ZNE Buildings

In the world of building codes and standards zero net energy (ZNE) design and construction principles don’t get much notice. In fact, it’s so early in the evolution of ZNE buildings that it could be considered a stretch to call ZNE a standard. But this may be rapidly changing if forward looking public sector officials in California and the Northeast have their way.

California has aggressively pursued energy efficiency for decades and its per capita electricity consumption is the lowest in the nation resulting in a savings to residents of more than $56 billion since the 1970s. Although California has long held the top spot in energy efficiency, just this last year - and for the first time - according to the American Council for an Energy-Efficient Economy (ACEEE), their State Energy Efficiency scorecard ranks California in second place behind Massachusetts.

Pushing to advance their respective leadership positions, both state governors, as well as other officials, have embraced zero net energy as a bold and comprehensive strategy. For starters, ZNE supports and expands energy efficiency standards (and building codes). ZNE buildings interact with the electricity grid and are a driving force in making them smarter. They also increase the installation of renewable energy sources and the management of energy to, in and from the building to the grid – intelligent building systems. Tied to this will be the collection, aggregation and analysis of streams of data related to energy load, costs and availability. In the IT world this is know as “big data” and smart buildings will demand similar analytic software, management tools and information dashboards to make the data useful to a new generation of facility managers and building owners. 

The Massachusetts Approach

In 2008 Massachusetts Govenor Deval Patrick directed the creation of a Zero Net Energy Buildings Task Force and charged it with providing recommendations to point the way to universal adoption of ZNE buildings for new residential and commercial construction by 2030. He also asked for a new state standard for its government buildings and at least one state ZNE demonstration project.

Ian Bowles, then-secretary of the Massachusetts Executive Office of Energy and Environmental Affairs reported back, “Over the past year, the Task Force, made up of more than 70 experts in various building and energy related industries, programs, and agencies, has deliberated over hundreds of ideas and proposals. The result is a visionary document that draws on the leading programs around the world, adapting the best ideas to the specific conditions in the Commonwealth.”

Recommendations from Getting to Zero, Final Report of the Massachusetts Zero Net Energy Buildings Task Force “attempt to do what no other state has yet done—establish a comprehensive set of policies, mandates, and programs that can dramatically improve building performance, reduce regulatory and financial barriers, unleash the market for technology and design innovation, and provide the necessary education and training to create a pathway that will lead to the universal adoption of zero net energy buildings and deep energy reduction retrofits throughout Massachusetts.”

Expanding on the work of this Task Force and focusing on public sector buildings the Northeast Energy Efficiency Partnerships issued a “Roadmap to Zero Net Energy Public Buildings” as recommended steps for the Northeast and Mid-Atlantic states.

The report recognized that ZNE buildings “remain, in large part, more of an aspiration than a reality” but goes on to state, “Northeast Energy Efficiency Partnerships (NEEP) believes the road to a full-scale deployment of zero net energy buildings starts with the facilities our states and communities construct. This report was developed in collaboration with a group of regional building energy stakeholders and outlines key steps the public sector can take to facilitate the eventual broad adoption of zero net energy building practices throughout the Northeast and Mid-Atlantic states.

California's Direction

In 2008 the California Public Utility Commission issued its ZNE goals as “Big, Bold Energy Efficiency Strategies” and called for zero net energy construction for all new residential construction by 2020 and for commercial buildings by 2030. 

More recently California Governor Brown’s Executive Order B-18-12 and accompanying Green Building Action Plan puts state government building construction and operations squarely on a new zero net energy (ZNE) standard.

California has had a Green Building Action Plan in place for state buildings since 2004.  This included LEED Silver for new construction over 50,000 sq feet, reducing grid based electricity use, and environmentally preferable purchasing. EO B-12-18 adds many new directives ranging from mandated demand response programs to building commissioning and pursuit of future electric vehicle charging stations and infrastructure.  Most notable among elements of this Executive Order is the ZNE building standard that is charting new territory for state agencies and departments.  ZNE buildings combine an aggressive pursuit of energy efficiency with renewable energy. They require new technology, innovative design and smart energy management systems.  Not to mention training for building professionals in their design, construction and operations. And financing.

