Imperial News

De-steaming towards Net Zero

by Jan Carberry

An update on the major project to remove central steam generation, reduce energy use, carbon footprint and emissions on South Kensington Campus.

The amount of electricity consumed on South Kensington Campus in 2022 was, roughly speaking, enough to power around 24,000 homes. That’s something like the electricity needed for the town of Corby for a day.

That’s a lot of power. Fortunately, we had our own onsite energy centre for more than 20 years which generated around 82% of that electricity. The waste heat from this used to heat buildings and provide hot water. Highly efficient and quality ranked by the Government, it was saving around £6.6m in utility costs and more than 3,500 tonnes in carbon emissions.

Despite that we knew we could do more to reduce our carbon footprint and help College become a more sustainable energy consumer.

To move the College towards decarbonisation and improve the efficiency of our heat generation and district heating network the College started work on its de-steaming project to remove central steam generation.

It would be hard for anyone to be on Campus and not see evidence of the major project underway to transform the Combined Heat and Power plant (CHP), reducing our energy use, carbon footprint and associated emissions.

Whether the blue hoardings decorated with information about the project surrounding the work areas, or the enormous temporary flues and ductwork running up outside buildings, or back in the summer the three new boilers lined up ready for installation, looking like something ready for a NASA launchpad, the signs are everywhere. Hard to avoid, disruptive? Maybe. Equally, as the saying goes, you can’t make an omelette without cracking eggs.

Funding allowed this major project to be undertaken in one go, although broken down into smaller packages, which also reduces the pain and disruption to a limited timeframe.

Unexpected challenges to the installation programme means some of that pain might be caused by temporary interruptions to heating and hot water in specific areas, and some slightly cooler than usual temperatures on occasions. We are working hard to mitigate this, notify those directly affected and keep you informed, and ask you to bear with this important programme.

Temporary steam and Low Temperature Hot Water (LTHW boilers), supported by local boilers will supply the heat throughout this winter. A switch over to the new boilers will happen around the start of 2024 in a managed way.

Where the project is now

Three new boilers were delivered to campus in August. Such was the size of the delivery load that it had to be escort routed through London.

Although factory assembled by the manufacturer Cochran, they were stripped back down for delivery, the ancillary parts arriving separately to reassembled in situ by Cochran in conjunction with contractor Vital Energi.

The energy centre was completely stripped out in preparation for the new arrivals, made possible once the temporary boilers and flues had been installed and commissioned, part of the project undertaken through the first part of this year.

First to go in, to the left, was boiler one, Tom, 12 megawatts, weighing 40.9 tonnes when empty and 71.9 tonnes when operational. This was followed to the right by the same sized boiler number three, Dick. Boiler two, 10 megawatt Harry, weighing just 35.1 tonnes when empty, 56 tonnes when operational, is in the middle. The sequence allowed systematic working and access.

New pipework is being installed, pressure testing is taking place, insulation going in, followed by electricals and controls, as well as safety coating and sealing the environment.

The aim is to complete this phase before Christmas.

While this is going on further packages of work are being carried out. This includes replacing pipework within buildings, heat exchangers and coils with air handling units as well as associated controls that link back to our building management system.

The background

In 2022 the College was awarded a Public Sector Decarbonisation Scheme grant of more than £12m which contributed towards the £40m cost of this project. 

For several decades heating and hot water for the buildings on South Kensington Campus came from two district heat networks, a heated water network and a steam network. Neither had enough heating capacity to replace the other.  However, with the College’s Net Zero 2040 ambitions something had to be done, as operating two heat networks is inherently wasteful and inefficient. With only relatively small demands for steam this could be replaced with heated water, making it possible to remove the steam and condensate heat networks.

 Works

The work being undertaken is in places complex but can be broadly broken down in to four categories:

  • The work currently in the Energy Centre: Removal of three large and end of life 12megawatt steam boilers and replacement with three new Cochran 10megawatt water boilers with integrated heat recovery units, these recover the heat from the CHP engine’s exhaust. Other steam infrastructure is also being removed such as a large water treatment plant and chemical treatment equipment.
  • Tunnels and heat network: the steam and condensate heat networks are being removed and in places the heated water network pipes are being replaced with larger, higher capacity pipes, which can carry more heat through them.
  • Plant rooms: steam heat interface units in plant rooms used for heating or hot water are being replaced with new systems to provide services to the buildings from the heated water district heat network.
  • Buildings: there are some systems in the buildings that require steam such as air handling units, these need to be modified to receive heated water instead of steam.

Benefits

The benefits of the works are significant:

  • The new boilers are much more efficient that the old ones increasing from 79% to 87% efficiency, 8% more efficient than the old ones in converting natural gas to useful heat. It might not sound much but it has a significant impact. They also ‘extract’ more of the waste heat from the CHP engines thus making the system significantly more efficient than previously. These efficiency savings are expected to save the College over 2,400 tonnes of CO2 per annum.
  • The removal of the steam and condensate networks, although much harder to quantify should result in significant reductions on the thermal demand of the campus.
  • Inherent safety benefits of not circulating 180oC steam; no longer having to comply with pressure systems regulations and having replaced plant with new which will be more reliable and have higher availability.
  • A significant reduction in NOx emissions, associated with poor air quality and respiratory conditions. This is currently being quantified and opens the possibility in the future to doing further work to further reduce NOx emissions.

Next phase

The next phase of the project will involve finishing the installation of all the pipework, heat exchangers and heating coils before fully commissioning the system and associated controls before it is handed back to the College and the temporary boilers are removed in early 2024.

Long-term

The strategy is to move the whole of the South Kensington Campus to a low temperature hot water system running at 80oC in preparation for further heat decarbonisation. A Net Zero Strategy is currently under development to develop a programme and associated costs up to 2040.

Wisdom is that we should reduce heat and electricity demand as much as reasonably practicable first, then look at low carbon ways of delivering the demands. The Net Zero strategy will help join up these plans.

SKZen

The College is one of 22 leading cultural and educational organisations in South Kensington in the Exhibition Road Cultural Group (ERCG) working with South Kensington Zero Emissions Nature Positive (ZEN+) Programme. This is an innovative neighbourhood response to the climate and biodiversity crisis. It been awarded £120k of GLA money to further explore options and viability of a number of schemes including making use of heat from ground water in Princes Gardens.

Further information about the project, along with and a downloadable document which is updated regularly, can be found on our webpages