Renewable Energy

Solar PV panel Tracker.

This page has been established to show our route to a more sustainable future. As a business, albeit a small one, we are doing what we can do be more environmentally friendly. We now use environmentally friendly packaging and routinely recycle boxes in which we receive goods.

What we have found to date is that getting a hold of good reliable advice on a number of renewable energy fronts has not been easy and a fair number of sources of information are at best incorrect and in others severely biased in favour of the firm's posting the information. We once read that you should steer well clear of any firm promising COP=3-4 on a GSHP installation - now go and have a look at some sites and you'll see what we mean. We're not sure what it takes to become an accredited installer, we suspect it is more to do with technical ability than any deep understanding of the products being installed or the theory behind them. That is not to say there aren't good installers, we don't doubt there are. A good test we've found is to start asking technical questions.

Since we moved into our property we have progressively improved it particularly from an insulation point of view. We are progressively stripping all the original lath and plaster (generally poor condition anyway) and battening out and using 50mm of Celotex/ Kingspan as a minimum target in the rebuild. The roof was done with 90mm between rafters with a 50mm overlay. The kitchen was done most recently where we installed the first UFH on a 90mm Celotex base and we overlaid the battens c/w 50mm Celotex with another 25mm.

We also replaced the old oil powered single burner Stanley with a more modern LPG condensing modulating boiler.

Solar PV Installation

We have been minded to pursue solar PV, solar hot water and a ground source heat pump (GSHP) options as time and money have allowed. The tracker and panels you see on this page are a stage in this direction and have been in operation now since July 2008 achieving accreditation in May 2009.

We spent sometime looking at a range of options. The house orientation doesn't lend itself to PV panels on the roof and the outbuildings roofs were judged to need a complete rebuild prior to covering them in panels so the decision was made to mount them eslewhere. This left the option of engineering a suitable fixed ground mounted frame or going the tracker route. Ultimately we used a Lorentz device (Lorentz). These aren't cheap given you provide most of the steel work (which needs galvanising). The BP380 panels were sourced from an eBay seller.

These were connected to a pair of Mastervolt Soladin 600, one bought off the eBay panel seller and the other a seperate eBay transaction via a pair of DC isolation swicthes (Santon Switchgear). These again weren't cheap but the problem of sourcing proper DC switches is now easing and there is also this supplier (Kraus & Naimer). We now sell the latter on our shop page (SHOP). These two Soladins are now sold on and we are using one of the eBay sourced SMA SB2500 grid tie inverters. This required the existing 16 panels to be re-wired in series.

MC4 Connector.

We should stress at this point that we are not 'qualified' electricians and we are not recommending any one course of action. That said the installation must be to the appropriate standards which include G83/1 and BS7671.

The output from the recently installed SMA SB2500 goes to an Elster A100C total generation meter supplied by (Universal Meter Services). This guy is great and given there are still some sites telling you that you need to 'hire' a meter for some £75 annually...............

Origianlly this the fed via a length of 2.5mm2 twin and earth to a Moeller 2pole AC isolator switch which I sourced from RS item No. 393-9721 (RS Components) or T3-1-102/I2/SVB from (Scattergood & Johnson) and from here to a secondary consumer unit on a seperate fused spur. This is all as per the 'regulations'.

We contacted Scottish & Southern Energy (our DNO) who I have to say were quite helpful but assumed I had a level of knowledge I didn't, that said once a couple of area's of confusion had been sorted we eventually filled the necessary paperwork out. What seemed like an age later and a couple more phone calls we had a visit from one of their representatives. You'll love this, he had come out to check that the the inverters 'hung' when the incoming supply was lost and had to borrow a meter off me to prove the line was dead!!

Despite having fitted a second Elster A100C as an import/ export meter the man from S&S was adamant we needed a new utility meter so there was then a further delay. Finally in May 2009 we were officially approved despite having been connected since July 2008. It has to be said we were somewhat fortunate in getting accepted as the application paperwork does require the details of the accredited installer. We think this is why the site visit was required. We do not know how 'tolerant' the DNO's will be in future.

Sunny Boy.

We have also acquired (via eBay) a further Soladin 600 and both a Sunny & Windy Boy 2500 (we also have a Mastervolt Mass Sine 24/ 1500W for use off battery banks) in the last 9 months. This Soladin has been sold along with two others we had and which have part financed the buying of another SMA SB2500.

At this point there has to be a reference to Feed-in-Tariif's (FIT's) as these are likely to have a significant impact on take-up of these renewables. The cut-off point for comment on the Government proposal's passed on Oct 15th 2009. Unfortunately we could lose out as our system was accredited prior to Aug 31st 2009 although there have been representations not to penalise 'renewable pioneers'. We're keeping our fingers crossed that we will be incorporated into the new system as it will make a difference between getting £0.09 per unit and £0.36 per unit (currently as of 19th Feb 2010 this hasn't worked in our favour and we are communicating with our local MP, Malcolm Bruce, over this issue).

