Cap-and-trade vs. carbon tax
There are many instruments for lowering carbon emissions. Cap-and-trade is one, and a carbon tax is another. In some ways, carbon taxes and cap-and-trade are equivalent, but not all. In particular, in the event of a clean energy innovation, a carbon tax produces a superior result. Check out the economics:
First, consider the demand curve that could be drawn on a graph with Quantity of CO2 (Q) on the x-axis and Price of CO2 (P) on the y-axis. The demand curve slopes down to the right because higher carbon emissions are only desirable if the price of CO2 goes down.
A carbon tax amounts to controlling the P variable. The government might charge a price P* for emitting CO2, in which case companies will settle on emitting some quantity Q* that balances how much tax they pay with making money by producing and selling goods, which creates CO2. The government’s tax revenue is P*Q*.
In the case of cap-and-trade, it is Q that is controlled. Perhaps the government declares that only Q* of CO2 can be emitted and auctions off the permits to do that. The price of a permit will settle at - you guessed it - P* because that is the price that companies will be willing to pay for the right to emit Q* in their operations and still make the maximum profit possible. Again, the revenue from permits is P*Q* (although not to the government this time). [Aside: Notice that the amount of money a company has to pay is identical whether there is a tax or cap-and-trade. These two choices are economically equivalent, even if they have a different psychological effect].
However, which axis is controlled affects what happens when there is a clean energy innovation. Such an innovation has the effect that less CO2 can be emitted for any given level of activity – in other words, the curve shifts to the left.
- If there is a carbon tax, then that means the price of CO2 is held at P*, and the result is that Q(new) is to the left of Q* on the Q axis – ie, less CO2 is emitted.
- But if there is a cap-and-trade system, then the quantity is held at Q*, and the result of the shift is that P(new) is below P* on the P axis – ie, the price of permits goes down.
Conclusion: Because the larger goal is less pollution, the carbon tax gives the better result.
The flip side is that the carbon tax gives the worse result if technology changes mean greater energy consumption. With a carbon tax, emissions would go up, supported by higher revenue from the new technology, while the cap-and-trade system would hold emissions steady at Q* (and the price of permits would rise). However, given that we are currently in a time of clean-tech goldrush, it seems far more likely that we'll benefit from the carbon tax. Thus, I support a carbon tax over cap-and-trade.
However, companies generally prefer cap-and-trade. Recall from above that they are totally economically equivalent to a company: the same dollars must be paid out. Maybe the preference has to do with maintaining some sense of control; the very word "tax" is annoying to companies. Or maybe there is an ulterior motive: they'd like to influence the type of cap-and-trade system such that it includes grandfathering.
There isn't just one way to set up the cap-and-trade system. One possibility is to do it like the Northeast is doing it, where the total emissions are capped at constant in the near term, and then begin declining. There is also a scheme that includes "grandfathering"-- allowing plants to keep emitting what they are already emitting even though the cap may go down in the future. That means the brunt of the lower emissions is borne by new power plants, the argument being that it makes more sense to start fresh building clean plants than to mess around spending money on improving old plants.
I'm not so sure it's worth "writing off" the old plants. And I suspect another reason why companies support grandfathering is that it allows them to buy time, hoping that the legislation will change before the cap starts going down. After all, the cap usually starts declining a few years in the future (2009 for RGGI)-- plenty of time to change political administrations and get the whole scheme changed.
Again, the carbon tax is the superior option for the actual goal.
On the other hand, I have a friend who just made the cut to proceed with a Phase II proposal to sell carbon credits to RGGI power plants. His little company could supply a couple hundred thousand out of the 188 million permits being issued. It's a neat energy production method too: a biodigester that turns manure into energy. This has the duel advantage of preventing the manure from turning into nitrogen pollution, which is a big problem in agriculture these days. So I wish him well.
[Supplementary note: I just ran across this bit from New Scientist (June 23):
New Scientist Magazine has undertaken a survey to measure the level of US public support for three different forms of carbon emission regulations on the production of electricity and the manufacture of vehicle fuel. The three forms of carbon regulations that were examined were: low-carbon standards (i.e. setting fixed carbon reduction targets for either producers of electricity or producers of vehicle fuel), emissions taxes and cap-and-trade systems (i.e. emissions trading). The survey found that US citizens showed a clear preference for schemes that would set mandatory low-carbon standards on either electricity generators or producers of vehicle fuel and cost the consumer the least. Thirty-nine percent preferred low-carbon standards for electricity generators, compared with 8 percent who wanted to see the introduction of a cap and trade system for the production of vehicle fuels by oil companies. The survey also found that 85 percent of US citizens believe that global warming is happening – similar to the findings of earlier research.
There is a third way to control carbon - just dictate that it must be reduced to X amount by some deadline. This is, hands-down, the least efficient and least pleasant way to do it. It's not even the most just. In other words, Americans are favoring the worst scheme from nearly any viewpoint. So we should not be surprised when policies created based on this viewpoint fail in the near future. Cause, effect.
Carbon taxes and cap-and-trade are both more likely to be effective.]