Efficiency of utilities

I have a wife who is becoming obsessive about the use of electricity
and gas, and consequently is pushing up my requirement to know
something about these things.

One thing I've been puzzling recently is why we are told that electric
heating is "less efficient" than gas heating. Is that really true?
Or is it that a) electricity is more expensive per kWh, so to achieve
the same output is more expensive or b) electricity carries high(ish)
level of transmission losses on the way to my house, whereas gas
arrives in an "unused" state, and therefore I get nearly all of the
benefit of its heating ability I use it to power my boiler?

On a similar vein, there is the standby / mobile phone charges etc
arguments. If (as my physics teacher once said) energy cannot be
created or destroyed, just converted from one form to another, we must
be "using" the energy. If they heat up, we're using the heat, if they
buzz then isn't that sound energy converted into heat through the air
(?), if they have a small LED on them doesn't the light again convert
to heat energy (save for the part that disappears through the windows
as visible light). So aren't they equally "efficient" as an
electrical heater?

Matt

"larkim" wrote in message
...
I have a wife who is becoming obsessive about the use of electricity
and gas, and consequently is pushing up my requirement to know
something about these things.

One thing I've been puzzling recently is why we are told that electric
heating is "less efficient" than gas heating. Is that really true?
Or is it that a) electricity is more expensive per kWh, so to achieve
the same output is more expensive or b) electricity carries high(ish)
level of transmission losses on the way to my house, whereas gas
arrives in an "unused" state, and therefore I get nearly all of the
benefit of its heating ability I use it to power my boiler?

There's not just the cost/losses in transmission of electricity: the
generation of electricity from (e.g.) gas is inherently inefficient - I
don't think they've ever achieved much more than about 50% efficiency - the
rest is lost in those great cooling towers they have at power stations, or
possibly used in "neighbourhood heating" schemes if there is a housing
estate nearly - though it usually is wasted.

(Theoretical, not just engineering considerations limit the efficiency of
electricity generation - heat is a "low grade" of energy as it is "random",
whereas electricity is a "high grade" of energy as it is "directed".)

On a similar vein, there is the standby / mobile phone charges etc
arguments. If (as my physics teacher once said) energy cannot be
created or destroyed, just converted from one form to another, we must
be "using" the energy. If they heat up, we're using the heat, if they
buzz then isn't that sound energy converted into heat through the air
(?), if they have a small LED on them doesn't the light again convert
to heat energy (save for the part that disappears through the windows
as visible light). So aren't they equally "efficient" as an
electrical heater?

The efficiency figure looks at the *useful* output of a device, e.g. forward
motion of a car, or light output of a lamp.

The "waste" heat *may* be able to be used, for example the heater of a car
using waste heat of the engine; similarly the heat output from a domestic
appliance might reduce central heating costs if it is controlled with an air
thermostat - but only in the winter months.

--
Max Demian

In article fdee4262-82c1-40ca-80cf-
, Larkim wrote:
One thing I've been puzzling recently is why we are told that electric
heating is "less efficient" than gas heating. Is that really true?
Or is it that a) electricity is more expensive per kWh, so to achieve
the same output is more expensive or b) electricity carries high(ish)
level of transmission losses on the way to my house, whereas gas
arrives in an "unused" state, and therefore I get nearly all of the
benefit of its heating ability I use it to power my boiler?

Yes to all of those I think. Burning fuel and converting it into heat
(with losses) to convert into electricity (with losses) to convey it to
your home (with more losses) to convert it back into heat again appears
intuitively less efficient than burning the fuel and converting it
directly into heat in your home. Perhaps somebody can provide some
figures, but I'm sure gas must be more efficient.

Rod.
--
Virtual Access V6.3 free usenet/email software from
http://sourceforge.net/projects/virtual-access/

On Nov 17, 12:05*pm, CD wrote:
On Mon, 17 Nov 2008 03:10:15 -0800 (PST), larkim

wrote:
One thing I've been puzzling recently is why we are told that electric
heating is "less efficient" than gas heating. *Is that really true?
Or is it that a) electricity is more expensive per kWh, so to achieve
the same output is more expensive or b) electricity carries high(ish)
level of transmission losses on the way to my house, whereas gas
arrives in an "unused" state, and therefore I get nearly all of the
benefit of its heating ability I use it to power my boiler?

I don't wan't to get into all this CO2 nonsense, I only care about my
bank balance. But on the subject of gas v electric the latter is
indeed more expensive.


I agree - and its therefore up to the powers that be to make sure that
I choose cheaper options which also have less carbon impact. That's
the way the "market" is supposed to work, isn't it?

If they can make nuclear / wind / tidal / hydro power cheaper for me
to use than gas, then I'll install an electric boiler, otherwise I'll
carry on with gas.