As I type this bit (02/06/10) we now have a new Government in place and both parties made various pre-election noises about changes to the MCS accreditation and FIT payment system. I suspect that we will need to wait for the emergency budget before anything becomes clearer.

We're gambling this will be the case and have just bought 16 off 'cheap' Chinese panels off another eBay seller along with 16 genuine BP380 panels at a good price. Both Mastervolt and SMA (SMA) provide useful pieces of software to enable you to plan what panels and in what configurations will work. Thus the 16off BP380's connected to the SB2500 in series and the new 32 panels are connected as two parallel sets of 16 using a very temporary arrangement of being lined up against the steading wall until we make a final decision on how to mount them. This is currently on hold pending deliberations over how FIT's will apply.

We may resort to another tracker despite the comments about the expense above? Ah but given we know all the steelwork dimensions for the bits supplied by Lorentz, we can get a 36V 36" actuator from several sources for about £100 and the existing electronics box can be slaved to drive any number of trackers it won't be anywhere near as expensive second time around. The 3m3 of concrete in the base won't be any cheaper though!!

MC4 Connector.

We've decided to be somewhat more electrically professional with this PV set-up and will be connecting all the panels using approved industry standard MC connectors (Multi-Contact) and cabling and have just bought the necessary bits including the tools. .We will be offering these connectors and a cable making service almost immediately so please enquire.

A further consideration for us is that we are establishing things on the west side of the steading and the electrics are on the east side (don't you love Sod's Law?). As a seperate fused spur was required for the solar insallation to start with we laid a 2.5mm2 twin and earth which in hindsight wasn't ever going to be big enough. There are several places where a voltage drop calculator can be found but we use the one at (TLC-Direct Voltage Crop Calculator) , mind we also tend to buy our general electrial bits from them as well.

MC4 Ready Made Cable.

As the proposed system (not allowing for efficiency losses) will be 3.86kW there will be some losses in the cabling, according to the above they recommend 4mm2 cable and predict a loss of 8.61V or 3.7% which is about 1.5off panels worth of electricity!! The calculator at (Doncaster Cables) calculates things the other way around allowing a 3% loss we'd need to use 6mm2 cable and lose 6.2V or about 1off panels worth. One day we'll need to work out the total system losses as these tend to be 'passed over' in some quarters.

In the end we decided on laying some new 6mm2 twin and earth cable to join up with the old incoming mains cable. We'll also need to look at another DC isolation switch which right now are getting very difficult to get a hold of. We are now actually stocking and selling these items.

(This bit to be re-written as of 19/02/10) Having run the system for a year we now know that our existing 1.28kW system has given us approximately 1.45MW in a year. The extra 26 panels should give us a total of 2.36MW giving a total annual production of 3.81MW (we should allow for the existing panels giving 1% less next year in line with predicted output 'run down' with age). Assuming our entire system is accepted into FIT's we should have an annual payment of 3810 x £0.365 = £1390.65 for the units generated.

Last year we exported some 329kW so given the system is expanding let's say our export is pro-rata so we would export some 606kW at £0.05 = £30.30. Thus our total earnings would be 1390.65 £30.30 = £1420.95. Not a bad return.

Once we've seen how the FIT's coming about in April 2010 actually work in practice we'll advance our planning for solar hot water and a GSHP. If you have any questions feel free to contact us.

You're probably wondering why we've made no mention of grants? It's quite simple they are of no benefit to somebody capable of doing the work themselves and who wants to hunt around to get parts at a more competitive price. We'll give you a for instance. We've just got off the phone to one of the above named suppliers of DC disconnect switches who wanted £110 ( VAT and shipping to us) for a 16A/ 500V switch. They'd just supplied the last 10 to a renewable energy supplier who will have their mark-up and be passing it onto you the customer. You'll pay 1/3rd of this from the other supplier.

The biggest issue will be getting the DNO to accept your self-installation!.

We may occasionally have some solar PV panels for sale - you'll need to check our Shop (SHOP) page.

GSHP/ Solar Hot Water Installation

We need to declare at the outset that this is our biggest bug bear currently and one causing us to be most 'critical' of 'experts'. There is some very good information to be had on this subject courtesy of Veissmann (Veismann Renewables), there are others but this gives a good overview as to what is currently achievable.

When we replaced the old oil fired Stanley with the LPG modulating condensing boiler from eco-services (eco-hometec) it was purchased with two thoughts in mind. One was that it was, relatively speaking a 'state of the art' boiler but also that it was capable of running a conventional radiator based system but was also capable of running UFH as well.

The firm that ripped out/ installed the old central heating system (a classic case of bodge upon bodge and work rounds to avoid penetrating 24" walls) were a local one familiar with the construction of circa 1859 farmhouses but they ended up returning to replace 6 radiators for larger ones such were the losses we were experiencing. We ended up replacing the bathroom one ourselves on top of this with one of the old radiators we'd saved. Now we've uprated all the upstairs insulation, done the living room, utility room and now kitchen (the latter c/w UFH) we run the boiler at the 55oC UFH setting. As the radiators are now all 'oversized' they are well able to liberate the required amount of heat.

