upgrading to 19th century technology

[emordnilap]

Fascinating article here from Kris de Decker of Low-tech Magazine on direct-drive water power.

[adam2]

Direct drive from a water turbine has the merits of simplicity and often greater efficiency.
The main drawbacks are lack of flexibility, only a single machine, or perhaps a small selection of machines may be driven.
Also the machine to be driven has to be adjacent to the water turbine which may not be convienient for other reasons.

If however electricity is to be generated, then it may be used for any purposes including lighting, refrigeration, computers, and the charging of EVs
Electricity may be transmitted a mile or more, depending on the voltage used.
Battery storage adds costs, complications and losses, but does allow very large peak loads, far beyond the turbine output, to be supplied.

Electric transmission may be safer than the numerous exposed drive shafts and belts innvolved in mechanical drive.

Whilst mechanical drive should be more efficient this is not allways realised in practice. The driven machine might only use a proportion of the available power, with the rest being wasted. An alternator can be set up to extract ALL the available energy with any surplus used for battery charging or heating. The driven machine may not need power continually, for example whilst being cleaned, adjusted, re-supplied with materials etc, this represents waste. With electric drive the power would be used elswhere.

[emordnilap]

Good stuff adam2, reinforcing several points mentioned or alluded to in the article.

[kenneal - lagger]

The article falls down in the way that the author can only see the advantages of his proposed approach but none of the disadvantages. Like many "visionaries in his field" he cannot see that there are many different approaches that can be used in different situations. This is one of the problems with "sustainable" technologies and exists among the gurus of timber frame, straw bale and hemp/lime industries, for example.

The main advantage that direct drive has, that he has not pointed out, is the huge reduction in complexity of the mechanical system and the consequent reduction in knowledge, maintenance and stares required. This is of huge importance in the third world where the introduction of western technologies by aid agencies often ends in failure as the technology cannot be maintained due to lack of technical knowledge or cost of replacements or both once the aid agency departs.

As Adam has pointed out, direct drive is only useful if you can set up close to, within metres of, the source of the water supply. If you are tens to hundreds of metres away the electrical option becomes a better bet. I have a gully about a hundred metres away from my house that I have my eye on for electrical generation in the future. Because of the topography and ground conditions I would have to use it for electrical generation because it would be very expensive to access the site to build close enough to make use of direct drive. Mine isn't a unique case.

[RenewableCandy]

He's also written a load on the subject of transmission of mechanical energy over long(ish) distances, so that would kind-of be a complement to a water-powered mechanical drive. It's surprisingly do-able, and was surprisingly popular back in the day. However, rotating or oscillating metal rods spaced out over fields strike me as being a bit ramshackle and vulnerable.

[adam2]

Mechanical drive was formerly used over considerable distances, normally confined to a single building but that could be over half a mile in a large mill or factory.

This was far from efficient and was also a considerable fire risk.
It was not adopted for efficiency ! but because it was at the time the ONLY way of driving numerous machines from a central steam engine.
A steam engine for each machine would be totaly impracticle, and electric power was not available.

Most such schemes were replaced with electric power as soon as this became affordable and generaly available.

Alternators, electric motors, and electrical equipment in general are now low priced commodities and can be obtained cheaply, new or used, almost anywhere.
Large scale mechanical drives via line shafting, countershafting, and pulleys and belts is now almost obsolete. The components are not readily available, and neither are skilled millwrights.
Electric drive is almost certainly safer than the vast amount of exposed moving parts in a Victorian factory. A regretable number of lives and limbs were lost in old type factories from accidents innvolving belt drives.
Other lives and valuable property were lost in fires caused by the equipment.
Electric drive also often meant the adoption of electric light which was far safer than gas light or candles.

[SleeperService]

Interesting post Adam2 Thank You.

Thinking through your comparison have we now got to the point where electrical power is as inefficient as the mechanical power you cover?

The losses involved in transmission from power station to (usually) a distant city must be considerable.

Could we reduce our energy consumption significantly by building new power stations closer to the consumers? Coupled with measures to reduce demand this could result in significant savings of energy.

On a related note when I were a lad me mam took us oop north to meet her side of the family in Lancashire and Yorkshire. One of my uncles had a huge red scar from the top of his left ear to the right armpit where he'd been 'whipped' by a broken drive belt. Lost his left eye and some use of his right arm. When WW2 started he retrained as an electrician. Thinking about it I wonder how many others he saved from a similar fate or worse?

[adam2]

Loses in the national grid are typicly reckoned as being about 10%, no great accuracy can be claimed as the figure is continualy varying, and there is more than one definition of "losses"

Most of the loss is in the the last few miles of relatively low voltage lines.

Losses can be considerably greater in the case of scattered rural dwellings, and supplying electricity to these at current prices should be considered as a charity, or at best a social service, and not as a business.

There would therefore be little gain in building local power stations, unless there was some other reason to do so.

Conventional power stations are cheaper to build per KW of installed capacity, and cheaper to run the bigger they are. Big is better.

In the case of wind turbines, big is also better, and placing these in windy places is more important than being near the load.

Solar is fine on a small scale, and lots of small PV installations do slightly reduce losses, but not by much.

[SleeperService]

Not as great a loss as I thought. Thanks for the explanation.

Looks like another example of one solution not being the answer?

[kenneal - lagger]

The main loss on a conventional power station is the 40% to 60 % loss that goes up the cooling tower. If power stations were sited next to the communities that they served this loss could be turned into a gain through the supply of heat to the local population. This would also lose some of the line losses from remote locations.

