This winter we commissioned our first two photovoltaic pumping systems: a small submersible on a farm outside Alessandria, and a surface transfer pump for an orchard cooperative. Both are now running daily without a grid connection.
Some honest lessons from those first installs:
The panels are the easy part. What makes or breaks a system is matching the pump's duty to the sun's schedule. We now size the array around the morning and late-afternoon hours, not just noon.
Water storage beats batteries. In both projects we chose an elevated tank over a battery bank. Water stores energy for free and never needs replacing. Batteries remain the weak link for cost and maintenance.
Controllers matter enormously. The difference between a basic controller and one that tracks the panel's maximum power point is not a few percent. It is the difference between a trickle and a working supply on a hazy morning.
Solar pumping in 2003 is not yet cheap. But where the grid does not reach, it is already the most reliable option we can offer. We expect this side of the business to grow.