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Profile Dave
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Message 100326 - Posted: 17 Aug 2020, 19:45:45 UTC

They haven't really paid for themselves, you've been given money by the government. It may be different in hotter climates, but in the UK solar panels are not a good way of generating power. We should stick to wind and hydro, we get plenty of rain and wind!


For hydro we just don't have the area with sufficient drop to make much difference. As to not being worth it the solar on our roof produces over twice what we use each year and that is with only 2KW there rather than the maximum of 4. If we get a car again at any time it will be an electric so we will be able to charge it using the solar and use more of what we generate so makes a lot of sense. I don't really believe solar farms to be that great an idea but putting as much on roofs as we can seems like a no brainer to me.
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Profile Dave
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Message 100333 - Posted: 18 Aug 2020, 7:02:10 UTC

How on earth is 2kW enough for you? 2kW is the absolute maximum the panels will give you on the equator at midday. In the UK that's never even remotely achieved. 20% (400W) if you're lucky.


Output right now is 1.3KW. It will be up to about 1.7KW at midday. That is enough that except when using vacuum cleaner or one of a few other items everything else is covered during much of the day until about half way through October. I turn freezer up or should that be down to -25C during the day so it gets through most of the night without using any electricity. I think you will find that the panels are rated for UK output.
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Profile Dave
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Message 100335 - Posted: 18 Aug 2020, 19:27:28 UTC - in response to Message 100334.  

Well I had some that were 250W each (pretty standard - folk with 4kW on their roof always have 16 door-sized panels). Never got anything remotely approaching that power. But then I'm in Scotland where the sun is very weak. I'm assuming chances are you're further south.

And I use a constant 2.5kW, and more when the heat pump runs.


We have solar thermal and a wood stove that I can get free (bar the cost of running a chainsaw) wood for so rarely have to use gas for heating. During the day there is fridge and freezer and nothing else except computers most of the time. I am in Cambridge and during June and July our panels peak at 1.9KW at midday.
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Profile Keith Myers
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Message 100339 - Posted: 19 Aug 2020, 1:35:36 UTC
Last modified: 19 Aug 2020, 1:55:26 UTC

If you only manage 2KW, than you don't have enough panels. I sized my system for two BOINC computers and an EV and ended up with a 8.32KW system comprising 32 260W panels. I was even-steven with the power company for two years. The ROI balanced out in six years. Every year after that was positive to the bottom line.

Until I added 3 more BOINC crunchers and the scales tipped the other direction because my consumption now exceeded my generation by 10MWh a year. I was generating 18MWh a year but consuming 30 MWh a year.

Added another 2.9 KW secondary system later but that still was not enough. Would have to triple my generation to balance my consumption.

Dropped back to two crunchers after Seti ended and will be in much better shape this year.

40° N. latitude so a bit more irradiance available for me than you in Scotland. I average around 13,800 kWh a year in production on the primary ground mount array and add another 4000 kWh a year with the secondary roof array on the garage.



The NREL PVWatts Calculator shows for Abeerdeen a 3KW system comprising 9 320W panels which should produce 2,396 kWh a year. That is the same configuration for my secondary garage roof mount array.
https://pvwatts.nrel.gov/pvwatts.php
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Profile Dave
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Message 100340 - Posted: 19 Aug 2020, 5:03:50 UTC - in response to Message 100339.  

If you only manage 2KW, than you don't have enough panels.

Agreed. Looking to get more soon even though they won't get the same rate of feed in tariff as the originals.
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Profile Keith Myers
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Message 100341 - Posted: 19 Aug 2020, 5:33:19 UTC

I have never benefited from any feed in tariff. I have simply reduced my consumption through my generation. Every excess kWh I produce and send to the grid gets subtracted from my consumption every month. I have never been on the positive side of the equation. From what my utility pays for any excess generation over my total yearly consumption is a pittance and not worth considering. Best scenario is to have exactly equal generation offsetting my yearly consumption so the yearly settle up bill is $0.00.
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Profile Dave
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Message 100342 - Posted: 19 Aug 2020, 7:09:25 UTC - in response to Message 100341.  

