A grid of their own

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Building: Scheme of 365 A-rated dwellings (phase one)
Method: Timber frame with block/brick outer leaf
Location: County Wicklow
Standard: NZEB

On Ireland’s east coast, just north of Wicklow town and a few hundred metres from the sea, a new residential development by D-RES Properties is taking shape. Nestled between the Wicklow mountains and the Irish Sea, within easy commuting distance to Dublin, these homes-to-be are within easy reach of many amenities.

The 365 units of Tinakilly Park, comprising 3, 4 and 5-bed family homes and duplexes, get their name from the estate of Tinakilly Country House, a Victorian home constructed in the mid 1800s, on which they are located.

The first phase of the development, which includes 125 properties, launched on 24 February, with the first 27 homes to be completed in June. But a total of 700 homes is expected, pending planning permission for future phases. The scheme is aimed at first-time buyers and families.

Building a community

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Robbie McGrath, head of sustainability with D-RES, has been involved with the project for the last seven months. With a background in engineering, he worked in Finland for 13 years as a sustainability consultant on projects ranging from offices, to airports, hospitals and universities.

He says that one of the aspects that drew him to D-RES was the company’s focus on community-building, rather than simply house-building. This focus shines through the project, from the layout of the site, to its amenities, and, crucially, to how energy is generated in the homes. “The aim is to have more functional spaces for people, not just a few benches, but connectivity to green spaces and biophilic design, which was championed by our creative design manager Aideen Leahy.

Having that connection to nature for people has been really important, especially in Tinakilly because we have a lot of green space,” he says.

At Tinakilly, the community will be able to generate its own energy, reducing demand on the national grid. All homes are A2 energy rated, and have mechanical ventilation with heat recovery, and fully electrical heating via heat pumps. “The heat pumps have been specially selected to communicate with the smart energy management system to maximise energy efficiency,” McGrath says.

Residents have the option to upgrade to an A1 building energy rating (BER) by installing six 400W solar PV panels on the roof and generating electricity that can be stored in smart batteries.

“We wanted to try and create a kind of mini power station in the house,” McGrath says. On cloudy days, the batteries can charge from the grid at off-peak times. At peak times, battery electricity can be used to reduce the demand load on the national grid.

We wanted to create a kind of mini power station in the house.

Renewable energy supplier Pinergy is acting as energy partner on the project, helping D-RES to provide the energy upgrade package.

Philip Connor, head of energy services with Pinergy, has an eclectic background in law, aircraft engineering, boat building, and professional yacht racing. Since 2015, he has been working in the renewable energy space, and is now leading Pinergy’s energy efficiency and renewable energy solutions.

The energy system for the homes works in a “fully optimised fashion”, he says. The homeowners can generate electricity, they can store it, and a cloud-based software system manages the energy for each home.

Energy tariffs are cheaper at certain times, and the system takes tariffs into account in making decisions to ensure the homeowner is using the cheapest energy available. The system looks at the amount of energy that is being used and when it’s being used during the day. It then looks at the cost of energy over that period, and at weather forecasts over three to four days, to understand what the solar opportunity is like, explains Connor. It then decides around how much energy to store and when to store it.

A home dashboard app shows residents how power is flowing in the household and how much energy is being generated and stored. Although the system’s decisions can be overridden by users, the automated system helps make “sustainability easy for homeowners,” says Connor.

It’s up to the homeowners to decide if they want the panels. “In the initial rollout, we’re waiting for the owners to order the systems, and, if they engage earlier in the process, we can install them as part of the construction phase,” says Connor, adding that retrofitting is going to be “very straightforward”, since the space for cables is built into the homes. “The home is basically battery and solar ready,” he says.

Connor says that the system has the potential to provide big savings, with optimisation modelling suggesting a reduction in energy costs anywhere from 40 to 60 per cent compared to the same homes without this optimisation.

This feat is achieved by a system which will run in the background and decide for the occupants when it’s appropriate to use energy generated on site or draw from the grid.

