Micro CHP

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Micro CHP

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dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Thu Jun 16, 05 4:05 pm Post subject: Micro CHP

Micro CHP exists! As a shipping product, not next year - now!

At Grand Designs Live, Powergen were showing the "Whispergen" unit - which they are now selling!

For anyone that doesn't know, CHP (Combined Heat and Power) is the running of a domestic electricity generator, and using the remaining heat for heating water and central heating.
In the first instance its expected that you would be on mains gas and electricity.
So why generate your own?
Efficiency. Carbon AND money saving efficiency.
Power stations unavoidably waste a lot of "low grade" heat. Only a very few have neighbourhood heating, tomato growing or fish farming to make use of this heat.
Domestically, running a CHP boiler when you need heat (and incidentally generating electricity at the same time) means that there's very little waste.

But don't condensing boilers waste very little heat? Yes, but they don't (normally) generate any electricity at all...
It really can be more efficient to generate your own 'leccy than to have it done industrially and then transported to you... Wow! Downsizing works!
Compared to an ordinary condenser, the same amount of heat is going to cost a fraction more on the gas bill, but the electricity bill will be much lower, and the planet will be better off by whatever *didn't* get wasted as heat to the cooling towers.
A unit of gas energy is much cheaper than a unit of electricity (ask anyone with storage radiators), so there is a real financial saving in prospect.

The problem is that Powergen's Whispergen unit is maybe a bit too Micro. It only puts out 6kw of heat - maximum. That might actually do quite well for a small, modern (well-insulated) house, but its a bit little. The ideal way of using it would be with a "thermal store" so that the boiler can build up a buffer for peak heating demand times.
One thing it ain't is a combi. It needs some sort of hot tank.
Anyway, while producing 6kw of heat, its generating 1.2kw of electricity. Thats 20% more than a Windsave claims in a Force 6 gale. It does "modulate" - varying the heat and thus power generated.
Just as with Windsave, money is saved by substituting your own electricity for the power stations'. Your own is used preferentially, and your meter clocks up less.
BUT Powergen's package includes a dual meter - you sell back the surplus! (Windsave gives any surplus to the grid.) There is no additional "standing charge" for this meter.
I do note however that the "two-way" tarrif does not have an "off peak" rate - its a dual meter NOT a triple - rats!
The tarrif is 7.8p per unit consumed (after the standing charge is met from initial 10p units) and 3.19p per unit exported.
Powergen suggest that the annual result of electricity saving would be a �150 benefit (�120 reduced bill & �30 of export). And there should be a little ROC income too.
Exactly how the economics pans out is going to depend on your pattern of use

The deal on offer is �3000, inc VAT and everything, meters, controller, etc, delivered and installed, with 2 years warranty and 5 years service, as a replacement for an existing boiler. They'll even do cavity wall insulation *included* in that price.
Thats not more than �1000 over the cost of an 'ordinary' boiler. So having one would cost about the same as a Windsave. And be a heck of a lot more practical and useful for a townie than a whirligig on the roof. Totally different situation out of town, perhaps.

Technically its interesting that the generator uses a Stirling engine. (Supposedly "maintanance free" - it just needs "normal boiler servicing".)

As well as mains gas and electricity, you need a solid floor for it to sit on, an unobtrusive location (it does make a little noise) the size of a kitchen unit on an outside wall (balanced flue and condensate drain) - and to be in an area where Powergen have a trained installer.

There is said to be a higher (double?) output unit due in the autumn. Maybe at the same price!

If its of interest to you, register that interest with Powergen on 0800-068-6515. (I gather that they may be "rolling out" to new areas based on demand...)

There's some info on the manufacturer's web site at https://www.whispergen.co.uk
and off-grid folks might note that there's a version running on bottled gas for battery charging... BTW, I don't think the standard unit would provide power during a powercut - its not marketed as a backup supply.