The problem we're currently having is that of two firms so far approached neither have come back to us with regards to the size of GSHP we require. We've no doubt there may well be good reasons for this but our view is that it 'tests' the actual capability of some of the people in the renewable industry. Call us cynical!

The aim is quite simple in our view. We need a GSHP fitting which is adequately sized for the task. It needs to operate alongside a solar hot water system. It doesn't need to be oversized as we intend keeping the existing LPG boiler and companies such as Veiesmann and IDM (IDM Energy) have controls allowing an existing system to 'top-up' under 'extreme' weather conditions. The only way we can determine how much enery we're currently using is to look at our LPG consumption over a winter period. You would have thought that firms dealing with calculations of all sorts and experience in the industry would have a handle on this - we're not so sure.

In desperation one evening we decided to see how difficult these calculations could actually be. Hang on as there is some simple maths to follow:-

1. Take it that LPG consists of approximately 60% propane and 40% butane.

2. Propane has a calorific value of 13.83 and butane 13.62kWHr/ ltr. Using the above ratio this gives a value of 13.746kWHr/ltr for LPG.

3. The weight of propane is 0.575kg/ ltr and butane is 0.505kg/ltr. Using the same ratio above this gives an LPG weight of 0.547kg/ ltr.

4. By taking information from LPG deliveries our average daily use of LPG through the winter is 15.9ltrs which gives 8.6973kg of LPG a day.

5. 8.6973kg x 13.764kWHr/ kg = 120kWHr of energy per 24hr period.

6. The worst case is some 17.4kg of LPG a day giving a figure of 131KwHr.

Thus we now have some figures to work from;

7. Our boiler runs 24/7 by design, when not a on a selected period drops back to a setback temperature some 7oC below normal. Selected peak periods are about 6hrs of this.

8. We have no precise idea of how much of the daily energy is actually used in this 6hr period but let's say at worst we use 50% of the days consumption during this 6hr period.

9. A worst case 131kWHr would mean 65kWHr would be consumed, which over 6hrs equates to 11kW.

Now that calculation wasn't exactly rocket science was it and it took us less than an evening to put together.


I have to declare at the outset I have a major chip on my shoulder on this subject and it is directed at this countries premier wind turbine manufacturer, Proven Energy.

It is a given fact that the power available from the wind increases with the cube of the wind speed. In simple terms this means you get nearly 100% more power from a 10mph wind than an 8mph one.

Why therefore do Proven supply their devices on short masts? Cost is a factor yes but the long term gains will far outway this. In the case of Proven devices it is not as if you are going to try installing them in an urban environment so there is the ground area to install a taller mast. Turbines need mounting as high as practicable to reduce the effects of turbulence which can lead to accelearted component wear.

I would also caution people to not completely believe the information available at (Wind Speed Tables). The information contained here needs to be tempered with any local geography and the presence of any obstructions.

Considered wisdom has it that you need to place your wind turbine some 30ft higher than any obstruction within 500ft in any direction.

We would strongly suggest consulting your local renewable energy expert after wll we have seen what an unmitigated disaster the B&Q Windsave project turned out to be.

We had an anemometer up for a year in our top field. We lie in the shadow of Suie Hill and have trees to the east and west of us. Our average wind speed at about 40ft was 7.8mph. We are still considering a turbine but there are some logistic difficulties further complicated by the need for everything to be MCS accredited currently (hopefully this will change under the new coalition government). We are happy to mount a quite tall tower, although the sloping ground complicates the erecting somewhat.

After some trawling about the internet I think the device available from (Anemometers UK) is the most suitable one stop package I can find. All you are left with is the problem of mounting a mast in a suitable location at a suitable height!!. Scaffold tube is more than adequate but needs guying appropriately.

Energy Efficient Lighting

As a part of our kitchen overhaul the other half of 'we' decided we wanted recessed ceiling type lighting, personally I had no problem with the two 4ft fluorescents! MR16 or GU10 halogens of any description were a non starter. We then scoured the web for information relating to high wattage LED lamps bearing in mind this was a year ago now (Oct 2008). It soon became obvious that our idea of bright and the industries were clearly some way apart.

We did eventually find 3off devices ranging in price from about £18 for a Brilux 6W LED at about £18-20 (Brilux), through to a Philps 7W at about £40 (Philips)culminating in the best currently at 8W at around $45 available from (Best Hong Kong))

On the conventional lamp replacement front you can now buy a 13W device (Evolux 13W)), we believe this to be the most powerful LED lamp currently available (Nov 2009) claiming the lighting impact of a standard 100W incandescent. It is apparently fitted with a cooling fan which is apparently audible and we have read one observation as to whether the fan would last as long as the LED!

What you can see is that currently going green is a very expensive option. As we type this in the kitchen under a total of 16off 6W, 1off 7W and 2off 8W LED's the lighting levels are certainly adequate and we've grown used to it. There is still more work type lighting yet to go in once the kitchen is finished.

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