Matt

On 17 Nov, 12:05, CD wrote:
On Mon, 17 Nov 2008 03:10:15 -0800 (PST), larkim

wrote:
One thing I've been puzzling recently is why we are told that electric
heating is "less efficient" than gas heating. *Is that really true?
Or is it that a) electricity is more expensive per kWh, so to achieve
the same output is more expensive or b) electricity carries high(ish)
level of transmission losses on the way to my house, whereas gas
arrives in an "unused" state, and therefore I get nearly all of the
benefit of its heating ability I use it to power my boiler?

I don't wan't to get into all this CO2 nonsense, I only care about my
bank balance. But on the subject of gas v electric the latter is
indeed more expensive.

For my son's bedroom I have turned off the radiator & put in an
electric heater. The way I see it is that if I used the gas radiator
it would be controlled by the stat downstairs, when that clicks on the
gas has to heat up water which then has to be pumped to every radiator
by electricity, heating up all the rads as it goes (unless I shell out
more on TRVs). With the electric heater it delivers instant direct
heat to his room. Me & the missus use a thick duvet.

A TRV would cost far less than a electric heater to buy, unless of
course you already have one.....

"larkim" wrote in message
...
I have a wife who is becoming obsessive about the use of electricity
and gas, and consequently is pushing up my requirement to know
something about these things.

One thing I've been puzzling recently is why we are told that electric
heating is "less efficient" than gas heating. Is that really true?
Or is it that a) electricity is more expensive per kWh, so to achieve
the same output is more expensive or b) electricity carries high(ish)
level of transmission losses on the way to my house, whereas gas
arrives in an "unused" state, and therefore I get nearly all of the
benefit of its heating ability I use it to power my boiler?

On a similar vein, there is the standby / mobile phone charges etc
arguments. If (as my physics teacher once said) energy cannot be
created or destroyed, just converted from one form to another, we must
be "using" the energy. If they heat up, we're using the heat, if they
buzz then isn't that sound energy converted into heat through the air
(?), if they have a small LED on them doesn't the light again convert
to heat energy (save for the part that disappears through the windows
as visible light). So aren't they equally "efficient" as an
electrical heater?

Matt

You should tell her that the human body is excellent at converting food to
heat, and she needs to warm you up every night..
PIEAYOW...

Google CHP and Microgeneration.
"hopefully" we'll see Hydrogen to the home in the next 10 or 20 years, with
small home microgeneration based utilitys and DC power through your whole
house.
AC power is really wasteful, esp as most of it we convert back to DC for
just about everything!

You need to keep in mind that changing something in your house to a "more
efficent" system may incure more cost than what you will actully save.
On the flip side, If you have something that's not cost efficent at all, you
may be able to buy a new replacement product, and PAY for it in a year with
the savings in utility cost!.

"Roderick Stewart" wrote in
message .myzen.co.uk...
In article fdee4262-82c1-40ca-80cf-
, Larkim wrote:
One thing I've been puzzling recently is why we are told that electric
heating is "less efficient" than gas heating. Is that really true?
Or is it that a) electricity is more expensive per kWh, so to achieve
the same output is more expensive or b) electricity carries high(ish)
level of transmission losses on the way to my house, whereas gas
arrives in an "unused" state, and therefore I get nearly all of the
benefit of its heating ability I use it to power my boiler?

Yes to all of those I think. Burning fuel and converting it into heat
(with losses) to convert into electricity (with losses) to convey it to
your home (with more losses) to convert it back into heat again appears
intuitively less efficient than burning the fuel and converting it
directly into heat in your home. Perhaps somebody can provide some
figures, but I'm sure gas must be more efficient.

Rod.
--
Virtual Access V6.3 free usenet/email software from
http://sourceforge.net/projects/virtual-access/


Once the generation and transmission losses are suffered (around 55-60% and
up to 10% respectively), electricity in the house is 100% efficient at
turning into heat - even tungsten light bulbs are over 90% efficient as
heaters. The domestic conversion of delivered gas (and there are
considerable pumping-energy losses here too) into heat is of course less
efficient.

First, gas boilers have been around 70-75% efficient for the last 30 years
at least. New condensing boilers (which recover some waste heat from the
flue gases by condensing out some of the water vapour) are claimed to be
around 90% efficient. What they usually fail to mention is that those
boiler efficiency figures are achievable only under steady, flat-out,
full-load operation - rarely seen in domestic use, in my experience. If a
boiler is crashing on and off every few minutes on its water-temperature
thermostat because it is over-sized for the house (very common), or its
output is being seriously throttled by well-meaning TRVs on most of the
radiators, or is being used only for hot water provision during the summer
(also very common), its efficiency will be drastically reduced from the
ideal figures quoted by the sales people. It is impossible to generalise on
the extent of that kind of operational efficiency loss, but I have heard
many horror stories about huge gas bills from people with boilers operating
under such conditions. Certainly, I find that switching from LPG-fired
central heating (no mains gas here) to electric heating has saved me money
over the last 4 years (both fuels have about doubled in price over that
period).

