The Baxi Ecogen micro-CHP boiler

ulsterman

Pincher wrote: »

I didn't know it was BG exclusive.

http://www.baxigroupspecification.co.uk/assets/baxi-ecogen-micro-chp.pdf

It says £3,000 "Incremental capital cost", whatever that means, on page 19.

http://www.bhl.co.uk/category/Baxi_Ecogen_MicroCHP

This says Coming Soon, check BHL for availability

It's just as well it's not available, or ridiculously expensive, because I can't rip out a brand new boiler to swap it in.

I was keen on it for a blackout scenario, but it probably doesn't work that way. What I want is a CHP that can startup without mains electricity, possibly using a battery backup or a manual ignition.

During a blackout, I would disconnect the main consumer unit, to isolate the house from the grid. Start the CHP, and run essentials like lights and heating (gas). 1kW should be enough to run the zone valves and circulation pump.

A lot of stuff that BHL sell, they just source from elsewhere (often national merchants) and then resell online adding their cut.

Regards

Ulsterman

chrisrimmer

I have had my Ecogen boiler installed since October 2010. It cost £5500. Our electric bills have gone from £50 per month to £25. I anticipte we will be paid somewhere in the region of £200 for the electricity we have generated. Add the amount of gas saved and this figure goes up quite alot. According to Britis Gas web page we are using a third less gas for houses of a similar size and in the same area.
Using the boiler takes thought. Heat your hot water when you will use the electricity generated. I try and use the washing machine in the mornings at the same time and in the evening TV, computers etc are on.
I will add more info when I have completed the full year.

Chris

brokenick

I suggest anybody interested in any micro CHP boiler download the Micro CHP Accelerator Final Report from the carbontrust.co.uk site.

It is very revealing and gives unbiased summary. I've copied a few quotes below:

"....based on current prices...could actually be more expensive to run than a condensing boiler in the absence of a reward for electricity exported.."

".... with the current FIT's ...the net saving is £158 per year...... payback period of just less than 16 years..."

Hardly a ringing endorsement!
Think my mind (I was looking forward to these boilers) has been changed.

There's also an acknowledgement that condensing boilers are not producing the efficiencies promised; returning effieciencies some 5% lower hen SEDBUK declared values. This is thought to be because installers habitually put in "oversized" boilers.

For condensing boilers to work at their peak efficiency the return temperature should be 57 degrees C or below (preferably closer to 50 degrees). The habit of "oversizing" boilers (combined with TRV's) tends to increase the return temperature.

brokenick

Tobyone wrote: »

I have been quoted over 8K fully installed. A lot of extra cash over standard condensing boiler for a small saving in electric bill??:(

According to the carbontrust site (see my later thread) the measured thermal efficiency for the micro CHP units is around 10% - 15% below that of condensing boilers. This means that any gains from electricity generated need to be calculated against increased cost of heating your home with gas. Even with the FIT's it will take at least 16 years to claw back an increased outlay for the CHP boiler. This is based on a stirling engine based CHP boiler being only £2500 more than a condensing boiler.

GrahamE

Thought it might be useful to give a 10 month update on the Ecogen, which was installed in February this year.Gas consumption has been 14,448kWh - compared to 19,756kWh for the same period in 2010, so a reduction of 26.8%. I take this as being due to going from an inefficient D rated boiler to the Ecogen - and given a similar level of usage over the time period suggests that the Ecogen is achieving efficiency equivalent to an A rated condensing boiler.Electricity generated by the Ecogen is 1042kWh. This means that the boiler has been running for a very slightly longer amount of hours during the period. However, using this figure for the hours run gives an average gas consumption of 13kW, or put another way the boiler has run for 587 hours at just 6kW and 455 hours at full consumption of 24kW.Electricity consumed from the grid during this period fell from 4265kWh to 2983kWh, a drop of 1282kWh. This is substantially more than the amount generated, so suggests we've been a bit smarter and more efficient about electricity usage as well.So far therefore I'm pleased with the performance.

Ben84

GrahamE wrote: »

Thought it might be useful to give a 10 month update on the Ecogen, which was installed in February this year.Gas consumption has been 14,448kWh - compared to 19,756kWh for the same period in 2010, so a reduction of 26.8%. I take this as being due to going from an inefficient D rated boiler to the Ecogen - and given a similar level of usage over the time period suggests that the Ecogen is achieving efficiency equivalent to an A rated condensing boiler.Electricity generated by the Ecogen is 1042kWh. This means that the boiler has been running for a very slightly longer amount of hours during the period. However, using this figure for the hours run gives an average gas consumption of 13kW, or put another way the boiler has run for 587 hours at just 6kW and 455 hours at full consumption of 24kW.Electricity consumed from the grid during this period fell from 4265kWh to 2983kWh, a drop of 1282kWh. This is substantially more than the amount generated, so suggests we've been a bit smarter and more efficient about electricity usage as well.So far therefore I'm pleased with the performance.