Another big advantage of the system is that, in the event of power outages, people can use their own energy, says McGrath.

Micro-grid

Having that connection to nature has been really important.

Unused excess electricity can be exported to the national grid or shared with neighbours in a peer-to-peer network, explains McGrath. In the past “you might have knocked on a neighbour’s door to get a cup of sugar, now you’re getting a few kilowatts of energy,” he says. Through this system, residents can set a price and trade with each other.

In future, they may also be able to sell energy back to the grid at times when it might be struggling. This payment is enabled by the Irish government’s ‘clean export guarantee’ tariff as part of its microgeneration support scheme, announced at the end of last year, but it is up to the market to decide on a price for the tariff. (In March, Pinergy became the first supplier on the Irish market to announce a clean export guarantee tariff, which will be available later in the year.)

“We tried to make it as joined up as possible,” says McGrath. “So, it’s not just individual houses. It’s the whole 300-house community which will be linked together in a two-megawatt micro grid,” he says.

Electric vehicle (EV) charging points are another option available to residents, Mc- Grath notes, adding that the battery in EVs may be used effectively as secondary batteries for the houses. According to Connor, at present this will be limited to using the EV batteries to soak up grid or micro-generated energy at the most opportune times, as the functionality of powering houses from EVs will require the development of new standards and will require engagement from the EV manufacturers.

McGrath says that by giving residents more control over their energy use, D-RES hopes to empower them to become energy citizens, who play an active role in the transition to a low carbon future.

Positive living

When asked what about Tinakilly Park excites him most, McGrath says it’s “the holistic approach that has been taken to sustainability. It’s not just an add on. D-RES are really interested in putting sustainability at the forefront of everything we do [...], from site selection, to design, construction, down to our waste management.”

The company is also interested in how sustainability and ESG (environmental, social and governance) principles can filter down to the process of house building, he says, explaining that ESG principles affect the entire business.

McGrath adds: “It’s how we run our business, how we look after the environment, but also how we look at the social side. We pay people on time, we look after our staff, we encourage companies who have apprenticeships, we select local businesses and local materials, and we try to tie in with local sports clubs, to show that we understand the impact we have and the impact we can have for the good.”

As well as hiring McGrath as head of sustainability, D-RES has established a company- wide ESG team to drive ESG actions throughout the organisation. D-RES is also listed on GRESB, an international benchmark for sustainability in property and real estate, with chief executive Patrick Durkan driving the company’s overall sustainability goals.

“We now have a sustainable purchasing policy,” says McGrath, adding that, going forward, they will be asking service providers to have environmental product declarations for materials.

Towards passive house

The houses at Tinakilly Park, which are timber framed, have an airtightness of about 1 m3/hr/m2 and were built using passive house, fabric-first principles — an element of the project driven by D-RES development manager Kevin Durkan. However, the price point of the houses meant it wasn’t feasible to adhere to all passive house principles. Triple glazing, for instance, would add a lot of costs, so the windows are double glazed, he says.

“If the market changes as the phases go on, and people say they really would like passive houses, it’s easy for us to just upgrade the house and get it to that level”, he says. Within the homes, the batteries are upstairs in the areas traditionally reserved for a hot press, and the heat pump cylinders are downstairs in utility rooms.

The PV panels are made of monocrystalline silicon and are self-cleaning, says Connor. The batteries, which are lithium ion, contain built-in inverters which convert direct current electricity from the panels on the roof into alternating current which can be used in the home. They have a 10-year warranty equivalent to 10,000 cycles, he says.

In future, says McGrath, it may be possible to increase the number of solar panels on the roofs from six to eight or ten.

Caring for ecosystems

Excess electricity can be shared with neighbours in a peer-to- peer network.

Given climate-change related extreme weather events, rainwater management was a challenge for the site, which currently has attenuation tanks that may be used in rainwater harvesting, says McGrath. Other ideas include allowing playgrounds to turn into wet playgrounds on very rainy days, he says.

