NVEnergy Rate Plan Comparison Utility
I had contemplated solar for a long time and we had already taken the plunge. As part of deciding to move forward with the project I had already put together quite a thorough anaylsis of our historical electricity usage, to better understand the financial implications: I needed to understand what the payback period / ROI could be, what the risk might be (what if electricity rates became cheaper in a few years), and I especially wanted to understand (and quantify) whether I could make a financial case for (or against) adding battery backup to our home.
NVEnergy Rate Plans
NVEnergy, our electricity provider in Nevada, has a number of "rate plans" available -- many of them are available all consumers in addition to a number of specialized plans available to those who meet specific criteria (small businesses, large single-family residences, electric vehicle owners, etc).
In many cases the other rate plans can have significant differences in the price you pay for electricity -- in concrete terms that most often means the price you pay "per kilowatt-hour" (kWh) along with varying standard flat-rate monthly service fees. Some of the plans are 'Time of Use' plans, which means that the price per-kWh varies based on time of the year, the day of the week, and/or the time-of-day; and if often varies dramatically between different times.
Most homes in Southern Nevada have what they call 'smart meters'. These electric meters monitor your electricity usage at any given time, with high-resolution on the time-axis, and that data is then subsequently available directly to the customer -- at similarly-high resolution and usually quite quickly, usually around 2 days of 'latency' or delay between usage & the data being available.
What is a kilowatt-hour?
See kilowatt-hour on Wikipedia -- but here are two fast examples to help understand:
Appliance pulling constant 1,000 watts (~8.33A @ 120V) for 1 hour = 1 kWh Usage.
Appliance pulling constant 500 watts (~4.18A @ 120V) for 1 hour = 0.5 kWh Usage.
NVEnergy Electricity Usage Data / Reporting
NVEnergy allows you to see your electricity usage, broken down into 15-minute intervals, and that data is generally available to you within approximately 2 days, for any given prior day. While it's not instantaneous or zero-latency by any stretch, it's still very high-quality data & it's available to you quite quickly -- and that's really all you need in order to compare rate plans. It just requires you to download the nicely-formatted data and then break out Excel (or your favorite programming language) and run the math!
'Best Rate Guarantee'
I had already been runnning these calculations occasionally, sometimes frequently, even before jumping on the solar bandwagon. NVEnergy offers what they call their "Best Rate Guarantee" -- that means if you switch to one of their non-default rate plans and, after 1 year of being on the new plan you realize that the default plan would have cost you less money, then they will refund the difference and let you switch back.
The only "catch" is that you have to stay on the 'new' plan for 1 year -- it's a guaranteed +EV situation -- you can only save money.
For me, simply switching to the "Time of Use" plan saved ~20%/year -- without changing usage habits.
After a few adjustments to our most power-hungry appliances, most of which were already programmable (thermostats & pool equipment were the primary offenders), we were able to end up saving around 35%/yr -- mind you, this is all BEFORE solar entered the picture!
Will you know if you have the 'best' rate plan?
Does NVEnergy proactively reach out after the first year to let you how much money your rate plan saved (or cost) you, versus your old? Maybe, I'm not sure -- so I wanted to be able to find the answer for myself. I had been running the numbers in Excel; it's not overly difficult, though a bit prone to error, but even after doing it a handful of times and becoming familiar with doing the analysis, it was still a very tedious process and one that was ripe for automation.
What bugs me a bit is that NVenergy surely already has this tooling in-house -- maybe it's old & slow, or perhaps it's written in FORTRAN -- but they obviously have the data, and while I don't know if their CS team can instantly run comparisons or not, they aren't automatically choosing the "best" default for everyone (despite the 'best rate guarantee'). Surely the 'average' electricity customer wasn't spending the time to run the numbers once, much less multiple times.
Rate Plan Calculator / Comparison Tool
One morning I was preparing to download my electricity usage data and run the numbers manually -- but I decided that I would just spend 2X the time and solve the problem once and for all. Plus the added bonus that I could then share the tool so other Nevada residents could run their numbers too, without even having to open the ZIP file that NVEnergy provides the data in, much less having to open Excel and tediously formulate VLOOKUPs to get to the answer.
And the result was...
NVEnergy Rate Plan Calculator/Comparison Utility
Even Better with Solar
After really crunching the numbers -- and thanks to a few random Redditors who validated my math -- I was even able to 'justify' adding several Tesla Powerwalls to my system, too. While their direct value (calculated ROI) is not great, especially compared to solar, and for our specific amount of usage -- the utility value is solid, but that alone wasn't enough for me to be able to pull the trigger. I'm able to give some weight to utility value, but in general I tend to want to see fiscal ROI as well.
By using NVEnergy's "EV Time of Use" plan and our usage patterns and, importantly, our ability to 'load shift' during the daytime, I was able to finagle the numbers such that adding battery backup only extended our ROI timeframe by a couple of years (NVEnergy also provided a larger incentive for energy storage systems if you were on a ToU rate, which helped) -- substantially better than the typical scenario that sees negative financial ROI, which is usually the case any time you have net metering available.
If you have NVEnergy, check out the tool above -- it's free & you really can't lose. For those located elsewhere, hopefully this at least provides some insight on how you may be able to leverage various energy rate plans to assist in making an energy storage system more than just a utility-value purchase!
Rate Tool Output Preview