Game Design, Programming and running a one-man games business…

First Solar Payment

Sooo.. at long last I’ve just made the first deposit payment for getting my much-talked-about solar panels installed. This has been at least 5 years in the making. ‘Sheesh’ etc…

This is what I’m getting:

A 2.15kWp system.

10 x MPE 215 PS05 schuco modules. Total area 14.96 square meters installed in 2 rows of 5 at ground level. (roof is unsuitable).

A sunny boy SB2500HF-30 Inverter.

The quote says that it should generate 1845.56 kWh per year. They calculate that if I use all that power (and I will) it will save me £230.70 a year based on 12.5p/unit electricity cost (bound to rise dramatically over the lifetime of the panels). (however my current provider charges 11.52p/unit).

edit: just investigated and in the last year we used 4,134 kwh, so this set of panels is slightly under half my total usage.  I bet that’s because we have an electric cooker…

In addition, the feed in tariff would pay 1,845 * 43.3p = £799.13 a year.

Total income is thus £1,029.82 per year.

Total installation cost is £10,608.

Assume the panels are worthless after 20 years, I’ll earn £21,216 over that, which would be a gain of £11,000. I can see that the performance of the panels will degrade by then, but I strongly suspect energy prices will rise enough to more than compensate. I also can’t see the feed-in tariff being reduced or abolished for existing installs by any government of any color.

Obviously the panels may not generate the described amount. There is some shading in the garden (bah!). And I’m not going to cry into my tea if the output is below maximum.

Interestingly, the cost of the panels+inverter dropped about £1,000 in the last 8 months. Also of interest is that VAT on them is charged at only 5% (although tbh, if the government really want to kickstart a domestic renewables industry that needs to be 0, not 5%).

Fun fun.

No point in me talking about my new game today. People are swooning over E3 videos :D


14 thoughts on First Solar Payment

  1. Interesting figures!

    Their estimates will, of course, be overstated to some degree – and you have to consider that in summer (more power generated) you use less power and in winter (less power generated) you use more – which unbalances the “what I use vs what I sell” formula substantially.

    I’m doubtful that the panels will last 20 years without some maintenance or replacement being needed either? Some friends of mine have had poor experiences with their panels – producing a fraction of their quoted power and failing altogether rather too often.

    For the record, my home/office uses 3200KwH/year – that’s a house with 2 people living in it, one of whom works from home (and no Electric Cooker!!)

    GL with it!!

  2. Very interesting indeed, thanks for sharing the details. Even if it were only slightly better than a break-even proposition it’d be a very interesting option.

    Am I reading those figures right that, if you were in an area with no feed-in tariff, it would take something like 45 years of maximum-output and zero-maintenance-cost to recoup the cost?

  3. Yup, the feed-in-tariff really makes the difference. The problem is, you are paying for the installation and the inverter and the delivery blah blah.

    I suspect a 40 panel setup would have minimal extra labour and inverter costs, and you would start seeing some slight economies of scale. With big industrial farm setups, it’s obviously even more efficient.

    I’m more doing it for the peace of mind + eco thing than the cash benefit, personally.

  4. Yea, I’ve always found the idea of running off solar power to be really cool too, for a variety of reasons.

    It’d be interesting to figure out what kind of values there would need to be in variables like initial-cost, maintenance-cost, scale-of-operation, and energy-use-per-person for solar to work out for general usage, and how much of a change those represent from current values, etc.

    One of my favorite moments in gaming was building tons and tons and tons of orbital solar collectors in Alpha Centauri, and later seeing the part in the epilogue where they were starting to actually build a collector grid around the star. Now that’s some serious power ;)

  5. Am I missing something, or does your math include both savings (from using the power yourself) and income (from selling the same power to the utility)?

  6. The other thing to consider is (though I am not an expert and don’t even live in the UK) my understanding is that the feed-in tariff payment comes to you tax-free. The money you’re spending on electricity and on panel installation is all after-tax money. So to compare apples to apples I think you need to gross up the 799.13 by your tax rate — making this an even better deal. …

  7. > No point in me talking about my new game today. People are swooning over E3 videos

    Honestly, more interested in anything you’re doing than the crap pimped at E3. Especially after seeing the travesty they’re doing to X-COM.

  8. That sounds like great return at 7.36% over 20 years, but to what’s the variance of the output of the panels like, and is there any expectation their efficiency deteriorates over time?

  9. I think it is great you are doing solar panels to get away from the energy companies and use solar energy and all that.

    But this sounds so much like a problem from my finance classes I can’t resist. An annual income of 1,029.82 sounds like a lot but with your initial investment you are only making about 3.5% a year over 20 years after accounting for the time value of money. Most government 20 year bills/bonds will get you a bit more than that and their are plenty of other investments that will get at least 5%/yr.

    Now you are speculating on rapidly increasing energy costs which can easily be true but right now it’s fairly small compared to the tariff. The increase might be offset by lower production than stated and maintenance/replacement.

    Looking forward to new cliffski game announcement!

  10. Hmm Fluke – the 5% stuff ist normally not this save.

    Also it won’t give you power for your lazors when the zombies attack! *

    Also it’s not green. I hear that some “green investments” are promising so much % it’s I can’t hardly believe that.

    * – given an big enough capacitor to store energy at daylight to be able to fend off night crawling zombies at night

  11. so without tarrifs i.e. subsidies they’re not worth it.. hmm like wind farms really (but without the crippling maintenence).

    oh and 20 years, you’d be lucky if they’re still working past 65% capacity by then.

    In the meantime 11k is far too expensive, but I hope that in the future more local power generation is used throughout the UK like the geothermal plant here in southampton

  12. Don’t forget gas prices just went up 19%, electricity up 10%. In the long term, producing your own power has to make more sense.
    And thats BEFORE we completely exhaust north sea gas and oil, and during a recession.

  13. Also the oil price coulnd’t get lowered again by the saudi-arabs on that OPEC meeting recently.

    So the price for the barrell will rise rise rise!

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