Guidance on Retrofits and Decarbonization for All Buildings

32tev__gEmbodied carbon is an important and complicated subject. Phius Senior Scientist Graham Wright helps sort it out and discusses Phius’ new REVIVE program in this post.

Let’s talk about retrofit, starting with the proposition that we need to decarbonize all buildings by 2050.

Stopping direct emissions is a good start; the electrification crowd is right about that. But only stopping direct emissions just moves the burden onto the utility/energy supplier, and they have to contend with transportation electrification as well.

The key question for the building sector, and for society at large, is how much effort/investment to put into increasing the clean energy supply, versus reducing the demand by such measures as passive building and heat pumps.  

The scale of the required transition is daunting no matter which way we approach it, especially considering that we have to do all of this utility infrastructure and building retrofit work without throwing off a lot of emissions in the process. The embodied carbon crowd is right about that, though I think a materials focus doesn’t go far enough.  

One way to get at the balance-of-investment question is with the idea of life-cycle cost. What mix of grid upgrades and building upgrades minimizes the total cost of getting the job done, on an annualized/life-cycle basis? I brightened up to this when it occurred to me that carbon could be included in that calculation by including a cost of carbon. Let’s use full-cost accounting!  

That price might be set based on the cost of, say, direct air capture of CO2, that is, at some point it becomes cheaper to actually pull the carbon back out of the air. The full-cost metric I am thinking of would include all of the following:

Tentative name: Annualized Decarbonization of Retrofitted Building Cost (ADORB Cost)

ADORB Cost = sum of the following components, each an annual/annualized cost:

  • Direct energy cost. E.g. site kWh * $/kWh = $
  • Direct building retrofit measures cost (material & labor) including building-level electrification cost. E.g. ft3 of stuff * $/ft3 = $
  • Social cost of carbon, upfront/embodied. CO2e kg * $/kg = $
  • Social cost of carbon, operating. CO2e kg * $/kg = $
  • Energy system transition cost (e.g. new utility solar + storage). $/MWh * MWh = $

The idea would be that a baseline cost in this sense is calculated for the scenario of continuing to operate and maintain the building as is for some decades. Any proposed retrofit should at least have a lower cost than that, hopefully much lower. Basically one designs as if there’s a carbon price. (In a baseline case I calculated for my apartment, 70 percent of it was the carbon cost of continuing to operate the gas furnace and water heater, even after the grid electricity was completely decarbonized).

This seems useful, but there are a few issues with it, therefore it can’t be our only lens. 

Issue 1 

It would not prohibit supply chain emissions from the retrofit work. Arguably the ideal is, call it Absolute Zero: No CO2 emissions occur anywhere in the building delivery/retrofit process, supply chain, or the building operating life, at any time. We need to decarbonize everything — the whole economy. In this view, the policy stance is that any carbon capture tech is devoted to removing carbon previously emitted, not keeping up with new work.  

All the current net-zero and carbon-neutral programs have this limitation. We can’t really do everything without emissions yet, so in order to convince ourselves we are zero there all these offsets and avoided-carbon credit schemes. I’m starting to agree with the youth climate activists that this is weaselly.  

Issue 2

At the system level, it’s tricky to use cost to decide grid-versus-building investment, because those costs in turn depend on which approach we decide to scale up in the first place. Commit to industrialized retrofit construction and those costs can come down. Commit to scaling renewable generation and transmission and those costs can come down.  

Issue 3

It’s not clear how to make this full-cost metric take into account that some things just can’t happen fast enough. For example, renewable generation and even transmission may not cost that much, but siting the required high-power transmission lines from remote western wind and solar farms to eastern cities might take too long.  

Issue 4

We’ve gotten into trouble across the board lately with our global economy by trying to minimize cost without regard to resilience. It’s more resilient to do extra things to reduce building loads rather than putting the ball in the grid’s court to both decarbonize AND stay up.  

McKeesport RetrofitTherefore, I am thinking that our new REVIVE Pilot program for building retrofit needs a number of different frameworks. I have listed them below along with a few possible elements of each:

Land use

  • Retrofit, replace/redevelop, or raze/rewild?
  • FEMA hazard assessment
  • Emerging climate hazard assessment (e.g. derecho, wildfire smoke)

Decarbonization

  • Cease direct emissions.
  • Use and generate renewable energy (reconsider off-site renewables framework).
  • Re-use high-embodied carbon structure.
  • Calculate a carbon score (no criterion, just how low can you get, i.e. without offsets).

Cost/Financial/Equity

  • Calculate ADORB cost, goal to at least beat the existing condition.
  • Use load reduction, grid interactivity and storage to financial advantage.
  • Limit the cost burden on low-income people.
  • Look to make policy cases for feebates, incentives.

Resilience 

  • Design for outages and known/emerging hazards.
  • On-site/local power, microgrids, on-site/local repair parts
  • Design for low loads.

Quality and Health

  • Assess existing deficiencies (EPA indoor air quality risk list).
  • Audits: tests, energy models?
  • Commissioning & documenting that goals are met (e.g. ASHRAE 202)

Phase planning

  • Scope includes operations, not just design.
  • Plan covers both an end state and interim retrofit phases.
  • Try to cover critical loads in the first phase.

I will have a bit more to say about this at PhiusCon 2021 this October 12-15 in Tarrytown, New York. The REVIVE Pilot program is in pilot phase, looking for sample projects, and the goal is to have an on-ramp in place. The general development strategy is to evolve from informational guidance to hard requirements in an orderly way, preferably without much backtracking.  

