Electricity Supply

Mine is 45 years old. It was built with open cavity walls - normal for that time. There was just 25mm of insulation in the roof. The floor was simply screed over an in-filled concrete base. Single glazed windows and doors with no draught proofing.

I have since had cavity wall insulation inserted, added about 350-400mm of loft insulation, fitted double glazed windows with draught-proof strips and virtually done away with the flue in the lounge. Can’t do a lot about the floor, but it will lose less heat to the soil than a ventilated timber floor. Even the patio door (fitted about the same time as the windows) has secondary double glazing for when not in use, as does the large window in the lounge. The back door is no longer used, so has been sealed with secondary glazing. The original back boiler in the lounge has been replaced by a balanced flue boiler in what is now the utility room (after an extention was built on).

So houses were not built to decent insulation standards, even 45 years ago. Older houses were likely worse. I know that these improvements have saved far more in fuel bills than the cost of the insulation. Just plain common sense to upgrade the soft-wood single glazed windows - to save umpteen coats of paint and still they would rot away

If all the lights of the original house were switched on they consumed about a kilowatt. Those same number of lights are now flourescents or LEDs. They would consume around 200W now.

Yes, we have gas central heating, but that will change in the future (likely long after I have expired) because the resource will have diminished to the point where the cost would be very high, compared to the last 50 years (when our North Sea supplies have basically been squandered). Norway will likely still have its gas reserves because they have refrained from using them up in the way the UK has used ours. It was simply a short term fix for the UK, back in the 1960s. Now almost gone!

Personally, I would not want to buy a new house from the major house builders, these days. Like most things - built to a cost, not a quality. My house would further benefit from 50mm of insulation on the inside of every external wall, but I doubt it will get it while I am here. But one never knows....

A few people have mentioned ground-source heat pumps, and a thought has occurred to me.

This should not be confused with geothermal water plant such as in Iceland, and I think experimentally in Cornwall.

If you drill a water borehole, you risk abstracting water faster than the aquifer can be recharged naturally, creating a funnel-shaped volume of drier ground which if I recall correctly is called something like the "cone of depletion". The natural rate of recharge depends on the local geology and of course weather; but will be affected if there are many other boreholes in the vicinity.

'

Now, does a similar depletion rule apply to extracting heat from the ground? Very little, if any, of this heat is from the Sun, except only in the surface soil - and that is obviously greater in Summer.

Most subterranean heat is conducted through the Earth's Crust and overlying cover rocks from the Mantle far below, which is heated by radioactive decay. It might be augmented very slightly in a few areas sitting on huge granite intrusions, like Cornwall, due to scattered traces of uranium still decaying in that rock; but these are exceptions.

So recharge of heat is not rapid, but slow and steady.

The volume of the ground, consequently heat held, is obviously enormous; but will estates of houses or large district-heating schemes with their ground-heat pumps all purring virtuously away, create similar depletion cones around themselves by extracting heat from their volume of ground faster than its replenishment? And of course, this will be when everyone needs that heat - in Winter, when any augmentation the Sun might offer, is minimal!

Not sure anyone is suggesting 'wind, solar, batteries and smart chargers will sort it' in the sense that life carries on exactly as it does today.

I don't see renewable energy as a one-for-one alternative to fossil fuels. Instead I see them as a way of softening the blow. Ideally most people most of the time can carry on. Otherwise, given time, people always adapt to what's available.

The good news for Alan and anyone else who absolutely must burn fuel is that everyone who switches to electric takes the pressure off the cost of oil. Electric Vehicles are valuable even if they don't happen to suit our personal circumstances.

More good news if you're Australian; not only does the continent have generous reserves of fossils fuels, there's also plenty of sun! It may be necessary for 60,000,000 winging poms to move in...

Dave

Edited By SillyOldDuffer on 13/06/2019 10:13:25

To answer my own earlier question I looked up the energy equivalent of petroleum (crude oil) which the International Energy Agency defines as 11.63 MWh/tonne.

1 million tonnes of oil per week (total used for all transport) = 5,952 tonnes/hour = about 69 GWh.

Current UK demand on the National Grid seems to average around 35GW, so switching all transport from petroleum fuels to electric traction would seem to require an increase of almost 200% in generation capacity, although potential efficiency savings might reduce this figure. However, roughly half current generation appears to be from fossil fuels so we will need to increase generation by at least 400% from 'other sources' if we are to stop using petroleum fuels altogether.

I can't begin to imagine the changes my grandchildren will see, but our current systems will certainly need upgrading pretty soon if they are to have any hope of a decent life, even if my figures are inaccurate . . . which will no doubt be pointed out shortly

Mike.

