Nordintown Blog

Rubbish musings, projects and hackerings from Nordin

Solar PV, Aberdeen and me - Update 3

May 062018

I am currenly holidaying in sunny Gran Canaria and whilst dozing by the pool, I caught sight of a bank of solar panels. "Ah" I thought, I have those.

Its also been a while that I last blogged, so I thought I would kill two birds with one diamond laser and post an update. See graph.


It has been up and down with the generation rate but it has surpassed the conservative expectation that the installer gave me. Quite pleasing. The generation estimate was made against the avg Aberdeen sunlight hours, direction of panels, angles etc and the performance tracks  the avergate sunlight hours/day nicely - below, yellow line.


The sunlight hours highs are May followed by August, which appears odd at first (July being the hottest month) until you realise heat and sunlight are not the same thing. It does make me want to investigate all this talk on micro heat-powered Sterling engines I hear so much about. These are dinky blacker-than-black heat traps that expand and contract gasses to drive turbines that generate UnLiMeD POWER!!@%@45£!

At a 60% to 70% efficancy rating, Sterling engines kick solarpanels and their 20% max efficancy off the ballpark. They are more complicated I am given to understand, however the clever dicks are working on the problem and hope to have something investors can overspeculate on soon [1]. When done, we can call China and ask actual ballparks of them - hurrah.



Project Intro: Research and design of self-organising, algae farming, soft robots

Apr 062017

An amateur home-based project to design and evaluate self-organising, algae farming, soft robots.

This is a project started inpersuit of a personal interest in home-grown complete food sources. The notes below for my project log and project substages will be added ad-hoc.

The project itself will take place in 3 phases: (1) Stable Spirulina cultivation and remote monitoring via a conventional self-built monitoring platform, (2) evaluation and improvement of a self-built remote sensing and actuator 'nodes', tethered and water-bound to distribute aeration, inspection and monitoring; and (3) Migration from central controller-based coordination to autonomous, untethered agent-based methods. Succinct project updates will be made on the Research Gate platform whereas informal project notes will be made on the Author's personal blog (


Phase 1: Stable Spirulina cultivation and remote monitoring via a conventional self-built monitoring platform.

1.1 Preparing the culture medium

Chemical ingredients for the cost-efficient RM6 culture medium [1] (Roof, Kaushik and Prasanna 2006) were obtained via various Amazon and eBay supplier sources. Super single phosphate (SSP) was substituted with an alternative inorganic phosphate source Potassium Phosphate due to SSP sourcing problems. Measures of all fertiliser ingredients were made for a 4l liquid volume within a 4.5l demijohn growth vessel, marked GV1:

  • Potassium phosphate 5g,
  • Sodium nitrate 10g,
  • potassium Chloride 3.92g,
  • magnesium sulphate 0.6g,
  • calcium chloride 1.6g,
  • sodium chloride 2g,
  • sodium bicarbonate 32g.

The stated measures of each ingredient were made within 0.5l of dechlorinated local tap water and added to 3.5l within GV1. Any crystallised ingredients were ground to powder form.


Trip Hazard

Nov 192016


Taken during a lunchtime walk; Garthdee along the river path, sometime over August 2016

As I was out on another lunchtime health work along the River Dee, I tripped over a log. Post-recovery, I saw the log was in fact a rare metallic shrub flowering it's polished topside. Its hard to imagine that in just a few years, this small sturdy fixture - a relative of the common paper-clip weed - will be a mighty 12ft boat anchor.

Wall Moss

Nov 152016


Taken during a lunchtime walk; Deeside, sometime over August 2016

I enjoy seeing things like this. On a wall, up a building, on a dead log - I tend to imagine a time-lapse version of it's progress with the Attenborough-esk fabricated 'plant' soundtrack of wet clicks and crackles.

Mosses are indicators of pollution and generally, they grow only in clean environments. This doesn't mean that the postcode the 'green thing' has found is free of man-made muck, but perhaps implies that a conscript of the local biome has judged the host object as something they can at least work with.

Solar PV, Aberdeen and me - Update 1

Sep 082016

The install consisted of 12 BenQ PM096B00 panels, each equipped with a optimiser unit, all tied to s Solaredge SE3680 4Kw Inverter.  The total installed capacity is rated at 3.96KWp or 8.54 KWac. 

