Is New Twin Cities Construction “Green”?

Whenever a new development is proposed, be it six-story mixed-use residences in Dinkytown, an overhaul of Downtown East on the Star Tribune lots, or most recently, a proposal for the southwest corner of Franklin and Lyndale, resistance will most likely show its face.  There are many reasons people or organizations oppose development, and simply writing them off as NIMBY (+1 in Bill’s metrics) ignores the potentially valid, sane arguments they may have.  Let’s save the discussions of height, shadows, traffic, crime, and others for a different day.

Fighting for historic preservation has become a big part of the debate in many developments.  I have my own personal questions on the merits of preservation for preservation sake, whether it’s conservation districts or individual decisions to save buildings.  I’ll readily admit that the benefits just seem too fuzzy to me (outside some seriously significant buildings), and a private approach where organizations or people pony up the money always seem better than making private benefits public (go ahead, call me a curmudgeon who doesn’t appreciate history if you must).  However, a more targeted argument comes up every so often on whether preservation or construction is good for the environment.

To aid this debate, a report [pdf] written by the National Trust for Historic Preservation released in early 2012 goes a long way toward quantifying the benefit of preservation + renovation compared to demolition + construction.  It provides great data points beyond the qualitative “all the old-world craftsmanship with embodied energy will hit the dumps,” which I greatly appreciate, and the information should be a valuable part of the discussion.

Source: National Trust for Historic Preservation

Source: National Trust for Historic Preservation

The study uses examples from across the country to determine environmental and climate impacts, with much of the variance stemming from electricity sources, local climate effects on heating and cooling, and local construction materials.  Chicago may be the closest to the Twin Cities for comparison in these respects, and the study shows that, depending on structure type, it may take between 10 and (gulp) 80 years for new construction to break even on environmental impacts vs. renovating existing structures.

Not Quite There

That said, the study has some shortcomings regarding evaluating total environmental impact, like any report (especially one authored by an agency focused on preserving historic structures as a key mission statement).  Among them:

Study Assumption: Like-for-Like Replacement (Source: National Trust for Historic Preservation)

Study Assumption: Like-for-Like Replacement (Source: National Trust for Historic Preservation)

  • I believe the study’s major flaw is its assumption that new construction will remain at roughly the same intensity, footprint, and/or height of what it replaces.  While it may be true that houses across the metro, particularly in first-ring suburbs and wealthy parts of Minneapolis, are being torn down for new single-family homes, the historic-as-green argument crops up for projects that  replace smaller structures with apartments, mixed-use buildings, or other.  Replacing two structures housing 4-10 people with a 45 unit apartment is hardly comparable.  This important because…
Running posts with pie charts: 3. (Source: National Trust for Historic Preservation)

Running posts with pie charts: 3. (Source: National Trust for Historic Preservation)

  • Transportation Energy Costs are Excluded:  The chart (page 17) shows how the US spends its energy today, and a big factor we should all be concerned with: transportation emissions – 29%.   The study avoids calculating these environmental impacts, most likely because calculating number of trips by mode and distance for average projects would be difficult.  But that doesn’t mean that a project in a transit-supported, dense environment close to thousands of jobs in a downtown core isn’t likely to see many of the new residents walking to stores or work, or taking transit more often.  More people using these cleaner modes may engage a positive feedback loop for existing residents, or give Metro Transit the kick in the pants they need to upgrade service.
  • Unintended Consequences of Restricting Growth: Assuming the population or business growth is retained in our metro area but halted on historic grounds.  New construction may happen at the fringe of the metro, potentially requiring new concrete, asphalt, energy transmission costs, or other potential impacts.  These avoided costs don’t seem to be calculated.
  • Sub-Optimal Regulatory Environment: The study ignores government policies that force higher new construction energy costs – namely required parking.  Does this mean all new construction builds only what is required?  Surely not, but it happens (University of Minnesota adjacent construction a relevant example), and other regulations may have similar impacts.
Fairly comprehensive lifecycle energy analysis (Source: National Trust for Historic Preservation)

