The Food Service Challenge: Zero Net Energy Projects & The Often Overlooked Commercial Kitchen

Richard Young, Director of Education

Zero Net richardEnergy (ZNE) is the hot new buzz word in residential and commercial building. Generally defined, a ZNE building generates as much energy onsite as it consumes. In California, the concept of ZNE is more than just a cool idea, it’s the law. All new residential buildings must be ZNE by 2020 and all new commercial construction must follow suit by 2030. That’s a big challenge: we have less than 15 years to figure out how to radically change the way commercial buildings use and generate energy. We will only reach that goal with a mixture of accelerated energy efficiency adoption and a big boom in renewable energy generation. It’s not an impossible task – there are a growing number of ZNE buildings currently under construction and in operation – but it is not going to be easy. Building designers will have a lot more to learn about commercial kitchens before these projects can be successful. Here’s why…

Every commercial building contains some kind of foodservice operation. Larger commercial and institutional buildings, like conference centers and schools, have full-sized commercial kitchens. Hotel buildings may even include multiple kitchens. The challenge for the ZNE design community is that these commercial kitchens are very energy intensive – consuming energy at 5 to 10 times the rate of other commercial spaces. The Energy Use Intensity (EUI) for an average office building is about 90 kBtu/ft²/yr, but the EUI of a commercial kitchen is closer to 800 kBtu/ft²/yr – a great deal more than the 20 to 30 kBtu/ft²/yr threshold that is typically required for a ZNE building. If you are an architect or engineer, here’s an important message for you: The commercial kitchen is an energy gobbling factory hidden inside of your ZNE building that you must address if you want a successful project. (If you are a foodservice consultant, please make giant signs with this message and plant them in the front yards of all your local architects and engineers!)

The challenge for the ZNE design community is that commercial kitchens consume energy at 5 to 10 times the rate of other commercial spaces.

With such an energy hog on premises, why hasn’t the commercial kitchen challenge been addressed yet within green building initiatives like the Leadership in Energy and Environmental Design (LEED) certification program? The sad (but true) answer is that most LEED buildings consider the commercial kitchen an untamable “process load,” ignoring it as an inconvenient, but necessary evil. In fact, most of the time, the foodservice space is an afterthought within the overall building design. Surprise! Too often these otherwise sustainable buildings end up with some pieces of kitchen equipment that operate in the 5 to 10% efficiency range. This strategy might work fine when the building is judged on the basis of an energy model, but it does not fly when the building has to prove its merit based on a zero net energy bill.

There are three standard green building design practices that need to change before commercial kitchens can be successfully integrated within ZNE buildings:

  1. The foodservice consultant needs to be a part of the building design process from the very first charrette so that the kitchen space is not regarded as an “empty box to be filled later.”
  2. The building mechanical and plumbing designers need to work closely with the foodservice consultant to ensure that exhaust systems move the right amount of air and hot water lines are designed for minimum heat loss.
  3. The spec sheet must include only the most efficient kitchen equipment and every available high-efficiency design and control strategy must be incorporated in the kitchen package.

The green building world is on fire with new ideas, better materials, and inspired designers – it’s time to add commercial foodservice energy efficiency to the list of ZNE resources!