The Renewable Heat Incentive

[An Inspector Calls]

As there's going to be an announcement this week on the operation of the RHI scheme, shouldn't there be a separate topic area in the 'Energy Beyond Oil . . ." section where people can discuss the various forms of renewable energy?

[lurker]

Surely RHI is either biomass or solar so its already covered

Apart from heat pumps

[An Inspector Calls]

Apart from heat pumps

Quite: heat pumps have no forum listing.

And I suspect the slant of the RHI for solar and biomass for heating will be different to the former's FITs/electricity generation and the latter's use as a fuel for transport.

[kenneal - lagger]

Quite: heat pumps have no forum listing

That's a good thing. They shouldn't be encouraged, in my opinion, especially as we are facing an electricity generation slump.

[An Inspector Calls]

All the more reason for a forum, so we can discuss your ridiculous assertion.

[JohnB]

The question I always ask when discussing any heating system that won't work without mains electricity, is "what happens during a power cut?". Even now, there are power cuts in cold weather.

[An Inspector Calls]

The question I always ask when discussing any heating system that won't work without mains electricity, is "what happens during a power cut?". Even now, there are power cuts in cold weather.

Is there a central heating solution that will run without electricity?

Coal fired, with gravity driven circulation to the upstairs rooms perhaps . . .

Even a glorious PassivHaus would be trousered.

Are there significantlly more power cuts in cold weather, or is this just another invented statistic? Perhaps in high winds, but mere cold . . .?

[JohnB]

Are there significantlly more power cuts in cold weather, or is this just another invented statistic? Perhaps in high winds, but mere cold . . .?

I've had a few this winter, and didn't have any last summer. Winter cuts have significantly more effect if you need electricity to keep warm. In summer you just have to go to bed when it gets dark, and may miss Eastenders.

[An Inspector Calls]

Well I'm on a rural, overhead line system and, apart from planned outages which are always well publicised, the last power cut we had was caused by a summer lightning storm - about eighteen months ago.

[adam2]

Power cuts can occur at any time but are more likely in winter for various reasons.
High winds are more likely in the winter and these can damage overhead lines.
Snow, ice and frost are likely and can cause damage, especialy ice build up on overhead lines, and snow drifts covering up transformers.
Winter is normally wetter, and water will penetrate into any imperfect joints in buried cables.
In winter frost heave can damage buried power cables.
Vehicle accidents are more likely in icy conditions, out of control vehicles may strike poles supporting overhead lines.
The load is greater and may expose any weakneses or deficiences that went unnoticed at times of lower load.
Finally bad weather can delay repairs if engineers cant readily travell to the site of the fault.

Summer hazards are mainly thunderstorms, fires, and the flying of kites or model aircraft.

As regards heating without electricity, Heat pumps are effectively reliant on the grid.
Most oil, gas or solid fuel heating needs electricity for a pump etc, but the loading is very modest and easily supplied by an inverter or a small generator.
A few older systems use gravity circulation, but that is not the norm these days.

[adam2]

Rota cuts due to lack of generating capacity are clearly more likely in winter also as the peak load is in winter, in the UK.

We have not had widespread rota cuts since the industrial disputes of the 1970s, but it could happen again, and would be most likely in severe cold weather.
Not a good time to be reliant on electricity for heating.

We had one day of rota cuts more recently, in mild weather, due to a most unusuall series of generating plant breakdowns.
Report here
http://www.nationalgrid.com/NR/rdonlyre ... Issue1.pdf

[emordnilap]

Is there a central heating solution that will run without electricity?

Solid fuel stove + electric central heating pump + a couple of leisure batteries charged from a pv panel + a cheap inverter.

The pump runs only occasionally anyway, especially if the house is well insulated.

[adam2]

Is there a central heating solution that will run without electricity?

Solid fuel stove + electric central heating pump + a couple of leisure batteries charged from a pv panel + a cheap inverter.

The pump runs only occasionally anyway, especially if the house is well insulated.

Certainly worth considering, AFAIK though the pump normally runs continualy so as to prevent the small amount of water in the stove from boiling.
Remember that cheap inverters are sqaure wave and may not operate a motor very well. A sine wave unit would be better, though more costly.
Or use a 12 volt pump, no inverter needed.

[JohnB]

AFAIK though the pump normally runs continualy so as to prevent the small amount of water in the stove from boiling.

My system was set up with gravity feed to the hot water cylinder. The heating circuit had minimum and maximum pipe thermostats, so the pump ran when the water was above a certain temperature. I originally had a room thermostat that controlled the pump, but was overridden by the maximum pipe stat to avoid overheating, but it didn't work properly. The maximum pipe stat was also set up to override the time switch, so that the pump would come on if it overheated at night. I wouldn't like to rely on a battery powered pump, in case it overheated when the battery was flat.

Masses of insulation, a system that doesn't need radiators, or a gravity radiator system seems safest and most sustainable to me. It may need a reduction in the size of living accommodation, or change of lifestyle.

[kenneal - lagger]

All the more reason for a forum, so we can discuss your ridiculous assertion.

Oooo, tetchy!!

If you had a house insulated to Passivhaus standards you certainly wouldn't need a central heating system and would only need the services of a woodburning stove for a limited number of very cold days every year. I'm not keen on the MVHR route as, besides requiring mains lecky for the fans, it is another mechanical system that would require maintenance and spares in the low tech future that I foresee. I much prefer passive stack ventilation which is a truly passive, rather than Passiv, system. Any wood burning stove should have an air supply from outside as direct into the stove as is possible.

The trouble with heat pumps is that they are at their most efficient during the summer when they are not required and at their least efficient during the winter when they are. Yes, you can get a COP of 4 or maybe 5 from them but that is during the summer when you can get hot water from solar. During the winter you are more likely to get a COP of 2 or 3, unless you have a source of free heat to work from. The Hockerton Housing Association use the heat from their conservatories to increase the COP of their heat pumps but they are small ones heating their Domestic Hot Water supply.