Fairly comprehensive lifecycle energy analysis (Source: National Trust for Historic Preservation)

  • End of Life Process for Existing Structures.  The study assumes all embodied energy is more or less lost to landfills, ignoring major re-use potential.  This could include moving the existing structure (saving it entirely) to a location where a single-family/detached home is warranted by the market.  It could include re-using beams, trim, bricks, fireplaces, and beyond in new construction or renovations for existing structures (which a local TV star lambasted a property owner for doing prior to demolishing a property).  There should be targeted public and private initiatives aimed at reducing lost embodied energy, and hopefully as many people as possible can turn a profit doing so (jobs!).

A Pragmatic Path for Minneapolis and St Paul

Despite these objections, I do believe lovable places, great urban design, and historic structures do play a role in lowering energy impact.  It’s obvious that century-old passive design elements found in our housing stock and street design help keep houses cool during our oppressive summer months without significant energy draws.

What should our cities do to evaluate project proposals on their environmental merits (among other issues that inevitably arise)?  I’m a math guy, so I like equations.  Absent a federal (or global) tax on carbon and other harmful emissions that level the playing field for how people spend their money on transportation, housing, and food, cities have the potential to implement their own metrics.

If the study’s methodology were updated to include some of the missing links discussed above, proposals could get an expected lifetime environmental impact value.  Obviously, the city would need to make assumptions for future behaviors – travel mode, distance, and frequency would need to be tailored to individual neighborhoods and use demographic (and infrastructure) trends.  For example, an apartment that’s a 5 minute walk from the West Lake SWLRT station may have low transit use today, but 5 years from now the share may triple.  This tool may require some heavy lifting up front, but the data is all there.

This information could help city leaders reach their sustainability and affordability goals, while also encouraging dense, new growth at key nodes and corridors.  Cities could give incentives in the form of lower property tax rates (just spitballin’ here..) the more a proposal reduces total environmental impact.  It may also steer developers to target certain lots, avoiding excessive hurdles  or costs set by the city by replacing surface parking or under-utilized industrial sites in the near-term.   Preservationists get a tool in the city’s pocket that’s fair, transparent, and tilts the scale toward keeping high-utility historic structures difficult to demolish by virtue of their embodied energy.

So, returning to my titular question: is new construction here in the Twin Cities green?  Well… it really depends on a host of factors, so perhaps I’ll leave it unanswered. What other opportunities are there to evaluate the merits of new development proposals?

25 thoughts on “Is New Twin Cities Construction “Green”?

  1. David

    Alex your swipe at “a local TV star” who you say lambasted a local property owner for removing finishings from a house they were demolishing doesn’t contain the facts. A known slumlord (recently featured in the Strib for his slum activities on the northside) is the property owner. He conned the elderly previous owner into selling the distressed property to him for around $40,000 and then planned to demolish it. Local preservationists, including the “local TV star” (with a national show) objected to the stripping of the house because there was a plan to purchase the home and move it to a vacant lot, thereby preserving ALL of the embodied energy and old world craftsmanship of this magnificent home. Demolishing the interior made this option less less viable, but viable nevertheless due to the quality of the construction. The slumlord had the idea that he could sell the components for much more money…and over a year later he is STILL trying to get a price for tbose components that he never will, and STILL trying to market the vacant lots where the house used to stand for around $1.5 million. So, he was lambasted for destroying the interior of a home that could have and should have been recycled, the whole house recycled, on a new lot. Instead all 230 tons of that house are now in a landfill and both the lot where it stood and the would-be destination lot are still vacant, awaiting the day when some inspired suburbanite such as yourself might invest in a plastic-clad wonder built to a 30 yr standard.
    Try not to twist the facts to support your anti-preservation angle.

