Passiv Haus and Net Zero are admirable goals and I believe that we can get there. I'm also suspicious about their applicability for all asset classes in the near- to medium-term. Residential is pretty viable because of limited occupancy time and highly predictable diurnal peaks. Offices are more straight forward, but there's a lot of uncertainty about psf energy consumption due to occupant density, increasing number of electronic devices that are simultaneously getting more efficient, and just plain high consumption that makes the balancing the supply side challenging. Institutional buildings, particularly healthcare, are very challenging due to highly variable occupancy patterns, density, and activities, very high-demand equipment like MRIs, CT scans, high-volume air handling with many sub-zones, etc., and in many cases continuous occupancy without downtime "troughs" to balance out peaks.
I recently toured a 100,000 sqft net zero commercial office building in Boulder CO and it's refreshingly normal in many ways, just exceptionally focused on energy performance and financial return. While its rooftop solar array is par for the course, its building-integrated PV (BIPV) array on its SE facade is the eyebrow-raiser. Starting with its SE exposure, this is because of the site's N/S orientation and abutment to a railway on the east side, so there is better direct exposure there and long-term confidence in its availability. Plus, Boulder typically gets more direct sun in the mornings than afternoons, which are often cloudy, so a SE exposure will yield more watts per day than SW.
What's also really interesting is that the BIPV array is actually more cost effective per watt than its rooftop sibling, despite the poorer watt per square foot generating efficiency of vertical PV vs rooftop. This is because the rooftop PV array is built on top of the roof envelope, meaning its owner pays for a normal roof and then pays for the PV installation. The BIPV is an integral part of the wall assembly and takes the place of exterior cladding, so the owner is not paying for a full envelope and then putting an array on top. The bottom line in all of this is that the array is modeled to produce in excess of the typical annualized office tenant energy consumption and the electrically-based HVAC system (air source heat pumps, heat recovery units, and variable refrigerant flow system with an atypically high number of sub-zones).
The owner includes electricity in tenant rent as a lump sum based on the psf consumption of the standard North American office tenant. If the tenant uses more, they pay for the increment at market rates. If they use less, then the flat rate is recalculated down the following year to the new norm, but they don't get a refund or credit. Considering the PV capacity is sized for the North American office tenant psf average, this means that annualized, the building can meet its tenant electricity needs and the tenant lease electricity charge can go straight to repayment of the PV cost and then become profit once it is paid off. The tenants are paying a reasonable rate for electricity and can budget with greater ease since it is a fixed monthly cost, but they're also incentivized to use less year on year. For the owner, encouraging tenant conservation and providing an exceptionally efficient building will ultimately create a cost advantage for tenants to locate in the building vs competitors, all while generating revenue from the sale of surplus power to the grid through CO's feed in tariff system. It also means that if and when the building is not fully leased, sale of the surplus electricity "budgeted" for the unused space can help offset the shortfall in lease revenue and potentially give the owner some additional financial flexibility to wait and find good tenants. Over time, as the average consumption of NA office tenants drops, the array is still sized to meet that original metric, returning an escalating surplus as feed in tariff revenue long-term.
Anyway, it's an interesting net zero project and exciting to see that it came to fruition without being a "capital P" Pilot Project with government support. The mantra of the project was that it had to make financial sense versus conventional development, had to lease at market rates without reliance on a premium of niche tenancy, and had to restrict itself to "state of the shelf" technologies, so no unproven tech or fingers-crossed assumptions of higher future energy costs or new laws.
Fun fact, the PV panels are the same ones used on the new Apple HQ and have about 17.5% efficiency. While not absolutely top of the line, it's still better efficiency than normal, and the specified Apple HQ panels had the highest build quality and reliability in the world at the time of purchase; no cheapo no-name Chinese panels for them. Furthermore, the PV panels for the net-zero office building are the same panels for the the Apple HQ: that project ordered a considerable surplus of panels to account for damage during transportation, installation, etc., and after retaining a modest replacement reserve, they sold off the balance.
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Last edited by SFUVancouver; Apr 5, 2019 at 6:32 PM.
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Now that the cat's out of the bag, I can confirm it did pass. Granted, it only made it by the skin of its teeth as the swing vote felt it didn't deserve to pass, but didn't want to have to spend time on reviewing it again.
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