Buildings, Housing and City Planning
The following material is from the book, Drawdown produced by Project Drawdown.
Project Drawdown is facilitating a broad coalition of researchers, scientists, graduate students, PhDs, post-docs, policy makers, business leaders and activists to assemble and present the best available information on climate solutions in order to describe their beneficial financial, social and environmental impact over the next thirty years.
Building retrofit support from government
Tighten building code energy requirements
County ordinance requiring new and remodeled buildings to be carbon neutral
County financial supported energy audits
Energy and water use disclosure ordinance for homeowners
Maintain green buildings in assessor data base
Support net metering
Parking lot solar panels
Convert street lighting to LED lights
Electric car power sources in city
Promote clean energy suppliers
Small-scale solar systems, typically sited on rooftops, accounted for roughly 30 percent of PV capacity installed worldwide in 2015. In Germany, a leader in solar, rooftops boast 1.5 million systems.
Rooftop solar is spreading as the cost of panels falls, driven by incentives to accelerate growth, economies of scale in manufacturing, and advances in PV technology. Innovative end-user financing, such as third-party ownership arrangements, have helped mainstream its use.
In grid-connected areas, rooftop panels can put electricity production in the hands of households.
LEDs work like solar panels in reverse, converting electrons to photons instead of the other way around. They use 90 percent less energy than incandescent bulbs for the same amount of light, and half as much as compact fluorescents, without toxic mercury. By transferring most of their energy use into creating light—rather than heat, like older technologies—LEDs reduce electricity consumption and air-conditioning loads.
Dense urban human settlement – the cities of the world and the buildings and infrastructure that comprise them – account for a significant percentage of human energy use, mostly for heating and cooling; ergo, they are a significant source of greenhouse gas emissions. The rapid urbanization of humanity ushered in inefficient design of buildings and infrastructure, and Project Drawdown identified, measured, mapped and modeled several solutions that address the operating inefficiencies of dwelling in and using buildings, and of living in cities.
For Buildings, 16 solutions were identified (8 of which were modeled) as listed here:
BUILDING AUTOMATION – through controls and sensors, automation systems turn appliances and other energy uses on and off according to need and use, increasing utilization and reducing space heating and cooling waste.
GREEN ROOFS (cool roofs and green roofs) – cool roofs reflect solar radiation and reduce air temperature, which leads to reduction in cooling loads. Green roofs have a similar effect as well as reducing heating loads in regions of high heat demand. Collectively, green roofs mitigate carbon emissions by reducing fossil fuel use in heating and cooling.
HEAT PUMPS – high efficiency heat pump systems are radically more efficient than conventional HVAC systems. The use of heat pumps reduces building heating and cooling loads.
INSULATION – insulating building envelopes reduces space heating and cooling loads, which in turn mitigates carbon emissions.
LED LIGHTING (COMMERCIAL) – replacing conventional lighting solutions (bulbs, ballasts and systems) with more efficient commercial light-emitting diodes.
SMART GLASS – specially designed glass that can be implemented in buildings to control the infiltration and emissions of solar radiation, leading to reductions in space heating and cooling loads which, in turn, mitigate carbon emissions.
SMART THERMOSTATS – internet-connected devices in buildingshouseholds that reduce the heating and cooling demand of homes by using sensors and intelligent settings to maintain building comfort.
NET ZERO BUILDINGS – not counted/calculated - composite
RETROFITTING – not counted/calculated – composite
Additionally, Project Drawdown modeled another key solution that depends on and interacts with buildings, but is categorized in the Energy Sector.
SOLAR HOT WATER – the use of solar radiation to pre-heat or heat water for residential and commercial use within buildings, which reduces the need for conventional fossil fuel-based water heating.
Five additional solutions were studied and modeled for Cities, as listed here:
BIKE INFRASTRUCTURE – modifying or augmenting urban right of ways to have specific infrastructure reserved for bicycle commuting and segregated physically or by marking from car and pedestrian right of ways.
DISTRICT HEATING – centralized heating systems and distribution of generated heat to the buildings of a defined community, through a network of buried piped, to satisfy the demand for space and water heating.
LANDFILL METHANE – capturing methane generated from anaerobic digestion of municipal solid waste in landfills and incinerating the captured biogas to generate electricity, reducing the need for fossil fuel-powered electricity production and associated emissions.
WALKABLE CITIES – designing and retrofitting urban environments to encourage walking for commute or transportation, thereby reducing transportation via internal combustion engine powered vehicles and their associated emissions.
WATER DISTRIBUTION EFFICIENCY – reducing water leakage or oversupply of regional water, which reduces pumping and pressurization electricity, which, in turn, reduces greenhouse gas emissions.
Heat always moves from warmer areas to cooler areas, until a temperature equilibrium is reached. This heat flow presents a central challenge when keeping buildings within a desirable range of 67 to 78 degrees Fahrenheit. To close the gap on unwanted heat gain or loss and maintain comfortable room temperature, we use more energy. Air infiltration accounts for 25 to 60 percent of energy used to heat and cool a home—energy that is simply wasted.
By better insulating a building envelope, heat exchange can be reduced, energy saved, and emissions avoided. What makes insulation effective is its capacity for thermal resistance, measured as R-value—the higher the better. Ideally, a building’s thermal layer should cover all sides—bottom floor, exterior walls, and roof—and be continuous. Sealing gaps and cracks is also critical to a more effective building envelope.
Insulation is one of the most practical and cost-effective ways to make buildings more energy efficient—both in new construction and through retrofitting older buildings that often are not well encased. At relatively low cost, insulation results in lower utility bills, while keeping out moisture and improving air quality.