Our existing Phius Certification program for retrofit projects remains available through the Phius CORE REVIVE 2021 and Phius ZERO REVIVE 2021 programs, outlined in Section 3 of the Phius Certification Guidebook.

Regards,

Graham

Breakthrough Project Aims to Bring Flood of Zero-Energy Housing to Milwaukee

 

 

Shilpa 12Shilpa Sankaran is a consultant driving adoption of innovations in the built environment and the health of the planet, societies, and people. She is currently an advisor to the City of Milwaukee, who is spearheading a breakthrough public-private partnership in offsite affordable, zero-energy housing production. Previously, Shilpa was the Executive Director of the Net Zero Energy Coalition, co-founder of the REALIZE prefabricated zero energy retrofit model, and co-founder of ZETA Communities, a modular zero energy buildings fabricator in Sacramento.

In the wake of a global crisis, a cocktail of pandemic, economic distress, political turmoil, and heightened awareness of social inequity, we sit in the still point of opportunity for change.

Cue the City of Milwaukee. This city has seen its share of change — including economic and social trauma from the depletion of its manufacturing culture — and it has shown amazing resilience through grit and innovation. Now, we see revitalized and thriving new neighborhoods, innovation in water and sustainability, and new industries popping up throughout the city.

MilwaukeeMilwaukee, led by Mayor Tom Barrett and the City’s Environmental Collaboration Office (ECO), is spearheading a project that could bring back the original spirit of the city, and serve as a model for other cities around the country. The City is seeking a partner to locate a factory that will build zero-energy housing as part of public-private social enterprise.

On the surface, this may sound like just another construction solution, but Milwaukee sees it as so much more. This one solution will create income opportunities and green skills development for the residents of one of the most economically depressed areas in the country. These very residents will also have new home ownership opportunities, and will be able to proudly support their own health and the health of the planet with zero energy homes. Local manufacturing will take place in this same area — the 30th Street corridor — restoring a culture of industry, while revitalizing the neighborhood.

The goal is to target Phius Certification for all buildings, which requires certification under EPA ENERGY STAR, DOE Zero Energy Ready Homes and EPA Indoor airPLUS as co-requisite programs.

To attract an aligned partner, the City of Milwaukee is deeply committed to lowering barriers to entry and supporting the long-term success of a factory partner with financial, training, pipeline, and policy and codes support.

The first step is garnering industry interest through a Request for Information (RFI) which is due on July 12th. Later this summer, a Request For Proposal (RFP) will be issued, and the hope is to secure a partnership by the end of 2021 or early 2022. Following the design and construction of demonstration unit(s), the goal is to open the factory for full production by 2023.

If you are interested in participating in this process, please submit your Intent to Respond, and respond to the short RFI by July 12th. The RFI can be found here.

Guest Post: Ben Newell on Zero Energy Residential Optimization Software

This is Ben Newell from Equinox Built Environment Engineering (www.buildequinox.com) writing a guest blog post about our ZEROs (Zero Energy Residential Optimization software) program now linked through the PHIUS Design Tools page. We are excited to offer this new design tool to the passive house community!

 ZEROs is an easy to use web-based energy prediction modeling program, but much more! Those experienced in designing and constructing super-performing buildings know that minimizing energy is not the sole factor in design decisions. Other considerations such as minimizing costs and maximizing health are just as important, if not more so. These design parameters are incorporated into the ZEROs model, giving you more control.

The goal of ZEROs was to develop a design tool that is very powerful and complex behind the computer screen, but with a simple interface that is easy to operate and very user friendly. We think we’ve accomplished that and plan to offer many tutorials that will help guide users in their own designs. Our centerpiece, Equinox House, was designed using ZEROs and the hundreds of thousands of data points we’ve collected since its completion validate the results. More about the design and construction of the net zero energy Equinox House can be found at http://buildequinox.com/projects/equinox-house/.

Equinox House, Urbana, IL

Modeling of both new and retrofit construction is possible. Main input parameters for the building envelope consist of the location, base house cost, wall, roof, and floor sizes, R values, and costs. The ground heat transfer is also included, an important factor dependent on the location. After defining the envelope, window parameters are entered for each side of the house consisting of area, U value, SHGC, and cost.

When the shell has been defined, characteristics of the building systems, energy, and comfort are selected. These relate to the efficiency of the conditioning systems, base load appliance energy, and the number of occupants, comfort set points, and fresh air ventilation. A solar module allows one to define a solar pv system to achieve net zero with the house design entered.

Once the parameters have been fully defined, running the model will produce a set of results which are broken down into five categories; costs, air quality, thermal loads, latent loads, and electric loads. One unique feature of ZEROs is its ability to predict air quality levels. This considers the use of ventilation and energy recovery equipment, including our soon to be released CERV (Conditioning Energy Recovery Ventilator). Another feature is breaking out the latent or moisture loads, which are extremely important in super houses, but often not handled in modeling software.

A validated energy model is important in designing a house, but as important is the validation of the constructed building’s performance. Blower door tests can point to construction flaws, but they don’t tell anything about the air quality and systems operation. In conjunction with ZEROs, our Black Box IAQ test (http://buildequinox.com/assessment/blackbox/) records data related to Indoor Air Quality. This test assures that when habited, a building is providing a healthy environment for its inhabitants.

Follow the ZEROs link to try a fully functioning free version of the software. The subscription version is also available, which allows you to save different project cases and generate reports with the data as well as go into more depth with the parameters for windows and temperature and humidity set points. We hope you will find ZEROs to be useful and easy to use and in the end result in many more high performance, healthy, net zero energy residences across the country.