Solar Powered Water Systems in Humanitarian Context II - Q&A
This page documents the questions that were asked during the webinar: Solar Powered Water Systems in Humanitarian Context - Making Sense of SPWS Expansion.
This page is currently being updated!!
Questions to All
Which are the preferable solar water pumping systems that would eliminate the use of generators in the long run. We have challenges with solar systems in South Sudan refugee camps. Use of generators still takes about 60% of water pumping
when converting from diesel generator operation, the full details of the system (as being explained by Jeff) need to be known so that the right PV size can be designed to supply the required amount. Where solar cannot meet the requirements, a hybrid operation is then chosen
Regarding daily demand and solar, what sizing consideration do you do for consecutive cloudy days?
Usually, SWP sizing is based on the worst-case i.e. design is based on the season or days when you expect the least irradiation. So it should be ensured that the design is able to meet the demand when you have the least sunshine.
We realised one more factor important in design - slope and direction
In case you are referring to the tilt angle/orientation of the solar panels, then indeed you are right as the tilt angle and orientation impact the power output from the solar modules.
While there seems to be little or no support for using batteries in solar water pumping scheme could it not be feasible someday since the cost of battery storage is plummeting (as PVs did making PV water pumping much more feasible) would it not be possible to find batteries useful in some applications such as a situation where well capacity is weak and a longer pumping cycle would be needed to meet demand. This could be more efficient than opting for a solar-diesel hybrid system, no?
You are right Robert. Battery technology is indeed evolving into batteries that have 15-20 years life as opposed to the current technology which has a short life (3-6 years) which has been the biggest deterrent for using batteries in SWP. However, the long-life batteries (lithium-ion etc) are very expensive prohibiting their wider use. Perhaps we will see this change in the coming years.
Questions to Jeff
I wonder how do you make solar systems like in Puerto Rico hurricane-resistant?
In a humanitarian context, how would you go about establishing the dynamic water level (where this information has not been established prior, but where there is anecdotal evidence of seasonal fluctuations and/or lowering groundwater levels?
Questions to Rick
Sometimes after geological survey, wells later start drying Not because of the aquifer condition but because of weather changes, what could be done to address such issues.
Questions to Alberto
using the LCCA is great for comparing between the generator, hybrid and solar systems. But how can you use it to calculate what potential user fees would be to cover costs for the system? Given that it uses present worth as its basis rather than looking at inflation, I know that this has caused some confusion when looking at what real-time costs will need to be paid.
