Net-Zero Energy Districts and the Grid: An Energy-Economic Feasibility Case-Study of the National Western Center in Denver, CO, USA

Benjamin A Saarloos,Jason C Quinn

doi:10.3390/buildings11120638

Abstract

Given the enormous impact of buildings on energy consumption, it is important to continue the development of net-zero energy districts. Opportunities exist for energy efficiency and renewable energy on a district level that may not be feasible in individual buildings. Due to the intermittent nature of many renewable energy sources, net-zero energy districts are dependent on the energy grid. The novelty of this work is to quantify and optimize the economic cost and grid independence of a net-zero energy district using the National Western Center (NWC) in Denver, CO, USA as a case study. The NWC is a 100+ ha campus undergoing a major redevelopment process with a planned 170,000 m2 of total building space, an emphasis on sustainability, and a net-zero energy goal. Campus plans, building energy models, and renewable energy performance models of on-site solar, biomass, and thermal renewable energy sources are analyzed in multiple energy scenarios to achieve net-zero energy with and without on-site energy storage. Levelized cost of energy (LCOE) is optimized as a function of variables defining the energy and economic relationship with the grid. Discussion herein addresses trade-offs between net-zero energy scenarios in terms of energy load, LCOE, storage, and grid dependence.

Highlights

The Levelized cost of energy (LCOE) is calculated with the corresponding technology solutions compared for scenarios successfully achieving net-zero energy
An interesting opportunity for renewable energy penetration is the development of net-zero energy districts
The work leverages detailed building energy modeling coupled with energy-generation modeling to evaluate the ability for different renewable energy system configurations to meet National Western Center (NWC)’s net-zero energy target, and quantify their economic viability and their level of grid dependence

Summary

Introduction

Sustainable energy building design has been a growing focus in the last couple decades. Design includes performance goals such as net-zero energy, where efficiency gains are implemented such that the balance of the energy needs can be offset by renewable technologies [2]. Zero energy has been expanded to “communities” [3], noting that larger districts provide opportunities for energy efficiency and renewable energy penetration that may not be feasible in individual buildings [1]. Zero energy district design principles have been outlined as a priority of maximizing: (1) building efficiency, (2) solar potential, (3) renewable thermal energy, and (4) load control [1]. While the goals may be consistent, how zero energy strategies play out in terms of technology and design are unique to each district

Methods

Results

Conclusion