Heatwave Resilience Case Study

Green Building Strategies to Mitigate Heatwave Impact

Outdoor Shade Spaces

Aging adults and people with chronic illness are at particular risk of heat stroke, dehydration and dangerous fainting spells. This is exacerbated by the fact that some people living in public housing do not have access to central air conditioning (AC) or cannot afford to run window AC units. Property owners can encourage these populations to walk the outdoor premises by providing amenities that accommodate such activity.

While the grounds of apartment complexes often include outdoor common spaces, they do not always have shaded areas and aging adults, who are susceptible to heatstroke, may not be able to take advantage of unshaded outdoor spaces. Owners may consider planting trees on property grounds as the presence of trees will contribute to improved air quality. Trees absorb pollutants and also help reduce the urban heat island effect by cooling the immediate environment through evapotranspiration and can reduce the need the demand for air conditioning in nearby buildings.[4] Heat island effect takes place when built up or densely developed areas experience an increase in temperature due to large areas of dark surfaces (i.e., pavement, roofs, etc.) that absorb heat from the sun. Rising temperatures result in increased energy demands, which can lead to higher air conditioning costs, increased greenhouse gas emissions, pollution, and increased risk of heat-related illnesses.[5] If planting trees is not feasible, owners can still incorporate planted areas, install canopies or umbrellas and provide seating to accommodate outdoor activities. Consider multipurpose components such as photovoltaic panels or vegetated roofs on structural canopies. High reflectance or “cool” paving stays cooler in the sun than darker paving. Consider using light-colored and reflective-colored pavers an alternative to asphalt and other dark materials for outdoor spaces.[6] Water features can also help cool the microclimate of an outdoor space.[7]

To help signal to tenants the appropriate times for outdoor seating or recreation, as well as opportunities to exchange air in the apartment via window opening, property owners can implement a visual outdoor air quality monitoring and warning system. The US EPA has an ‘Air Now’ online tool (www.airnow.gov) that lists air quality conditions by zip codes.[8] A highly visible flag system that correlates to a scale of air quality on site can help provide information about current air quality.

Vegetated Roofs

A vegetated roof, or green roof, is a system of lightweight growing media and plants that can be installed on most new or existing roofs with the input of a structural engineer. Vegetated roofs can improve air quality, reduce the urban heat island effect, manage stormwater and reduce the need for heating and cooling within the building. Accessible green roofs can also provide opportunities for producing food as well as providing additional outdoor space and wildlife habitat.[9]

For example, vegetated roofs serve as a carbon sink, helping to offset carbon emissions. Vegetation traps dust and particulate matter as well as other contaminants such as nitrogen oxides.[10] The multiple layers of a vegetated roof provide insulation. By increasing a building’s thermal mass, vegetated roofs can help keep temperatures cool in hot weather and warmer during the heating season translating into less energy spent on climate control for the building.[11] In the event of a power outage, common during heatwaves, vegetated roofs can help keep temperatures cool in the hot weather.

Cool Roofs

Cool roofs, typically white, light-colored or reflective-colored roofs, reflect and radiate heat away from the building and are “cooler,” or have higher levels of reflectance and emissivity, than dark roofs. Many building codes and green building programs have a cool roof and urban heat island mitigation requirements that refer to ENERGY STAR and the Cool Roof Rating Council (CRRC) voluntary labeling programs. Cool roofs and proper insulation levels can reduce heating and cooling loads, reducing stress on the grid, and help to regulate thermal comfort during a power outage. [12]

Energy-Efficient Landscaping

The careful selection and placement of trees, shrubs and other vegetation can help reduce a building’s cooling needs. For example, planting trees on the southside of the building can minimize summer solar heat gain. During a heat-wave, shade-providing trees help mitigate the urban heat island effect, reduce indoor cooling loads, and reduce stress on the power grid.[13]

Smart Metering

Smart meters or advanced meters, a component of the broader smart grid, [14] use digital meters to record and transmit energy consumption and generation data, namely electricity, but also natural gas or water usage in intervals of an hour or less through secure wireless network back to the utility and consumer at least daily. [15] As opposed to traditional analog or automated meter readers, smart meter technology includes remote reading, two-way communication, support for dynamic pricing,[16] and remote disablement and enablement of supply.[17] Smart meters provide documentation for participation in utility-sponsored demand response programs, which incentivize property owners and managers to interrupt or adjust energy use by reducing or shifting loads or storing energy during peak demand and periods of higher energy costs or enable utilities to remotely switch electricity services on or off based on the cost or availability of energy.^[18] For example, consumption data from smart meters can signal a utility or consumer to remotely turn off air-conditioning units to avoid peak load issues or to run appliances during lower demand, lower-cost times of the day. Smart metered buildings with on-site renewable energy generation (e.g., photovoltaic systems) and energy storage (e.g., thermal storage, battery storage, fuel cells) can signal consumers to use renewable electricity when available, store excess when not needed or sell excess electricity to the grid. Smart metering and participating in demand response programs can help reduce water and energy costs and prevent peak demand-related grid-outages.

Smart meters increase heatwave resiliency by supporting the smart grid, which aims to diversify and strengthen the electric grid through better energy management and the integration of cleaner energy sources such as wind and solar as well as electric vehicle charging. During heatwaves or power outages, smart meters help accelerate service restoration by identifying problem areas and efficiently sending work crews, thereby reducing repair costs and total outage times and limiting business closures, health and safety hazards, food spoilage, and inconvenience from schedule disruptions. [19]

Heatwave Prevention and Preparation: Energy Storage and Back-up Power

In the last 20 years, an increase in the frequency and the intensity of extreme weather events, such as major hurricanes, heatwaves, thunderstorms, and ice storms in New Jersey and the associated costs of storm-related power outages, highlights the need for resilient energy systems that provide backup power in the event of a grid failure.[20]

Historically, generators fueled by fossil fuels, such as diesel or natural gas, provide backup power in the event of a power outage or natural disaster. In New Jersey, Hurricane Sandy exposed the vulnerability of generators, as the storm disrupted access to fuel and competing fuel demands from the transportation sector quickly depleted local fuel reserves.[21]

Energy storage refers to storing energy (e.g., batteries, thermal storage) for later use when it is needed, such as during a heatwave and power outage, or storing low priced energy and using that energy during peak demand, such as increased air conditioning usage during a heatwave, when prices climb.[22]

Backup power refers to supporting critical building functions by utilizing stored electrical or thermal energy (energy storage), power from on-site power generation with islanding capabilities, or power from local microgrids and distributed energy generators.