True sustainability has to start with the masterplan, and this means there’s a seat for services engineers at the table
There’s a revolution under way in masterplanning. Fashion is out. Nature is in. To improve energy efficiency, cut carbon and create more sustainable communities, designers have to think harder about working with a development’s surrounding environment – not against it.
Building services engineers are central to understanding this building/nature interface. Which is why, almost overnight, they have become a key member of the masterplanning team, helping to define the layout of future developments, the form of buildings and how they will be powered.
Don’t expect to be sizing fancoils, though. “You cannot just have a pipes and wires person,” says Adam Selvey, technical director at WSP, and a building services engineer. “You are offering advice about shape, form and function of buildings and how they all interact with each other.”
Go back five years, when the term “zero carbon” was barely known, and masterplanning seemed relatively straight-forward. The planners and architects would put their heads together, perhaps with input from a highways engineer, and come up with a plan for how the area might be developed and what buildings went where.
Then came an avalanche of carbon awareness. Plans were made for ambitious eco-cities, starting with Dongtan in China. In the UK, the Code for Sustainable Homes and the Merton rule – requiring a percentage of energy to come from onsite renewables – triggered changes in practice at the masterplanning stage.
Now there’s a host of people who need to be pulled into the process, from sustainable urban drainage experts to intelligent building specialists. Although in the UK the focus is very much on carbon, water and waste must also be part of the masterplanning mix. The building services engineer will be involved from day one, brainstorming with other team members.
“You need a good cross-section of people in the [masterplanning] team so they can debate the options. That way we know what the conflicts are early on,” says Lesley Dinnett, Buro Happold’s project leader on the EcoBay masterplan. “It’s much more efficient to look at sustainability at the early stage rather than go along with a masterplan where you have not considered it and try to slot it in later. If you start at the earliest stage, it often means the cost uplift is marginal.”
Sustainability experts play a key role but building services know-how is also vital, says Arup director Chris Twinn, who has advised on masterplans from Dongtan to Stratford City. There is an influx of young environmental professionals bringing skills such as communication, but they don’t necessarily understand the engineering principles, he says. “A lot of people are quoting and advising on technologies without having had experience of implementing them. The classic example is micro wind turbines.”
The impact of a building’s position, facade material and size on its energy efficiency must all be considered. For example, says Twinn, you may find yourself arguing against the highways engineer for a quiet street next to an office building so windows can be opened to allow natural ventilation, potentially halving energy use.
Having decided broadly on orientation and position, the next questions involve energy: how much will be needed and how will it be produced? Working out the loads requires assumptions on how the buildings will be used and can involve modelling, historic data and empirical rules of thumb. “We want to ensure that the masterplanner makes the correct assumptions on the energy use of these buildings and that the images they produce are not incompatible with those targets,” Twinn says.
Then comes the search for an energy source. The choices vary with location, particularly for renewables. Wind turbines in the sea were the best solution at Azerbaijan’s windswept Zira Island (above). For a smaller urban development, the choice may not be so obvious. Selvey, who has advised on masterplans for Paradise Street, Liverpool, and Sevenstone, Sheffield, warns against being too prescriptive: “All energy service companies have their own specialisms. One may get a brilliant deal on biomass, another in wind turbines. If you define one particular energy source, you may exclude people from the process.”
For Twinn, specifying energy sources goes beyond the immediate carbon footprint of a development: “It’s about where it ends up in 30 years’ time. The new area masterplans are attempts to try to get there in one or two steps.” So London’s Stratford City initially will be fuelled by gas CHP, but the infrastructure will be there to switch to a different source once there are enough properties to make it viable.
Which brings us to thermal master- planning, where engineers look beyond the boundaries of single communities or developments to consider the energy profile of a whole area, existing and planned. In theory, local authorities should be doing this already: a planning policy statement published in December says councils must be able to demonstrate that the planning requirements they ask for – such as a percentage of renewables or a reduction in carbon – are achievable. In practice, few are. When the long-awaited definition of zero carbon is produced by the government’s consultation process, thermal masterplanning will become vital.
It is likely that “zero carbon” developments will be able to source energy from a mix of on-site and off-site renewables. Many masterplans are on hold until the term is defined. Once it is, expect the process to become ever more complex and expensive as a host of other energy specialists are called into the room.
