Explaining the ‘trade’ in ‘cap and trade’

David Osterberg
David Osterberg

“Cap and trade” is a term growing in use but still needing explanation. We all get the “cap” part. The way to clean our water and our air is to “cap” the amount of pollution entering it. The “trade” part is a little more confusing.

The ‘cap’
Let’s assume that we see health or aesthetic damage from all the pollution in the air and that we have identified 121 tons of it being generated by a finite number of factories and other sources. Assume that good science says that we need to cut those identified emissions by half — 50 percent — to have an effect. Because it will be easier to get to that goal by giving the polluters some time to put in the pollution control or close down heavily polluting plants, we decide to reduce emissions by 10 percent a year over the next five years. The identified firms are told they need to cut the entire 121 tons to 110 tons by the end of the first year. That is the “cap” part of cap and trade.

The ‘trade’
The trade part of pollution reduction lets firms choose how to get to the total reduction. A firm with 10 plants equal to 11 total tons can decide to cut a quarter-ton from each of its four newest plants to reduce the 1 ton it is required to meet, and let the other plants produce as they formerly did. This works because we are interested in the total number, and it allows the company to meet the mandate to cut emissions by choosing the cheapest way within the company. A 10 percent reduction from all 10 plants would also get us the 1 ton, but this might be more expensive.

Firms also can trade with each other to help the economy achieve the desired reduction in emissions. The company that chooses to concentrate pollution in a few plants might want to go further than the 0.25 tons in each new plant. Its managers know that next year there will be another 10 percent reduction and 10 percent the year after that, so they might want to cut emissions just once and begin the process of eventually reducing even more. Going further than required this year will earn the firm credits, which can be saved for the next round of reductions, or purchased by a firm with mainly old plants that are hard to refurbish. This creates a market in which a broker agency sets up something like a stock exchange to trade the extra credits of one firm to the firms that want to purchase them. It is assumed that this marketplace will produce a cheaper solution to getting the same 10 percent total reduction in pollution that a simple mandate for each company, or even each plant, to reduce emissions by 10 percent.

The credit marketplace
The price of the credits is not known at the beginning. A firm might plan for a reduction on its several plants when learning that the price of credits is cheaper than first thought. The firm would then buy credits and do the plant cleanup next year. Alternatively, a firm might find the market for credits is so high that it can cut more emissions immediately and pay for part of the job by selling extra credits. That is how markets work and it shows how the trading part of cap and trade can address pollution from the big-ticket generators.

Posted by David Osterberg, Executive Director

Author: iowapolicypoints

The Iowa Policy Project is a nonprofit, nonpartisan organization that provides research and analysis to engage Iowans in state policy decisions. We focus on tax and busget issues, the Iowa economy, and energy and environmental policy. By providing a foundation of fact-based, objective research and engaging the public in an informed discussion of policy alternatives, IPP advances effective, accountable and fair government.

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