The houses’ avian names, from kingfisher, to redwing, to guillemot, conjure up images of local wildlife. Right beside the development lies Broad Lough, the largest estuarine habitat in Co. Wicklow and an important area for migratory and resident birds.

Working with an ecologist on site, wildflower meadows and about 1,400 trees are being included, he says. “Obviously the site had to be cleared to an extent, so we are trying to increase the ecological value of the site after we’ve worked on it,” he says, adding that D-RES are trying to reuse felled trees in the playground areas.

Other options include installing bee boxes, and including better linkages between ponds and meadows to facilitate movement of reptiles and amphibians. These natural features could tie in with educational events for local schools, where children could come in and see things like frogspawn, he says.

Other green infrastructure will include off-road cycleways allowing people to easily travel to and from Wicklow town. McGrath hopes that centralised bike storage facilities with green roofs or solar panels could be added as well. He also wishes to include more facilities for teenagers, such as skatefriendly solar furniture.

• Ground floor build-up features a 150 mm reinforced concrete floor slab with a minimum of 50% GGBS, with 150 mm Xtratherm PIR floor insulation underneath and 25 mm upstand perimeter insulation to the edges Ground floor build-up features a 150 mm reinforced concrete floor slab with a minimum of 50% GGBS, with 150 mm Xtratherm PIR floor insulation underneath and 25 mm upstand perimeter insulation to the edges
• Ground floor build-up features a 150 mm reinforced concrete floor slab with a minimum of 50% GGBS, with 150 mm Xtratherm PIR floor insulation underneath and 25 mm upstand perimeter insulation to the edges Ground floor build-up features a 150 mm reinforced concrete floor slab with a minimum of 50% GGBS, with 150 mm Xtratherm PIR floor insulation underneath and 25 mm upstand perimeter insulation to the edges
• The prefabricated attic roof trusses on site The prefabricated attic roof trusses on site
• Vapour control/airtight membranes to walls and ceiling Vapour control/airtight membranes to walls and ceiling
• Progress continues on the site, which is located close to close to Broad Lough, Wicklow Town and the Irish Sea. Progress continues on the site, which is located close to close to Broad Lough, Wicklow Town and the Irish Sea.
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Image gallery

• 1818_T_P_02_126UNITS_ EAST SITE PLAN - 126 units Soft Landscape Plan Rev.0 (1) 1818_T_P_02_126UNITS_ EAST SITE PLAN - 126 units Soft Landscape Plan Rev.0 (1)
• 1818_T_P_02_126UNITS_ EAST SITE PLAN - 126 units Soft Landscape Plan Rev.0-1 1818_T_P_02_126UNITS_ EAST SITE PLAN - 126 units Soft Landscape Plan Rev.0-1
• 1818_T_P_02_126UNITS_ EAST SITE PLAN - 126 units Soft Landscape Plan Rev.0 1818_T_P_02_126UNITS_ EAST SITE PLAN - 126 units Soft Landscape Plan Rev.0
• D-123-C11_ HOUSE TYPE M1 SECTIONS & ROOF PLAN Rev.C D-123-C11_ HOUSE TYPE M1 SECTIONS & ROOF PLAN Rev.C
• D-123-C35_ TYPICAL TIMBERFRAME DETAILS SHEET 1 Rev.A D-123-C35_ TYPICAL TIMBERFRAME DETAILS SHEET 1 Rev.A
• D-123-C36_ TYPICAL TIMBERFRAME DETAILS SHEET 2 Rev.A (1) D-123-C36_ TYPICAL TIMBERFRAME DETAILS SHEET 2 Rev.A (1)
• D-123-C38_ TYPICAL TIMBERFRAME DETAILS SHEET 4 Rev.A D-123-C38_ TYPICAL TIMBERFRAME DETAILS SHEET 4 Rev.A
• D-123-C39_ TYPICAL TIMBERFRAME DETAILS SHEET 5 Rev.A (1) D-123-C39_ TYPICAL TIMBERFRAME DETAILS SHEET 5 Rev.A (1)
• Tinakilly Site 1 Tinakilly Site 1
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