Green Sky Thinking: district heating for London unraveled
Penoyre & Prasad’s Crouch Hill scheme suggests one way forward
One of the recurring topics at this year’s Green Sky Thinking was the planning and development of efficient energy infrastructure solutions, particularly district heating networks. Over forty people gathered to hear a debate on this subject, hosted by Penoyre & Prasad and suggestively entitled ‘Is descentralised energy the way forward for London?’
The talk, chaired by Sunand Prasad, used their Crouch Hill development in Islington as a starting point for a lively discussion on the pros and cons of community heat and power networks.
The evening kicked off with short presentations by the speakers:
Charlotte Large – Decentralised Energy Project Manager, Environment & Regeneration, Islington council
Peter North- Senior Manager, Programme Delivery (Sustainable Energy), Development & Environment, GLA
Ian Goodfellow – Partner, Penoyre & Prasad
Richard Davidson – Design Manager, Willmott Dixon
Brian Mark – Director, Mott MacDonald Fulcrum
Charlotte briefly introduced the two main district heating schemes currently under way in Islington, the Crouch Hill scheme and the Bunhill network, as well as other options to capture waste heat that are being explored by the Council, such as from the TFL ventilation shafts or the UKPN substation. The Crouch Hill development has an Energy Centre equipped with CHP, which will power the site, as well as delivering heating for the school and the nearby Coleman housing estate. A biomass boiler will supply top-up heating during winter. The Bunhill scheme will provide heat for around 710 homes and several leisure centres.
Peter North spoke about GLA’ s vision to decarbonise the energy used in London, quoting DECC’s heating strategy report conclusion that most energy is used in heating homes. ‘There are four waste to energy plants around London’, he explained, ‘ the supply is there, the demand is also there, the missing link is the pipework connecting the two’. Sunand asked the key question of the evening: ‘are district heating networks the way forward?’ - to which Peter gave a clear answer that he sees it as a viable long term strategy.
Penoyre & Prasad’s Ian Goodfellow presented the Crouch Hill project, focusing on the main design strategies used to reduce energy demand. Set within a park, the development comprises a new-build Ashmount Primary School, Bowlers nursery, Cape Youth Centre and an energy centre housed in the refurbished building of a former electrical substation.
The primary school achieved BREEAM Outstanding (in design), and showcases a number of low-energy features such as the use of thermal mass, and e-stack low energy ventilation which provides heat recovery in the winter and safe night time cooling in the summer, as well as grey water recycling. By using the community heat and power network to connect a diverse mix of buildings and functions, and exporting the excess heat off site to the Islington Council-owned estate, the scheme creates a carbon negative in-use development. More info about the project here.
In a fast-paced and energetic presentation, Willmott Dixon’s Richard Davidson provided the contractor’s view on the project, highlighting some of the challenges and opportunities, which ranged from getting everyone in the team on board by explaining what the zero carbon concept meant and keeping an existing nursery functioning on site. ‘Everyone wants to do something that’s innovative, but tried and tested,’ he explained. Willmott Dixon will monitor the building, as both architect and contractor are very interested to see how the building performs in use.
The presentations became more focused on energy sources with Brian Mark’s presentation which discussed UK’s current energy mix and renewables strategies. He noted that urban networks are the way forward, and gave examples of energy to waste plants which are providing a lot of the energy required for other cities (such as Malmo).
Following the presentations, the panel of speakers touched on key issues related to district heating:
Charlotte explained that the most complex issue is the management of a district heating scheme. In the Crouch Hill case, management will be done by the Council. Boroughs will need to work together to make these schemes work (and Ian added there would probably also be a competition between the boroughs, in terms of which is more energy efficient). Since the district heating schemes require large investments, (the Council used grant funding), Charlotte argued that it would be difficult for these schemes to be done with only private sector involvement.
Peter North reiterated the fact that we need a systematic approach to planning to make district heating networks viable. Brian noted that on the continent more low temperature pipes are used; they are non-insulated, cheaper and easier to install, making the network schemes easier and faster to promote. The commercial arrangements to get the heating to the end consumer tend to be difficult and time-consuming, and it was suggested that having a contractual frame work set in place would help get these types of schemes started.
Charlotte explained that once a network is in place, the source of energy in the energy centre can be changed and updated to suit the size of the network, or a greener energy source, or they can even be moved to another centre for a new/start up network with lower energy demands. Each site has its own specific needs in terms of energy, and possible mix of buildings and loads, so site-specific analysis and solutions
In summary, with careful planning and pro-active planning authorities (who appear to be the key players right now), district network schemes might become a viable solution for London in the future. The increased presence of various councils and GLA representatives at many of the Green Sky Thinking events this year seems a good sign that designers and planners are working together to find more sustainable solutions for London.