Municipal Decarbonization Feasibility Study of New Town Hall

About This Project

The green focused Town of Corte Madera leveraged free municipal decarbonization services from the BayREN Zero Net Energy (ZNE) Technical Assistance Program to help achieve its goal to reduce carbon emissions through a feasibility study of zero net energy and zero net carbon (ZNC) building upgrades at its planned new Town Hall. kW Engineering provides technical assistance for the ZNE program and developed Corte Madera’s Zero Net Energy / Carbon Feasibility Study Report which recommends potential building upgrades that would provide long term cost, energy and sustainability benefits to the facility.

After completing the analysis, we proposed the ZNE upgrade scenario as a cost-effective improvement to the current plan. This scenario will achieve site zero net energy for the new town hall, which translates to the total projected site energy use being offset by on-site renewable generation. The ZNE option achieves a 67% reduction in carbon emissions and a 37% reduction in annual energy use compared to the current plan.

The Town plans on making the ZNE recommendation for the Council to approve.

graph decarbonization zero net carbon energy northern california municipal

Zero Net Energy / Carbon Feasibility Study Tasks

For this study, kW Engineering completed the following tasks:

  • architectural drawing review of the new expansion and other site documents,
  • reviewed plans and community input with Town personnel,
  • developed an energy model using EnergyPlus software with OpenStudio to estimate energy consumption, and
  • calculated the potential for on-site clean solar PV generation.

space

Construction Options

We investigated three scenarios, analyzing the energy impacts and associated costs of each. The Town Hall scenarios included:

  • current plan which meets code efficiency requirements, and partial solar PV installation;
  • zero net energy;
  • zero net carbon.

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Building Energy Use Impact

We analyzed the energy impacts of the following Town Hall building components:

  • building envelope,
  • lighting,
  • HVAC and
  • other equipment and controls.

We broke out projected energy use by end use as shown in the following graph to demonstrate the energy savings between the current plan and ZNE and ZNC upgrades. You can see the energy savings as the difference between the light green bars (energy use for current plan) compared to the darker green bars (ZNE and ZNC). The ZNE and ZNC upgrade options results in a 37% and 55% reduction in energy use, respectively, compared to the current plan

zero net carbon decarbonization graph versus zero net energy city hall california

Recommendation

After completing the analysis of each option, we proposed the ZNE scenario as a cost-effective improvement to the current plan to support municipal decarbonization. The proposed ZNE upgrade includes:

  • going all-electric for the new expansion and
  • adding insulation to the existing building.

With these improvements only a fairly small additional amount of solar PV is needed to reach 100% zero net energy and a achieve a 67% reduction in carbon emissions compared to the current plan.

Read more here for additional information on achieving decarbonization goals through zero net energy / carbon and free services available to Bay Area governments.

energyplus energy model solar pv array decarbonization city hall

ZNE GHG Emissions Reduction

67%

ZNE Annual Energy Use Reduction

37%

On-Site Clean Energy Generation

100%

Date

September 2020

Category
Case Studies, Energy Modeling
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