Demand Side Management

Demand-side management is used to describe the actions of a utility or utility consultant, beyond the customer's meter, with the objective of altering the end-use of electricity - whether it be to increase demand, decrease it, shift it between high and low peak periods, or manage it when there are intermittent load demands - in the overall interests of reducing utility costs. In other words DSM is the implementation of those measures that help the customers to use electricity more efficiently and in doing so, reduce the customers utility costs.

As energy needs and population continue to grow in our country, and concerns about clean air, energy security and global warming increase, maintaining cost-effective and viable energy efficiency, demand-side management, and demand response plans is of crucial importance to our nation, as well as to utilities, government agencies, and end-use customers.

Reducing energy costs effectively is much more than just “turning off the lights.” Electric Solution has been helping clients reduce their energy costs while making a positive impact on the environment since 1991. Our products and services not only address the financial side through bill auditing and rate analysis, but offers sound, technical engineering solutions through our demand side management programs.

Demand Control Explained

When it comes to electric utility billing on a time of use rate schedule, utility customers are billed not only for the amount of electricity used, but also on the rate at which the electricity is used. On the bill, the utilities refer to the amount of electricity used as “Energy” (kWh) and the rate at which the electricity is used as “Demand” (kW). Electric Solution does not try to lower Energy (unless asked to do so); we concentrate on Demand.

Demand is the highest amount of kWh’s used over a half-hour period (some utilities use a fifteen minute demand period.) Monthly bills are calculated based on the half hour period during the month that had the most kWh’s. So, one bad half-hour (spike) will drive up an entire month’s bill.

Electric Solution lowers electric bills by identifying deferrable loads and controlling them to a pre-set limit using advanced load control and micro-processing technologies and hardware. Those deferrable loads are not typically part of production equipment, but will be other loads such as multiple HVAC units and chillers. By strategically cycling these deferrable loads, or briefly shutting them down for a few minutes, and moving that load to a neighboring 30-minute period, we can maintain the pre-set limit and reduce demand (kW).

This hypothetical demand profile bar graph represents the amount of kWh’s in a given 30-miniute period. Note that it has peaks and valleys, typical of most facilities. Each bar represents a 30 minute demand period.

Utilities assess fees based on the highest peak for the entire month. Electric Solution’s objective is to cut the tops off those peaks and strategically defer that demand to neighboring 30-minute periods.

Let’s look at the same demand profile and identify the excess demand that may be controlled:

Excess demand is shown in red. Electric Solution can clamp the demand at the black line. The excess red demand has to be moved somewhere. Remember, we’re moving this demand by simply cycling deferrable loads such as your HVAC. If we shut down a few HVAC units for a few minutes (not all at the same time), and then bring them back online as soon as the 30 minute demand period has ended, your employees are not going to notice (completely transparent). By strategically shutting down and turning back on multiple units in series, we can prevent the average kW in a given 30-minute period from exceeding the preset limit represented by the black line. When the demand is not as high, we can let those HVAC units run without any cycling.

The new demand profile now looks like this:

Note that the overall amount of electricity used has not changed.   We have simply modified the time at which you use it.  With this new demand profile, the highest average 30-minute demand is much less than it was before.  As a result the Demand Charge on your monthly bill will be significantly less as well.  This process is known as Demand Control and is exactly what Electric Solution does.  When set correctly, your employees will never even know something has changed, but your bottom line will.

The environmental impact of demand control allows more users to be on the same grid during peak hours and therefore eliminates the need for additional power plants in the local community.

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