After the site power fiasco of 2019 (the small cheapo generator supplied to power several sculpture on Esplanade was utterly unreliable) we are exploring ways to better power the Whisper Tree.
Explorations in solar didn’t yield the expect answers – $1800 would be the minimum cost for a second hand system capable of running WT (assuming not more than one day of poor sun). A silenced Honda generator could be had new for <$1500.
Instead it has been decided to use a larger UPS with a custom AGM battery pack (~200Ah of second hand batteries) and run off the grid. This should keep the costs, noise and carbon footprint as low as possible.