Martina Schäfer, Noara Kebir, Daniel Philipp (editors) - TU Berlin

PROCEEDINGS Conference MPDES 2011
and fro and leaves the end-user uncertain about what to do
or whom to contact. As systems are not monitored
properly, it remains unclear, whether the user tempered
with the system, for example through by-passing the
charge controller, or if the technology itself has caused a
failure, and warranty enforcement becomes a challenging
task. Most clients go through several credit cycles with
the MFI and are afraid to lose their reputation, if they do
not pay their instalment as protest measure against broken
systems. In very remote regions, spare parts are simply
not available even though the end-user would pay for
them and self-made repairs, e.g. replacing a blown fuse
with metal thread, exacerbate the problem (Sandgren,
2001).
End-of-Life
At the end of the system life, the biggest issue is the
disposal of the battery. The material within is not only
environmentally harmful but also valuable when recycled,
but nevertheless most of them end up being dumped or
burned with the household trash. As systems are not
traced, the component manufacturer is not able to receive
feedback about the product and can therefore not include
user experiences into design iterations (Zühlsdorf, 2010).
For a better overview, all focus problems are illustrated
along the lifecycle of a solar home system in Figure 3.
Figure 3: Focus problems along the life cycle
Taken together, these results imply three underlying
assumptions:
1. Maladjusted systems
2. Inadequate installations
3. Disorganized after-sales service
The first statement summarizes a number of reported
problems – charge controllers overheat due to ambient
temperatures, they are not adapted to, batteries have a
much shorter life time than expected, because of daily
cycling patterns, the overall system output is lower than
planned, because the amount of scattered radiation was
not taken into account and product counterfeits of
insufficient quality lower the system performance.
The second assertion explains, how methodologically
flawed system design leaves end-users dissatisfied with a
system that does not meet their electricity requirements,
how a mismatch of components leads to early system
failure and how a lack of quality in activities such as
wiring increases system losses significantly.
And thirdly, irresponsible after-sales organization
leaves the end-user alone and allows that minor problems,
which could be fixed without great effort, weaken the
whole system and impede a sustainable solar home system
dissemination.
Standardization of SHS
Experiences made in different field studies show that the
quality of installed solar home systems is better, if
standards have been enforced. Demands made on solar
home system quality and performance vary widely, partly
because of particular country characteristics or the
regional supply situation, but also because of a lack of
binding standards or knowledge on their existence
(Fahlenbock & Haupt, 2000). Thus, to define a good
compromise between affordability and quality, various
sources have been consulted: international standards from
recognized standards committees, national standards from
countries that have adopted solar home systems widely,
best practices from organizations such as the World Bank
and IEA PVPS and specifications for the evaluation of
tenders of substantial aid-funded programs have been
researched for suitable certification approaches that
specifically address the problems identified earlier. In
addition to that, these specifications have been backed up
by opinions from experts in the field of SHS
dissemination.
The leader in standards development for the
Photovoltaic panel as well as the balance of system (BOS)
components is the International Electrotechnical
Commission (IEC) as representative of relevant
committees and working groups of standards agencies
from most manufacturing countries. While a number of
IEC standards deals with batteries in general, appropriate
sizing for PV systems or correct charging procedures are
not covered to date (Wilshaw, Bates, & Oldach, 2004).
According to a World Bank guidance note, the attempt to
fill this gap and to assure quality through the PV Global
Approval Program with a quality seal stating PV GAP
certification has shown to be largely ineffective in
practice, because neither manufacturers nor end-users
requested it (World Bank, 2010).
While IEC specifications detail on how to conduct
component testing in a standard and repeatable manner,
the value of the measured feature is then set in
procurement standards (Cabraal, 2010). A look at such
standards from countries that have implemented solar
home systems successfully facilitates the proposal of
adequate values for decent quality at affordable prices.
For this, the technical specifications developed for the
Rural Electrification and Renewable Energy Development
Project (REREDP) in Bangladesh have been found very
suitable (TSC Bangladesh, 2005).
Valuable recommendations are also made in the
proposal for a “Universal test standard for solar home
systems” (UTS-SHS) – the Instituto de Energia Solar
224