Cashflow proposal by solar company - which panel option should I choose?

Hi Everyone,

I'm new to the solar world and this forum. I live in Baltimore, MD and am working with a local solar company to purchase and install solar panels on my roof.  The link below is the cashflow proposal they've provided, with three different options. This proposal was put together without an on-site survey, just via a satellite map.

12 panels
6099 kW consumption/year
No inverter type or brand was specified, so I will have to assume it will be a string inverter

Panels and Cost
Trina 260, 3.12 kW - $9,048
Suniva 275, 3.30 kW - $11,550
SunPower 327, 3.92 kW - $15,304

Proposal link:

I'm open to thoughts:
  • on this proposal in general
  • panel quality
  • costs
  • ROI
At face value, Trina appears to have the best rate of return. However, I know Trina is a Chinese panel and don't know if quality or long-term effectiveness (and warranty) will be an issue.



  • BB.BB. Super Moderators, Administrators Posts: 33,317 admin
    What is the cost of electric power from your utility? What is their Net Metering rate plan?

    In major cities, presently the 1 year net metering plans with low monthly minimum fees can make solar pretty cost effective.

    However, in rural areas and new with some major utilities they are reducing the amount of solar subsidies (raising minimum monthly billing from $4 per month to $10 per month and some places $48 to even a possible $96 per month). Also, instead of "crediting" you retail power rates ($0.12 to $0.30+ per kWH) to wholesale power rates ($0.06 or less for actual generated power costs). It all depends. This is a highly political issue and things are changing.

    In general, if you have not done any major conservation measures yet for your home (insulation, double pane windows, more insulation, energy star appliances, LED lighting, possible HVAC upgrades)--I would suggest conservation first. It is usually cheaper to conserve power than to buy or generate your own power.

    Also note that the Federal Tax credit ends soon (unless extended). When the system is turned on, and how much credit you can use (if you cannot use the full credit the first year, and the credit is not extended, the balance may be lost).

    Do not look at the solar power system adding value to your home--It may for some buyers, and others it may reduce the value of the home. In any case, at best the solar power system has a declining value over time. If you do not plan on living/owning the home for 10+ years--You may want to rethink solar (also, you may have to replace the roof if getting old, before installing panels).

    Don't get me wrong--GT solar can make economic sense--But you have to understand the utility billing plan to see if it is right for you (time of use billing is required in California--In some cases, TOU rates can increase your utility bill rather than reduce it. Be careful.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Hepcat65000Hepcat65000 Registered Users Posts: 2
    Hi Bill,

    Thanks for your feedback.  The cost of electricity from Baltimore Gas and Electric is $.094 c/kWh.  Add in the cost of delivery and you get the $.14 used in the proposal.

    BGE has details about their Net Metering Rate Plan here. I will get SREC annually in April - you can see those estimates in the proposal as well.

    "If the energy generated by the customer-generator exceeds the energy supplied by the utility during the month, the customer-generator shall be required to pay only the customer charges for that billing month, as required by the Rate Schedule under which the customer-generator is receiving service. The utility will carry forward a negative kilowatt-hour reading for a period not to exceed 12 months and that ends annually with the April bill. The utility will pay each eligible customer-generator for the dollar value of any accrued net excess generation remaining at the end of the previous 12 month period ending with the billing cycle that is complete immediately prior to the end of April."

    I've attached the proposal as a file, in addition to the dropbox link above.

    Based on my calculations I should go with either Trina or SunPower modules.

    Thoughts on the specific modules?


  • BB.BB. Super Moderators, Administrators Posts: 33,317 admin
    The estimates look reasonable (I am not in the solar business).

    If you use around 600 kWH per month (around 600-1,000 kWH per month is national average, depending on where you live, have natural gas/air conditioning/etc.)--That is not too bad. You may be able to cut that by 1/2 (if you have never done much conservation efforts before). If the house is newer with lots of insulation, weather stripping, double pane windows, and non-electric heating/hot water--Then you may have less you can do to conserve.

    Energy usage is a highly personal set of

    Picking a brand--I won't suggest anything (I picked BP Solar--Large well funded company with years of experience--My first panels lasted about 6 years and were 100% replaced--And shortly thereafter, BP shut down their solar subsidiary--Although, I think BP is still supporting their warranty).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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