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grid tie feasibility on small Oklahoma coop

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  • grid tie feasibility on small Oklahoma coop

    Looking for some thoughts on a grid tie system in Oklahoma. The coop did send me an interconnection agreement which basically shows the requirements and fees. its basically a $1m liability policy and an additional fee of $20/month to do net metering. Along with a host of other requirements and a $25 application fee for systems <5kw, or $50 for 5kw-100kw.

    Currently my usage averages about 800kwh/month and we pay about .10/kwh. plus a $30/month customer charge. so we'd pay about $120/month on average.

    I'd plan to do the install myself and could fit about 6-8kw of panels easily on my south facing metal shop roof. And we have plenty of acreage for expansion later if needed. I already have a small <1kw system setup with batteries that I run my small shop with, fridge and lights, etc. It works well and was a fun small project.


    Some of my initial questions to start planning are as follows:

    1. Do we always have to go through the same approval process from the PoCo for interconnection even if we don't plan to export power (i.e. using a zero export capable inverter like a solar edge)? I think the answer is yes but couldn't get a firm answer yet from the engineer. He did tell me that he has customers who connect just certain circuits in their panels to their solar equipment and he doesn't have to require any agreement with them. I would not plan to isolate circuits like this as it is not very practical.

    2. Is it worth the expense? I've seen similar DIY systems costing around $9000 and with tax credits would put it around $6k invested. So about 6 year ROI. assuming electricity costs remain constant. But I know there will be other equipment expenses, maintenance,etc.

    3. How detailed of a plan do they want to see for the application? And is it worth paying for design services on solar web sites like Renvu that offer full permitting plans for a few hundred bucks?

    Any other thoughts are appreciated. I'm looking at solar edge and sunny boy for inverters, and renvu and a couple other sites for panels.

    Thanks!


    .

  • #2
    $50 a month just to be connected is a lot, its about $15 here in IL, non of that is for my net metering.
    I'd probably try to negotiate giving them $20 of generated KWH a month instead of that fee.

    Your first PV system should give you a big leg up on the project. Putting it on a roof is very convenient,
    but the tilt won't be optimum and you may lose most of your winter production to great difficulty in
    clearing snow. A ground mount will allow best tilt for warm weather, then set it near vertical for snow
    months, to minimize the stuff and get better sun. good luck, Bruce Roe

    Comment


    • #3
      At 10-cents p[er Kwh you ill never achieve ROI. Being a Coop exempts them from Net Metering Laws which means the POC is forced by law to pay you retail for power exported. Coops are not under OCC rules and if you look I bet they will only pay you Wholesale for what you export, and you buy at retail. Example tetail you import at 10-cents per Kwh and retails 5-cents for what you export. So at 10-cetns per Kwh and limits on export means you self inflicted and volunteered for a rate hike. In other words generating free power for the POCO to sell at a 100% profit to your neighbors at your expense.
      MSEE, PE

      Comment


      • #4
        This coop does have net metering within the same billing period for <25kw facilities. so they would not pay for anything produced above my demand in a given billing period. I guess they do this on a voluntary basis if they are not required by law. It still seems like its not as beneficial to us than some other states that allow the net metering beyond a single billing period. I need to confirm the additional monthly fees. Also, the rates don't remain constant, they have gone up some since we became customers. I expect they will continue to increase.

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        • #5
          Originally posted by bcroe View Post
          $50 a month just to be connected is a lot, its about $15 here in IL, non of that is for my net metering.
          I'd probably try to negotiate giving them $20 of generated KWH a month instead of that fee.

          Your first PV system should give you a big leg up on the project. Putting it on a roof is very convenient,
          but the tilt won't be optimum and you may lose most of your winter production to great difficulty in
          clearing snow. A ground mount will allow best tilt for warm weather, then set it near vertical for snow
          months, to minimize the stuff and get better sun. good luck, Bruce Roe
          We don't get much snow here and it usually is melting the next day. But for the lower winter sun I expect the steeper angles would be a benefit as well. I will have to talk to them about the fees, I'm not clear if they are in addition or just in place of the customer fees we already pay. If anyone knows different for my PoCo let me know. It is VVEC and KAMO Power in Oklahoma.

