ITM Power's total pipeline has increased by £2.82m since 18 April.
The company said it currently had £23.02m of projects under contract and a further £4.16m in the final stages of negotiation constituting a total pipeline of £27.18m.
Chief executive Dr. Graham Cooley said: "The international hydrogen bus market is becoming very exciting for ITM Power.
"Because buses use a depot refuelling model the fuel revenues are bankable and with 10 buses using 1MW of electrolyser demand per day, the market for our equipment is therefore very large given the number of hydrogen buses funded in Europe alone."
At 9:06am: (LON:ITM) ITM Power PLC share price was +0.75p at 24.75p