Friday, October 24, 2008

Good article on 'green electricity'.

I always lampoon 'green electricity tariffs' in my lectures. The Grauniad published a good article on them yesterday. Key points: the electricity companies sell some MWh of 'green' electricity multiple times; and the big power generation companies are falling way below the fraction of green electricity that they are meant to produce under the subsidy scheme.


Adam Bernard said...

The readers' comments on that article make reference to companies that generate all their energy from renewables. Is this a sensible alternative, or another variety of the same scam?

David MacKay FRS said...

Companies that generate all their energy from renewables - yes, such as Good Energy... I switched to Good Energy a couple of years ago, but not because I think it makes any difference at all. I switched because I got fed up with Powergen's customer support sending me stupid leaflets hyping up their green credentials and refusing to answer the question "what fraction of your electricity is actually from green sources?" (The answer is that Powergen, at that time, got 2% of its electricity from renewables.) Their promotion of their "Go Greener" tariff infuriated me, telling people to believe that they had "done their bit" and "made a difference" by switching, when it clearly made no difference at all to do so. So I switched to Good Energy. But I don't claim that this does any good. As
I said in this webpage
, whenever I turn on my kettle, what actually happens is more fossil fuels get burned. Green tariffs are a delusion. The only good things that can be said about Good Energy are (a) they retire a tiny fraction of their ROCs (about 5% I think). This slightly increases demand for renewables, and causes the non-complying big power companies to have to pay slightly bigger fines; (b) if they charge more for electricity than the big fossil companies then some good might be done by switching to them. I haven't checked prices recently, but I don't think Good Energy charge much more, sadly. :-)

Heather said...

We switched to a company here in NZ (Meridian) that generates all its power from renewables and pledges to continue to do so. I know it doesn't change the source of the electrons that come down the wires into my house, but I figure, if more people change to them then more electricity will have to be generated from renewables (they are both a generation company and a retail company but not a lines company - this is the norm in NZ, I have no idea if it is the norm in other countries or not).

Of course, in NZ around 70% of our electricity is hydro, (with the rest divided between wind, geothermal and coal), so one heck of a lot of people would need to shift before the coal proportion went down. Hmm... maybe that wasn't such a logical move after all.

On the other hand, our previous supplier was the main coal generation company (Genesis), but their website really bugged me. It had this cute graphic about how electricity is generated that at no point mentioned coal. When I emailed them about this they told me that I had no reason to believe that my electrons were generated by coal.

Meridian also has some kind of 'carbon zero' certification that means that they plant trees (themselves, on their own land I believe) to compensate for the carbon released by their fleet, and they allow us to get our bills by email. All of which is to the good.

Random musings...

Unknown said...


Ecotricity currently generates about 50% of the kWh it sells to end customers such as you and me from its own (ever-expanding) fleet of wind turbines AFAIK; no messing about with certificates, etc, though I pay the higher 'all green' tariff to cover the remaining part too, nominally, with those ROCs. (And indeed generate most of that remaining chunk from my small grid-tie PV system...)

OK, the timing of generation and use of those kWh may not match exactly, but I believe that fossil-fuel burn is being deferred/displaced.

I think that a long-term solution would be some type of smart metering where we pay (a) in proportion to the wholesale price in each half-hour slot to encourage reduced peaks/strains on the system and (b) a surtax for power in each HH slot based on the carbon intensity in kgCO2e/kWh of generation supplying that consumption to again explicitly encourage efficiency, conservation, use of RE, and movement to less-carbon-intense primary energy timing.

That would firmly push people in the direction of renewable power and prick the marketing bubble of the browner suppliers, IMHO.

I suggested to National Grid last week that when it revamps the realtime stats section of its site that it adds a HH CO2-intensity estimate too.



Unknown said...


Your idea is charming. I trade power using APX Power UK and would love to be in a position to vary my electricity consumption according to wholesale price. However, I am convinced that the implementation would be too complicated for the mass market. It may be instructive to consider EDF's Tempo tarriff in France, which does a comparable thing, but attempts to balance load over a year rather than over a day. It's fairly sophisticated but seems to have caught on well in France - does it represent a practical upper limit to complexity?

I am not sure that the result of it would be to trend consumption in favour of renewables so much as it would to attempt to flatten the peaks, thus pushing the competitive advantage towards baseload plant - which isn't necessarily the same thing as renewable plant at all.

I am most amused by the thought of consumers choosing to defer their electricity-intensive activities in response to major stations tripping; over the last month or two, we've seen massive volatility in spot markets and prices varying by a factor of probably 15-25 from trough to peak. (Next week might set things higher still.) When household-scale fuel cells become a commercial reality, it's really cute to think of people choosing to charge their own fuel cell, possibly implemented within vehicle-to-grid technology, when power is cheap and then using it locally when power is expensive. (A Dinorwig in every home!)

Unknown said...

Ah Chris,

How damned I am to have my idea be 'charming'! B^>

I don't know where the limit of tariff complexity is, and some/many in future may be prepared to pay a premium for a simpler tariff like current ones in the same way that I am prepared to pay a premium for a fixed-rate mortgage even though I have sat amongst the fixed-income traders for ~15 years and ought to be able to handle interest rate risk as well as any.

Still, the mixture of carrot (being able to get cheap electricity if you can/do move loads) and stick (surtaxed if you cause extra CO2 to be belched out in support of stuck-in-the-mud ways), seems to be the right sort of approach.

I favour forcing this per user above ~500kWh/month in fact, which is where the greatest (emissions) savings are to be made I expect.



Unknown said...

BTW, thanks for the Tempo lead: very interesting.

Various US utilities do already have tariffs that vary by hour of day and by season, and a mix within each delivery area may be a good thing, too, so it's interesting to see how yet another variant works.



nommo said...

"Companies that generate all their energy from renewables - yes, such as Good Energy..."

But are they building new sources of energy or just reselling what is already there?

"Green tariffs are a delusion."

Only because there aren't enough new green sources of energy being built. If that *was* the case, then when you turned on your kettle - no more fossil fuels would be burned. Or am I missing something?

No prizes for guessing who I work for ;-)

Here's another clue - why not see what Dale Vince has to say about he subject of green tariffs...

(he is linking to you in his blogroll!)