I have never benefited from any feed in tariff. I have simply reduced my consumption through my generation. Every excess kWh I produce and send to the grid gets subtracted from my consumption every month. I have never been on the positive side of the equation. From what my utility pays for any excess generation over my total yearly consumption is a pittance and not worth considering. Best scenario is to have exactly equal generation offsetting my yearly consumption so the yearly settle up bill is $0.00.

Here in UK, they had a feed in tariff to encourage the industry. This has been steadily reduced and is now not available for new adoptees. I am looking, probably next year to double what we have on the roof connected to the grid bringing it up the the 4KW maximum we are allowed and another 4KW off grid which could run computers and some other stuff but that depends on finances and while it looks like it might be possible now, in the current situation (pun not intended) that could easily change.
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betreger
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Message 100352 - Posted: 19 Aug 2020, 18:57:52 UTC - in response to Message 100349.  

I learned something new today, my day is successful.
Both roofs and rooves are listed as plurals in the Oxford Dictionary of English, 2005 edition.
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Profile Keith Myers
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Message 100364 - Posted: 20 Aug 2020, 19:31:10 UTC - in response to Message 100350.  
Last modified: 20 Aug 2020, 19:41:09 UTC

I have never benefited from any feed in tariff. I have simply reduced my consumption through my generation. Every excess kWh I produce and send to the grid gets subtracted from my consumption every month. I have never been on the positive side of the equation. From what my utility pays for any excess generation over my total yearly consumption is a pittance and not worth considering. Best scenario is to have exactly equal generation offsetting my yearly consumption so the yearly settle up bill is $0.00.


With no feed in tarrif, how did you get any money from it? I tried without a tarrif and just threw away money. Panels are very expensive and take decades to pay for themselves. Maybe if you're in California, but in Scotland no chance, not enough sun!

I have paid for the cost of the system in avoiding 6 years worth of higher utility bills without solar production. That was when the ROI was balanced. Now every kWh I produce directly reduces my consumption and thus my monthly power bill.
I live in Northern California and have around 5kWh/m²/day of solar irradiance.

and for the World.
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Profile Keith Myers
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Message 100365 - Posted: 20 Aug 2020, 20:08:52 UTC

My system payback was actually a lot faster than the original planning document outlined. Payback was in 4 years and 9 months. Paid off in August of 2018. The solar generation credit of 30% of the system value was deducted from my first two years tax bills. Plus I pay a lot more for power than you I suspect. My power tariff has ranged from $0.13 - $0.52 kWh depending on the season since I put the system in.
Generally I knocked about $175 off each month's power bill since installation. My annualized ROI was around 22%.
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Profile Gary Charpentier
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Message 100368 - Posted: 21 Aug 2020, 1:09:29 UTC - in response to Message 100367.  

My system payback was actually a lot faster than the original planning document outlined. Payback was in 4 years and 9 months. Paid off in August of 2018. The solar generation credit of 30% of the system value was deducted from my first two years tax bills. Plus I pay a lot more for power than you I suspect. My power tariff has ranged from $0.13 - $0.52 kWh depending on the season since I put the system in.
Generally I knocked about $175 off each month's power bill since installation. My annualized ROI was around 22%.


Wow, an American paying more than a Brit!? I thought power was cheap everywhere over there. I've also never seen a variable power bill - you pay differently per season? Mine is fixed at about 21 US cents per kWh. Your 13 cents is what I usually hear Americans quoting for all year round.

Is it California I saw in the news getting rolling blackouts during the heatwave? They charge you that much and they still can't invest in enough power stations. Maybe it's all the treehuggingness in that state! California is the one with severe restrictions on car engines? Probably only use green power generation too, which we all know costs a fortune. The UK government throws money at wind farms.

By the way, all my engines are switched into Milkyway gear, and I believe I'm only a few places ahead of you.... yip, 357 to 362. [Beckons cheekily over my shoulder]

Less to do with hugging trees, more to do with not setting them on fire.

https://www.statista.com/statistics/322874/electricity-consumption-from-all-electricity-suppliers-in-the-united-kingdom/
301.76 TWh
https://www.energy.gov/sites/prod/files/2015/05/f22/CA-Energy%20Sector%20Risk%20Profile.pdf
259.5 TWh

Now over there you likely don't have A/C in every home because the summers aren't 30°C at night and 50°C in the day.
https://www.currentresults.com/Weather/California/Places/death-valley-temperatures-by-month-average.php
:)
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