MINOR MEMOS. A US carbon tax of $20 a ton would raise $1.5 trillion over the next 10 years, according to a study released in August by the Massachusetts Institute of Technology. The study assumed the tax would start in 2013 and increase in amount by 4% a year . . . . President Obama issued an executive order on August 30 setting a goal of installing another 40,000 megawatts of cogeneration facilities at industrial sites by 2020. A cogeneration facility is a power plant that produces two usable forms of energy — for example, steam and electricity — from a single fuel. The order directs various federal agencies to work on eliminating barriers to installation of such facilities, including through use of set asides under emissions trading programs, grants and loans and use of “output based approaches” to regulating pollution that recognize the emissions benefits of moving to cogeneration . . . . IRS statistics confirm a trend toward greater use of passthrough entities. The IRS large business and international division has responsibility for the 250,000 largest US taxpayers of whom 75% are now partnerships and other pass-through entities rather than traditional  corporations. The IRS is trying to devote more resources to auditing companies with annual revenues of $10 to $250 million. Only 11.9% of such companies are audited currently.