Boilers
Boilers have been the backbone of thermal generation for many decades. Boilers will use natural gas to create heat which is then distributed to the building. Boilers typically have a low capital costs but are challenged with the operational and maintenance costs.
Legacy Boilers
The efficiency of legacy boilers range from 50 to 80%, and greatly depend on how they have been maintained. Legacy boilers can last 30 to 50 years and as such continue to be the work horses of industrial and commercial heating systems.
Condensing Boilers
Over the past decade, high efficiency condensing boilers have entered the market and now command a greater market share for new boilers. A condensing boiler uses not just the heat from the combustion of natural gas, but also from this otherwise unused energy. Inside a condensing boiler, the vapor is converted back into water droplets, which surround the heat exchanger, which in turn extracts the heat and converts it into additional heating energy.
Condensing boilers can achieve efficiencies of over 90%
Both legacy boilers and condensing boilers can also use “renewable natural gas” (RNG) to address the emissions concerns. RNG is created with bio-digestors, bio-fuels, sewage waste and is injected into the existing natural gas distribution system. There is no difference between RNG and natural gas (from the perspective of the boiler), but RNG purchase contracts are more expensive than regular natural gas.
Hydrogen Boilers
A hydrogen boiler does what it says - it is a boiler that burns hydrogen as opposed to natural gas (or methane). These appliances work in a very similar way to natural gas boilers, by burning the gas via combustion, which in turn creates hot flue gases that can be used to heat water.
As hydrogen is a thinner gas than methane, some parts of the boiler may differ slightly, including the flame detector and the burner but they work in much the same way as a traditional boiler.
Hydrogen boilers have no carbon emissions. However, access to and storage of hydrogen remains very expensive resulting in very poor financial performance.