    1. Alex CecchiniAlex Cecchini Post author

      To be perfectly honest, I didn’t mean it as a swipe. That particular issue is more complicated than my one-off comment or even your take on the matter. Certainly, moving the structure itself is a great option; I note that as a great means of preservation in that very paragraph! Additionally, I note that there are far more materials that can be re-used even in demolition beyond just a few items. This piece wasn’t meant as an anti-preservation angle, since I actually challenge my own assumptions and push for a much more comprehensive way of looking at energy impacts as they relate to structures.

      1. Nathanael

        Here in progressive Ithaca, NY, it’s become standard practice to “deconstruct” buildings rather than “demolishing” them. There are multiple companies which do it.

        (Unfortunately, superinsulation hasn’t become standard practice. It should.)

  2. David

    Missing from your commentary is the negative affect that some of the new construction has on adjacent areas when it is out of step with land use in that area. Some areas are appropriate for the density boxes, but dropping one into the middle of a residential area that is lower density has a destructive affect on the livability of adjacent properties.
    There also needs to be some thought given to the construction materials and their effect on occupants’ health and eventually the environment when they are deposited in the landfill…older structures are built of brick, wood, plaster, etc. New structures are plastic, formaldehyde, and other petro chemicals, some of which are more than a little toxic.
    Why do you go right to public subsidies to encourage a higher standard of efficiency that might make the carbon footprint payback less than 80 years? Why would this standard not simply be a requirement of the new construction? Afterall there is plenty of profit for developers in den$ity.

    1. Peter Bajurny

      I’m not sure why developers are vilified for making money. They’re not making exorbitant profits, they’re getting 5 to 10 percent annual returns on their investment. Does that make them evil?

      1. David

        Not at all, the point is just that there IS profit in these developments, if a higher standard is required to get beyond the “green washing” factor, why would it necessarily be a public subsidy when in fact the developers can afford it themselves.

    2. Alex CecchiniAlex Cecchini Post author

      I still haven’t really seen a hard commentary (ie not subjective descriptions of what makes a place livable) for why additional density has a negative effect on existing residents. Considering millions of people pay exorbitant sums of money to live in places far denser than most Minneapolis neighborhoods, I think there’s plenty of room for debate, and any potential negative could be countered by neighborhood positives (ie, positive feedback loops discussed in the post).

      As to construction materials, I’m not an expert. Like Bill, I’d be curious to see comparisons (I’m not certain that brick firing furnaces are substantially more eco-friendly, but that’s the whole point of the report – to take into consideration all the impacts of material sourcing, construction methods, etc and put it into a lifecycle environmental impact analysis, right?). My guess is that brick and plaster manufacturing in the late 19th century/early 20th was none too green. We also place old home builders up on a pedestal for their use of high quality timber in homes, forgetting that in a very short span, most of northern MN and WI were nearly completely deforested.

      I turn to property tax subsidy for new development because 1) we don’t (and likely won’t) have a carbon (or other toxic material) tax anytime soon. This tax would represent the lifecycle impacts to the environment in monetary form and steer manufacturers away from it as profit margins would sink relative to other options. Without that, how can we incentivize better development? We have tax incentives for solar and wind because we recognize there are environmental cost avoidance by using them. Do the same here. Or flip it around, no tax subsidy, just higher property tax rate for demolition/new construction that doesn’t improve on total impact. Use the extra revenue to fund bike lanes, transit improvements, park management, etc. Thoughts?

      1. David

        How about making the building code reflect it? Why even mess with subsidies? Regarding the high quality of lumber in older structures…the real point is that new construction can’t possibly duplicate that because we no longer have 400 year old trees. Trees harvested for new houses are usually around 30 yrs old, sometimes less….they are also fast-growing varieties which makes the wood softer and less sturdy. In the same board there is frequently BOTH heartwood and sapwood which are parts of the tree that would previously have been rejected. Trying to evaluate the “green” or ecological impacts of something done 100+ years ago is a red herring…it is done and it won’t be duplicated, but we shouldn’t carelessly destroy the resource yielded by those processes.