Plugging these stats together with the southern angle, plane elevation and shading factors, the Annual Solar PV Yield was predicted via the MCS method and PVsol simulation to be around 3277Kwh per year. Factoring in panel degradation, energy price inflation and the guaranteed FIT tariff (12.03p/kWhr) and export tariff rates (4.85p/kWhr), I am predicted a return of just under 12k over the next 20 year period. The system cost about £6.5k to install with the 20yr kit warranty. O/c this payback is realised over the long term with both the FIT payments as income and cheaper electric bills.

The predicted and actuals over the past month are below: 

Est. Generation Est FIT, Export income & Savings Actual   
Month kWh % of total Month Quarterly
(Running total)
kWh % of Est
Jan 166 2.83% £20.35   10   -
February   166 5.08% £36.52   187  111%
March 304 9.27% £66.67 £123.54 310  102%
April    367 11.21% £80.68   393  107%
May 440 13.43% £96.65   502  112%
June 432 13.19% £94.87 £395.45 482  110%
July 417 12.71% £91.45 £262 Paid from SSE, est. £133 saved on bill 430  103%
August 381 11.63% £83.66   460   -
September 292 8.90% £64.04 £634    
October* 211 6.43% £46.30 est. £230 due from SSE (tbc)    
November 122 3.71% £26.72      
December 53 1.61% £11.56 £719.47    
YEAR 3277 100.00% £719.47 £719.47    


Happily, so far I have generated more per month than the estimated - an average of 108% infact. This can only be a good thing but I have yet to compete the estimated bill savings against reality, which may eat up the extra 8% gain. Only time will tell. (updated Oct 5, 2016) 

Project Intro: Solar PV, Aberdeen and me

Jan 202016


Around January this year, I invited the chaps from AES Solar round to quote me for the installation of solar panels on the roof.

Up to that point I had received a few quotes from other installers, gripped as I was by the impending cut-off date before the tariff dropped. For those that are not aware, many of those opting to install panels do so not just for the green karma (although the true 'greenness' of solar has yet to be totally proven in my eyes) but also for the financial return.  In a nutshell, anyone installing prior to January 13th 2016 is paid at least 12.04p per kWHr returned back to the national grid - the so-called 'Generation Tariff'. You also get an additional export tariff per kWh you export, which is currently 4.85p.  Those who installed Solar panels earlier received much better tariff rates, but this has be offset against the high costs of install back then.

Now or never

Assuming you managed to find a good installer, January 2016 was a good time for PV install. This was primarily down to two reasons:

  1. Hardware was the cheapest it had been due to manufacturing advances etc, and
  2. Tariffs were then due to sharply drop of a cliff by 80%.

Why the drop? well officially the government reasoned that more efficient and affordable panels meant the top-up paid to consumers to 'go green' need not be so attractive. I have since read that a second reason for dropping the tariff was that the uptake was higher than expected which was costing the government rather too much. Whatever the reason, a post-Jan16 install was not going to be quite as lucrative and so if I was ever going to sink some savings into my house in this way, it really was now or never.

The two quotes I had received over xmas all contained recommendations for panels on both roof planes of my house. The maximum size of domestic installation that the government will support via FIT is 4kW, which would on my total roof space. I have SSE facing and NNW facing roof spaces and whilst the NNW plane would get some light at sun rise and sunset, it did not feel great knowing that for most of any given sunny day, the NNE panel array would receive considerably less light (see seasonal sun plots below).   


Summer prediction (End June)


Winter Position (Late December)

The summer sun will reach the north-facing roof, but it will be late in the day when the sun's intensity is much less. It seemed that getting as much sun coverage facing south during those peak hours was preferred but the problem was a lack of southern roof space. The installers I worked with were very accommodating and allowed me to incorporate a 'house addon' in to the array layout. This would be a temporary structure that will accommodate the remaining panels in the beneficial direction. 


 'Lean to' design to accommodate the extra panels.

To proceed with the design, one panel has to be placed on the wall but I was not particularly put off by this. The structure was built, the panels installed and the whole system commissioned 3 days before the cut off date for the old tariff (phew). I will post an update with the predicted earnings/savings some point soon.