I attended a lecture on DP yesterday, and learned some new things that I thought I'd share. If anyone has something to add on this topic, then please post. DR is when you install a generator at its point of use, like perhaps a 20 MW unit at a hospital or hotel. Payback is often as short as 2-4 years. They can sell vars back to the pwr company to decrease the reactive load on the grid. They do this by adjusting the differences between the phases. You can save a whole lot of money by peak shaving. Pwr bought thru the grid has a typical overall efficiency of 35%. DR efficiency can be as high as 80% using combined cycle and heat recovery. Some units installed in remote locations run unattended for as long as 9 months between maintenance visits. In some cases the pwr company will give it to you and install it for free if you sign a load shedding agreement. I know of one business that is collecting 56K per month on a LS agreement on a 4MW unit. They installed a 10MW unit on my former employer's site for free in exchange for a LS agreement.