The sums will be different for mains gas, which even now is much cheaper
than LPG, but anything you can do to maximise your boiler's actual
efficiency will pay well. Almost certainly for most households, a
time-switched electric immersion heater in a well-lagged cylinder will be
cheaper for hot water provision when you don't need room heating. Re. hot
water-only running, another iniquitous tendency has been towards "combi"
boilers, which fire up from cold every time someone opens a hot tap to rinse
their hands or wash out a cup. These must waste huge quantities of gas in
that kind of operation, where the user may not even wait for the hot water
to arrive at the tap.

TrevM

In article
,
larkim wrote:
I have a wife who is becoming obsessive about the use of electricity
and gas, and consequently is pushing up my requirement to know
something about these things.

One thing I've been puzzling recently is why we are told that electric
heating is "less efficient" than gas heating.

It's not. At the point of use it is pretty well 100% efficient. Gas only
about 92% in the best boiler - and much less in a fire.

Is that really true?
Or is it that a) electricity is more expensive per kWh, so to achieve
the same output is more expensive or b) electricity carries high(ish)
level of transmission losses on the way to my house, whereas gas
arrives in an "unused" state, and therefore I get nearly all of the
benefit of its heating ability I use it to power my boiler?

More to do with generation. If you use the same gas to generate
electricity you have those costs to pay for.

On a similar vein, there is the standby / mobile phone charges etc
arguments. If (as my physics teacher once said) energy cannot be
created or destroyed, just converted from one form to another, we must
be "using" the energy. If they heat up, we're using the heat, if they
buzz then isn't that sound energy converted into heat through the air
(?), if they have a small LED on them doesn't the light again convert
to heat energy (save for the part that disappears through the windows
as visible light). So aren't they equally "efficient" as an
electrical heater?

Problem is the waste energy from these things is often just that - wasted.
Same as the heat generated in the average household kitchen. To my mind
things like washing machines might be better situated in the bathroom
which is rarely too hot. Rather than in a kitchen which is.

--
*Don't byte off more than you can view *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
CD wrote:
For my son's bedroom I have turned off the radiator & put in an
electric heater. The way I see it is that if I used the gas radiator
it would be controlled by the stat downstairs, when that clicks on the
gas has to heat up water which then has to be pumped to every radiator
by electricity, heating up all the rads as it goes (unless I shell out
more on TRVs). With the electric heater it delivers instant direct
heat to his room. Me & the missus use a thick duvet.

TRVs are one of the most cost effective things you can buy. As are
programmable thermostats.

--
*Never miss a good chance to shut up *

Dave Plowman London SW
To e-mail, change noise into sound.

One thing I've been puzzling recently is why we are told that electric
heating is "less efficient" than gas heating. Is that really true?

Well, in terms of your home, absolutely not. It's more efficient. Gas or
oil boilers waste 8% to 30% of the heat through the flue. Electric heaters
give off heat with 100% efficiency.

Or is it that a) electricity is more expensive per kWh, so to achieve
the same output is more expensive

Yes, I think there's something in that. I haven't actually worked out the
cost in "delivered heat" of the two energy sources, but the information you
need is on the bill, I believe.

or b) electricity carries high(ish)
level of transmission losses on the way to my house, whereas gas
arrives in an "unused" state, and therefore I get nearly all of the
benefit of its heating ability I use it to power my boiler?

That is a very good point. The so-called "well-to-wheel" efficiency (the
term is used for automotive fuels, but you get the idea, I'm sure) is what
matters. I've done some online research in this area, and it is incredibly
hard to find out the *real* cost in energy when it gets delivered to your
home.

My gut instinct is that electricity involves more stages, and more losses,
than gas, and therefore will have a much worse overall efficiency.

On a similar vein, there is the standby / mobile phone charges etc
arguments. If (as my physics teacher once said) energy cannot be
created or destroyed, just converted from one form to another, we must
be "using" the energy. If they heat up, we're using the heat, if they
buzz then isn't that sound energy converted into heat through the air
(?), if they have a small LED on them doesn't the light again convert
to heat energy (save for the part that disappears through the windows
as visible light). So aren't they equally "efficient" as an
electrical heater?

Spot on. All the energy from your devices - including those on standby -
ends up as heat in your home. This means it is NOT wasted, except in the
summer when it's warm enough already.

SteveT