Coal, for use on steam hauled heritage railways - merged posts

[whole diary]

[Bmblbzzz]

I know someone who I think works there.

[TonyK]

What a good idea!

[broadgage]

I couldn't resist putting this link here rather than on a perhaps more relevant thread but feel free to move it if it seems more appropriate.

It may be the "End of Coal" power as we once knew it but it might be the beginning of coal mines as a source of low carbon energy.

https://www.bbc.com/future/article/20210706-how-flooded-coal-mines-could-heat-homes

The water from flooded coal mines is not warm enough to directly heat homes or other buildings. A heat pump is required at significant capital cost and ongoing electricity consumption. Arguably better than burning oil or gas, but not as cheap or as green as is often implied.

[Western Pathfinder]

Here's a thought why not use the sites for geothermal,after all there's a fair amount of water already present ,and a good deal of the drilling has been done for you,I'm thinking something along the lines of what's happening at the Eden Project in Cornwall.

[GBM]

Here's a thought why not use the sites for geothermal,after all there's a fair amount of water already present ,and a good deal of the drilling has been done for you,I'm thinking something along the lines of what's happening at the Eden Project in Cornwall.

https://www.theguardian.com/environment/2021/jul/01/full-steam-ahead-for-cornwalls-geothermal-energy-project
Full steam ahead for Cornwall’s geothermal energy project
Team behind project at United Downs site near Redruth say power plant will be producing electricity and heat by next year......
(Continues)

[Bmblbzzz]

I couldn't resist putting this link here rather than on a perhaps more relevant thread but feel free to move it if it seems more appropriate.

It may be the "End of Coal" power as we once knew it but it might be the beginning of coal mines as a source of low carbon energy.

https://www.bbc.com/future/article/20210706-how-flooded-coal-mines-could-heat-homes

The water from flooded coal mines is not warm enough to directly heat homes or other buildings. A heat pump is required at significant capital cost and ongoing electricity consumption. Arguably better than burning oil or gas, but not as cheap or as green as is often implied.

But once the heat pump is in you get far more heating (or cooling, depending which way it's running at the time) than the amount of power put into the pump. If you can run that pump off PV or wind or whatever's green at the time, you get more heat for your kilowatt than using that electricity directly for heating.

[broadgage]

Agree, heat pumps can produce several times the heat that would result from direct electric resistance heating.
My point was that electricity is still required, some reports state or imply that water from old mines can provide free heating.

[TonyK]

Here's a thought why not use the sites for geothermal,after all there's a fair amount of water already present ,and a good deal of the drilling has been done for you,I'm thinking something along the lines of what's happening at the Eden Project in Cornwall.

The heat in the "hot rocks" being exploited in Cornwall is found in granite. Coal is formed by peat being compressed by sediments, so the ground is much softer and a lot cooler. The temperature of the water in an abandoned coal mine is around 16°C. Although warm enough to be of benefit in a heating system, because warming water from 16°C to 50°C takes a lot less energy than starting at 4°C, you can't make electricity directly from it. In the hot granite in Cornwall, the temperature of the water is around 180°C. The steam can be used directly to power turbines, or through heat exchangers to heat water to above boiling point. The cooler waste water can be fed to zonal heating systems, as is proposed in Cornwall, or pumped back underground to heat up again.

The heat in the hot rocks comes mainly from radioactive decay. The Cornish hot water contains much higher concentrations of Thorium than are found elsewhere, although not sufficiently high as to be harmful in normal circumstances. I believe the drilling has found aquifers, but "dry" rocks can be exploited by pumping water into boreholes at sufficient pressure to form cracks.

Don't say it too loudly - this is nuclear energy, that could be exploited on a much wider scale by fracking.

[johnneyw]

Government confirms that the environment bill will not apply to steam trains. 

According to Railadvent it's not just steam locomotives but heritage engines in general.

https://www.railadvent.co.uk/2021/11/government-confirms-environment-bill-will-not-apply-to-steam-locomotives.html

[broadgage]

Good.
I am opposed to large scale coal burning for power generation, and the UK^▸ (United Kingdom) has ALREADY greatly reduced coal burning in power stations.

I would support limited coal burning for heritage or historical purposes. Since this is ungreen, I would hope that heritage railways and other heritage coal users would be as green as possible in other respects.

[ellendune]

But once the heat pump is in you get far more heating (or cooling, depending which way it's running at the time) than the amount of power put into the pump. If you can run that pump off PV or wind or whatever's green at the time, you get more heat for your kilowatt than using that electricity directly for heating.

Yes correct.  A near surface ground source heat pump (without any significant geothermal energy) used for domestic heating typically has a Coefficient of Performance (COP) of 4 which means that it will typically produce 4 times more heat than the electricity put in. The amount of electricity required depends on the temperature increase you require so if there is some geothermal energy it would increase the COP but increasing the output temperature will decrease the COP. 

The COP of an air source heat pump is typically 3. 

[TonyK]

Yes correct.  A near surface ground source heat pump (without any significant geothermal energy) used for domestic heating typically has a Coefficient of Performance (COP) of 4 which means that it will typically produce 4 times more heat than the electricity put in. The amount of electricity required depends on the temperature increase you require so if there is some geothermal energy it would increase the COP but increasing the output temperature will decrease the COP. 

The COP of an air source heat pump is typically 3. 

A family member is about to start building a house, and looking into the different options. He has the luxury of a blank canvas within a field. It seems ground source is better, but more expensive - is this right?

[PhilWakely]

Yes correct.  A near surface ground source heat pump (without any significant geothermal energy) used for domestic heating typically has a Coefficient of Performance (COP) of 4 which means that it will typically produce 4 times more heat than the electricity put in. The amount of electricity required depends on the temperature increase you require so if there is some geothermal energy it would increase the COP but increasing the output temperature will decrease the COP. 

The COP of an air source heat pump is typically 3. 

A family member is about to start building a house, and looking into the different options. He has the luxury of a blank canvas within a field. It seems ground source is better, but more expensive - is this right?

A ground source installation is somewhat more complicated, requiring pipes to be buried underground. See here

[ellendune]

Yes correct.  A near surface ground source heat pump (without any significant geothermal energy) used for domestic heating typically has a Coefficient of Performance (COP) of 4 which means that it will typically produce 4 times more heat than the electricity put in. The amount of electricity required depends on the temperature increase you require so if there is some geothermal energy it would increase the COP but increasing the output temperature will decrease the COP. 

The COP of an air source heat pump is typically 3. 

A family member is about to start building a house, and looking into the different options. He has the luxury of a blank canvas within a field. It seems ground source is better, but more expensive - is this right?

A ground source installation is somewhat more complicated, requiring pipes to be buried underground. See here

Yes and it will normally require a more space than the average garden for the pipes.  More suited to a rural location than a town.  Unless you want to go for a borehole in which case it is even more complicated. 

[broadgage]

For a new house, I would favour great thermal mass and excellent insulation, together with MVHR. Such a house will need no heating in average winter weather, and only a very little heating in severe weather.
This very small heating demand is affordably met from direct electric heating.

In such a home I would install a small solid fuel stove, unlikely to be much used, but most useful to have in case electricity becomes unavailable for an extended period.

Grid tied PV to reduce electricity bills.
A small battery charging PV system to supply limited emergency power in case mains electricity becomes unavailable for an extended time.

Cooking all electric normally, but perhaps a small LPG^▸ (Liquefied Petroleum Gas) hob in addition, with gas bottles in a safe external store.