When the buildings in a community are built to the standards we strive for, we have a huge head-start when trying to make that whole community sustainable.
However, there are still measures that can be taken at this level to make a greener and healthier home for residents. Broadly speaking, the changes fall into two broad categories: urban planning and development and district energy solutions. |
SUSTAINABLE PLANNING
An essential part of planning green communities is creating walkable streets. Making sure people are comfortable walking around instead of driving everywhere lessens fuel consumption, encourages exercise, and improves commerce on those streets.
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There are many ways to make walkers feel comfortable:
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Of course, nobody's going to be walking if there's nothing they can walk to. Making sure that parks, plazas, and other public amenities are offered within walking distance of residential centres gives people a reason to walk. More time spent walking around a park means less time inside using energy.
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Making communities bikable follows a similar vein as making them walkable. However, the steps to getting there are quite different.
Communities with interconnected networks of dedicated bike paths give cyclers a way to travel safely and efficiently through it. Limiting these paths to quiet streets that run parallel along major thoroughfares makes them accessible, convenient, and can actually have a positive effect on automotive traffic by taking cars off the road. |
Growing food can be a sort of primal joy that often isn't possible in many urban environments. Although Carbon Busters designs homes with growing potential in mind, the problem can also be solved at the community level. Designating portions of park space or freeing up lots for community gardens allows people to grow a portion of their own food.
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When people can grow, they need fewer groceries, thus limiting trips to the grocery store and freeing up streets. As more food is grown locally, the community relies less on carbon intensive importation. Furthermore, a community garden provides a place for people to meet and the sense of community grows.
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DISTRICT ENERGY
There are countless ways a community can share the burden of providing energy. We'll be making the delineation between electrical and thermal energy in an effort to simplify the topic, but it should be noted that in a truly integrated district energy system, the supplies and demands of each would be considered together.
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Electricity
Technically, the electrical grid is already kind of like a gigantic district energy system. However, the grid was being made when we only used centralized generation, big coal plants and hydro-dams.
Distributed generators can already share the electricity they sell with neighbours who then buy it from a retailer. However, there are several improvements that can be made to the grid to make it work better with distributed generators like net-zero buildings. |
One of the biggest improvements that can be made to the grid to adapt it to the shifting renewable realities is energy storage. With centralized generation, grid operators can essentially order the amount of electricity they need on a real-time basis.
Most forms of renewable energy aren't dispatchable in this manner. You take the energy when it comes, but can't control the Sun or the wind. |
This means that having a way to store the energy that's generated when it isn't needed is great for the cloudy, still days. Many options for energy storage exist, including a range of batteries, pumped hydro storage, compressed air storage, flywheels, and fuel cells.
By having pockets of energy storage dispersed throughout the grid, operators gain a dispatchable energy source to buffer the highs and lows. |
Another huge improvement that could be made to the grid deals with the way electricity is metered. Bi-directional meters with real-time data updates allow operators to see how much electricity is being generated or consumed by a given building.
This allows them to develop complex pattern analysis for generation and consumption, enabling the utilization of various energy storage techniques to accept and deliver electricity more efficiently. |
Many renewable generators have advanced inverter technology that helps them translate their highly variable energy source to clean, usable power.
Many of these inverters can also alter the electrical signal they produce to help clean the power quality on the grid itself. This could prove to be another service sold to the grid in addition to selling electricity, improving the economics of renewable energy generators even further. |
THERMAL ENERGY SHARING
One massive benefit to linking a community's thermal energy system is the ability to share that energy as needed. There are a multitude of factors that determine what a building's temperature would be without conditioning the air.
For example, the sun heating the Southern end of a row of townhouses can be enough to make these houses require cooling, while the houses in the shade require heating. The district energy system can be set up such that the heat rejected from the sunny houses can be used to heat the shady houses. Thus limiting the work done by the energy centre and improving the performance of the whole system. |
The same principle holds true on a community level as well. Some types of buildings, such as offices, manufacturing plants, gyms, ice-rinks, and some types of commercial predominantly require cooling because of their internal activities and processes.
This means that heating dominant buildings can use the rejected heat, while the cooling dominant ones use the cooled water rejected during heating. This lowers the overall load on the geo-field and any other thermal sources that might be employed. |
Some communities, such as Edmonton's upcoming Blatchford district, have the benefit of access to external heat sources. Their land lies on top of sewer mains collecting from Northwest and West Edmonton. Since most of the properties in these areas aren't using drain-water heat recovery, these mains are typically quite warm. This heat can be siphoned off with a heat exchanger to provide supplementary heat to the Blatchford energy centre.
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ECONOMIES OF SCALE
As with pretty much anything, as you buy more of something, each one gets cheaper. In the case of sustainable communities, many components become more economical as they're shared.
All the fixed costs of bringing installers, drillers, and other contractors are distributed over the whole community rather than being multiplied for individual buildings or parcels. Furthermore, equipment sized for greater and more consistent loads are typically far more efficient. For example, the central heat pump in Blatchford's energy centre is expected to pump 10 units of thermal energy for every one of electricity, double that of standard household heat pumps. |