    3. Payton Chung

      The view out my window includes 2-3 story townhouses and several 10-story high-rises. There’s a 70/30 split of land vs. residents, where the townhouses fill most of the land and most of the residents live in the high-rises. I don’t think that the high-rises have any “destructive affect on the livability of adjacent properties” — quite on the contrary, seeing as it’s we high-rise dwellers who pay most of the taxes, provide most of the customers for the local shops and transit, etc.

      Meanwhile, the health risks inside my apartment are from the old materials, like asbestos glue under the tiles and lead paint on the walls. “Natural vs. artificial” rarely has clear-cut environmental answers, as with the age-old “paper or plastic” question.

      1. David

        High rise dwellers don’t “pay most of the taxes”. Taxes per finished square foot are actually less. Yes, it is a more intense use of LAND, so per square foot of land it might be more but it brings the complications of density that require excess public expenditures on infrastructure so whether that is actually a good thing or not is debatable.

        1. Alex CecchiniAlex Cecchini Post author

          Well, I think you both may be right. I would bet that the levied property tax per person of a dwelling unit is higher in denser development (even if they pay it through their rent rather than directly as condo owners do). This piece links to an article that finds, across the US, ” multifamily rental housing bears an effective tax rate (tax divided by property value) that is at least 18 percent higher than the rate on single-family owner-occupied housing”:

          Yes, it’s a few years old, and yes, I’m not sure if it applies here in MSP. Anecdata by clicking a few properties on Hennepin Cty’s GIS site won’t confirm or deny it (maybe someone else can).

          Either way, to say that density requires “excess public expenditures on infrastructure” is a bit off, IMO. A block with 500 units on it uses far less square feet of asphalt and concrete, miles of sewage pipe, etc than a block with 20 SFHs. The postal service can more efficiently deliver mail, and plows spend less minutes per capita running by. Electricity can be more efficiently delivered from central sources, and denser development lends itself better to microgrids.

          Of course, you hit a certain point where buses become necessary, and beyond that grade separated transit, etc – all of which are expensive to build and run. But I would wager a bet that European compact (dense) suburbs require far less local government spend per person than ones in the US do.

  3. Bill LindekeBill Lindeke

    Alex, I think you nicely describe the complexity carbon footprint analysis, which can become endlessly complicated to the point of absurdity if you let it. I think the best thing might be to come up with as simple as possible an equation that gets at the key measures you mention:

    (walkscore + energy efficiency + lifecycle + density) = rough carbon impact

    Use that as a way to measure sustainability in our cities.

    (OTOH, we could just mandate green paint (from lima to emerald to british racing) which would superficially take care of the matter without much impact beyond aesthetically horrifying our built environment.)

    Finally, David, you’re illustrating one of my pet peeves by using vague terms like “out of step” and “livability” to describe things that are pretty subjective. To one person, livability means easy parking. To someone else, livability means a high frequency bus route. (That’s just one example.) Often these differing concepts of livability come at expense of one another, and we shouldn’t use terms like that as if they’re universal or neutral.

    Finally finally, I’m curious about this building material angle. Is this true? Where can I find out more about modern building materials v. older building materials etc.?

    1. Alex CecchiniAlex Cecchini Post author

      Thanks, Bill. I agree, simplicity is best. If you can get to the “80/20 rule” of the issues and leave the minutiae out (the small stuff is probably where the debate is strongest anyway), you’re mostly there from a carbon footprint perspective. I’m merely proposing something that city leaders can use as a gut-check, along with other issues like how a structure relates to the street, for evaluating proposals. The property tax idea was a way to quantify the environmental impact and take the decision making out of a few key individuals and “letting the market decide,” so to speak.

      But yes, I could go for some BRG buildings. Throw some Jaguar hood ornaments around as well.

  4. Janne

    Chicago isn’t that comparable, as our buildings are significantly more energy efficient for a few reasons, like being quite a bit newer. But that’s niggling. Great post!

