[RE-wrenches] diesel vs. solar
Does anyone know of an efficient calculator tool to help compare diesel /gas generator to PV + batt + small generator for an off-grid vacation house? Regards, Erika ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] diesel vs. solar
Erika - HOMER (http://www.homerenergy.com/) is a hybrid power system modeling tool for on- or off-grid applications. There is a 2 week free trial period and then it costs $100 for a 6 month software license. I haven't used it yet but have heard good things. - Andrew Truitt Sent from my iPad On Mar 25, 2013, at 7:15 AM, Erika Weliczko er...@repowersolutions.com wrote: Does anyone know of an efficient calculator tool to help compare diesel /gas generator to PV + batt + small generator for an off-grid vacation house? Regards, Erika ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] diesel vs. solar
Also, Windy Dankoff's old spread sheet that I adapted calculates generator run time per week, and Maui SOlar software does a good job of calculating generator hours per year. I've used Homer and found it to be pretty far off from off grid reality. Any off grid application is going to benefit from inverters and batteries to keep the generator from having to run 24/7. Next, adding at least some PV to trickle charge the batteries is often a no brainer. . You definitely don't need as much battery in a hybrid system. Its not just a fuel issue, generator replacement and maintenance, along with more esoteric considerations like noise, and smell, need to be factored in as well. Figuring the ratio of generator run time vs. PV is a bit trickier, but I found you can sneak up on that calculation by starting with the generator, batteries, inverters, and smallish PV, then add more PV incrementally while monitoring gen run time. Real performance numbers always beat computer simulations, especially off grid, where it is often tough to characterize the real life complexity of the loads. There is a point if your baseline 24/7 loads are large enough, a full time generator makes sense, but unless its in Alaska, some PV almost always makes sense as well. Also the loads will determine how much design time to put in before hand. If your looking at a 50kw generator or up, you need to invest in some software and/ or get an off grid design specialist on board. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 3/25/2013 7:37 AM, Andrew Truitt wrote: Erika - HOMER (http://www.homerenergy.com/) is a hybrid power system modeling tool for on- or off-grid applications. There is a 2 week free trial period and then it costs $100 for a 6 month software license. I haven't used it yet but have heard good things. - Andrew Truitt Sent from my iPad On Mar 25, 2013, at 7:15 AM, Erika Weliczko er...@repowersolutions.com mailto:er...@repowersolutions.com wrote: Does anyone know of an efficient calculator tool to help compare diesel /gas generator to PV + batt + small generator for an off-grid vacation house? Regards, Erika ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org mailto:RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org http://www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] diesel vs. solar
To add to Andrew's comments There are legacy versions of Homer developed by NREL that are free but unsupported and updated available at the same website. Good Luck On Mon, Mar 25, 2013 at 7:37 AM, Andrew Truitt atru...@gmail.com wrote: Erika - HOMER (http://www.homerenergy.com/) is a hybrid power system modeling tool for on- or off-grid applications. There is a 2 week free trial period and then it costs $100 for a 6 month software license. I haven't used it yet but have heard good things. - Andrew Truitt Sent from my iPad On Mar 25, 2013, at 7:15 AM, Erika Weliczko er...@repowersolutions.com wrote: Does anyone know of an efficient calculator tool to help compare diesel /gas generator to PV + batt + small generator for an off-grid vacation house? ** ** Regards, Erika ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -- Mac Lewis * Yo solo sé que no sé nada. -Sócrates * ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] diesel vs. solar
