Alkaline fuel cells developer AFC Energy posts a pre-tax loss of £4.3m for the year to the end of October - up from £3.0m last time.
Administrative expenses rose to £4.4m from £3.2m and operating losses increased to £4.4m from £3.0m.
Chairman Tim Yeo said: "Fuel cells are gaining increasing acceptance worldwide as companies seek progressively to decarbonise, requiring them to embrace renewable technology.
"To date however, AFC Energy believes that there has been little consideration of the cost per kilowatt hour of electricity produced when fuel cells are used.
"This is likely to become an increasingly important component in any calculation and thus play to one of the many key strengths of AFC Energy's fuel cells.
"2011 was another year of strong progress towards commercialisation, with the first Beta systems deployed in the field.
"The further strengthening of the management team will enable AFC Energy to maximise its potential in 2012 and beyond."