As Congress gets set to reconsider a long-awaited, long-postponed renewable-energy incentive package Tuesday, two regional efforts to reduce greenhouse-gas emissions in North America also could advance this week.

The U.S. Senate is expected to vote on about $17 billion in renewable-energy tax credits and incentives Tuesday as it renews debate over a massive tax package that would cost $83 billion over 10 years (see Senate Delays Vote on Energy Tax Credits).

Both the Senate and the House of Representatives have tried and failed several times this year to extend the renewable-energy tax incentives, which are set to expire at the end of the year.

Solar, wind and other renewable-energy investors and executives say renewing those tax credits, which would offset 30 percent of the cost of a solar or wind-farm project, will be critical to maintaining investment in their industry (see No Tax Credit, No Solar Power and PG&E to Buy 800MW from Optisolar, SunPower).

Meanwhile, the Western Climate Initiative - a group of seven western U.S. states and four Canadian provinces -on Tuesday plans to release an outline of a proposed cap-and-trade system aimed at reducing greenhouse-gas emissions to 15 percent below 2005 levels by 2020, according to the Union of Concerned Scientists, an environmental-advocacy group.

And on Thursday, the Regional Greenhouse Gas Initiative will hold its first auction of carbon-dioxide permits for a mandatory cap-and-trade system for power plants in the six New England states, New York, New Jersey, Delaware and Maryland, the UCC reported.

The system goes into effect in January and aims to cap all power-plant emissions at the same level through 2014, then reduce them by 10 percent by 2019 (see NYMEX to Trade Carbon-Emission Allowances and U.S. and Canada to Create Carbon Cap-and-Trade System). The idea is that power companies would buy emission permits at auction and the proceeds would be spent on energy-efficiency and renewable-energy initiatives.

Lance Pierce, UCC's climate program director, praised the Regional Greenhouse Gas Initiative's goals, but urged the group to use more up-to-date emissions data to press for greater emission reductions than the initiative is expected to demand.

Pierce said he believes the initiatives' caps, set using 2005 data and with built-in expectations for higher growth in emissions than has actually taken place since then, may be too low.

As for the Western Climate Initiative, Pierce said individual states and provinces may be able to push for deeper greenhouse-gas reductions by demanding that all the emission permits involved in the initiative be auctioned, rather than doled out for free.