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A Year Ago on Zero Resource – November 2010

Snippets – Water

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Image from the report appendix

The Union of Concerned Scientists just released a new report on the effect of power plants on freshwater systems.  “One plant had to curtail nighttime operations because the drought had reduced the amount of cool water available to bring down the temperature of water discharged from the plant,” the report says. It quotes Kent Saathoff, a vice president of the Electric Reliability Council of Texas, who said last month, “If we don’t get any rain between now and next summer, there could be several thousand megawatts of generators that won’t have sufficient cooling water to operate next summer” (New York Times Green Blog).  You can read the entire report here Sewage overflow is the No. 1 source of pollution for New York’s waterways, says Leif Percifield, a graduate student at the School of Art, Media, and Technology at the Parsons New School of Design… Percifield’s dream is to place simple sensors at each of New York City’s 490 “combined sewer overflow” points. The sensors will be primed to send out text-message notifications every time the city’s drainage maxes out (Grist).  UC Berkeley has begun work in its quest to significantly taper its campuswide water use. The campus is aiming to cut its water usage by over 65 million gallons by 2020 (The Daily Californian).

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Earth From Space

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Earth | Time Lapse View from Space, Fly Over | NASA, ISS from Michael König on Vimeo.

This video is striking for a number of reasons. Earth is so small. And yet you can see city lights all over the place, a sign of how much of an impact we have had on the planet. You can also see flickers of lightning through the clouds.

THIS POST IS PART OF OUR FRIDAY VIDEO SERIES.
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Zero Net Energy part 2

photo attribution: CalderOliver at en.wikipedia

Zero Net Energy (ZNE) is a term that is increasingly heard throughout the architecture and building sector, but it is also a term that can mean different things to the different people who use it. This series of posts is an overview of the four common definitions of  ZNE, and a brief expansion on their respective implications in relation to policy structures and physical infrastructure. Part 1 of the post can be found here

The four common definitions of ZNE are: 1. Zero Net Site Energy, 2. Zero Net Source Energy, 3. Zero Net Energy Cost, and 4. Zero Net Energy Emissions. All four of  these calculations are as measured over a calendar year, or on an annual basis. The difference is in the metric (the “thing” being measured) and the boundary (what is included in the calculation). All four definitions can be applied to –and calculated at– a “community” or multiple-building scale as well. In all cases the “net” part refers to how energy is accounted for at the grid level; low energy buildings that are not grid tied would therefore not be under a zero net energy designation.

 Part 2: Zero Net Source Energy

what this is: A source zero net energy building  produces at least as much energy as it uses in a year when accounted for at the source.

what this means: “Source energy” refers to both the energy used by the building and the energy lost in the generation and delivery of the energy to the building. To illustrate the point, think of carrying a bucket of water with a small leak across a room; you then water a plant with it. The ZNE site definition would only be concerned with the water that was applied to the plant; the ZNE source definition would be concerned with both the water that was applied to the plant, and the water that leaked out onto the floor.

pros, cons & considerations:

  • A ZNE source definition can be a benefit if one is striving to be extra conscientious about accounting for energy use and could have benefits depending benefits depending on the fuel mix of your building.

further reading:

P. Torcellini et al., Zero Energy Buildings: A Critical Look at the Definition, National Renewable Energy Lab, 2006.

This post is part of our definitions series on “eco-lingo” and technical terms


Snippets – Zero Net Energy

The International Living Future Institute (ILFI), owner of the Living Building Challenge, is going where no certification program has gone before with a new Net Zero Energy Building Certification program (BuildingGreen.com).  You can read the International Living Future Institute press release on the NZE Building Certification program here There is a zero net energy gas station in Beaverton, Oregon (OregonLive.com).  KB Home, one of the largest homebuilders in the U.S., has developed ZeroHouse 2.0, a house designed to achieve net-zero energy. The home is currently available in Tampa, Florida, and in San Antonio and Austin, Texas, but the company plans to expand the availability of net-zero options to other cities throughout 2012 (BuildingGreen.com).

