Do We Have A Gas Boiler Expert?

[1581960]

For a year or so Flow Energy have been marketing their hi-tech gas boiler which produce electricity whilst the central heating is on. When first introduced I was told by Flow that my gas consumption was too low to make the change viable, they now tell me that modifications have been made and the new boiler could well be suitable for my usage.

I have read through the Flow Energy blurb and it seems almost too good to be true, hence my questions on AB. Do we have an expert that can comment on the pros and cons of the Flow boiler? If any AB'ers have installed a new Flow boiler how is it performing?

Thanks in advance.

[hc4361]

I'm interested in any comments and opinions on this subject, so thanks for bringing it up

[Dogsbody2]

This was a new one on me too, but it looks interesting.

There are two bits to it - using Flow Energy as an electricity provider, and installing a Flow Energy gas boiler. It seems you can do the first without the second, but not install a boiler without being on their tariff system.

The boiler itself is a miniature version of a Combined Heat and Power system - the industry seems to have dubbed it Micro CHP. This established technology within industry uses the boiler that produces heat for industry processes or office supply to also generate electricity for office power and lighting. The principle is that local electricity generation, almost as a bypass product of generating joules from gas to produce heat, is cheaper for industry than buying electricity from a supplier.

That's fine, but electricity can't be stored, of course, so it works in industry where electricity is required at the same time as industrial heat.

Flow Energy seem to be using this approach to apply it to domestic consumers, using the Feed-in-Tariff system that has become mainstream with PV systems (solar panels), and applying it to micro-CHP. OFGEM currently show a FiT of 13.45p/kWh, so this is where the Flow Energy 'subsidy' comes from - you either use it or feed it back to the grid. The interesting thing about this seems to be that the FiT electricity is being generated at precisely the times the PV systems don't generate electricity - cold dark nights when the domestic heat is on (but the sun isn't shining).

I did a quick fag packet estimate on the numbers. If domestic gas costs 20p per cubic metre, and 1 cubic metre of gas generates 11kWh, and this boiler is 90% efficient (it is claimed to be 94%), the generated electricity costs about 2p/kWh. Compare that to current tariffs available at about 12p/kWh. And the excess goes into the grid at a hugely generous sum of 13.45p/kWh - however, there's no knowing how long that level will last and it will go down as the technology is more widely adapted.

Finally there's the boiler - its got more whizzy bits on it, so more to potentially go wrong. As happened with condensing boilers in about 2014, some of the early ones were unreliable as the technology developed fast.

Personally I'm just going to sit back and wait, as I only buy a boiler once every 12 years or so and Worcester Bosch (amongst others) boilers have a reputation of being reliable. I don't want to be trying a source a technician to repair my new fangled appliance whilst learning from the circuit diagram.

[Dogsbody2]

Oops - condensing boilers in about 2004, not 2014.

[1581960]

Thanks Dogsbody2, interesting and helpful.

My existing boiler predates condensing boilers so is obviously less efficient, and probably close to the end of its life as well. I'm tempted to go for the new one.

[bhg481]

The advice from my plumber-neighbour when I asked him about replacing my 30-year old boiler with a new condensing one was - don't. The new ones seem to have a finite lifetime (about 10 years) and seem to be more troublesome. A colleague I used to work with replaced the boiler when he moved house and he's had a lot of bother with the condensing one. My (now 35-year old) boiler seems to just keep going.