Consumers could be forgiven for being confused as to the strengths (and weaknesses) of the raft of new low carbon technologies being presented to them. 

Foremost among them, hydrogen solutions are being put forward as an alternative energy source to mains gas, oil, LPG, and electric heaters. 

There are, of course, pros and cons to all these solutions, but one thing often overlooked is that air source heat pump technology is available right now, and is a truly low carbon technology, whereas other technologies such as hydrogen solutions are still in their infancy.

Because the UK government has set ambitious targets to reduce emissions by 2035 by at least 78% compared to 1990 levels, there is real pressure on the industry to install alternative technologies, regardless of whether it is a practical choice for consumers.

An imperfect option

There are in fact at least seven different categories of hydrogen, which are colour-coded by the energy industry. Broadly speaking, green or white hydrogens are the most low carbon, while grey, brown, and black hydrogens (created from fossil fuels) sit right at the other end of spectrum, potentially generating more carbon than fossil fuels. 

The amount of energy required to create hydrogen also needs to be taken into consideration, as well as the emissions created by that process. Currently nine tonnes of CO2 are produced as waste to get just one tonne of hydrogen. 

There is also a need to store the hydrogen created. 

The most sustainable version, green hydrogen, currently only accounts for about 1% of global hydrogen supply, and it isn’t yet an option available with any domestic heating solution. 

Green hydrogen is created from electrolytic water cleaving, before being used for power generation. During this process, renewable electricity is used to split water (H2O) into hydrogen (H) and oxygen (O2). 

Unfortunately, the process uses more energy than is later produced from the resulting hydrogen. The loss can represent up to 50% of the energy initially used. 

Hydrogen will have its place in the new energy mix but, in my view, its use will be limited to industrial processes that require high temperatures. 

Boiler manufacturers are working to adjust their product portfolios, but using the existing gas network to distribute a blend of natural gas and hydrogen is still only at the trial stage, while perfectly viable, low carbon technologies are available for installation in homes across the country right now.

The most notable of these is air source heat pumps, using the free, kinetic energy in the ambient air, generate, store, and deliver energy on-site to provide sufficient heating, hot water, and cooling (for certain units only) to heat or cool our homes on demand, delivering what is needed, when it is required, and with little to no energy wastage. 

Energy efficiencies

If we look at our current gas boilers – the heating loads currently modulate at 14-22kW. A 20kW gas boiler will generate a minimum of 7kW, even if that’s more than required. 

A heat pump, and its inverter, can modulate its output to match the demand. As such, air source heat pumps are far more energy efficient than current gas boilers. A gas boiler or LPG system uses approximately 7.2kW of energy per litre, whereas a heat pump has around five times the output to the input depending on the type of heat pump, and the temperature at which the heat pump is set. 

As homes become better insulated, and the climate warms up, the need for cooling will also become greater. 

Hydrogen can only produce heat, whereas air source heat pumps can cool or produce heat as needed.

In conclusion, if we are to meet the UK government net-zero targets by 2050, the mandate is to support and develop heat recovery, the use of heat pumps, and better insulation. 

A heat pump is a proven, readily available technology, whereas other options, such as hydrogen, are still in their infancy, and will require further development before the technologies are sufficiently reliable and command enough customer confidence to be fully adopted for wider usage.