Achieving Net Zero

"Net Zero" denotes an achievement in energy-efficient building design and construction, and for on-site clean energy generation, that will produce a balance between user consumption and user generation. The concept is simple. Net zero means that the consumer generates as much energy on site as he or she takes from the grid, if not more.

Demand for net zero building is rising, but for many the apparent obstacles to achieving this balance may appear too dissuading. Yet, as the featured case study will demonstrate, by incorporating available project level solutions, net zero can fall within reach on slim budgets, even at a commercial scale.

Starting Out

No matter your geographic location, the first challenge to achieving Net Zero is to reduce current energy consumption as significantly as possible. The minimization of consumption effectively reduces the required amount of generation to achieve the offset balance. And that need is increased if generation is at all limited by factors such as space, budget, and geography or climate. 

Setting out to reduce consumption has gotten easier with time, but the most important factor for a client is retaining a design team (builder, architect and engineer) committed to a common goal. Traditionally, building and design partners who share a Net Zero vision were hard to come by. Consumer demand has alleviated that challenge and builders and design partners are now marketing this capacity and embracing efficiency building practices. They now realize that a growing portion of the market is looking past the short cuts to quick profit and recognize the clients who demand a quality building, looking at a long-term investment and price premiums garnered by efficiency measures. These design teams appreciate the integrity of creating better structures, achieving greater client satisfaction, and eliciting pride in their work. 

Through careful design and attention to specific details, builders and architects can also help projects overcome regionally specific challenges. For example, climate and geography are major challenges in the Northeast. The colder climate places a greater focus on heat retention and optimizing solar gains. The forested geography of the Northeast presents an additional challenge and with it, the need to strike a second balance between landscape preservation and solar maximization. 

Managing Your Costs

Case Study: The Friends School of Portland (Maine) recently completed construction of a net zero facility in Cumberland, Maine, of 15,500 square feet.

As significant as these challenges are, the most daunting obstacle for consumers remains the perceived and actual costs. The costs of passive house construction and net zero need not be significantly greater than standard construction and in some cases the exacting vetting and planning process can in fact reduce costs or reallocate costs in favor of the efficiency measures. 

To be sure, the challenge of financing is real and varies from state-to-state and with each project. However, it is an absolute hindrance to assume achieving net zero and financing the investment can't be achieved until broad, market-based changes begin to take hold.  In fact, states like Vermont have taken the lead and are experiencing great success with new policy initiatives. Much of Vermont's success is due to an engaged utility (Green Mountain Power) and a model efficiency agency known as Efficiency Vermont.

Bill Maclay of Maclay Architects in Waitsfield, Vermont has been building net zero since the 1970s and literally wrote the book on net zero design. In his estimation, Green Mountain Power has realized that the future is not in bulk power plants, but in brokering. As such, the Vermont utility welcomes distributed generation and smart grid evolution. 

For evidence, Maclay points to the utility's solar incentive program. GMP Solar is a net metering program that pays customers who generate solar energy based on the utility's value of the energy plus an additional 5.3 cents per kWh for installations less than 15 kw, and 4.3 cents per kWh for installations larger than 15 kW. Its programs like this that have led to Green Mountain Power asking the state's public utility commission for a rate decrease, which took effect in October.

Despite the significant incentivizing of generation, efficiencies still must be incorporated to achieve net zero. That's where Efficiency Vermont steps in. The agency has numerous programs that assist consumers in reducing consumption and is recognized as a national model. However, what is most impressive is the scale at which the agency demonstrated net zero could be achieved.

In January of this year, Maclay's firm published a net zero feasibility study for Efficiency Vermont that explored the financial feasibility of net zero building. The report ultimately demonstrated, "that net zero and net zero ready buildings are a viable and cost effective investment, as compared to code compliant buildings."

The most compelling scenario analyzed was a mixed-use campus in Hinesburg, Vermont, measuring 300,000 square feet. Compared to code-compliant buildings, the analysis detailed a $3.8 million savings over 30 years within the net zero residential buildings, and a $4.8 million savings over 20 years within the net zero commercial buildings. The analysis factored in financing at current rates for both residential and commercial buildings, and also financed the cost of solar installation. 

This mixed-use scenario also further demonstrates the value of energy efficiency. The required solar energy generation to offset consumption and achieve net zero in a code-compliant campus runs more than twice that required by a net-zero-ready campus. Of course, not all states are Vermont, but solutions exist at the micro level to achieve net zero.

A Case Study from Portland

The Friends School of Portland (Maine) recently completed construction of a net zero facility in Cumberland, Maine, of 15,500 square feet. This facility, a private day school for pre-k through 8th grade, became the first school in Maine, the first commercial project in Maine, and the third school in the nation to achieve Passive House Certification - the highest international energy efficiency standard. These two achievements - net zero and passive-house certification - were accomplished through innovative and replicable project-level solutions.

The first step for the school's building committee was to become educated, particularly regarding pricing. Among the reasons the Friends School marks a compelling case study were the school's relatively short-term existence, its non-profit status, and its related budget constraints. The building committee needed to make informed decisions, but through the course of the project it appeared that a solar electric system would be out of reach. Out of necessity, the school prioritized energy efficiency to keep to a minimum the size and scope of the potential PV (photovoltaic) array required to achieve net zero. 

The building committee partnered with a design team and builder that would optimize efficiencies. For design they worked with Phil Kaplan at Kaplan Thompson Architects. Among the efficiency components his team prioritized in consideration of topographic and geographic challenges were "R" values, fenestration, ventilation, and heat gain. With an efficiency plan and the passive house pre-certification in place, the school now had a clearly defined and minimized target of the solar PV output needed to achieve net zero.

The efficiencies achieved by the design reduced the school's PV need to a 36-kW, 144-panel rooftop array in order to achieve net zero. In need of financing, the building committee began exploring options, ultimately landing on a solution with a partner - OceanView at Falmouth - a senior living community with 278 residences over 80 acres.

OceanView at Falmouth provides a continuum of care for aging Mainers and the guiding principle of their very successful model is sustainability. Residents will tell you it is an amenity as important as any other consideration and the community's commitment to sustainability made it an ideal partner for the school. Ultimately, it was this intergenerational partnership that made net zero achievement possible. But how?

The mechanism that brought young and old together was a power purchase agreement. In the absence of funds or financing, a power purchase agreement is a viable option. The U.S. Environmental Protection Agency defines a Solar Power Purchase Agreement (SPPA) as a financial arrangement in which a third-party developer (OceanView) owns, operates, and maintains the photovoltaic system, and a host customer (the Friends School) agrees to site the system on their roof or elsewhere on its property. The host then purchases the power generated by the system from the developer.

In the agreement between OceanView and the Friends School, OceanView received the tax credits, and via the grid tie-in, the Friends School campus has zero energy costs averaged over the course of a year. As this case study illustrates, a power purchase agreement resolves the cost issue for the host customer by offering no upfront capital cost, predictable energy pricing, no system performance or operating risk, so that projects can be cash-flow positive from day one. Additionally, they have the potential to increase property value.

As this case study shows, the notion that financing is an insurmountable hurdle at the micro level should be dispelled. It requires more work and some creativity, but the solution is achievable and more to the point, so is net zero.