Bloom Energy builds solid oxide fuel cells that generate electricity on a customer's own site, converting natural gas, biogas or hydrogen into power through an electrochemical reaction rather than by burning it. The appeal is independence from the grid: data centres, hospitals and manufacturers that cannot tolerate an outage, or cannot get a utility connection quickly enough, buy power capacity they control. The same stack technology runs in reverse as an electrolyser to produce hydrogen. Each installation is a large capital commitment with a long sales cycle, so results depend heavily on the timing of a relatively small number of sizeable orders.