Just to make it absolutely clear, other than as a potential customer (for the larger unit, in an area where they don't have an installer), I don't have any connection or involvement with any of this stuff!

tahir

Joined: 28 Oct 2004
Posts: 45674
Location: Essex

Posted: Thu Jun 16, 05 4:12 pm Post subject:
About flippin time, thanks for posting that dougal i was beginning to think it was never going to happen. Sounds really good, if you had one of those and solar water heating (and super insulation) you'd cut down your energy bills significantly, add in LED bulbs at some time in the next couple of years and that's real progress.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Thu Jun 16, 05 8:16 pm Post subject:
From the small print on the manufacturer's website - Powergen (E.ON UK) have committed to buying 80,000 ( EIGHTY THOUSAND ) of the things over the next five years... This looks very real...

Behemoth

Joined: 01 Dec 2004
Posts: 19023
Location: Leeds

Posted: Fri Jun 17, 05 8:32 am Post subject:

Sounds good - if we stay in the current property we may extend which will involve a reworking of the plumbing and heating and an opportunity to install one. I still think the price will put most people off. Things like this have to be forced through by changing regs.

A friend has recently converted a barn to a house and installed a heat exchanger and he reckons heating bills are practicaslly zero as the unit recylces body heat and heat generated by domestic appliances. They managed to keep the place at a steady 15c while working on the place with the doors and windows missing or open! The only problem is they are imported from europe under a franchise and the fella who has got the franchise wants an easy life so he only brings in 4000 a year. The units cost about �4k of which �2k is his profit and he's not interested in expanding. His license expires in a year or two and my friend is looking into trying to buy it and push the numbers accesibility by maintaining the exclusive contract but selling as many as he can. They''re only really suitable for new builds of full refurbs but are a fantastic piece of kit. he's gotm on the Council's sustainable development committtee and is a demonstration project for the council in sutainable housing. To be honest this was a bit of back scratching to get his planning permission. Will try and get more details when I see him next.

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Fri Jun 17, 05 11:59 am Post subject:

Behemoth wrote:

Sounds good ... I still think the price will put most people off. Things like this have to be forced through by changing regs.

I think the economics don't look too bad at all...
Replacement boiler, fully installed, two year warranty, five years labour plus cavity wall insulation for two grand total? Thats competitive. And then think of the additional grand for the genny that could save you something like �150 a year...
I really do think the economics are pretty reasonable.
The big unknown is the longevity of the Stirling engine, and the cost of the spare part. (Its a sealed "maintenance-free" unit.)

Each unit is claimed to save one and a half tonnes of CO2 each year.

80,000 of the things means the same generating capacity as a 90 megawatt power station. With no powerlines across the countryside.
And the generation is going to be "peak following" - electricity demand is highest at the same sort of times that heat demand peaks - that's ideal.

Its a shame, CHP having been in use on an apartment block scale in Europe for a while, that this unit should be quite SO "micro". Rats!

dougal

Joined: 15 Jan 2005
Posts: 7184
Location: South Kent

Posted: Fri Jun 17, 05 12:02 pm Post subject:

Behemoth wrote:

A friend has recently converted a barn to a house and installed a heat exchanger and he reckons heating bills are practicaslly zero as the unit recylces body heat and heat generated by domestic appliances. ... Will try and get more details when I see him next.

I think that deserves a thread of its own, if not an article...

Behemoth

Joined: 01 Dec 2004
Posts: 19023
Location: Leeds

Posted: Fri Jun 17, 05 12:07 pm Post subject:

dougal wrote:

if not an article...

Have you Tahiritis?

tahir

Joined: 28 Oct 2004
Posts: 45674
Location: Essex

Posted: Fri Jun 17, 05 12:10 pm Post subject:
Does sound excellent though B

Behemoth

Joined: 01 Dec 2004
Posts: 19023
Location: Leeds

Posted: Fri Jun 17, 05 12:36 pm Post subject:
It is. I've even crawled into the loft to see it at work. He's got a computer that monitors inputs and out puts and it comes up with something along the lines of 5p/month or similar. I'll try to get some info out of him. The problem is he's so keen that you ask how it's going and get a 20 min seminar and thermodyamics and cost benefit ratios......and I'm lost.

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