Infographic: The Commercial Solar Plus Building Energy and Communications Layer Cake

Buildings consume about 40% of global energy[i] and are increasingly interacting with commercial solar systems, energy storage, the utility, and the overall grid. And yet, while the U.S. has 5.6 million commercial buildings, most of these buildings have a two-dimensional relationship to the grid in a multi-dimensional energy world. The reason for this isolation is due to an intricate layer cake of interactive communications and options for energy savings and building control optimizations.

Depending on each building, there are 8 to 12 layers of potential energy optimization between the coordinators and users of electricity. Unfortunately, these layers are not always consistent and clearly delineated. Some companies specialize in one layer, and others specialize in two or more.

While these relationships are complex, the good news is that the various layers provide endless opportunities for solar, storage, and energy efficiency companies to collaborate and maximize value for commercial building owners.

The graphic below is a starting point to understand the intermediaries between the grid and how they can work together. Below the graphic, we explain each layer's role.

-------------------------------------FRONT OF THE METER LAYERS BEGIN---------------------------------

INDEPENDENT SYSTEM OPERATOR (ISO) The ISOs manage the entire grid and are ultimately responsible for making sure ‘supply’ or generation of electricity meets ‘demand’ or loads at every moment. They do not have any control over specific building loads, commercial solar, or onsite energy storage. In our layer cake analogy, the ISO is the cherry on top of the entire layer cake.

UTILITIES or MARKET PARTICIPANTS Regional and regulated utilities ensure that the transmission and distribution lines are working properly and charge people for using electricity. They coordinate with the ISO and can send a signal to demand response providers (see below) to let them know about a grid management need.

DEMAND RESPONSE (DR) PROVIDERS & AGGREGATORS The DR providers accept a signal from the utility and send it to either aggregators or directly to groups of buildings that consume large amounts of electricity. The aggregators organize a significant number of buildings or loads to respond to the DR signals and create the payment infrastructure to control the buildings’ loads.

------------------------------------------FRONT OF THE METER LAYERS END-------------------------------

METERS Utility meters simply inform the customer and the utility about the amount of electricity the building is using. Utilities use both regular meters and smart meters. Smart meters can give minute-by-minute data and enable the utilities to charge based on peak usage or time of use (TOU). Generally, electricity pricing is becoming more dynamic, charging commercial building customers based on many complex factors.

___________________________BEHIND THE METER LAYERS BEGIN______________________

ANALYTICS/MONITORING/SENSORS Some building owners want a more granular understanding of what is happening in their building in real-time. Additional sensors can provide more information.

BUILDING ENERGY MANAGEMENT SYSTEM (BEMS) The BEMS connects to all the major loads in the buildings; advanced BEMS can save energy by automatically turning off the loads in unoccupied buildings.

EFFICIENCY (and financing) Retrofit companies and Energy Service Companies (ESCOs) customize a retrofit of energy-hogging equipment and seal up leaky buildings. Some companies tie their compensation to customer savings.

LOADS/ELECTRICITY-USING EQUIPMENT (and installers/electricians) This layer includes HVAC, lighting, and EV chargers. An electrician installs different types of equipment. The building owner decides what to install based on budget and performance (occasionally considering connectivity to external signals). Extensible Energy flexes building loads by coordinating usage with utility price signals and distributed generation resources, which utilities reward by reducing the building’s demand charges and overall electricity bills.

DISTRIBUTED GENERATION: SOLAR AND ENERGY STORAGE Buildings can generate their own electricity onsite through solar panels or other means and store the excess energy in onsite batteries. Depending on how they are installed and managed, these distributed generation resources can provide resiliency or uncertainty to the grid.

Each of these Behind the Meter (BTM) layers is set up to speak to the step above and below it. There are many companies in the building energy universe in part because of the existence of these specific BTM sub-layers. Different companies specialize and provide accountability in different layers, and even the most vertically integrated companies do not adequately address most of these layers.


Today, building owners and facility managers do not have a one-stop-shop or an end-to-end solution for optimizing their energy usage and reducing utility costs. However, they do have a very innovative ecosystem of companies within each layer. Many of these companies have an understanding of how to work together to achieve both individual building energy cost-reduction goals and the world’s collective decarbonization goals. Each energy solution ingredient may have a different flavor for accomplishing the building’s energy goals, but all layers are equally important.


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