jargon2

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


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
local

BART Seat Lab

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Bay Area Rapid Transit, or BART is a common fixture in the lives of Bay Area  California residents. The above-and-underground train network spans northward to Richmond, southward to Fremont, and regularly ferries passengers between San Francisco and points to the east.

Despite their centrality to Bay Area daily life, BART cars have not seen a replacement since the 1970s when the system opened; and that is about to change. BART is actively seeking feedback on its ‘Fleet of the Future’, a long-range plan to replace its cars.

This estimated $3 billion project will be the single largest upgrade expenditure that the BART has ever seen—that could be why BART is enlisting the help of the public to get it right.

A series of ‘seat labs’ are taking place at BART station near you! There, you can try out several configurations of seats and aisle widths, and give feedback on materials, lighting, signage and more. What is most important to you on your commute?

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Remaining BART seat lab schedule and locations

Read more:

Seat lab early feedback: Majority of riders want wider aisles in Fleet of the Future

FTC To Issue Revised Guidelines for “Green” Product Claims

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image: Wikimedia Commons

Many products these days make claims on their labels that place them somewhere on the nebulous spectrum of “green”. These endorsements range from “all natural”, to  “environmentally friendly”, “biodegradable”, or “eco”  just to name a few.

But what do these labels really mean? “Environmentally friendly” compared to what? “Biodegradable” how, and under what conditions?

The fact is, many manufacturers in recent years have taken note of strong consumer appetite for safer products and have responded– but not always with meaningful changes. Products and services that gratuitously toss around vague environmental claims have come to be known as “greenwashing“.

For example, many product labels feature environmental seals – little pictoral “stamps” with a tagline; while there are some legitimate third party verification seals that attest to a products’ safety, environmental performance and/or the manufacturing process, some may be nothing more than ornament. Other examples of deceptive advertising practices may include misleading claims, or overstatement of environmental benefits of a product during its manufacture, use or disposal.

The Federal Trade Commission (FTC) first  adopted its “Green Guide” in 1998 to help provide a baseline of clarity for both consumers and the manufacturers making environmental claims about their products; the revisions that are in the works now will be the first since 1998.

The new revisions will be based on research done by the FTC to gauge consumer understanding of various “green” labeling terms and practices. However, the FTC stops short of providing legal definitions to terms and the guidelines will still be voluntary and self-implemented by manufacturers.

Listen to the KQED Forum “An End to Greenwashing” that provides a discussion of the new FTC guidelines, here

Visit the Good Guide, a group that helps you find “healthy, green, ethical products according to scientific ratings”

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Battle of the Buildings

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Early this month the U.S. EPA launched its 2011 National Building Competition, “Battle of the Buildings“. 245 buildings from across the country will be battling it out “head to head” to see how much each can reduce energy consumption by a given deadline.

The buildings represent a mix of  buildings including 26 different commercial building types and a range of building ages up to 100+. The Competitors will be using EPA’s online tracking tool Energy Star Portfolio Manager to keep track of results.

With the building sector contributing near 20 percent of the country’s energy use and emissions according to the EPA, this competition will help raise awareness and provide practical case studies for a variety of real-world situations.

the competition site even features a tweet stream to follow along with participants’ progress.

The top scoring buildings move on to the finals in July, with an overall winner announced in November.

Bay Area Plan/YouChoose Bay Area

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Image: USGS

A bevy of  Bay Area planning agencies have joined together for a series of interactive public workshops all over the Bay Area this month and next.

Using a web-based simulation tool workshop participants can consider different transit, land use and other policy choices for their region and see the implications. Participants will also be able to and voice their opinions and give direct feedback to the agencies.

The events are being sponsored by the Association of Bay Area Governments (ABAG) and the Metropolitan Transportation Commission (MTC) in conjunction with the Bay Area Air Quality Management District,  the Bay Conservation and Development Commission (BCDC) and a group of nonprofits.

But why wait for a workshop? Check out the YouChoose tool here

Register for an event and make your voice heard here

Read more about the comprehensive regional planning process and the “One Bay Area” kick-off report here

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Reconnecting America: Transit Space Race 2011

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image: Wikimedia Commons

Reconnecting America has just released its 2011 report on transit projects in the United States.