+1 for Maui Software. It is really helpful for finding the array-to-battery-to-generator capacity sweet spot. You can also use it to model things like the impact of various generator start/stop triggers. If you have monthly kWh meter readings for the site, you can build a daily average load profile on a month by month basis. (Better yet, monitor the daily load for a few weeks or months in the design season and use this as the basis for your model.) Then you can model system performance over a typical year and see when the generator is expected to run. The equipment library used to be pretty thin—and probably still is—but you can add equipment to the database. Or just model performance using similar equipment. When I used the software it didn't have the ability to model an AC coupled system. But for a typical DC coupled system, it will produce a lot of interesting/nerdy charts that will help designers anticipate high level performance trends for a proposed system. On Mar 25, 2013, at 10:18 AM, Ray Walters wrote: Also, Windy Dankoff's old spread sheet that I adapted calculates generator run time per week, and Maui SOlar software does a good job of calculating generator hours per year. I've used Homer and found it to be pretty far off from off grid reality. Any off grid application is going to benefit from inverters and batteries to keep the generator from having to run 24/7. Next, adding at least some PV to trickle charge the batteries is often a no brainer. . You definitely don't need as much battery in a hybrid system. Its not just a fuel issue, generator replacement and maintenance, along with more esoteric considerations like noise, and smell, need to be factored in as well. Figuring the ratio of generator run time vs. PV is a bit trickier, but I found you can sneak up on that calculation by starting with the generator, batteries, inverters, and smallish PV, then add more PV incrementally while monitoring gen run time. Real performance numbers always beat computer simulations, especially off grid, where it is often tough to characterize the real life complexity of the loads. There is a point if your baseline 24/7 loads are large enough, a full time generator makes sense, but unless its in Alaska, some PV almost always makes sense as well. Also the loads will determine how much design time to put in before hand. If your looking at a 50kw generator or up, you need to invest in some software and/ or get an off grid design specialist on board. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 3/25/2013 7:37 AM, Andrew Truitt wrote: Erika - HOMER (http://www.homerenergy.com/) is a hybrid power system modeling tool for on- or off-grid applications. There is a 2 week free trial period and then it costs $100 for a 6 month software license. I haven't used it yet but have heard good things. - Andrew Truitt Sent from my iPad On Mar 25, 2013, at 7:15 AM, Erika Weliczko er...@repowersolutions.com wrote: Does anyone know of an efficient calculator tool to help compare diesel /gas generator to PV + batt + small generator for an off-grid vacation house? Regards, Erika ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List
Re: [RE-wrenches] diesel vs. solar
I totally agree with Ray. Generator scheduled maintenance is a huge issue that I have not seen quantified monatarily. The dire de-rate factors from every piece of software and every spreadsheet we've tried seriously underestimate actually off grid system performance we measure in the bush -- that's the correct direction to be off on the calcs, but still. Same with generator de-rates for altitude. They de-rate the performance of the engine, but not the electrical output. Some engines deal with it far better than others. And Dan Fink, Executive Director; Otherpower Buckville Energy Consulting Buckville Publications LLC NABCEP / IREC accredited Continuing Education Providers 970.672.4342 On Mon, Mar 25, 2013 at 9:18 AM, Ray Walters r...@solarray.com wrote: Also, Windy Dankoff's old spread sheet that I adapted calculates generator run time per week, and Maui SOlar software does a good job of calculating generator hours per year. I've used Homer and found it to be pretty far off from off grid reality. Any off grid application is going to benefit from inverters and batteries to keep the generator from having to run 24/7. Next, adding at least some PV to trickle charge the batteries is often a no brainer. . You definitely don't need as much battery in a hybrid system. Its not just a fuel issue, generator replacement and maintenance, along with more esoteric considerations like noise, and smell, need to be factored in as well. Figuring the ratio of generator run time vs. PV is a bit trickier, but I found you can sneak up on that calculation by starting with the generator, batteries, inverters, and smallish PV, then add more PV incrementally while monitoring gen run time. Real performance numbers always beat computer simulations, especially off grid, where it is often tough to characterize the real life complexity of the loads. There is a point if your baseline 24/7 loads are large enough, a full time generator makes sense, but unless its in Alaska, some PV almost always makes sense as well. Also the loads will determine how much design time to put in before hand. If your looking at a 50kw generator or up, you need to invest in some software and/ or get an off grid design specialist on board. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
