The messiness of those politics is coming into sharper focus once again, as U.S. legislators attempt to revive some of the clean-energy initiatives included in President Biden’s failed Build Back Better bill.

Annual investment in physical assets will have to increase by $3.5 trillion to $9.2 trillion a year in order to decarbonize the global economy, according to estimates from consulting firm McKinsey. Only a fraction of that will come from public sources, but the incentives, goals and regulations politicians set strongly affect private investment, risks and returns.

In the absence of a global carbon price—a political nonstarter—well-designed national energy plans can be powerful ways to accelerate the transition by coordinating action and reducing investment risk. To reach anything close to the common goal of net-zero emissions by 2050, change needs to be at least twice as fast as when the world shifted from coal to oil last century.

However, elected leaders have incentives to lean toward short-term, partisan thinking and local issues. This is the opposite of the consistent, linked-up kind of planning needed.

Britain’s latest energy security plan, published last month, is a useful example. It contained some much-needed initiatives to streamline approvals for offshore wind farms and accelerate investments in energy efficiency. However, it also focused too much on shiny new infrastructure projects to be built many years from now, while avoiding more contentious solutions that could be delivered much sooner.

There were headline-grabbing ambitions for up to eight new nuclear plants, as well as funding for small nuclear reactors from British corporate icon

Rolls Royce.

Those will take years or even decades to start producing energy, if they happen at all. New U.K. nuclear plants have been a political hot potato for years.

Britain also aims to become the “Saudi Arabia of wind power” and is boosting incentives for offshore turbines, including streamlining planning and permitting, which is many developers’ key gripe. However, the plan didn’t include any significant incentives for onshore wind. Land-based turbines are relatively cheap and quick to build, but often face local opposition. The system could be simplified, but would inevitably mean limiting people’s right to object, rarely a winning political strategy.

In the U.S., where the energy transition is a much more partisan issue than in the U.K., the politics are arguably even tougher. Upcoming midterm elections are weighing heavily on the timing, content and approach to reviving any of the clean energy incentives from the failed Build Back Better bill. Even the name is verboten.

There are political ambitions to foster domestic solar-panel production, but they will take years to bear fruit. Meanwhile, a U.S. Department of Commerce investigation threatening retroactive antidumping tariffs on solar panels made in Cambodia, Malaysia, Thailand and Vietnam has led to delayed and canceled orders. It is threatening projects and ultimately local installation jobs, causing a “rapid degeneration of the U.S. solar industry,” according to Solar Energy Industries Association.

Yet there are signs of progress in other areas. One key bottleneck is approval for transmission lines: A record 1,400 gigawatts of total generation and storage capacity are currently seeking interconnection to the grid, more than the current U.S. generating capacity of 1,200 gigawatts, according to a new paper from Berkeley Lab. The Federal Energy Regulatory Commission is now working on a series of proposed rule changes to streamline the processes for approving transmission lines.

“You can think of the grid as being the interstate highway for electrons”, says former FERC chairman

Norman Bay

of Wilkie Farr & Gallagher. “Imagine what the national highway system would look like if the federal government had not taken the lead in 1956 of planning it, getting rights of way, and covering the costs.”

President Eisenhower’s Federal-Aid Highway Act of 1956 wasn’t universally popular, but it was fairly successful in delivering a national road network. Such a sweeping national act seems unlikely in the current political climate, but more mundane actions by officials at the FERC and elsewhere might benefit from flying under the radar. Key areas of the energy transmission that rely on them, such as transmission lines, may not be a bad place for investors to look.

Write to Rochelle Toplensky at rochelle.toplensky@wsj.com