Fuel for thought05 February 2019

Liquefied natural gas is a relatively new fuel that is available to off-grid consumers. What benefits can this alternative to oil-based energy bring to site?

Cochran, a manufacturer of industrial steam and hot water boilers, was previously using oil for space heating at its site in Newbie, Scotland, but in late 2016 it switched to liquefied natural gas (LNG) from Calor to facilitate the development of a proposed R&D centre. LNG is now used for space heating at the boiler manufacturer’s site, as well as for powering the boilers to be tested at Cochran’s R&D facility.

The conversion process was carried out by Calor’s sister company PrimaLNG and involved supplying a 20,000-litre LNG vessel, supported by vaporisers that offer extra power when demand increases.

Vaporisers are designed to respond to the maximum gas offtake when demand increases. From the on-site storage vessel, LNG runs through a pipe into the vaporisers, which are big aluminium structures that essentially act like radiators. These take in relative warmth from the outside atmosphere, boiling the LNG inside the vaporisers, to produce gas. This creates ambient temperature gas, that can then be burned. Civil works to accommodate the storage tank and adapting the site’s steam boiler to burn gas were also carried out.

David Branch, business development manager at Cochran, explains: “We had been looking for greener fuel alternatives for a long time before deciding on LNG. The majority of boilers we manufacture are fuelled by gas and, when considered alongside the environmental and cost advantages LNG has over oil, it made commercial sense for us to introduce LNG as our fuel partner of choice.”

Cochran says that it has made annual savings of £12,000 and reduced CO2 emissions by 28% – or 169 tonnes – annually, since making the switch to LNG.

LNG is a colourless, odourless, non-toxic liquid fuel that is created from cooling natural gas to a temperature of -162°C. This process shrinks volume to 1/600th of space used in gaseous form.

Flogas, another supplier of LNG, says that LNG is specifically for high-end energy users not currently on mains gas. Its website explains that businesses using a significant amount of oil for heating or any industrial process or production, replacing oil-fired systems for an LNG-fired equivalent could deliver savings (www.is.gd/jiwija).

Kevin Houlden, business development manager at Calor, echoes that LNG is seen as an ideal solution for facilities where there is a continuously high demand for fuel, such as a process or manufacturing plants, that operate all year round. He explains that for many sites, connecting to mains gas is not a feasible option or simply too expensive. There are around 250,000 businesses located off the mains gas network in the UK, he adds, meaning that there are a significant number of operators who will face the additional challenge of choosing the cleanest, most economically-viable energy solution when their boiler needs upgrading or replacing.

“LNG has been imported into the UK for more than 50 years and forms a key part of the UK’s energy mix,” he explains. “While it is categorised as a cryogenic liquid due to its extremely low temperature, LNG is a purified form of methane. The result? An extremely high-efficiency fuel, with an impressive calorific value of 15.2 kWh/kg, which is higher than propane gas.”

Houlden claims that the efficiency of LNG heating systems will typically realise energy savings of up to 10-15%, helping to cut daily running costs.

He continues: “The environmental benefits of LNG are another key driver. Legislation such as the Medium Combustion Plant Directive (MCPD), which has been introduced to control emissions, has accelerated this issue.” (see also www.is.gd/jovexe). “Aiming to reduce harmful sulphur dioxide (SO2) nitrogen oxides (NOX) and particulates in exhaust gases from all combustion plant rated between 1MW and 50MW thermal input, from 20 December 2018, all new plant must be registered with the competent authority and comply with the MCPD’s emissions limit values.

“Heavy fuel oil installations do not meet the new emissions limit values for SO2 or particulates without abatement. This, understandably, may make some operators more cautious about investing in oil-fired technologies. In contrast, LNG is the cleanest burning of all fossil fuels available off-grid, typically reducing CO2 emissions by 15-20%, and potentially as much as 30%. Its non-toxic and non-corrosive qualities also means it poses less health and safety risks than other fuels.”

After the decision to switch to LNG has been made, Houlden says that the actual process is “very simple” to carry out. An engineering team will work closely with a site to determine how best to proceed with an LNG installation, from plant sizing through to the location and design of the concrete foundation for the LNG storage vessel and vaporisers, connecting it to the intended application, delivery, logistics and financing the investment. This is all delivered in line with stringent industry health and safety requirements, to ensure the LNG solution is delivered in the most safe and secure way possible. Training is also offered to site personnel, so they understand the investment and how it operates too.

“In terms of adapting a boiler to use LNG, with Cochran – for example – the organisation was able to adapt the burner to run on gas due to its expertise and engineering capability in-house,” Houlden says. “In other scenarios, Calor would liaise with the incumbent burner or boiler manufacturer to establish the most efficient and cost-effective way of replacing these. It is crucial that the burner, boiler and fuel are compatible.”

Flogas has a similar process. The company looks to understand energy requirements, design a solution, and feed back savings expected and costs. This is followed by its team taking care of everything from civil works to installation and commissioning of new plant equipment (www.is.gd/jiwija).

When asked if anyone can adapt a boiler to use LNG, Calor recommends that a competent and fully trained industrial services engineer is used, who has been awarded the relevant gas certification and passed necessary modules from industry bodies such as the Gas Safe Register.

Houlden concludes: “Energy demands are growing each day. With natural gas predicted to be the fastest growing major energy source in the 21st century, LNG delivers all the benefits of natural gas to businesses that do not have access to the mains gas grid. LNG also has a huge future within the UK transport sector.”

Specific energy content, BTU/lb fuel

CO2 emissions: energy-basis: lb CO2/mill BTU

Wholesale cost, pence (p), 01/18


Heavy fuel oil










Methane(natural gas is 70-95% methane)





Sources: chemistry: www.is.gd/ojavac; oil and diesel prices: www.is.gd/omuyaj; gas prices: www.is.gd/axehet

*Method: Converted to kg and then to lb using fuel-specific density sourced from www.is.gd/ojavac. 1 therm=100,000 BTU

Adam Offord

Related Companies
Calor Gas Ltd
Cochran Ltd
Flogas UK Ltd

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