The aim with the Zira Island development (pictured) is to go beyond carbon neutrality to total self-sufficiency. “We wanted to make it self-contained in every possible way so we would not need to import energy or water and we would not need to export waste of any kind,” says Jorn Treldal, chief consultant with Ramboll, which is working on the masterplan with Danish architect BIG.
“It’s an idea that was not always practical,” he admits, “but we have gone as far as we can.” Sewage is processed, the water cleaned and the sludge dried, emitting gases which are burned. The resulting product is mixed with the organic part of household waste to produce a sort of soil – a scarce resource in Azerbaijan.
The island’s climate offers challenges and opportunities for the engineer: it is sunny and windy all year round, humid in summer and as cold as -5C in winter.
Most of the electrical energy, therefore, will come from the wind, which blows ferociously from the north or the south, allowing big turbines to be aligned efficiently 200-300m from the island. Domestic hot water will be provided by solar panels, with a limited amount of electricity from photovoltaics. Cooling will come from the Caspian Sea, through pipework embedded in buildings (see diagram).
The architecture of the development, which will be 50% residential and 50% holiday resort, is inspired not only Azerbaijan’s mountains but its traditional housing, with features such as balconies that can be closed in winter and open in summer, and plants to provide shade.
“We would like to reproduce some of these old and very sensible measures so that we will be able to use as little mechanical cooling in the apartments as possible,” Treldal says.
Wind power seemed the obvious source of energy for this eco-town near Tallinn in Estonia because it is an extremely windy site. But its location next to a nature reserve and bird sanctuary on the Paljassaare peninsula put this solution in a different light. Birds and big wind turbines do not mix, so that was not an option for a district-wide scheme.
The EcoBay project is an example of how engineers must be willing to compromise on the optimum solution to produce the most sustainable answer for a particular site.
A CHP system will be the main source of energy, with the possibility of drawing waste heat from a water treatment plant still under investigation. Small wind turbines will be used to provide power for street lighting.
CHP was a good solution because it works most efficiently with a uniform load, says Lesley Dinnett, project leader for Buro Happold, which is working alongside architect Schmidt Hammer Lassen and landscape architect Moller & Gronborg. Loads will be evened out because EcoBay will have a mix of development – houses, schools, shops and offices.
However green a masterplan’s intentions, it must also be financially deliverable. At EcoBay, which will be home to about 6000 people at the end of its 15-20-year building period, the master- planning team had to go back to the drawing board once the cost consultants had run through it.
“We had to look at increasing the footprint to make the per unit rate slightly cheaper,” says Dinnett. “We managed to do that without impacting on the quality of the living environment. Making a place where people want to live, and live for a very long time, is just as important as carbon.”
The government is trying to accelerate the housebuilding industry’s response to climate change with the Carbon Challenge programme, an attempt to fast-track the creation of new communities with the highest environmental goals.
Faber Maunsell’s sustainability group was commissioned by English Partnerships, now the Homes and Communities Agency (HCA), to prepare with consultant EDAW the development brief and technical guidance notes for Peterborough’s flagship Carbon Challenge scheme of about 350 homes (pictured: courtesy of pPod Consortium – Brown Smith Baker Architects).
In developing the brief, which requires all homes to deliver level 6 under the Code for Sustainable Homes, masterplan options testing was undertaken to consider:
- size and location of the energy centre
- storey heights and implications for solar generation
- building orientation impact on daylight and potential overheating as well as solar power potential
- space for cycle storage
- space for storage and handling of recyclable waste
- area and form of sustainable urban drainage
- location, space and approaches for rainwater collection and reuse, and grey water recycling.
Options for the masterplan were developed in workshops led by Faber Maunsell and EDAW in consultation with the HCA, Opportunity Peterborough and East of England Development Agency. These highlighted implications of national targets in the site context and helped to shape the development brief.
The HCA has chosen a preferred developer and it is working on a detailed planning application. It is understood that a CHP plant with district heating is being discussed with key stakeholders. The energy centre will be on an adjacent site and it will be sized to serve proposed development nearby.
Ben Smith, associate director at Faber Maunsell
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