### Energy Management Systems for Distributed Load Complexity Management
\begin{table}
\begin{tabular}{l l l l} \hline
**System Type** & **Sensor Inputs** & **Devices Controlled** & **Paper** \\ \hline HEMS & Appliance status, renewable energy and energy storage & Schedulable appliances, renewable & [76] \\  & status, electric car battery status & energy storage devices, electric car & \\ \hline HEMS & Occupancy sensor, PIR, camera & Lights, HVAC, security & [77] \\ \hline HEMS & Energy prices, user behavior, renewable status, weather, indoor temperature, occupancy, CO\({}_{2}\) sensor, fuel cost & HVAC & [78] \\ \hline HEMS & User behavior, user feedback, indoor temperature, luminosity, humidity, appliance demand, motion & Savings recommendations, lights, HVAC, appliances, devices & [79] \\  & sensor, camera & & \\ \hline HEMS/BEMS & Energy prices & Heat pump & [80] \\ \hline BEMS & Indoor temperature & Boiler & [81] \\ \hline BEMS & Calendars, computer activity, employee badge & Lights, HVAC & [82] \\  & scanning, Wi-Fi & & \\ \hline \end{tabular}
\end{table} 
Table 2: Examples of sensor-based energy management systems for the distributed load. The next section will explain the current operating mechanism of the DR aggregator, the plethora of information it requires from the distributed load, which may include personally identifiable (PI) data, and the challenges associated with future DR aggregator operations in US electricity markets. The intricate Role of Demand-Response Aggregators in Large-Scale Distributed Load Integration with Safety  
DR plays a strategic role in improving the safety and reliability of power systems from a demand-side management perspective [67]. According to [30; 69], DR can carry out the following:  
* Reduce CO2 emissions;
* Postpone or prevent the construction of new power plants;
* Improve the power system's reliability and security (ramping and reshaping demand [24; 95]). DR is a type of demand-side management [65; 96] and includes market-based DR programs that are available via DR aggregators, which allow the distributed load to access higher profits than utility-based DR programs (see Table 4 for a list of US DR aggregators). These programs are very efficient for energy savings, monetary rewards, grid reliability, and overall market performance [95]. DR loads are increasingly participating in different markets (Table 5), and based on PJM, their main role is that of a capacity resource [97]. The main disadvantage of market-based DR is that although investments in market-based DR are growing (slide 34 in [98]), the total payments are not significantly changing, leading to payment reductions per player over time (diminishing marginal returns). According to a Brattle study [99], \"the nationwide benefits of load flexibility could exceed $15 billion per year by 2030 and are driven by avoided investment in generation capacity, reduced energy costs, geographically-targeted transmission and distribution investment deferral, and the provision of ancillary services\". However, it is important to consider that the implementation of DR comes with some overhead cost (administrative, incentive, and enabling technologies like telemetry, hardware, software, communication systems, etc.). Another study performed by FERC for the California grid estimates the total benefits from DR across the 3 years of 2012-2014 to be slightly over USD 50 million, and the costs are estimated to be slightly over USD 40 million [100]. The same study emphasizes that if the period is extended, the cost-effectiveness would improve for DR due to the fact that some