  5. Brendon SlotterbackBrendon

    Great post. Some great LCA work comes from Chris Jones out of Berkeley. He’s developed a whole series of lifecycle carbon calculators to help you get your arms around these things. From his review of the literature (which is sparse), construction of a new, single-family home (2,150 sq ft) requires 100 mt CO2e. By my calculations, and given our energy utility mix, a new home that is 30 percent more efficient would take 20 years to pay back, rather than 38.

    FYI, the 50-year annual amortized carbon impact of the construction of a new home in the Minneapolis area is a little more than half of what your household is responsible for emitting by eating an average amount of meat.

    1. Nathanael

      And if the new home is 80% more efficient, which is pretty easy to achieve with superinsulation (see below), what does the payback period come out to?

      I think the real problem is that lots of new buildings are still being built which aren’t really energy-efficient at all!

      1. Nathanael

        OK, I did the calculation for you — the answer is that the payback period is 6 years. SIX.

        Of course, you can do even better by retrofitting an old house to superinsulate it.

  6. David

    I’ve seen numerous articles on the building materials, though I would need to look them up…google will yield some results too, of course. The articles I’ve seen maintain that the greenest building you could ever have is the one that is already there, because when you add the carbon footprint of the materials for the new construction (shipping materials all over the globe, petro chemicals that come from fracking, etc) even the “greenest” new construction can’t compete with what is already there…because of course whatever nastiness may have happened in the history of the existing structure is essentially a “sunk cost” at that point, whether it was built in 1890 or 1990. The obvious point is that demolishing usable structures for the sake of “green” is nothing more than green-washing.

    1. Alex CecchiniAlex Cecchini Post author

      Yes, but… the whole point of the post was to show that this is true… unless you include transpo savings, savings from moving up in intensity to a building that shares more walls than a lower-functional class, etc. I think that’s the whole point, and it’s why a city like NYC emits far less CO2 per capita than Minneapolis. Replacing 2 SFHs that house 7 people with an apartment building that houses 40 has all sorts of different effects than replacing 2 SFHs with 2 SFHs.

  7. Nathanael

    OK, so here’s the thing.

    All of these numbers are based on a building which is “30% more efficient” than the previous building.

    That’s chump change.

    Heating costs are dominant in Minnesota. Replace an uninsulated single-wall building with a superinsulated building, and you can reduce the heating energy expense by upwared of *80%*. That’s right: you can spend less than 1/5 of the energy on heating as you did in the old building.

    At that level of improvement, the payback from replacing (or at least gutting) the building is very high.

    The trouble is that most new buildings are not actually superinsulated. They’re built with relatively low insulation standards, and the builders brag because they’re better than whatever uninsulated junk was there before. The superinsulation method has been understood since *1981* and was published back then (_The Super Insulated Retrofit Book_). But practically nobody in the US uses it! We get insulation techniques which were state of the art for 1965, instead, and they’re advertised as “green”! It’s appalling,

    Further, it’s actually quite viable to retrofit most old buildings with superinsulation: the exception is single-wall masonry where you care about the exterior look, which is very hard to do.

    So basically, I’d say that most developers are not really trying to be energy-efficient. They’re greenwashing. Ant that is reprehensible.

    1. Nathanael

      I started learning about superinsulation when I bought a house which had heating costs — heating is gas here — which were about 20% of the typical gas heating costs for a house of similar size in my area. I went “What’s going on here?”. Turned out my house wasn’t actually superinsulated, even — it simply applied *most* of the rules of superinsulation. If all of them had been applied it would have been even more efficient.

      I later switched my lighting to LEDs and had a 50% drop in my electric bill.

      There are a lot of massive energy-efficiency improvements which are just being ignored by most homeowners and developers. Ignored.

      At this point, I think command-and-control is the only way to go about it: start mandating vapor sealing, HRVs/ERVs, and high R-value insulation for the new building code. It may be the only way to convince the developers to learn how to do superinsulation.

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