Tech giants are gathering in support of the Obama administration's contested plan to shift the US toward clean energy. Apple, Google, Microsoft, and Amazon joined together to file a court brief on Friday, describing their reasons for supporting the Environmental Protection Agency's Clean Power Plan. "Delaying action on climate change will be costly in economic and human terms, while accelerating the transition to a low-carbon economy will produce multiple benefits with regard to sustainable economic growth, public health, resilience to natural disasters, and the health of the global environment," the brief says.

The Clean Power Plan intends to cut carbon pollution 32 percent below 2005 levels by 2030. Accomplishing this will require more than just deployment of renewable energy sources; states will likely have to make their existing coal-fire plants more efficient, or else reduce their usage of them. The rules are currently being challenged in court by 27 states. In February, they were put on hold by the Supreme Court, signaling that the court — as it was then composed — may be leaning in the plaintiffs' direction.

It may be fair to question how much weight the DC federal Court of Appeals, where the case is currently being tried, will give to the input of technology companies on a case about energy. But the four companies say there's good reason to listen to them: they're "major purchasers of electricity" who all hope to eventually use entirely renewable sources and are already making large strides in that direction. That makes them "well positioned to offer a practical perspective on the issues raised by this case," they write.

The tech companies write that implementing the EPA's rules will make renewable energy supplies "more robust, more reliable, and more affordable." Affordability is a point they return to on a few occasions, mentioning that this plan ought to improve energy pricing by removing volatility in the market. Renewable energy, they write, "provides greater long-term cost certainty" and is often equivalent to or cheaper than current options.

States argue that the rules are onerous and represent and overreach of the EPA. Apple and the others try to argue that these rules don't represent that much of a challenge. They've been moving toward renewable energy for years, and the power companies complaining about this rule can use the "same techniques that [Apple, Google, Microsoft, and Amazon] have successfully used to help accelerate their sustainability goals." It's already proven that these goals are achievable, they essentially argue.

The case will go first to the DC court, where arguments are scheduled for June 2nd. The Obama administration seems to have a better chance of prevailing here, as judges in this court declined to put the rules on hold pending trial. That's fortuitous for the EPA (and anyone who doesn't want to see climate change ravage the world), because the case will probably proceed to the Supreme Court, which is, at this time, likely to produce a split decision. That means the DC court may have the final say here, which is why clean energy advocates are coming out in force to support the case now.