Boston Goes Neutral

Across the globe, many cities have committed to becoming net zero energy, or net zero for short, in the near future, and Boston is one of them. Net zero is achieved when the amount of carbon burned is equal to the amount of renewable energy created or eliminated. Mayor Marty Walsh has signed an executive order requiring all newly constructed city-owned buildings to be net zero, and Boston as a whole has committed to becoming completely net zero by 2050. While the city prepares for the future of rising sea levels, changing climates, and natural disasters, it must also prepare for a population increase as Boston proper’s urban density increases. As urban density increases, the per capita carbon footprint decreases; this combined with the rise of net zero buildings can pave the way to become completely carbon neutral by 2050.

For buildings to become net zero, architects and engineers use specific strategies to minimize the energy needed to run the building. Some of these tactics include orienting the building to maximize the reliance on natural light and air flow, installing thermal masses that absorb heat during the day and slowly release it at night, incorporating air tight building envelopes including floor and ceiling insulation, and using wall materials that work with the environment to keep the interior at a comfortable temperature. These buildings also use energy efficient cooling and heating systems, LED light bulbs, low flow shower heads and faucets, heat pump water heaters located near the kitchen or bathrooms, and solar panels or other on-site renewable energy. If the on-site renewables are not enough to run the building, some net zero buildings will buy energy from off-site renewable sources.

These practices can be adapted to any environment, from extreme humidity and heat in Florida to snowy Michigan. Many cities and states, domestically and internationally, are taking steps to make these buildings the new status quo. California is requiring all new residential buildings and single-family homes to be net zero by 2020. Similar plans are taking place in cities like Salt Lake City, Utah, and Boulder, Colorado. Closer to home, Cambridge is now requiring buildings to rely solely on on-site renewable energy sources by 2040, and is considering giving developers a chance to build more square footage than zoning usually allows in exchange for net zero buildings.

While the city prepares for the future of rising sea levels, changing climates, and natural disasters, it must also prepare for a population increase as Boston proper’s urban density increases.

Boston is also taking steps to reduce its carbon footprint and move towards net zero energy as a city. Senior Architect for Sustainable Development for the Boston Planning and Development Agency, John Dalzell, cites the increasing popularity of high performance buildings because of “a growing understanding of the practices of how they work.” According to Chris Cook, Boston’s Chief of Environment, Energy and Open Space, 80 percent of buildings that are going to exist in 2050 are already built, meaning that these buildings will need to be retrofitted in order to comply with the net zero commitment.

Numerous studies have shown that taking steps towards net zero costs no more than constructing their polluting counterparts. “Practices and products are now readily available, and it doesn’t take much to achieve these outcomes. Practices are also becoming normalized, which make costs similar to conventional construction,” says Dalzell. In addition, energy expenses will be much lower, so the costs will be paid back.

Numerous studies have shown that taking steps towards net zero costs no more than constructing their polluting counterparts.

Boston’s increasing urban density also contributes to a lower carbon footprint per capita compared to non-urban areas. For example, Houston has a density of about 10 inhabitants per hectare and uses about 75 gigajoules per capita per year, while Hong Kong has a density of over 300 inhabitants per hectare and uses about 3 gigajoules per capita per year. This is partly to do with transportation; low density areas rely almost entirely on cars, while city dwellers have easy access to public transit, biking, and walking. High density also impacts housing emissions. “In cities, we live more comfortably in small spaces. We can put more units in a small space by sharing walls,” says Dalzell.

As the impact of global warming are becoming increasingly pressing, there is a need for regulation and actions that will make a big impact. Carbon neutrality is necessary to combat some of these effects. As put by Dalzell, “By combining net zero homes with Boston’s increasing urban density, there can be a significant impact in the step towards carbon neutrality by 2050.”

SAPIENS (2009): http://journals.openedition.org/sapiens/914

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