We've covered a lot of good news in the energy business this year. But the most compelling stories are often the ones about people, companies and governments doing questionable things. Or bad things happening to them. Or both.

We found plenty of those stories to discuss and debate this year on the Energy Gang podcast. 

Below is a curated list of our best conversations about poor business decisions, bad government policies and general turmoil -- what we like to label the top turkeys of the year. Coincidentally, they happen to be some of our most-listened-to shows. 

1. Exxon

The world's second-biggest oil company is in hot water. A series of stories this fall from Inside Climate News, the Los Angeles Times and the Columbia journalism school showed that Exxon was once a leader in climate research. In the late 1970s and 1980s, the company found alarming results about the potential for greenhouse gases to warm the planet. But it later ditched that research, wound down most of its alternative energy investments and started funding climate denial groups. That history remained largely untold until this year.

The company is now on the defensive. The New York Attorney General is investigating Exxon for potentially misleading shareholders about risks to its business, and members of Congress have also called for a federal inquiry.

Listen to our conversation with Neela Banerjee, a reporter with Inside Climate News who broke the story with her colleagues:

2. The coal industry

The last few years have been extremely difficult for the coal industry. Since 2012, more than 40 U.S. coal companies have filed for bankruptcy. But 2015 was a particularly bad year financially and politically. Cheap natural gas and renewables have made building coal plants infeasible, prospects for coal export facilities continue to worsen, and the bankruptcies continue. Making matters worse, international demand for coal is softening. 

Things have gotten so bad, Republicans are hardly defending the industry on the campaign trail. 

Listen to our conversation with Taylor Kuykendall, a coal reporter for SNL, about the dire situation for coal:

3. SunEdison (and a bunch of other publicsolarcompanies)

The year started off well for SunEdison. The company was building record numbers of projects, expanding its portfolio through acquisitions and selling projects to its YieldCo at attractive prices. Investors seemed to like the growth strategy -- until they didn't.

After the $2.2 billion acquisition of Vivint Solar, things fell apart quickly for SunEdison. Investors seemed confused by the purchase of Vivint, and worried that the company was over-leveraged. Those factors, combined with concerns about interest rate hikes and low oil prices, caused SunEdison's stock -- and the stock of its YieldCos -- to drop precipitously. After a frenzy of activity, the developer is now cutting staff, making some executive changes and reining in expansion plans.

SunEdison wasn't the only one to take a hit. Enphase, NRG and SolarCity all faced challenges this year that caused their share prices to plummet -- some due to real issues within each company, and some due to fickle market sentiment.

Listen to our conversation about why the market turned on SunEdison so quickly:

4. Australia, Spain and the United Kingdom

Australia, Spain and the United Kingdom have each been considered leaders in renewable energy development. Australia has over 1 million solar rooftops. Spain gets more than 40 percent of its electricity from renewables some months. And the U.K.'s robust wind sector is having a strong impact on natural-gas use.

But these countries are also dealing with severe problems. The Spanish government passed a "sun tax" that makes solar-plus-storage systems cost-prohibitive for most consumers. Meanwhile, Australia and the U.K. continued to roll back their domestic promotion of renewables and efficiency. All of these countries are dealing with legitimate issues related to taxpayer and ratepayer cost -- but advocates and businesses say none of them have put in place plans that would provide both certainty and cost efficiency.

Listen to our show on the politics behind changes in Spain and Australia:

5. The Republican party

Remember when Nancy Pelosi and Newt Gingrich sat together on a couch and talked about the need to address climate change? That seems like ancient history now. In the years since, prominent national Republicans have disparaged cleantech and deceived the public about climate change -- drowning out the many voices within the party who have good, conservative ideas on both.

This year brought a genuine shift to the discourse, at least on the local level. Conservative grassroots activists accelerated their successful campaign to open up grid access to solar. Libertarian organizations are working behind the scenes on a (still very unlikely) carbon tax in Congress. And former Congressman Bob Inglis continues to build a coalition of young, passionate conservatives who believe that the future of the Republican party depends on addressing climate change.

We had a few good shows with conservative thought leaders on these issues (see the links above). However, the one below features a conversation with Vox's David Roberts, who argued that the structure of the Republican party is not currently built to accept their ideas.

Honorable mention: YieldCos

For the last two years, we've had dozens of articles on the promise of YieldCos. But the second half of 2015 was all about the YieldCo bust. 

The premise is simple: shovel projects with contracted long-term cash flows into a public entity, issue dividends to investors looking for a low-risk investment in clean energy, and use the rising stock price to finance projects at a lower cost. But the market is not that simple.

Many YieldCos were structured on the promise that their share prices would continually go upward. Some companies were also making big promises about cash available for distribution to investors, which meant they needed to buy up as many projects as possible at high prices. Making matters worse, a glut of YieldCo shares hit the market over the last year and a half, and there wasn't enough demand to support them.

The bubble finally popped in 2015. In a recent episode of the Interchange, we talked with investor Tom Konrad about what a recovery for YieldCos will look like: