting the balance of system

8. Installing the system
In fact, rather than buying a PV system, users buy the solution to their energy
problems.Installing the systemis what will make the solution available for them.
Just as an undersized system does not provide what is expected from him, a poorly
installed system also might cause the energy needs of users not to be met, worse, it
could be dangerous.
The installation of a photovoltaic system shouldcomply with standards and result on a
system working as specified by the designer.A state of the art installation is also an
important system durability factor.
Some key points to consider when installing a PV system are the PV array orientation;
and the location of the battery bank and balance of system.
For best year round performance, a PV array should be mounted facing south for
systems located in north hemisphere and facing north in south hemisphere. The
correct tilt angle should be determined based on energy usage and also the local
weather conditions at different period of the year. A mounting arrangement can
allow the adjustment of PV array tilt to increase energy output.
Batteries should be installed in a well ventilated enclosure with restricted access.
Equipments in the enclosure should be readily accessible formaintenance.
The charge controller is installed in the immediate close to the batteries.
However, a minimum distance of 50cm should be respected.
The inverter and the charger should not be exposed to the element. Wherever
possible, the inverter and the charger should bekept away from the batteries and
installed in a separate weatherproof and well ventilated enclosure.
The generator,if there is one, should be kept away from users tominimizenoise.
9. Understanding off grid solar power consumers
1.3 billion People, almost a quarter of human population have no access to electricity. Of
which 635 million live in Africa and 526 million in South Asia.
Decentralized electrification using renewable sources of energy is emerging as the
solution to fill the gap left in socio-economic development of those in need: investments
in small and medium scale electrification projects have a positive impact on improving
the energy situation of population in underserved locations. In addition, it has been

observed that solar energy has the preference of communities in off grid locations. This
might be explained by the modularity of solar making possible to set up the smallest or
the largest power generation unit and subsequently fitting within the smallest or the
largest budget.
However, most of the off grid energy market often interrelates with high percentage of
population living in poverty. Even seemingly modestly priced, solar products can be
prohibitively expensive for low income consumers who are accustomed to purchasing
energy in small increments. It is therefore important to recognize that local conditions
will demand tailored solutions and approaches.
What are the problems off grid energy customers want to solve, what are the benefits
they want to see, what is their ability to pay for energy access? Keeping these questions
in mind, what should be the right implementation strategies for off grid entrepreneurs,
how should they develop profitable and sustainable revenue streams?
The relation between what an off grid solar entrepreneur offers and what his customers
are expecting is what can make his business fail or succeed. Off grid solar entrepreneurs
should always find the minimum balance between products features and customers
expectations. Translated to off grid context, when planning for products or services,
entrepreneurs should find out products having the minimum specifications to meet the
needs, preference and budget limitations of customers. This means that off grid solar
systems should be designed to supply a set amount of power for a set amount of time
such as they fully meet customers energy needs for the preset amount of time.
The trick here is that many communities are skeptical about solar energy and consider
them risky investments. They may be unfamiliar with solar products, making it difficult
for them to discern quality. Alternatively, they may have had a negative experience with
unreliable solar products. Accordingly, to introduce solar energy products to low –
income communities, entrepreneurs must prioritize building and maintaining trust with
the people they seek to serve. In that view, understanding customers is crucial.
Understanding customers is also central when it comes to charge them. Conventional
payment schemes are often not compatible with off grid customers. In addition of
understanding customers motivations, needs and preferences, off grid solar
entrepreneur should understand customers’ ability to pay and then design the most
relevant and appropriate financing and payment model to help consumers purchase
their products.
10. Overcoming consumers’ budget limitation
Many are predicting an exponential growth of the off grid solar market, making parallels
with the telecommunication sector during the last twenty years. Turning that prediction
into reality will require to overcome the barriers encountered by off grid solar
consumers. Most of them have low income and live whether in rural communities