NDIY, the improvements that you list having carried out to your house almost mirror the improvements to mine, cavity insulation, loft insulation, replacement doors and windows, we haven’t sealed our flue in the living room but have installed an inset wood burner which generates a large amount of heat that circulates throughout the house meaning the condensing gas boiler only needs to provide some background heating, meaning low gas bills. Recently had solar PV panels fitted on the roof, so far this last winter we reduced our electricity bills by £50 a month and we also get a payment for all solar electricity that is generated so a win win situation. Next project will be a battery to store solar generated electricity but not till the prices come down to a sensible level. I keep threatening the wife I would like to erect a wind turbine in the side garden to make use of the wind, we live in a coastal area so no shortage of wind, she is not keen on the turbine idea. In respect of modern houses I personally wouldn’t touch them with a barge pole, there are currently 5 estates of new houses being built in or around our village, watching them go up I shudder at how tacky they are, even down to a fake fibreglass chimney perched on the roofs. They may be a more thermally efficient building than mine was when built but will they last, I think the jury is still out on that.

Dave W

UK energy use

Suprisingly we appear to be reducing total energy demand albeit importing a heck of a lot more as a percentage. If we switch to an electric based system and try to go renewable then the figures are quite scary - something of the (guesstimated) order of a 50 fold increase in off-shore wind and a huge increase in solar deployment (every south facing roof and road embankment?). Wind I understand has an order of 80x payback for deployment compared to solar in the UK at about 4x. Allowing for calm and sunless times one also needs a method of storage.. molten salt apparently is one method, perhaps with enough space leccy one could consider electrolysis and H2. Biomass is a waste of farmland better used for crops and CO2 sequestration

Undoubtedly there needs to be a will to succeed and undoubteldy we are going to be forced along that route. At least there is a benefit to reduced imports and balancing our lousy economy.

Of course none of this makes a jot of difference unless the rest of the world complies.

Dave

Thats exactly what Transpower said in their document that I quoted

We will see the mainstream commercialisation of distributed solar, electric vehicles and energy management systems. These will start to significantly change the profile of demand and operation of the system with solar and batteries as well as other distributed energy resources enabling load to be partially flattened within a day but also adding additional intermittency. Despite growth in distributed supply, there will also be significant growth in grid energy demand. In the short and medium term we do not expect these batteries and distributed energy resources to be sufficient to flatten the daily or annual load curve, however it has an important potential to shave off peaks and it is critically important that it doesn’t accentuate existing peaks and troughs

Wow, that's quite a bit more than I pay in total per month for electricity. Obviously I'm not using my machine tools enough!

Andrew

Farmboy,

You have completely missed the point, once again.

Liquid petroleum burned as liquid fuel for transport is very inefficient, - I repeat that petrol engines are only a little over 25% efficient. Diesel are more like 30% efficient.

The same amount of electrical power as the energy content of the fuel is just not required! Electric vehicles are over 70% efficient (indeed, the Tesla electric motors were 93% efficient and the latest versions are 97% efficient. Compare 25% to 90% and you might understand that only one third of electrical energy is needed compared to energy input for internal combustion engined transport!

Burning oil to raise steam is only about 40% efficient as an electricity generating energy source (much the same as coal), but if utilised in the same manner as combined cycle gas powered plants the efficiency could rise to about 60%.

So your sums are totally flawed. Using all that oil efficiently, could provide twice the amount of electricity needed to replace the oil as liquid transport fuel. Instead of 69GW (your units seem to be all at sea - as power is not energy), assuming your poor use of units is still providing the correct numerical values, only about 20GW extra of electricity would be required. Current maximum generation of the grid is currently about 50GW (little leeway for any unplanned outages) and average grid usage about 35 GW.

Clearly, without extra generators, the extra power required (20GW could not be provided - and certainly not in winter. In twenty or thirty, or more, years time, it could be. But the simple point is that your sums are a completely worthless. Comparing gross heat energy with nett electricity requirement is FLAWED.

Farmboy,

You have completely missed the point, once again.

Liquid petroleum burned as liquid fuel for transport is very inefficient, - I repeat that petrol engines are only a little over 25% efficient. Diesel are more like 30% efficient.

The same amount of electrical power as the energy content of the fuel is just not required! Electric vehicles are over 70% efficient (indeed, the Tesla electric motors were 93% efficient and the latest versions are 97% efficient. Compare 25% to 90% and you might understand that only one third of electrical energy is needed compared to energy input for internal combustion engined transport!

Burning oil to raise steam is only about 40% efficient as an electricity generating energy source (much the same as coal), but if utilised in the same manner as combined cycle gas powered plants the efficiency could rise to about 60%.

