Lack of interest at the time. Half the funds raised for the bonds would be locked into bitcoin, and with bitcoin falling in price, and, if I remember correctly, a chunk of the funds would also go into developing the geothermal plant and mining bitcoin. We've seen public bitcoin mining operators lose 90% from their ATHs, so it's not a surprise that the bonds conceived of almost a year ago no longer have sufficient interest from investors.

I wouldn't count it out though. Geothermal is a great renewable energy source for generating power, and it is a great match for bitcoin mining since it provides a constant supply 24/7. So if bitcoin mining will help subsidize the plant (by increasing its revenue potential), it becomes a viable economic endeavor (whereas without bitcoin mining it might not get built simply because there wouldn't otherwise be sufficient demand for the generation capacity on day one when production begins).