The report, titled “Transit Space Race 2011: A Catalog and Analysis of Planned and Proposed Transit Projects in the US“, is a compendium of transit planning across the country. Due to the fluid and changeable nature of transit planning, the report comprises  a “snapshot in time” during a survey period of late 2010.

The result is a window into transit demand in communities nationwide, and most notably the huge gap between the volume of competitors and the number of available transit infrastructure dollars from the federal New Starts program.

Download the report here

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Plastic Bag/ Retail Bag Laws in the U.S.

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Remember the statewide plastic bag ban that almost happened here in California in 2010? AB1998 which passed the CA State Assembly in June of 2010 would have banned single-use plastic bags from all grocery stores beginning in 2012, and all convenience stores beginning in 2013.

The bill was contentious and narrowly missed passage in September of 2010. If it had passed, the state of California would have been the first in the nation to enact such a ban; However, plastic bag bans are already in effect in several California cities including Palo Alto, Malibu, Fairfax and San Francisco.

Too many retail bags in general?

California is not alone;  there are other single-use plastic bag bans in effect in a number of cities across the country, as well as increased effort to reduce the impact of retail bags in general.

The Florida Department of Environmental Protection released a Retail Bags Report in February of last year. Among the findings is that only 12% of plastic bags and 37% of paper bags are re-used or recycled by Americans.

Apart from plastic bag bans, legislating retail bags can also come in the form of recycled content requirements, bio-degradable requirements, phase-outs, fees or taxes (although none have been successfully enacted in the U.S. to date), or combinations of impact-mitigating actions;

For example California mandated in 2007 that all retail stores over a certain size mark bags to indicate take-back and provide recycling bins for their customers, as well as re-usable bags for purchase.

The  map from the Florida Department of Environmental Protection Retail Bags Report shown below, highlights the locales that have retail bag legislation in some form. See the full interactive map here.

An interesting site on plastic bags and their many laws:

plastic bag laws.org

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Pay-As-You-Throw

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

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Image: Wikimedia Commons

“Pay-as-you-throw” is a variable rate pricing  tool used by communities to increase participation in recycling programs. Under a “pay-as-you-throw” structure, residents are charged for undifferentiated waste that must go to a landfill or incinerator and charged nothing for disposing of separated recyclables. This provides an obvious economic incentive for opting-in to recycling for the consumer and has been used throughout California to great success and  high diversion rates. The question, though, is whether we have finally outgrown “pay-as-you-go” policies.

With the state struggling with crippling budget deficits on every level of government, and with high participation rates in recycling (including newer higher-cost offerings, such as organic waste collection), the value captured from recycled products is not keeping pace with the cost of collections, routing, and processing.  In essence, while “pay-as-you-go” pricing structures may have had a vital role to play at a vital time, we can almost assuredly expect to see new pricing structures in the coming years.

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What exactly does “sustainability” mean? How about “green”, “eco” or “environmentally friendly”? The truth is that these terms are just vague enough to mean many different things to many different people. With the staggering array of “green” products, ‘lifestyles’ and concepts being promoted by marketers and environmentalists alike (as well as the necessary coining of new terms to match new ideas) our definition series aims to make sense of the rising tide of “eco-lingo” and technical terms.

Water Conservation Calculators

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Image: Wikimedia Commons

In honor of  World Water Day March 22, here is a list of  online Water Conservation Calculators:

H20 Conserve Calculator

This calculator is less a predictor of actual water usage than a comprehensive look at daily habits that affect water use.

Water Use Calculator

Manufacturer Kohler, has a simple online calculator to estimate your home water usage against the U.S. average

H2Ouse Calculator

This is a more nuts-and-bolts calculator that will let you plug in your actual water usage (from your water bills) along with home appliance and landscaping details to come up with an overall “water budget”.

Water Footprint Calculator

A calculator that extends past showering and watering the lawn to detailed information on food consumption by food-type.

Happy World Water Day!

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