Buildings and Cities
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.
As a first step I have generated a list of the most relevant go-to options we have. For now I will strictly focus on The Netherlands. As a general guidance I will use the book 'Drawdown - The most comprehensive plan ever proposed to roll back global warming' by Paul Hawken.
Together with experts in the field I am going to challenge this list. It is therefore an ongoing framework. You will find all the updates below, specified for each specific solution we can opt for.
01. District Heating
Drawdown: 'In district heating and cooling (DHC) systems, a central plant channels hot and/or cool water via a network of underground pipes to many buildings. Heat exchangers and heat pumps separate buildings from the distribution network, so that heating and cooling are centralized while thermostats remain independent. Rather than having small boilers and chilling units whir away at each structure, DHC provides thermal energy collectively—and more efficiently.'
Drawdown: '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 19 and 26 degrees Celsius. 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.
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.'
03. LED Lighting
Drawdown: 'Lighting accounts for 15 percent of global electricity use. LEDs transfer 80 percent of their energy use into creating light—rather than heat, like older technologies—and reduce electricity consumption and air-conditioning loads accordingly. LED streetlights can save up to 70 percent of energy and significantly reduce maintenance costs.
The question about LEDs is not whether they will become the standard in lighting fixtures; it’s when. The price (per watt equivalent) is two to three times higher than incandescents or flourescents, but falling rapidly. Virtually any bulb currently in use can be replaced by LEDs.'
04. Heat Pumps
Drawdown: 'The building sector worldwide uses approximately 32 percent of all energy generated; more than one-third of that is for heating and cooling. Maximum efficiency in heating and cooling could cut energy use by 30 to 40 percent.
In winter, that means pulling heat from outside and sending it into a building. In summer, heat is pulled from inside and sent out. The source or sink of heat can be the ground, air, or water. While cost can be high and efficiency fluctuates depending on local climate, heat pumps are easy to adopt, well understood, and already in use around the world. They can supply indoor heating, cooling, and hot water—all from one integrated unit. When paired with renewable energy sources and building structures designed for efficiency, heat pumps could eliminate almost all emissions from heating and cooling.'
05. Building Automation
Drawdown: 'Energy courses through buildings—in heating and air-conditioning systems, electrical wiring, water heating, lighting, information and communications systems, security and access systems, fire alarms, elevators, appliances, and indirectly through plumbing. Most large commercial buildings have some form of centralized, computer-based building management, used to monitor, evaluate, and control those systems. Adopting automated rather than manual building management systems can reduce energy consumption by 10 to 20 percent.
A building automation system (BAS) is a building’s brain. Equipped with sensors, BAS buildings are constantly scanning and rebalancing for greatest efficiency and effectiveness. Lights switch off when no one’s around, for example, and windows vent to improve air quality and temperature. New buildings can be equipped with BAS from the start; older ones can be retrofitted to incorporate it and reap its benefits.'
06. Smart Thermostats
Drawdown: 'Smart thermostats detect occupancy, learn inhabitants’ preferences, and nudge users toward more efficient behavior. The newest technologies also integrate demand response; they can reduce consumption at times of peak energy use, peak prices, and peak emissions. The net effect: Residences are more energy efficient, more comfortable, and less costly to operate.'
07. Smart Glass
Drawdown: 'Smart glass relies on chromism, the term for any process that causes material to change color. Electricity triggers it in electrochromic glass: When exposed to a brief burst of voltage, ions move into another layer of glass and the tint and reflectiveness change. Thermochromic glass is triggered by heat: Based on outside temperature, it transitions automatically from transparent to opaque and back again. Photochromic windows operate similarly, on the basis of light exposure. Currently challenged by cost, smart glass will become much more common in the coming decades.'
08. Water Distribution
Drawdown: 'Improving the efficiency of water distribution largely depends on management practices. The torrential bursts that cut off service and submerge streets are not actually the worst from a waste perspective: They demand attention and immediate remediation. The bigger problem is with smaller, long-running leaks that are less detectable. Vigilant, thorough detection and speed to resolution are key. Addressing leaks requires financial investment, but doing so is the cheapest way to source new supply and serve growing urban populations. Those same practices make municipal water systems more resilient to water shortages.'
09. Green Roofs
Drawdown: 'Cool roofs achieve similar impacts but with different methods. When solar energy hits a conventional dark roof on a 37-degree Celsius day, just 5 percent of it is reflected back into space. The rest remains, heating the building and surrounding air. A cool roof, on the other hand, reflects up to 80 percent of that solar energy back into space. Cool roofs reduce the heat taken on by buildings and the overall urban heat island effect in cities.'
10. Net Zero Buildings
Drawdown: 'A net zero building is one that has zero net energy consumption, producing as much energy as it uses in a year. In some months it may generate excess electricity through distributed renewables; at other times it may require electricity from the grid. On balance, it is self-supporting. Net zero buildings are more resilient during disasters and blackouts, are more carefully designed by necessity, and generally have reduced operating costs.'
Drawdown: 'Worldwide, buildings account for 32 percent of energy use and 19 percent of energy-related greenhouse emissions. They pull from the electric grid or natural gas lines to heat, cool, and light the spaces within them and to power appliances and machinery. As much as 80 percent of the energy consumed is wasted—lights and electronics are left on unnecessarily and gaps in the building’s envelope allow air to seep in and out, for example.
Much of the attention paid to green buildings is in new construction, but retrofitting brings energy efficiency to the existing built environment. The world has 1.6 trillion square feet of building stock, 99 percent of which is not green. Retrofitting ('Duurzame renovatie') addresses how heat and cold are escaping or entering the building, the systems that cool or warm inhabitants, and how spaces are illuminated. It ultimately improves the experience of being inside the building.
Retrofitting is a well-understood practice, and good building performance data is making it increasingly effective. The payback on retrofits, depending on the building, is five to seven years on average. A recent retrofit of New York’s iconic Empire State Building will cut energy use by 40 percent and avert 105,000 tons of greenhouse gas emissions.'