Electricity Export Regulations

[ukdiyuser]

I'm considering installing a Micro-CHP central heating boiler such as the AC Whispergen, connected to my domestic electricity supply. I won't use all the electricity generated at the time the m-chp boiler generates it, so I will be exporting the excess to the UK grid. Can anybody tell me the current regulations regarding electricity export, and Micro-CHP installation in general? Based on web research, my best guess at the moment is:

- I can install the m-chp boiler for my central heating as long as I use a Corgi installer for all gas work and the remainder of the heating system meets the Part L building regulations.

- I'm allowed to connect it to the grid without requiring authorisation, as long as the equipment conforms to grid connection standard 'G83/1' and I inform my electricity supplier

- There appears to be no requirement for me to have any modified/additional metering installed, so any measurement of electricity export is initially down to my current meter. (This is a traditional electro-mechanical meter which I think will just run backwards when exporting.)

- My supplier may decide to install alternative metering, but if they do then they need to pay for the new meter and the meter installation costs.

By the way, I realise I could get Powergen to handle the whole thing with their Whispergen service, but I'm exploring the DIY route first, not least because I don't want to be tied in to a particular gas/electricity supplier or m-chp boiler.

[Colin Wilson]

I wouldn`t like to say on that one, but I thought it was something like G58 protection. Its not the easiest thing to google for though - i`ve tried !

Specialist metering may well be required, and speaking as someone within the industry, I can tell you for certain that Scottish Power's metering dept. have not come across this type of installation yet, and have no metering capable of handling the export.

This has been the case for at least ~18 months or so from when I first heard about the Whispergen (and the other one, for which I forget its name), before any had been installed in the UK.

I believe United Utilities and one site in the Newcastle area may now have had these installed in an estate as a trial, but it was with specialist metering IIRC.

[meow2222]

Theres always the option of simply 2 meters in series, types that only turn one way, with them facing in opposite directions. One will read import, the other export.

Its unlikely to be what your suplier wil eventually decide on, but since theres no decision meantime this may well be accepted for now, seeing as they have nothing else set up. I would be upfront about offering a metering solution suggestion for use in case they have not yet finanlised their net metering plans. IOW as well as presenting thme with a problem, youre helping them resolve it, this may make life easier.

NT

[Adrian C]

Maybe not relevant, because for this type of application they might be other meters and measuring devices that I don't know about (er, not my field - guv), but I recently did a little web research into the Model Type '5196' electronic meter gizmo the supply company installed under the stairs; mainly to investigate possibilities remote reading of the device via the IEC 1107 optical port - actually covered in an electronics magazine (Elektor) article.

This company, Energy Controls manufactures a range of electronic meters - the single phase kWh Meter, which do detect (for the benefit of fraud protection) and measure energy passed in the export direction. This might be useful to the OP?

[ukdiyuser]

Thanks for the replies.

Apparently G83/1 was introduced in Sept 2003 specifically aimed at small scale generators, ie:

[Colin Wilson]

I spoke to someone else today, and it would appear I am wrong in that very small generation "is" allowed, but that the "export" is not accounted for (due to the expense of metering) other than by offering a small discount based on x number of unit(s) per day.

Its not a well known or understood situation though by any stretch of the imagination.

Generation above that nominal amount is tricky, as you have to weigh the additional cost of specialised metering against the "value" of the export to be made.

[David Hansen]

On 19 Feb 2006 05:46:12 -0800 someone who may be "ukdiyuser" wrote this:-

I can't. However, it may be worth asking on uk.environment as well.

You might also consider the information from Good Energy at

and ask them if they are interested in Micro CHP as part of their scheme. I have no idea whether they are or not.

[Sparks]

Just got the following from Powergen, after requesting some further information...

Thank you for your recent interest in the WhisperGen micro Combined Heat and Power unit (micro CHP) Given the high volume of interest in the WhisperGen we have decided to put all further orders on hold until January 2007. This is so that we can negotiate a mass market production contract with a European manufacturer.

Since 2004 we have produced a relatively small number of hand built units. Recent product developments which improve the WhisperGen's reliability, coupled with an increasing demand have led us to discussions with a major manufacturer. We have listened to our customer's feedback on what they require from the WhisperGen and we have put these developments in place so we can provide you with the best product possible.

We can place your details on file and will be in contact when we are in a position to offer you a mass manufactured model of the WhisperGen, alternately if your needs are more pressing we can provide you with a range of condensing energy efficient boilers, which will save you money and come with a 5 year parts and labour warrantee.