[woodburner]

I don't think so. There is a power station just south of St. Neots. in the '70s it was coal powered, then demolished and rebuilt to run off gas. There were plans to build lots of dwellings a few hundred yards away, - now built, did they put in pipes for district heating? Of course not. The power station runs three days a week as it is too expensive to produce electricity from.

There is another problem, this year is a good example, where the past few months have been warm enough for most people not to need any heating. The power station would have still needed to get rid of the heat.

It would also go against the mantra of increasing GDP by every possible means. GDP encourages waste.

[adam2]

The utilising of waste heat from a power station sounds attractive in theory but is seldom practical in the real world.

The cooling towers in a power station are designed to reject heat at a very low temperature, seldom exceeding blood heat.
This condenses the used steam more effectively and gives a beterr vacuum in the steam condenser and thereby better efficiency.

Water at such low temperatures is not suitable for district heating, huge volumes are needed, with significant capital costs and pumping energy.
The radiators or other heat emmiters in the homes would also have to be very over sized and therefore more expensive and unpopular.

And of course cooling towers are still needed as well for summer operation of the power plant, and an alternative heat source is needed for when the power station is not running.

Power stations can be designed to reject heat at higher temperatures, but so doing significantly increases the cost of the electricity. It is only worthwhile if there is a large and PAYING demand for the heat such as a large hospital, hotel, industrial laundry or the like.
It wont be paying proposition if the heat is expected to be free rather than sold.
District heating schemes exist, and are generaly hated by the users !

[featherstick]

District schemes are used extensively in Russia. They fit in well with the overall cultural biases to centralisation, gigantism, and passivity. They are usually enormous, and incredibly wasteful. A power station squats in the centre of a residential district. Homes closest to the power station are overheated, furthest away are barely heated. Radiators have no valves and people regulate temperature by opening windows. The heating is switched on on 1st October, irrespective of whether it is needed or not. Every August, the hot water is turned off across the district for maintenance to take place. The massive pipes that carry the water to the blocks of flats are poorly insulated and chuck off heat all the way, keeping birds and bums alive in winter. I’m not a fan. However I don’t know whether they are, or could be, more efficient in overall terms than having hundreds of thousands of individual gas boilers as we do over here. Orlov, on the other hand, loves them, and his arguments are powerful ones.

“Heat, house fires... see, living in Russia, I almost forgot about these things. In St. Petersburg, apartment buildings are heated using waste heat from power plants. Steam is distributed throughout the city using a network of buried pipelines which provide both heat and hot water. Their cost is just the cost of distribution (which is, at this point, mostly a matter of upkeep) since the energy would otherwise be wasted. The buildings are so warm that nobody wears sweaters indoors, and it is usually warm enough to lounge around in lingerie. On day one of a cold spell it can get a bit chilly indoors, but then somebody somewhere gives a giant steam valve a quarter turn, and things are again toasty. On the first day of a warm spell it can get positively sweltering indoors, and people start cracking windows open even though it's still below freezing outside, until somebody somewhere gives that valve a quarter-turn in the opposite direction. If you find this arrangement inefficient, then you must be sketchy on the concept of waste heat. Power plants are heat engines, subject to thermodynamic limits which cause 2/3 to ½ of the energy consumed to be released as waste heat. Now, there is enough heat wasted by all the power plants in the US to heat every single inhabited structure in the entire country, but instead that heat is vented to the atmosphere or used to heat the rivers and the ocean, and then quite a bit of the electricity they generate is wasted using electric space heaters. In turn, these space heaters cause a lot of house fires.

During my stay in St. Petersburg I did not see a single fire or fire engine, or hear a single fire engine siren. Buildings in St. Petersburg do not have fire exits or fire escapes; they don't need them. The place does not burn. The Emergencies Ministry publishes weekly statistics for things such as fires, and they bear out my casual observation. The reason for this is that houses in St. Petersburg are made of nonflammable materials: masonry and, more recently, reinforced concrete, insulated with hard plaster. If you proposed building something out of flammable materials, such as wood or vinyl siding, your project would not be approved. The walls tend to be thick—5 courses of brick or more—to provide both insulation and the thermal mass to hold in heat. Doors are made with a core of steel plate. Thus, the worst that can happen there is an isolated apartment fire.”

http://cluborlov.blogspot.co.uk/2013/02 ... ation.html

[woodburner]

............apartment buildings are heated using waste heat from power plants. Steam is distributed throughout the city using a network of buried pipelines which provide both heat and hot water.

Someone is just wasteful. Steam has far too much heat in it to be described as "waste".

[kenneal - lagger]

Old systems are wasteful therefore all systems are wasteful!! What sort of thinking is that?:roll:

Slough Heat and Power has been running for years, and recently on 100% biomass waste, although I think it has now closed as a casualty of the EU regulations. That heated a large industrial and housing estates quite successfully and charged for their product. I think that they have a backup boiler for time when the plant wasn't running. that's still more efficient than having a hundred and one individual boilers chuntering away.

There's no reason why each house can't be fitted with its own thermostats(s) and the system can be fitted with an accumulator as well as an emergency cooling tower. Our temperature range isn't as wide as Russia's so designing a system without waste is a lot easier. Insulating all the houses so that only domestic hot water is required most of the time helps as well. with a well insulated house a single radiator at the core will provide the small amounts of backup heat required for two to three weeks a year. Insulated underground piping has a very low heat loss, especially at our ambient temperatures.

It's just a question of making the economics work properly by putting an environmental cost on fuel.