So your sums are totally flawed. Using all that oil efficiently, could provide twice the amount of electricity needed to replace the oil as liquid transport fuel. Instead of 69GW (your units seem to be all at sea - as power is not energy), assuming your poor use of units is still providing the correct numerical values, only about 20GW extra of electricity would be required. Current maximum generation of the grid is currently about 50GW (little leeway for any unplanned outages) and average grid usage about 35 GW.

Clearly, without extra generators, the extra power required (20GW could not be provided - and certainly not in winter. In twenty or thirty, or more, years time, it could be. But the simple point is that your sums are a completely worthless. Comparing gross heat energy with nett electricity requirement is FLAWED.

Andrew, we as a household are big energy users, previously our combined electricity and gas was costing us a direct debit of £135 a month. Need to explain that I have two large ponds in our garden, both using power for circulating pumps, air pumps, and UV sterilisers, these are working 24 hours a day so approx 8kw per day, a lot of energy. The install of solar PV has meant a big reduction in energy usage from the grid, we also now observe the rules of using the washer, dryer and dishwasher whenever the sun is shining, that means free electric, I am sure my wife will also cotton on to restricting use of lathe and mills to only when the sun is shining. The install of solar PV has certainly made us very aware of our energy usage.

Dave W

There are issues with retrofit cavity insulation like damp as moisture is transmitted between outer leaf and inner as we found out (1965 bungalow) on a wall that faces the prevailing weather. That cavity insulation was removed as I can live with slight increase in heating bill but not damp. Probably compensated for that loss of insulation when I had the garage/workshop built on the end as the whole roof was insulated at rafter level with 120mm of Kingspan/Celotex between and over rafters.

More from Transpower. This time their views on battery storage from a grid owners perspective.

**LINK**

The conclusion being that its better done at the consumer end of the network. Which aligns with suggestion of using your EV as a battery backup and to feed power back to the grid. You EV probably has the biggest battery you own.

What it does to the lifecycle of the battery is another consideration.

Regarding ground-source heat pumps, I recall my physics teacher, forty years ago, telling the class that we could all install them but we'd very soon have a thick layer of permafrost.

Incidentally, around the same time, I seem to remember that the experts were telling us we were heading for another Ice Age - "polar bears on the Thames" springs to mind.

But if we all move there, surely the World will tilt on its axis and Australia will end up at the south pole

Given that Oil Tankers are being attacked in the Gulf things might come to a head rapidly and which of type of power we use in our cars and homes might become one of the lesser worries in life.

We might even have to start digging dirty coal and stop closing power stations fuelled by it, who knows where it all might end up!

Pessimist thinking over for today, the Wife says “we” are going shopping.

Edited By V8Eng on 14/06/2019 10:32:32

One solution to the range problem for EVs might be to only allow them to be made with say 100km range for lightness and hence efficiency but arrange for small power trailers with say a 3ookm range that you hire part way down the motorway. It would power you while also charging your internal battery and you would drop it off 50km from your destination. To combat a shortage/pile of them in the wrong place the remaining diesel trucks running in the opposite direction would receive a small payment for pulling a train of half a dozen to another location, perhaps recharging them a bit with regenerative braking on the downhills.

Another big change is needed in planning for domestic solar and wind. I have room for both but National Parks would stamp on the idea and anyway the application fee alone would be about ten years electricity cost after allowing for interest on the expenditure let alone capital repayment.

Here we go, and no mention of EV's

government-s-energy-policy-could-drive-electricity-prices-up-39-percent

Ref Ground Source heat pumps. I have been running one for coming up 13 years.
They do work best with very well insulated homes with underfloor heating and I have neither! Though the former has been much improved, which has helped with running costs. We run it with radiators. It works well, but we do supplement it with a wood burner in the winter. The ground loop is about 5 feet underground and does reach temperatures of 20C in the summer. For the first year I did used to regularly check the temperatures regularly, but now I just let it run. In the winter the ground loop can get well below freezing and the system efficiency does drop as the pump has to work harder with the greater differential.

Our village has no gas, so it is either Electric, oil or bulk LPG. Our unit draws about 2.2Kw which is not bad for the hot water and heating the whole house.

As for costs it was very expensive to install, we did get a small grant which helped a bit. We were laughing when heating oil rocketed a few years back, but oil is cheaper now.
Big advantage is no annual service cost. Just had the unit serviced for the first time as a sanity check. Nothing to report. All working well within expected parameters. Air Source are much more popular now, they weren't an option 13 years ago. Much lower install cost and efficiency has improved.

So what are the Aussie going to do? If you drive from Adelaide to Perth ( 2700km) you have to cross the Nullarbor Plain which only has fuel stops every 300km and no charging points. If you breakdown it could be days before someone rescues you!