          Comment


          • #6
            Originally posted by df0rster View Post
            1. Do we always have to go through the same approval process from the PoCo for interconnection even if we don't plan to export power (i.e. using a zero export capable inverter like a solar edge)?
            In general, yes.
            I think the answer is yes but couldn't get a firm answer yet from the engineer. He did tell me that he has customers who connect just certain circuits in their panels to their solar equipment and he doesn't have to require any agreement with them. I would not plan to isolate circuits like this as it is not very practical.
            Yeah, that's a transfer switch and wouldn't be worth it.
            2. Is it worth the expense?
            Provided they do net metering (and it sounds like they do) then it would likely pay for itself over time. You'd save about $1K a year with an appropriately sized system.
            Any other thoughts are appreciated. I'm looking at solar edge and sunny boy for inverters, and renvu and a couple other sites for panels.
            Both are good options. If you have unobstructed and all-same-angle panels, then SMA is a good option, and their secure power supply gives you some power during blackouts which is nice. If you have any shading, or any differing angles, SE (with optimizers of course) is a good option.

            Comment


            • #7
              Originally posted by jflorey2 View Post
              In general, yes.

              Yeah, that's a transfer switch and wouldn't be worth it.

              Provided they do net metering (and it sounds like they do) then it would likely pay for itself over time. You'd save about $1K a year with an appropriately sized system.

              Both are good options. If you have unobstructed and all-same-angle panels, then SMA is a good option, and their secure power supply gives you some power during blackouts which is nice. If you have any shading, or any differing angles, SE (with optimizers of course) is a good option.
              so with a transfer switch since you physically disconnect from the grid when you are using your solar power, you don't need to have any permits or approvals from the PoCo? That seems like it would be just a potentially dangerous since you have to remember to manually disconnect from the grid at times when you want to use solar.

              As far as SE vs SMA, I was interested in the SE ability to limit power export so that towards the end of a billing cycle if you knew you were going to be giving free electricity to the PoCo (meaning you had enough credit with them to cover the last few days) you could use a zero export option or potentially divert that power to something else like a battery bank or some other load. Not sure if that's possible or not. We don't have any shading issues at all around the shop.

              Comment


              • #8
                Originally posted by Sunking View Post
                At 10-cents p[er Kwh you ill never achieve ROI. Being a Coop exempts them from Net Metering Laws which means the POC is forced by law to pay you retail for power exported. Coops are not under OCC rules and if you look I bet they will only pay you Wholesale for what you export, and you buy at retail. Example tetail you import at 10-cents per Kwh and retails 5-cents for what you export. So at 10-cetns per Kwh and limits on export means you self inflicted and volunteered for a rate hike. In other words generating free power for the POCO to sell at a 100% profit to your neighbors at your expense.
                That's not necessarily true regarding coops. I have a coop (Connexus Energy) and they pay me $0.1289 per kWh year round. Cost to customers is $0.1289 June-Sept and $.0.1189 Oct-May. For 8 of the months they are paying me more than I pay them for electricity. Last month was my first full month with my system turned on and then ended up sending me a check for $269 for over production. Prior to this I was paying $251 a month year round. I've been extremely impressed with Connexus and their speed of approvals and inspections. Approvals came in 2 days and inspection with PTO was within the same week the system was finished.

                Comment


                • #9
                  Originally posted by CodeeCB View Post

                  That's not necessarily true regarding coops. I have a coop (Connexus Energy) and they pay me $0.1289 per kWh year round. Cost to customers is $0.1289 June-Sept and $.0.1189 Oct-May. For 8 of the months they are paying me more than I pay them for electricity. Last month was my first full month with my system turned on and then ended up sending me a check for $269 for over production. Prior to this I was paying $251 a month year round. I've been extremely impressed with Connexus and their speed of approvals and inspections. Approvals came in 2 days and inspection with PTO was within the same week the system was finished.
                  I agree that not all COOP's are the same depending on which state you live in.

                  I get my power from one here in Florida and while I do not have a solar pv system (yet) the paperwork states they will pay me true Net-metering for every kWH I send them.

                  Comment


                  • #10
                    Originally posted by CodeeCB View Post

                    That's not necessarily true regarding coops. I have a coop (Connexus Energy) and they pay me $0.1289 per kWh year round. Cost to customers is $0.1289 June-Sept and $.0.1189 Oct-May. For 8 of the months they are paying me more than I pay them for electricity. Last month was my first full month with my system turned on and then ended up sending me a check for $269 for over production. Prior to this I was paying $251 a month year round. I've been extremely impressed with Connexus and their speed of approvals and inspections. Approvals came in 2 days and inspection with PTO was within the same week the system was finished.

