The EcoBlock energy-efficiency retrofit analysis project is designed to occur over two project phases. Phase 1 consists of a research and development effort to identify and evaluate block characteristics and housing type characteristics, at a conceptual level, to support the
preliminary designs of deep energy retrofits at a block scale, as well as an annual energy consumption and peak electrical demand estimate to support the preliminary design activities described in Chapter 3. Phase 1 tested the ability of the project team to estimate household energy consumption using a limited data set of building description information, drawing from real estate Multiple Listing Service (MLS) data, drive-by audits, and online mapping image resources. Through this initial energy modeling process, the team identified target energy-efficiency upgrades, established reduction targets, and developed preliminary block-scale renewable sizing and storage systems. The team then was able to develop a series of EcoBlock retrofit packages into the models at a higher level of capital investment than would typically be cost-effective at a individual household scale.
In Phase 2, the project team will conduct on-site investment-grade building audits and targeted diagnostic testing, and develop site-specific and calibrated investment-grade energy models to validate or refine the assumptions and recommendations developed during Phase 1. During Phase 2, the team also will provide final construction documents and work scopes for the installation of each identified house and block-level upgrade. In addition, the team will further evaluate the scalability of the EcoBlock concept as a cost-effective model to achieve deep energy-efficiency savings and carbon emission reductions within existing residential buildings in California.
Three Tiered Retrofit Scenarios
The City of Oakland is located in California Climatic Data Zone 3 (CZ3) (Figure 2-2), which covers the moderate climatic regions of the San Francisco Bay Area.
Figure 2-2: California Climatic Data Zones
Source: https://engineering.purdue.edu/DLAT/help/cacz.htm
Along with most of the coastal climate zones in California, CZ3 experiences difficult energy-saving payback calculations for many capital-intensive residential energy efficiency retrofits due to moderate space-conditioning loads and by extension relatively low monthly utility bills.
As a result, the team’s analysis methodology did not use the conventional method of removing long payback (i.e., greater than 10 years) upgrades. Instead, all commercially available upgrades for the building envelope, space conditioning equipment, electrical lighting, and major
appliances were included in three separate EcoBlock retrofit scenarios, and the cost-effectiveness of each scenario was analyzed at the block microgrid scale.
Fuel switching from natural gas to all electric is a core component of the EcoBlock building retrofit process. Once converted, the building can access the on-site solar-powered microgrid serving the block and therefore access a better payback calculation for energy-efficiency retrofit investments. This is in contrast to a typical non-upgraded house with its own separate utility budget for the ZIP code EcoBlock location. This typical house would be a 1968-built, 1800 square foot, single-story house with a natural gas central furnace and domestic water heater. Assuming that this hypothetical house had not been upgraded in the past 20 years, it would likely have only six cost-effective energy-efficiency upgrades with less than a 10-year simple payback (Figure 2-3).5
5 This was determined using a full default Home Energy Saver Professional (http://hespro.lbl.gov) session, entering only
Figure 2-3: Typical Cost-Effective Retrofits for a 94608 ZIP Code, Single-Family Detached Home
Source: UC Berkeley
It is important to note that all the capital-intensive retrofits in fall below the cost-effective line, an unfortunate outcome of this moderate climatic region, which often pushes the payback of commercially viable retrofit measures beyond 10 years.6
A core concept of the EcoBlock analysis is to access extended financial payback opportunities through the on-site solar-powered microgrid, thereby enabling deeper energy-efficiency retrofits. With that in mind, our energy modeling analysis for the 27 EcoBlock buildings occurred through the following stages, leading to three scenarios of energy-efficiency retrofit packages:
1. Assemble 27 existing as-built models (electricity and natural gas fuels) 2. Convert as-built models into all-electric baseline models
6 Note that all Home Energy Saver equipment upgrades are calculated using incremental costs that assume that the upgrade is done at the time of equipment replacement.
3. Implement the three scenarios of EcoBlock Energy Efficiency (EE) Retrofit packages on the all-electric baseline models
● Scenario 1e – AC Solar/Storage Microgrid with EE Retrofits:
o Air sealing on building envelope (reduce infiltration by >25 percent) o Upgrade wall cavity insulation to maximum possible (R11 to R21) o Upgrade existing attic or roof insulation by R30 or R15, respectively
o Convert to a high-efficiency heat pump water heater (Sanden n.d.), delivering domestic hot water (DHW) and heating hot water (HHW)
o Replace the existing furnace with a new air handler and HHW coil o Seal the existing heating air distribution ducts
o Install high-efficiency LED lighting fixtures and lamps. Where applicable, use fixtures with integrated ceiling fans
o Install new ENERGY STAR®-rated major appliances
o Install web connect smart thermostats and a home energy monitoring system o Install a smart ventilation system that meets the current California Building
Energy Efficiency Standards (CEC 2016, 55–89) for indoor air quality
● Scenario 2e – DC Solar/Storage/EV Microgrid with EE Retrofits – Includes all Scenario 1e EE upgrades plus:
o Upgrade windows to high-efficiency, double-glazed, argon filled, low-e with wood or vinyl frames
● Scenario 3e – DC Solar/Storage/EV Microgrid with EE Retrofits – Includes all Scenarios 1e EE and 2e EE upgrades, plus:
o Install direct current (DC)-powered major appliances
Each model generated results for annual energy consumption, peak electrical demand, and an annual 8,760 hour kilowatt load profile. The 27 individual model results were then summed into an EcoBlock aggregate load profile.