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Energy-Related Recovery Act Money

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 I’ve been having quite a bit of fun investigating where some of the energy-related recovery act money has gone via the interactive map here. If you zoom in to look at the Bay Area, you can hover your mouse over each circle to see who received the money and how much. For example, the City of Berkeley received $118,155 for a renewable energy project, and Fremont received $1,891,200 for energy efficiency.

JARGON

Zero Net Energy part 1

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photo credit: Alan Walker

Zero Net Energy (ZNE) is a term that is increasingly heard throughout the architecture and building sector, but it is also a term that can mean different things to the different people who use it. In this series of posts I will give an overview of the four common definitions of  ZNE, and a brief expansion on their respective implications in relation to policy structures and physical infrastructure.

The four common definitions of ZNE are: 1. Zero Net Site Energy, 2. Zero Net Source Energy, 3. Zero Net Energy Cost, and 4. Zero Net Energy Emissions. All four of  these calculations are as measured over a calendar year, or on an annual basis. The difference is in the metric (the “thing” being measured) and the boundary (what is included in the calculation). All four definitions can be applied to –and calculated at– a “community” or multiple-building scale as well. In all cases the “net” part refers to how energy is accounted for at the grid level; low energy buildings that are not grid tied would therefore not be under a zero net energy designation.

Part 1. Zero Net Site Energy

what this is: A Zero Net Energy Building is one that uses no more energy than it can produce on-site within one calendar year (this is the most commonly used definition of the term “zero net energy” at present).

what this means: A “site” can be defined as either the building footprint itself or the building and the property it sits on. In this definition, the building/ building site would incorporate a form of on-site renewable energy such as solar (most common), wind, small hydro or biogas. As mentioned, a ZNE building is still tied to the larger energy grid. For example, a ZNE building that generates energy through the use of solar panels would create a surplus of power while the sun was shining (and the excess power would be fed back into the grid), but would have to draw power from the grid in the evening or during cloudy days. The goal here is for the overall power drawn within one calendar year to be less than or equal to the power generated.

pros, cons & considerations: The chief benefit of this definition is that it promotes deep efficiency at the single building scale. This is because in order to viably (and cost effectively) achieve this definition of ZNE, it is much more desirable to build the lowest energy-use building possible and then add a source or renewable generation. In addition, ZNE sets a concrete goal to achieve and thus can be a more useful target than trying to meet or best shifting baselines as building performance codes change.

However, buildings are built in many types and have many necessary functions- not all of which are compatible with the site definition of ZNE. For example, hospitals, restaurants, industrial activities, etc., may all have a very hard time achieving a ZNE facility because of unusually high energy demands. In addition, high-rise buildings and urban infill sites have their own challenges due to physical constraints (poor solar access, low rooftop-to-building ratio, proximity and density issues, etc.)

The implication here is that if a ZNE site-definition goal is in place on a policy level, at a certain point it becomes necessary to start looking at the issue from a multiple-building, or “community”scale, that would allow energy balancing between buildings to achieve an overall ZNE outcome (this is a simplification, but that is the main point).

Further reading:

P. Torcellini et al., Zero Energy Buildings: A Critical Look at the Definition, National Renewable Energy Lab, 2006.

This post is part of our definitions series on “eco-lingo” and technical terms
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Thermographic Infrared Maps

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A program in Belgium is using aerial thermographic infrared maps of neighborhoods to give folks a contextual sense of their home’s heat loss. On the image above, the blue homes are losing much less heat than the red ones and are better insulated. Viewing this kind of map gives folks a sense of how their home’s insulation levels compare to that of their neighbor’s home.

You can click the image above to watch the video (it will take you to another page), or watch it here. Unfortunately, you will have to watch a brief ad before you can see the video clip.

This post is part of our Friday video series.