[ukdiyuser]

So much for the Powergen option. I guess that explains why I've had no reply from them as yet to my queries about their Whispergen service. All the more reason to explore the DIY route.

Oh well, at worst, even if I get no compensation for exporting, I calculate I should still be saving around £100 a year on the electricity I can use as I generate it. Plus all the electricity I generate, whether being used directly by me or being exported to my neighbours, is environmentally friendly compared to getting it from a power station.

Interesting idea. I don't think they would regard m-chp as a 'renewable generator' as I'm still burning gas to create the electricity, but it's the next best thing so I'll fire off an email to them.

Time to test the water with my electricity supplier as well.

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[Andrew Gabriel]

Oh dear. That sounds like PR department speak for "sorry, the product was too unreliable and we're currently looking for another manufacturer".

[John Cartmell]

Or "Oops they don't match the new 'lead-free' regs and we need to do a re-design.". There will be a number of such hiccups this year.

[meow2222]

yes, and too noisy and too much maintenance. These are exactly the things one would expect from an engine running in the house for years on end.

NT

[Andy Hall]

Not least of which is that the legislation is a shambles. Again. The government just about managed to achieve an SI on ROHSS for operation from July 1st. but with enough exceptions to drive a bus through. That at least seems to be reasonably harmonised throughout Europe. Activity on the accompanying recycling directive, WEEE, is a total and utter mess with huge variations between countries and HMG running around totally clueless.

[Matt]

It's more a case of WhisperGen having limited production facilities and rather than expand them, and continue to have the huge costs of transportation from New Zealand to Europe impact the selling price of their product, they are, I believe, licensing their design to enable it to be manufactured more locally in the region/area they will be sold.

[Matt]

While the AC version is significantly noisier than a modern boiler, careful siting or enclosure design can make this a non-issue. I've slept within a few feet of a DC version (slightly quieter) on numerous occasions and despite the total lack of added noise insulation its never been a problem (some of the sleep was alcohol assisted though!)

I can only vouch for a couple of units I am immediately aware of (both marine installed DC versions) but maintenance required for around 2500 hours of operation has been very minimal over the past 4 years, certainly way less than any internal combustion generator on a similar duty cycle and probably less than a typical gas fired central heating boiler.

I still think a condensing boiler is a significantly better option for the majority of households though.

[ukdiyuser]

That's a little defeatist isn't it? We're not talking about internal combustion engines here so comparisons with the average car or diesel generator engine are misleading. A number of large companies with a great deal of technology expertise are reportedly investing millions of pounds in developing this technology, so they clearly don't share your view.

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[ukdiyuser]

The UK government certainly seem to be tentative about going all out to support this technology, but they don't appear to be actively blocking it either. Purchase of Micro-CHP boilers is now covered by 5% 'green purchase' VAT, and the G83 grid connection standard now makes it easy to connect small scale generator equipment like this in parallel with the domestic supply. However one thing they've failed to do so far is to provide any regulation for electricity export to the grid.

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[Tony Bryer]

The new Part L Building Regulations and SAP-2005 explicitly cover them too

- I'm still trying to get my head round the equations.

The practical bit of this I don't understand is that someone I know who worked in power generation said a long time ago about needing to get power station generators up to exactly the right speed before connecting them into the grid as if the frequencies weren't matched 'bad things' happened

- I don't remember the details. So is this handled if you are generating your own electricity via Microgen or PV panel and wanting to export it?

[Andrew Gabriel]

The associated electronics for the generator will be keeping it in sync with the mains. Actually, this is such a key part of the design that a number of these generators cannot operate in the absence of a working mains supply (so they are not suitable as a backup generator). If you want to use the boiler for this purpose, do make sure it is capable (and you need extra protection to prevent backfeeding a dead supply network).

[David Hansen]

On Sun, 26 Feb 2006 22:23:13 GMT someone who may be Tony Bryer wrote this:-

All the alternators connected to the grid are synchronised so they rotate together. If they did not then currents would flow between them and the system collapse. If an unsynchronised alternator is connected to the grid then the other alternators will effectively force it to synchronise. If the newly connected alternator (and any mechanical equipment connected to it) can synchronise quickly enough there will just be some electrical disturbance. If it cannot synchronise quickly enough it will suffer damage, probably severe in nature.

DC links are used to join two unsynchronised grids.

So is this handled if you are generating