What about finances? A number of the directives in the Green Building Action Plan have financial restraint clauses which makes sense in state government’s current challenging fiscal climate. On the other hand, government’s view of buildings as long-term capital investments make energy upgrades a logical strategy for saving money. As Amory Lovins notes, “Energy efficiency is cheaper than fuel”.  So, execution centers on getting upfront funding to catalyze the implementation of efficiency and renewable energy technologies with the payment coming through reduced energy and building operation costs.

While the Action Plan does not mandate any new construction it is designed to integrate in with the state’s ongoing construction and renovation efforts.

Most notably the Action Plan in section 2.1 states that “The State shall identify at least three buildings by January 1, 2013, to pursue Zero Net Energy as pilot projects. These shall include at least one new building to be designed and constructed, one major renovation, and one existing building.”

Statewide commercial and residential building construction and renovations will be guided by energy codes. These are now aligned with the goal of ZNE buildings and Governor Brown is intent on using the state’s building program to lead the adoption of zero net energy building practices in California.

As outlined in an earlier story, “California Launching Zero Net Energy Standard” a roadmap is already in place through the state’s energy and green building standards codes (Title 24 parts 6 & 11) to achieve the 2020 and 2030 ZNE construction targets laid out in the California Energy Commission’s recently issued draft 2011 Integrated Energy Policy Report (IEPR). Current energy code is the 2010 edition of the California Energy Code and the 2013 Energy Code will be published in July. The 2013 Energy Code will reach 70% of the residential ZNE goal, the 2016 Energy Code 85% and the 2019 Energy Code will meet the goal of ZNE. The state will also link CALGreen and the Energy Code so that both are on the same path traveling at the same speed while providing access to successively higher levels of energy efficiency through the Tiers (voluntary reach codes) for local jurisdictions to adopt.

How does EO B-18-12 align and advance these objectives for state buildings? The order sets a target of zero net energy consumption for 50% of the square footage of existing state-owned buildings by 2025 and zero net energy consumption from all new or renovated state buildings beginning design after 2025.

Zero net energy consumption for all new state building construction after 2025 advances the ZNE timetable by five years over the 2030 requirement for general commercial construction in the state.

Independent of voluntary renovations by building owners (which are covered by Title 24), there are no existing or envisioned codes that will require ZNE for existing buildings.  So, this is clearly a major new initiative for the state to undertake.

A Standard in Search of a Definition

As for any standard, an important starting point is a definition. In 2006 the National Renewable Energy Lab (NREL) presented a paper, Zero EnergyBuildings: A Critical Look at the Definition that provided four definitions within which a building could be classified as ZNE:  1) zero net site energy, 2) zero net source energy, 3) zero net energy cost, and 4) zero net energy emissions.  

Too many options?  The NEEP Roadmap offers a practical approach that is insightful to practitioners and government officials alike:  “Previous discussions about “zero net energy buildings” have included spirited debate about what that phrase actually means. Points of discussion range from whether the appropriate measure is zero net site energy or zero net source energy, to the appropriateness of different forms of renewable energy, and whether renewable sources of energy must be building-integrated or at least on the property to “count.” Without dismissing the value of these discussions, NEEP adopts a simple definition – a zero net energy building produces as much energy as it consumes over the course of a year – and directs its focus to the simple premise that the path toward zero net energy begins with (1) significant reductions in as-designed building energy consumption, and (2) building operations that ensure as-designed performance. The near-term focus must be on creating conditions and incentives that promote these two goals. “At this stage in development the zero net energy standard is clearly a work in progress but there is little question that it signals a major shift in building design and construction practices. Based on Massachusetts and California state government commitments to a ZNE building standard there is every reason to continue to watch its evolution.