Not so crazy talk: net-zero energy buildings

This article was originally published in the New Hampshire Business Review and can be found here.

By: Tom Burack | August 29, 2018

Or imagine this: You’re a residential landlord, and the net energy usage by your rental units is zero. That’s right. Zero. Imagine this: You own a commercial building, but the net amount of energy that you must purchase to heat and cool and light the building is zero. That’s right. Zero.

You’d think this was crazy talk – except for one thing: This is happening, and it’s even starting to happen here in New Hampshire. And if it can be done here, with our climate, it can be done pretty much everywhere.

In West Lebanon, Twin Pines Housing, a not-for-profit that builds and manages affordable housing for low- and moderate-income households, has broken ground on the Tracy Community Housing Project, a 29-unit net zero energy apartment building that will make all the energy onsite that it needs to operate. This highly energy-efficient building will keep rental rates down and affordable over the long-term.

There’s an ever-growing number of ways to help cut building energy usage and the seemingly ever-increasing costs that go with utility bills, and the National Institute of Building Sciences has cataloged many of these tools and approaches.

With new buildings, it starts with applying design strategies that reduce the demand or need for energy. For example, the Tracy Community building’s envelope will include R40 insulated walls, an R60 roof, sun control and shading devices, and triple-glazed windows, making it easier to maintain a steady indoor temperature year-round.

Zero-energy buildings (ZEBs) also often employ features like natural ventilation to ensure excellent indoor air quality, and water conservation. The Tracy Street building’s design is so efficient that it will only use 10 to 20 percent as much energy as a comparable-sized standard apartment building. Couple this structural skeleton with highly efficient equipment and systems, like high-performance air source heat pumps for heating and cooling, and LED lighting with smart controls, as well as onsite generation of renewable power with rooftop and side panel solar arrays, solar water heating, wind turbines, geothermal energy or even fuel cells, and you have a complete net-zero energy building.

The Tracy Community building will sport over 450 high efficiency solar panels to generate about 180 kilowatts of electricity – enough to meet the needs of all the building’s tenants.

Financial benefits

Initial construction costs for ZEBs can be higher than for traditional buildings, but Bill Maclay, the architect who designed the Tracy building, contends that on a monthly cash flow basis, ZEBs are usually cheaper because they use far less energy to start with and they inexpensively generate for themselves all the actual energy that they need.

The Net Zero Foundation, which is focused on helping to cut the roughly 40 percent of total U.S. energy use that is consumed by buildings, points out that, with ZEBs, the total cost of ownership is lower, the resale price is higher, and the relative value increases compared to traditional buildings as energy costs continue their inexorable upward trajectory.

And those are just some of the financial benefits that come with the better quality of ZEBs, which hold their temperature longer during extended winter power outages, have better indoor air quality, automatically conserve energy and have more reliable energy systems.

Of equal moment, new, on-site battery storage technologies are now commercially available and economically viable, and these can be combined with on-site renewable generating capacity to virtually assure an uninterrupted power supply for several days without the need for a backup propane-, gas-, or diesel-powered electric generator.

ZEBs of the future may increasingly be part of a “distributed” power system in which each building stands on its own by generating all of its own power and balancing its load with on-site battery storage. But, as with the Tracy Community building, it’s likely that for many decades to come most buildings will still be connected to the existing electric power grid, and this is where another important concept that can help cut energy costs comes in – “net metering.”

Simply put, solar panels or other sources of renewable energy on a building are connected to the electric power grid of the local electric utility company and any surplus power generated by the building is transferred onto the grid, so that the building’s total cost of electricity is reduced or offset by the value of the power that it sends to the grid.

While there are unresolved policies in some states around what price a building owner should be paid for the power it sends to the grid, the cost of generating electricity at the building scale can actually be lower than the cost of generation at large, utility-scale power plants, so building owners are likely to see on-site generation as a long-term economic no-brainer even as they continue to pay service charges to help ensure that the overall electrical grid is well-maintained so there’s a stable power supply at the community and regional levels.

Energy performance contracts

Already own a building that’s an energy hog? Don’t despair: Existing buildings can be retrofitted to move toward a ZEB profile, even if they may not be able to become net generators of power.

The growing use of energy performance contracts allows building owners to take advantage of the expertise and capital of energy service companies. Under this business model, to energy service companies study a building’s current energy usage and develop and fund projects that cut energy costs and reduce operations and maintenance expenses and are paid a percentage of the actual savings over a defined time period.

This and other forms of energy performance contracts enable building owners, including state governments, to replace heating systems, upgrade to LED lighting systems, and even install solar panels using someone else’s money if they don’t have other access to capital.

In addition, the state’s electric utility companies have financial incentives and programs to help building owners work with ESCOs and other experts to help reduce their energy demand and costs. So, truly, that concept of net-zero energy buildings may not be so crazy after all.