having no access to electricity or within communities victim of unplanned and frequent
power outages. Consumers in these underserved areas are in most of cases accustomed
to purchasing energy in low increments: solar product are seemingly prohibitively
expensive for them. The challenge for energy entrepreneurs dealing with them is to
build sustainable revenue stream: how to charge low income consumers without pricing
being a barrier for them, how to make a solar product offer without compromising on
quality?
Energy entrepreneurs in low income off grid areas should focus on overcoming
consumers' budget limitations. They should emphasize on small payments; energy
should be sold in small increments fitting to consumers' budget. Drawing a parallel with
telecommunication sector, the winning mobile phone pay as you go model has been
adapted to off grid solar market:; as for mobile phones users, energy users also, in
certain cases, can buy a set amount of power time and top up again once they have spent
it. Pay as you go model has the advantage of allowing them to spend amounts of money
strictly fitting to their budget.
We have seen the massive introduction of solar lanterns as substitution product for low
income off grid areas, but there is still a need for comprehensive energy solutions as
provided by solar home system. Revenue models such as end user financing, energy as a
service and pay as you go tend to help customers accessing comprehensive systems they
could not have afford through upfront payment of solar equipments.
Without the appropriate payment scheme, those of the consumers in low income off grid
areas interested by solar home systems are attracted by cheap products, price only
guiding their choice. As one can guess, cheap solar products are often low quality. They
are quick to fail and subsequently, they contribute in developing consumers' skepticism
about solar products. Accordingly, in low income off grid areas, it is crucial for energy
entrepreneurs to offer quality products together with the payment scheme which will
make the products fit to consumers' budget.
Off grid revenue model differ one from another by what end users are paying for and
how they are paying for it. It is either:
• a prepaid energy usage fee allowing consumers to buy small increment of power time
as developed by pay as you go model;
• a loan repayment fee when using end users financing model. Entrepreneur basing their
revenue stream on this model sell solar products under the umbrella of micro finance
institutions (MFI). The strategy for entrepreneurs here is to partner with a MFI and
continuously run demand creation activities among the MFI's members. MFI are known
as being the banks of the poor. In the case of end users financing, they are the economic
buyer, granting loans to those of their members committed to acquire a solar system,
helping them bearing the full cost.
• or it is a performance based subscription. Energy as a service being the model based on
performance. Under this model, end users pay for services enabled by energy access

rather than paying for energy access itself. Lighting and charging devices are the most
widely services offered under energy as a service model.
The role of energy entrepreneurs operating in low income off grid areas is to find the
right balance between products, consumers' needs and revenue model.
11. After Sales Service
Experience as shown that off grid solar power products users are satisfied only if their
power product keeps meeting their energy needs days in and day out. Accordingly, in
case of technical deficiency, an off grid solar business should be able to provide quick
and reliable repair. A long term customer relationship is not only based on the quality of
the products but also on the quality of service and customer trust in the reliability of the
business. At that title, after sales service should not exclusively focus on a product
technical ability to function but also on customer satisfaction.
Successful off grid solar businesses always put after sales service at the center of their
customer relationship strategy. As a result, after sales service play a key role in:
 Keeping customers. This happens in two steps; customers first develop trust in the
business, then trust changes into loyalty and as a consequence the businessbecomes
their only supplier.
 Growing customers. We describe growing customers as selling as many products as
possible to one customer over the time and through different products lines. In addition
to solar power kits, a business could be also selling energy efficient appliances for
example.
 Getting new customers. Mostly through the development of a viral loop. This is when
someone has bought a solar products and then starts telling around him all the benefit

he got from the product, all the improvements the product brought in his life and then
start asking his friends to buy the same product and experience what he is experiencing.
Actually, the satisfied customer we are talking about has become a powerful sales
person.
Solar businesses who want to put in place the conditions of a good after sales service
must:
 Listen to customers and try to understand their needs and unspokendesires
 Clearly explain to customers the benefits and drawbacks of solar powersystems
 Indicate to customers the conditions necessary for a solar power system towork
properly
 Inform customers about energy saving devices
 Take into account the worst case scenario when sizing a system
 Always go for quality when choosing components
 Ensure state of the art installation
 Train customers on how to use their solar powersystem
 Inform customers of guarantee, service and maintenance features

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