Hillary Clinton's goal of installing half a billion solar panels by the end of her first term would prove highly profitable to firms connected with the Democratic front-runner.

First Solar, Inc. and NRG Energy — the two largest solar contractors in the country, according to Solar Power World — both gave significant contributions to the Clinton Foundation.

The fourth-largest solar energy company, SolarCity, tapped the Podesta Group to lobby the government on its behalf. The powerful Podesta Group was founded by Tony and John Podesta, the latter of whom now chairs Clinton's presidential campaign.

SolarCity's founder, Elon Musk, reportedly led California's donors to the Clinton presidential campaign.

Clinton's Federal Election Commission disclosure forms indicate some of the lobbyists — including Tony Podesta — that bundled large donations for the campaign also lobbied the government on behalf of solar companies that stand to benefit from a federal push toward more solar energy.

For example, David Leiter, who bundled $36,500 for the Clinton campaign last quarter, has lobbied for Strata Solar, another major renewable energy company.

But Clinton's longstanding ties to big oil, minimized in her Sunday clean energy video, raise questions about her push to move away from the industry.

Like her support of Wall Street reform, which contradicts the fact that many major financiers support her campaign, Clinton's push for renewable energy contradicts her past support of more traditional energy sources.

Her family's foundation has also accepted generous donations from top corporations — such as ExxonMobil, ConocoPhillips and Royal Dutch Shell — that rely on fossil fuels.

Clinton's ties to Chevron, for example, include the fact that top lobbyists for the company have bundled huge contributions to her presidential campaign.

In fact, Clinton's campaign finance disclosure forms reveal several lobbyists who are fighting against the very protections Clinton has advocated for are bundling for her campaign, a Mother Jones report noted.

Chevron lobbyists pushed the State Department to intervene on its behalf in a consequential environmental lawsuit that could have cost the corporation billions.

The oil conglomerate had been accused of severely polluting rainforests in Ecuador.

Jackson Dunn, who bundled $231,554 for Clinton's campaign between April and July, lobbied for offshore oil driller Noble Energy, according to the Center for Responsive Politics.

Dunn was the largest lobbyist campaign bundler Clinton reported for the most recent quarter. His client, Noble Energy, donated between $250,000 and $500,000 to the Clinton Foundation.

As secretary of state, Clinton had the authority to review a proposed plan for the Keystone Pipeline because the project would have crossed the Canadian border.

Her handling of Keystone while at the State Department was called into question at the time by her close relationship with Paul Elliott, a lobbyist for TransCanada and former Clinton campaign aide.

Emails between Clinton's staff and Elliott suggest he leveraged his relationship to gain access to the secretary.

Another Clinton Foundation donor, Anadarko Petroleum, was reportedly forced into the largest environmental settlement in U.S. history after it was accused of tainting thousands of sites with chemicals.