Considering they’ve designed and built some of the world’s tallest buildings—including the John Hancock Center, Willis Tower, and Burj Khalifa—Skidmore, Owings & Merrill (SOM) was the perfect firm to tackle the upcoming Pertamina Energy Tower—the world’s first supertall tower for which energy is the number one design driver. Created for the Indonesian state-owned energy company and set to rise more than 1,640 feet above the city of Jakarta, this stunning new 99-story “beacon of energy” and skyline landmark will boast a performing arts and exhibition pavilion, a mosque, and a central energy plant.
“What makes Pertamina particularly interesting is that while it’s geared toward corporate use, its auditoriums, exhibition space, and mosque are all also open to the city and the community,” says Mustafa K. Abadan, design partner at SOM, who orchestrated the overall vision for the project with a team that, at times, reached 60 or 70 people firm-wide. “There’s also a visitor center that has more controlled access, like a museum, that allows for direct interaction between the corporation and the public in educating them about what they do, how they harness energy, their petroleum products, etc.” Abadan also notes that a series of additional employee-specific elements will also be dispersed around the campus, such as a fitness center/sporting pavilion and major cafeteria/food court.
Although practicality (Pertamina brings together 20,000 formerly dispersed employees in one central location) and community (on top of the aforementioned, green spaces and parks will also be open) top the list of design drivers at play, sustainability is the focus. The development is targeting net zero by harnessing geothermal energy; a wind funnel at the top of the tower’s crown will generate additional energy, and the building’s curvature will mitigate solar heat gain throughout the year—just a few specifics among a myriad of boundary-pushing innovations.
In addition to talking with Abadan on the subject, gb&d spoke with design director Scott Duncan, and Luke Leung, director of sustainable engineering, to learn more about Pertamina, which is tentatively set for a 2021 completion date.
gb&d: So seeing as this is the world’s first supertall tower for which energy was the primary design driver, I’m curious as to if the sustainable strategies were a demand of the client or something SOM brought to the table or a mixture of both?
Scott Duncan: It was a mixture of both, but we brought it to the table as an idea, and it was immediately embraced by the board and the then-president, Karen Agustiawan, in particular. We felt immediately when we did our first presentation and proposal for net zero that it was the right direction for the project.
Luke Leung: In the current world, the largest net zero building is about 360,000+ square feet. In contrast, Pertamina will be close to four million.
gb&d: Wow! And atop all of that is the wind funnel. What inspired this method of harnessing energy; had you guys done it before?
Leung: We wanted to do something to react to the natural forces of nature, and wind speed increases as it gets up the tower. So the strongest wind is going to be at the top of the building, and the design naturally aligns the opening with the wind direction in the area to enhance it more. Wind speed is the most important driver for any wind turbine’s power generation. It’s not the largest, single most important power generation element in the building; but adding it as a feature that people can look at and get inspired by will hopefully generate a rich dialogue about what the building is about.
Duncan: The majority of the power of the project is coming from geothermal, but it was important for us to look in all directions at all renewables, and as Luke pointed out, wind was a good candidate for the accelerated wind forces at the top of the tower. It is also a renewable source that is not daylight-dependent, so we made the decision to use the energy generated to power the nighttime lighting.
Leung: In another SOM building, we had experience using this sort of accelerated wind funnel before—on the Pearl River Tower [in China]. With Pertamina, it’s a little different because we have it at the very top of the building, and it’s more effective because the stronger wind is up there. What is really interesting is that the output of the wind turbine can vary, so the light in the nighttime will actually change color depending on how much power the wind is generating.
gb&d: What other sustainable elements or examples of green design are at play here?
Leung: I think the key thing here is, while people are fascinated by the visual component of the wind turbine or the energy component or geothermal heat, some of the key things here are the fundamentals of saving energy, using good systems and good, basic practices. In this case, we have good daylight in the space, which is very important, and we have studied 600+ different shading options so that the building will be shaded from the Indonesian sun. Inside the building, we have LED lighting, which is state-of-the-art in terms of lighting efficiency.
Duncan: Also, the mosque is a low-tech solution that was arrived at through some high-tech analysis. We’re using a night flush system here. A mosque is not unlike a church in its volumetric configuration. The majority of the masonry surfaces on the inside are used to absorb the heat from the large quantity of people that are in there over the course of the day. Then that heat is re-radiated in off-hours and as the building is flushed out. Through computer simulations, the team at first developed a full-time naturally ventilated space that would have allowed air through it at any time during the day. But since it is almost always warm during the day, the daytime air would counteract the cooling benefits of ventilation. We found it was actually better to draw in the cooler air only at night and release it throughout the day. Additionally, the crenelated surface on the interior of the mosque is cast stone that’s lining every single wall surface that acts as more of a radiator in reverse—more of an absorber—for the body heat of the 1,000 people or so that will be there at a time.
Another big part of the story is water. This is a zero water runoff project. Basically, no water leaves the site. Throughout the site, there are recharging wells that recharge the aquifer. Our water management system is designed so that it doesn’t burden the very fragile infrastructure of Jakarta, which is plagued by floods.
Leung: We recycle all the water inside the building: grey water, black water, etc. Most buildings send it back through the sanitary line back to the city for treatment. But in this case, we designed the system more like a tree. We absorb whatever water we can, we recycle whatever water we can, but then whatever extra we can, we let some that go back to the ground to refill the water table.
Duncan: To talk about the tower a little bit, the form of many parts of the project was driven by the idea and need to save energy. The big story with net zero is reduction first— trying to reduce the loads that are the demands. And then generation is the second part. So we’ve talked about geothermal, we’ve talked about the winds. The low buildings incorporated solar; the canopy incorporates solar. But the building’s shape helps substantially on the reduction side. The plan geometry is aligned with the sun path. The east and west notches have the specially designed façade with vertical fins counteract the low-angle east and west sun. The north and south facades have horizontal shading arrays, the two leaf-like forms that define the tower’s profile on the skyline.