The electrical efficiency of solid oxide fuel cells (SOFC) is in the 50-55% range, which is higher than for thermal power plants that use steam turbines but only on a par with combined cycle gas turbine (CCGT) power that costs less than a tenth of Bloom Energy's servers.
Both SOFC and CCGT put out about 0.8 lb of CO2 per kWh generated, but while Bloom's unsubsidized equipment cost is $7,000-$8,000 per kW of peak capacity, CCGT capacity can be added to the grid for a mere $600 per kW.
CCGT are a proven technology, the combination of two other technologies (steam turbines and gas turbines) that have been in industrial use for more than a century / more than half a century, respectively. CCGT achieve thermal efficiencies of up to 58%, which works out as an electrical efficiency comparable to the SOFC's 50-55%, hence the virtually identical CO2 output per kWh.
Even if we give Bloom the benefit of doubt and hope their fuel cells will prove to be reliable and low maintenance of their 10 year life cycle and that production costs will come down as volume increases, it still means they will have to reduce their costs by over 90% and establish a near perfect record just to pull even with current proven technology.