Communal Heating and Hydrogen

The Logic:

• Hydrogen is inefficient compared to local heat pumps
• Hydrogen has the advantage of being able to deliver higher temperatures (Exergy)

Sizing heat sources can be roughly divided into 3 parts:

1. 90% load. This is the hot water and normal central heating, as can be delivered by a heat pump running at 60C.
2. 10% load. This is driven by central heating when it is very cold. It only happens for a few days or weeks a year, and accounts for only 10% of total load, but required temperatures higher than 60C.
3. Redundancy. This is an oversizing factor there to allow for times when a heat source is offline (failed).

This is seen in the graph below looking at real loads for 2020.

The conclusion:

Hydrogen can form a critical role in communal heating by acting in a topping up boiler role, providing high temperature heat to satisfy load on the colder days.

When converting existing sites that run on gas boilers to renewables, the optimal approach would be to replace 1/3 with heat pumps and convert the remaining boilers to run on hydrogen to provide the top-up and backup roles.