Archive for January, 2009

BT line rental increases - Why do paper bills at BT cost so much?

The Telegraph reports that line rental for all British Telecom customers will increase by £1/month.

Communication Breakdown
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For somebody who receives paper bills, this is a rise from £11.50/month to £12.50/month for those on paper billing. For those on paperless billing (i.e. online), bills will increase from £10.25/month to £11.25/month. According to BT, customers can mitigate the price rise by switching to paperless billing at the same time. This is a fantastic demonstration of price discrimination.

On face value, having to pay an extra of £1.25/month for a paper bill seems ridiculous. It is obvious that this £3.75 per quarterly bill charge isn’t there to cover BT’s costs. There is no way that printing, processing and mailing a phone bill every quarter would cost more than 30p. That would leave BT with an additional £3.45 of pure profit per quarter for every paper bill customer.

I’ll explain using the old prices of £11.50 for paper billing and £10.25 for paperless billing.

The market rate for line rental is £11. BT’s rivals such as Virgin Media charge approx. £11. For BT to be price competitive, it must have a lower line rental than Virgin. If BT generally offered line rental at the paper bill rate of £11.50, it would be extremely uncompetitive against Virgin. However, at the paperless rate of £10.25, BT would be much cheaper than Virgin. But they’d probably make a lot less money as the profit on each line rental would be lower than it could be.

Companies get the best of both worlds by charging customers who don’t mind paying more (price inelastic customers), more. Customers which do shop around for line rental and do care how much they pay (price elastic) will pay less.

Red London Phone Boxes
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The costs of paper and paperless billing have absolutely nothing to do with the different line rental charges. It’s simply a way for BT to differentiate between how price elastic customers are. My grandmother can’t be bothered to shop around or to go to the effort of accessing electronic bills. She has paper bills and pays £11.50.

On the other hand, somebody like me will shop around to find the best deal. If BT charged me £11.50 as well, I would choose Virgin for a saving of 50p/month. But as BT’s paperless line rental is lower than Virgin’s line rental, I would choose to go with BT and paperless. For me, the cost saving would be worth the small extra effort to check an online bill.

By charging different prices to different customers depending on how much they are willing to pay, BT can increase their customer base without cutting their prices for everybody and their profits.

It is quite a clever way of operating price discrimination and has a double whammy in allowing BT to proclaim that it is encouraging people to be green. It’s something businesses do a lot and something well worth being aware of. See my previous post , “Why is popcorn at the cinema so expensive?”, for another example.

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“Carbon cost” of Google search same as boiling a kettle

Google Lego 50th Anniversary Inspiration
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The BBC reports today on a study by Harvard physicist Alex Wissner-Gross. Wissner-Gross claims that performing a standard Google search on a desktop computer produces 7g of CO2. A quick session with two searches will produce 14g of CO2 - the same as that from boiling a kettle.

From the BBC article:

Although the American search engine is renowned for returning fast results, Dr Wissner-Gross says it can only do so because it uses several data banks at the same time.

Speaking to the BBC, he said a combination of clients, networks, servers and people’s home computers all added up to a lot of energy usage.

“Google isn’t any worse than any other data centre operator. If you want to supply really great and fast result, then that’s going to take extra energy to do so,” he said.

According to Google Web History, I’ve performed 9,308 Google searches and it’s only counted the searches I’ve performed whilst I was logged on.

I’m guesstimating I perform about 40 searches a day; that’s 15,000 Google searches per year (sounds scary when you put it like that). My annual Google carbon footprint would be 105kg of CO2 (0.15 tons).

Google have disputed this figure; saying that a search only produces 0.2g of CO2.

I’m not able to comment on what I think of the methodoly as I don’t know how either figure was reached. But I think it is important to point out the difference between average cost and fixed cost.

As an example, imagine a server farm which was responsible for 100g of CO2 emissions every day. If ten people perform searches, the average carbon cost of a search is 100g divided by 10 searches = 10g of CO2 per search. This is the average cost of the search.

Beijing smog
Creative Commons License photo: kevindooley

Whereas, the marginal cost would be the CO2 cost of performing one more search. If we then performed an 11th search, the CO2 emissions of the server farm stay the same (we assume it’s running with spare capacity). The marginal cost of performing a search of zero grams of CO2.

With eleven searches, you could claim each search had a carbon cost of 9g. But that’s a bit unfair - considering the CO2 output of the server farm if you had made the search and if you had not, you find the CO2 output it exactly the same. Your search had a marginal cost of zero grams of carbon.

Whether Wissner-Gross and Google stated the average cost or the marginal cost I don’t know (although I suspect the first may have been the average cost and the second the marginal cost).

With Google’s server farms, we know that they will be running regardless of whether we perform searches or not. The important thing then is the marginal cost of a search - this being so close to zero, I don’t think any of us should feel a guilty conscience from using Google.

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