Constellation gives the following energy/environmental benefit:
Ares V heavy lift - Heavy lift could be used to launch major environment monitoring satellites. However, it's not clear that such expensive heavy lift rockets or their payloads are affordable by environment or energy agencies, or that alternate strategies like dry launch and in-orbit fueling, docking, and in-space assembly wouldn't work better even if such payloads can be afforded in the first place. Also, Ares V heavy lift would not be available until about the year 2028.
The new NASA budget gives the following energy and environment benefits:
Critical Technology Demonstrations - This portfolio includes technologies useful for environmental stewardship on Earth like closed-loop life support systems (i.e. recycling). It also includes technologies that ultimately should allow us to better maintain and service environment monitoring satellites, such as in-situ resource utilization and in-orbit propellant transfer and storage. This effort also includes power generation and storage technologies that could have use on Earth.
Space Technology - This effort in general space technology includes many technologies that can benefit Earth observation satellites that can monitor the environment, help transportation systems on Earth run more efficiently, and assess energy resources on Earth. Examples presented in the budget documents include communications, sensor, materials, small satellites, and low-cost access to space.
Full Utilization of the ISS - Remarks by NASA management in the budget rollout indicate that one of the uses of the ISS would be to fly Earth Science payloads. Use of commercial crew for ISS transportation and demonstrations of inflatable structures on the ISS could help bring about commercial space stations that could be used for the same purpose.
21st Century Launch Complex - The upgrades to the Kennedy Space Center include enhanced environmental cleanup.
Earth and Climate Science - NASA's Earth Sciences portfolio gets a large increase, which is directly applicable to monitoring the environment. This includes accelerating the development of several new environment monitoring satellites. It also includes expanding and speeding up the new Venture-class Earth science missions, which are small Earth science investigations appropriate for suborbital rockets, small satellites, and other low-cost platforms.
Aeronautics and Green Aviation - The increases for Aeronautics include environmentally responsible aviation work.
It's pretty clear that the new budget is a win from the energy/environment perspective.