A major debate is taking place in the hot water and heating industry in regards to Hydrogen boiler technology vs heat pump technology. We really are moving at a pace with renewables and the migration of homes on the gas grid to alternative options and this debate is a “heated one” doing the rounds.

Two most commonly proposed methods of providing hot water and heating for buildings are “Hydrogen to power hot water boilers” or “electricity to power heat pumps”. The subject of Hydrogen is an area of interest as a science in its own right, but we know two key factors in relation to this topic:

  • Hydrogen needs a primary source of energy to be produced such as solar, electricity, hydro, nuclear power, gas, oil or coal to name a few
  • Hydrogen production processes are categorised by energy source usage that determine whether hydrogen will be classified a Green, Blue, Grey, Pink, or Yellow

For the purposes of raising awareness to the debate, we will focus on one example being Green Hydrogen. This is hydrogen produced by splitting water by electrolysis. This produces only hydrogen and oxygen, with Hydrogen being used as a fuel and Oxygen being released into the atmosphere with no negative impact. Electrolysis is a process that requires power and electricity. If the process to create “Green Hydrogen” uses renewable energy sources, such as wind or solar this identifies as the cleanest option (i.e. Green Hydrogen).

If we use Green Hydrogen as the direct example against a heat pump from a power consumption perspective we have the following assessment. The overall end-to-end efficiency of providing heating and hot water into a building with Green Hydrogen produced using renewable electricity is estimated at around 46%  The largest losses occur during the electrolysis process, which is estimated at around 75% efficient. This would see 100 kWh of renewable electricity generating just 46 kWh of space heating and hot water using Green Hydrogen.

By contrast, a heat pump can deliver 3 to 4 times more heat than the electricity it uses. Assuming a “Coefficient of Performance” (COP) of 3, a heat pump powered by 100 kWh of renewable electricity delivers about 270 kWh of heat into a building which is six times (600%) more heat than supplied from a green hydrogen boiler using the same amount of electricity. So given the two options for Hydrogen boilers vs heat pumps, there can only be one winner right here, right now. Statistic information was sourced from the online Hydrogen Science Coalition website.