                    Oh wow! What state are you in? Mine basically does net metering month to month only. And I confirmed they add a $10 fee for net metering customers and require a $1m liability policy.

                    I did confirm today that they don't require approval in order to do grid tie as long as we use an inverter that will allow no export of power (posted separately with specific questions regarding that option). So I'd have to do something else with excess production.

                    I'm estimating to do net metering it will add $40/month to my bill with the insurance, so is it even worth that expense plus additional capacity to produce and sell back 400kwh when I only use 800kwh total/month. I could size my system to provide only my daytime usage and avoid the $40/month in fees.
                    Last edited by df0rster; 06-12-2018, 11:39 AM.

                    Comment


                    • #11
                      Originally posted by df0rster View Post
                      As far as SE vs SMA, I was interested in the SE ability to limit power export so that towards the end of a billing cycle if you knew you were going to be giving free electricity to the PoCo (meaning you had enough credit with them to cover the last few days) you could use a zero export option or potentially divert that power to something else like a battery bank or some other load. Not sure if that's possible or not. We don't have any shading issues at all around the shop.
                      Well:

                      1) Why would you need to limit power? There's no penalty for overproducing, and your costs are the same either way. (In fact it's cheaper to overproduce, if that saves you the cost of the current-sense transformers you need to implement the "grid zero" option.)

                      2) There is an option called the StorEdge that can be used with a HV battery. It's relatively new; Butch could probably comment on it better than I could. But it's expensive and you wouldn't make the money back, since it does not increase the energy you are generating.

                      Comment


                      • #12
                        Originally posted by df0rster View Post


                        Oh wow! What state are you in? Mine basically does net metering month to month only. And I confirmed they add a $10 fee for net metering customers and require a $1m liability policy.

                        I did confirm today that they don't require approval in order to do grid tie as long as we use an inverter that will allow no export of power (posted separately with specific questions regarding that option). So I'd have to do something else with excess production.

                        I'm estimating to do net metering it will add $40/month to my bill with the insurance, so is it even worth that expense plus additional capacity to produce and sell back 400kwh when I only use 800kwh total/month. I could size my system to provide only my daytime usage and avoid the $40/month in fees.
                        Connexus Energy is a coop in MN. Seems weird they would require a insurance policy of a certain size for your own property? Is that just meant to be a deterant? One thing I don't know is 15 years from now if the electric rates go up, what happens to the rate they pay me? Would have been a good question to find out when I was signing the interconnect agreement if I had thought of it. I used to be on the budget billing plan where they take my yearly usage and spread it out over equal payments each month of the total but I changed to monthly billing once my system went active

                        Comment


                        • #13
                          Originally posted by CodeeCB View Post

                          Connexus Energy is a coop in MN. Seems weird they would require a insurance policy of a certain size for your own property? Is that just meant to be a deterant? One thing I don't know is 15 years from now if the electric rates go up, what happens to the rate they pay me? Would have been a good question to find out when I was signing the interconnect agreement if I had thought of it. I used to be on the budget billing plan where they take my yearly usage and spread it out over equal payments each month of the total but I changed to monthly billing once my system went active
                          The insurance is just liability in case my system hurts a lineman or some homeowner that gets hurt thinking there is no power on the grid, if my inverter would fail to function properly during a power outage.

                          Sounds like you have a sweet deal for now.

                          Comment


                          • #14
                            Originally posted by jflorey2 View Post
                            Well:

                            1) Why would you need to limit power? There's no penalty for overproducing, and your costs are the same either way. (In fact it's cheaper to overproduce, if that saves you the cost of the current-sense transformers you need to implement the "grid zero" option.)

                            2) There is an option called the StorEdge that can be used with a HV battery. It's relatively new; Butch could probably comment on it better than I could. But it's expensive and you wouldn't make the money back, since it does not increase the energy you are generating.
                            Dont necessarily care if I limit power, I would want to limit export, I just don't want to give it to them for free. They don't credit me for excess fed in over my current billing cycles usage. SO I could possibly feed it to a water heater, batteries, AC for the shop, etc..

                            I will look into the HV battery.

                            Thanks!

                            Comment


                            • #15
                              Originally posted by CodeeCB View Post
                              That's not necessarily true regarding coops.
                              Like I said COOPS are exempt and can do whatever the members want. In th eOP's case they will not even allow them to export. Like any utility, solar i snot needed and they do not want it and Investor owned utilities in states with Net Metering are forced by LAW to mandate export at retail prices.

                              Would you work for free?

                              MSEE, PE

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