Home vs Public charges: which one cheaper?

Our system is peak 7.3KW. I elected to spend more for better panels (20 panels @ 365W) so our system was a bit higher cost than the typical system. Total was about $25K. 30% Tax Credit from federal and a rebate from CA, and a $1,000 bonus from the electric company, brought the cost down to about $14K. The system has been generating about 1 megawatt per month. It was sized only for the house so charging the car is a bonus.

In these moderate temperatures of April and May we are generating more power than we are using from the grid. Hopefully by the end of the first year we will be near zero balance with the grid which would be ideal. Summer with typical 105F temperatures for a couple of months will be the big test. The solar system has reduced output with high ambient temperatures. The house air conditioning runs 24/7 for about 3 months. However with our son out of school for summer break we won't be driving 25 miles round trip 5 days a week.

Most people, as did we, want to make sure the pay-back period is reasonable; how many years of electricity cost savings will equal the cost of the system. But another factor for me was equally important. I am retired. I moved money from the stock market to pay for the solar system. This means that chunk of money, which hopefully would have included annual stock market gains, will no longer be generating profits which are taxable. Further I worry about identity theft which, in an extreme case, could empty that coffer. The solar system is much more difficult to steal. The money was moved to an asset which does not generate taxable income; rather it generates savings. As electricity rates rise so much the better.

Now add to that the addition of the Clarity and we are way ahead. We drive 100% on electric around town and only use gas on trips out of town which might be every six weeks or so. So the Clarity is not far from 100% free to drive in terms of energy purchase.

We've saved almost $500 in the first quarter of 2018 when compared to the same period in 2017.

Solar isn't for everybody. We live in Redding CA, second sunniest city in the United States. We do not plan to move so don't have to be concerned about the gain or loss of selling the house with solar installed. If you lease a solar system you don't get the federal tax credits and when you sell the house the lease complicates the sale. Still a lease might be beneficial for some who can't afford to lay out cash. Getting a loan is an alternative and often the electricity savings is enough to pay the loan.

For our area I think our system is typical at roughly 7KW.

 

In Canada, they do not allow to connect to the grid and for 10kw panels the total cost is upwards of $40 000/- and thus payback time is too much with tight government regulations. Once tesla wall becomes reasonable, I will think about it. Also n in Canada, we do not have more than 4 to 5 month of good sun light.

Thanks for sharing your thoughts and valuable time.

 

I believe you have PG&E as utility company, it just sucks. My PG&E rate is slightly lower than you at 19.9c/27c now. I just installed solar system. I would suggest you to do the same. I installed a 6.5kw system which should generate 100k kWh per year, cost is $12k after tax credit, and it should pay itself in 6 years at most.

 

10kW? That seems rather large to me, but it might be a factor of Canada's relative location on the planet and therefore lower average insolation.

Where I live (which admittedly has quite favorable plans for PV, but also has notoriously bad weather year-round) I don't think I see many home systems larger than 5kW. In very hot parts of California people might tend toward bigger systems due to the increased cooling loads, but the capacity factor is also much better.

I tend to see quoted total costs for residential systems (panels, inverter, racking, installation labor, electrical, etc) of $3-4 a watt before any government incentives. Last year I payed around US$3.30 installed for my 3.8kW AC (4kW DC) system (which is plenty for all my electric loads).

 

I was just quoted a pre-incentive price of $2.52 per watt for Hanwha Q-Cell panels, grid tied. Post incentive about $1.39/watt. This is in Iowa. 30% federal credit plus half of federal credit as state credit, so 45% credits.

I was quoted for a 10 kw system to replace 100% of my power (on average, more in summer, less in winter), net metering for a given month, with monthly surplus sold at wholesale (about 3.5 cents per kwh). About $25k pre incentive, $14k net after tax credits.

 

That's $2.52/watt fully installed? That's an impressively low price, although I suppose the larger 10kW system does help a bit with economies of scale. US national average is apparently $3.16 currently.

 

In Canada, the sun time is down and thus bigger size is suggested for us 10kw installed cost 4o to $45 000 and thus people do no go for it.

 

In Canada, due to high supply of nuclear power, they do not promote solar installation. Since they do not allow to connect to grid it is useless. I have heard some guy complete installation but not connected to grid over a year and still struggling

 

There are lots of variables, so the range might be a better metric than a typical cost. Also depends on where in the USA the system is being installed, material used, etc. Given the new tariff (thanks, Trump) it's going to cost more. My guess at the range is somewhere between $28k and $33k. The average cost of solar according to several sources is about $3.15/watt. Unfortunately, there's no standard deviation, so it's a little harder to know exactly what that means - therefore the range I've invoked. By the time the 30% Federal ITC is applied, a new installation is somewhere near $22k ± $1500. With that in mind, the payoff period for the system would likely be between 4-7 years. So it's not a decision that's lightly entered into. Add a new EV or PHEV payment to that and you're talking real money. Add a battery or two and the price goes up a little more - but the potential for not having to import electricity is also greater.

I fully expect to see electricity rates in this state at 60¢-70¢/kWh within the next decade. Prices per kWh are already over 50¢/kWh around here during the summer for on-peak use, and the entire state will be moving to TOU rates within the next 5 years. Net metering will be under constant pressure by PoCos as they seek to dismantle the policies. At least here in CA, we were somewhat successful in forcing them to keep the net metering in place (though we had to accept a Net Metering 2.0 that diminished the value of exporting solar energy).

 

This is true, although actually the deal you're getting on grandfathered net metered rates even under NEM2 in California is fairly huge. Thanks to the duck curve, marginal price for bulk energy at the utility scale during cool, sunny spring and fall midday hours are actually negative--that is, your utility is literally getting paid to use more energy because of excess generation, and the more solar is producing the more it costs them.

If you locked in the initial NEM2 time-of-use rates, you are getting paid peak prices for PV excess generation in the afternoon (and with EV-A, part peak for nearly the entire middle of the day), your full peak ends relatively early in the evening, and you've got those rates for either 10 or 20 years (I forget how long the grandfather period is, I think 20). If you built the same system today, peak doesn't even start until 4pm, and that actually much better matches the prices the utility is paying, so you've basically scored a deal under which your utility is actively losing money on your excess generation for the next decade or two.

It makes sense to do this to encourage distributed solar and meet renewable goals--it results in a predictable payback period for the owner and guaranteed economics--but don't think you're getting ripped off with TOU pricing or current NEM2 plans. You're getting a good deal thanks to the CEC's willingness to encourage distributed generation.

In the long term the only thing that really makes sense is either required storage (I wouldn't be surprised if we see that within a decade even on residential systems) and/or a smarter grid in which, for example, EV chargers across the state are smart enough to ramp up during midday periods of excess generation during the day. Some big wind projects currently in the early stages of planning could also work to balance out the evening peak periods in the northern half of the state.

 

The article I linked before (this one) gives price ranges for 6kW and 10kW systems in a number of states, and shows statewide averages for about 20 states, so while it isn't a standard deviation it does give you a pretty solid idea of what you should expect to pay depending on where you live.

An aside, it's funny that these days the racking and labor costs are a bigger fraction of a home PV system than the panels. Sure didn't think I'd see that day so soon if you asked me 20 years ago.

 

I look forward to the day when charge station competition is sufficient to drive down the cost of public stations. Maybe Dieselgate will help: https://www.electrifyamerica.com/