Powerit Solutions provided our business with a system that controls our electrical demand very well and they were able to meet our tight delivery requirements at a competitive cost.Doug Smith
Renewable power sources like solar and wind present a challenge for grid operators: balancing intermittent production with power users’ needs. Facilities that produce solar power on-site face a similar challenge. While facilities can draw power from the grid to balance demand that shoots higher than solar production, they’re likely paying more for that power than they need to, which undercuts their solar investment. That’s why, if you’re considering solar, you should also consider a demand management system (DMS).
One advantage of solar power is that production is fairly regular, barring inclement weather and depending on the location (unlike wind, which is highly dependent on weather patterns). For example, you might be able to rely on solar power kicking in at 7 a.m. and dying at 6 p.m. on most days. But there’s some variability within that window, and in some cases the solar power will drop off and the facility will start drawing grid power during the utility’s highest peak period. In short, if your facility has a fairly steady demand level and you add solar, you’ll decrease peak demand, but you’ll probably also introduce some variability.
Solar volatility in action
The following two examples, based on our analyses of data from in-operation facilities, show what happens. In both situations we calculated the load factor by dividing the average kW by the maximum kW over an average 15-minute period—a measure of demand efficiency. In a perfectly optimized energy environment, the load factor would be 1: in every period you’d have the same amount of peak demand, and thus incur the minimum demand charge for the kWh you’re consuming. A high load factor (as close as possible to 1) means that you’re making good use of your billed peak demand and operating with little energy volatility.
At an 8 MW beverage facility in California, energy usage data showed that the volatility of the facility’s demand from the grid increased by 30 to 50 percent after adding a 2 MW solar PV system. The load factor went from 0.79 to 0.63. The facility was drawing less power from the grid, but its demand was more volatile and therefore less efficient. Our analysis indicated that Powerit’s Spara DM™ system could shift potentially 370 kW of demand on peak and 400 kW at midpeak to smooth the demand profile, saving about $127,000 annually.
In a 7 MW frozen-food manufacturing plant in Nevada, a similar analysis, using a proposed solar PV system, found that the load factor would drop from 0.67 to 0.62 after installation. The system would reduce peak demand overall, but solar output would start to fall off while the utility was still charging peak rates. We estimated that with the solar system, Spara could reduce peak demand by 150 kW to 270 kW, depending on the month, resulting in savings of about $21,000 per year.
Demand management optimizes loads
As these examples illustrate, a DMS can ensure maximum benefits from a solar power system by counteracting the volatility that solar introduces. Spara typically improves a facility’s load factor through automated actions such as curtailing noncritical loads, shifting loads, and taking advantage of process buffers. That means even lower energy charges and even less stress on the grid, since a more predictable load means the grid needs less reserve capacity.