This is interesting. Another big aspect of these boilers and why people are interested in them in environmental too, so I'm wondering if you have any calculations on potential carbon savings since you installed it?

Ecokev

The chp won't be any more efficient than a normal condensing boiler with good control ie weather comp, only saving will be the electric and fit.

Ben84

Ecokev wrote: »

The chp won't be any more efficient than a normal condensing boiler with good control ie weather comp, only saving will be the electric and fit.

The potential pollution savings I'm thinking of wouldn't be from the heating, they would be from the electricity. Electricity from the national grid is made with a number of fuels, but a decent amount is from coal and oil which emits much more pollution than gas. It also tends to be generated a long way away from people's houses and suffers losses in the wiring between the power plant and the user. So, by turning gas in to electric at home any electric that would otherwise have come from the national grid that is replaced with the electric from the CHP could be less polluting.

Of course, it could also be more polluting. I live very close to a nuclear power plant and assume most the electricity I'm using is actually very minimally polluting so using a gas CHP to generate electricity could increase the carbon dioxide my house emits.

GrahamE

Ben84 wrote: »

This is interesting. Another big aspect of these boilers and why people are interested in them in environmental too, so I'm wondering if you have any calculations on potential carbon savings since you installed it?

Depending on whose website you use the figure given for the amount of CO2 produced in the UK generating mains grid electricity is between 0.47 and 0.53kg/kWh, for the total fuel mix (i.e. coal, natural gas, oil, nuclear and renewables).

So for the 1042kWh my microCHP system has generated during the 10 month period, either for my own use or for export, the CO2 saved is about 521kg.

grumpyoldsteve

GrahamE wrote: »

I have just installed a Baxi Ecogen 24 on 2 February. Total installation cost was £5,977. This compares to the quoted cost of installing a standard SEDBUK A condensing boiler of £2900. Part of the higher cost is the Ecogen unit itself which is priced at £3,743 and the cost of electrical installation that you don't have with a standard boiler. So the "incremental capital cost" is the difference between installing a standard condensing boiler and a mCHP unit.

Based on the results of the 9 days of operation it has generated an average of 8kWh/day of power and reduced normal electricity consumption by 4kWh/day. Based on my marginal electricity costs and the FIT rate of 10p/kWh for generation and 3p/kWh for export (which is assumed to be 50% of the quantity of electricity generated) I'm currently forecasting a total economic benefit of around £35 per month during the winter months. Gas usage is about 10% lower than the previous boiler but that was SEDBUK D rated, and of course is complicated by the external temperatures being different, i.e. warmer weather means lower gas usage.

So from an economic perspective, and assuming just 6 months of substantial use in winter, that means income/savings of around £210/year, which divided by the incremental capital cost of about £3000, gives a simple yield of 7%. Whether this justifies the investment depends on what your cost of capital is. Taken over the 10 years of the FIT period and assuming a) that energy costs rise by around 10% per year on average, and b) the boiler lasts that long I calculate the nominal Internal Rate of Return at about 2%. Not great, but I'm betting on energy costs rising substantially more than 10% per year over the period.

As the data improve with time I'll re-post with an update.

Some other background information : The Ecogen design was developed by British Gas who then sold it to Baxi - part of the condition of sale being that only BG is authorised to install the Ecogen for Baxi. So you get slightly higher installation costs because it's BG rather than your average local heating and plumbing company. However, to get the FIT payment the installer needs to be MCS authorised, and most local companies aren't.

Graham E, I am just in the process if getting quotes for a replacement boiler (initially considering standard condensing boiler) and was glad to find this thread on the forums.

According to the British Gas website it cannot be installed above kitchen units and is more suitable for larger homes, so I am wondering what exactly constitutes a larger home (we are a pretty standard 1983 4 bedroom end terrace house, not huge, but much bigger than the latest "rabbit hutch" homes).

Does "not above kitchen units" mean it cannot go where our standard wall mounted boiler currently is (i.e. above floor standing units but level with wall mounted units)? - Ok just looked in detail at the British Gas website and it mounts on a load bearing wall - exactly where our existing boiler is located
How noisy are they? I noticed it says an attached garage would be a suitable place for installation - we have a double garage which is unfortunately not directly attached.
I would also be interested if anyone has installed one of these boilers where they already have solar PV installed.