In East Hanover tomorrow, protesters will demonstrate against plans for a giant new power line running from Susquehanna, Pa., into Roseland in Essex County.

You have to have some sympathy for them. This line will be ugly and sections will stretch nearly 200 feet tall, dwarfing the existing line. As it winds through the Highlands region, it will tarnish unspoiled views.

But the hard fact is that New Jersey needs this line, or we will soon be at risk of brownouts and blackouts. Imagine how helpful that would be to the region’s economy, to the quality of life and to public safety. Let’s face it: We need the juice.

The opponents of the line say it’s not needed. But that is wishful thinking.

The existing line was built in the 1920s, long before television, computers and hair dryers. It simply can’t handle a modern load much longer.

That’s the conclusion of experts empowered by the federal government to manage the regional grid. The state Board of Public Utilities studied it as well and came to the same conclusion.

Some worry that the line will be a conduit for coal power from our west and add to pollution.

But this line will carry all kinds of power. Of the new generation waiting to connect to the grid, wind power far exceeds coal power.

We favor a moratorium on new coal plants, a cap on carbon emissions and tough regulations to force cleanups at Midwest coal plants. To control coal by killing transmission lines would close out cleaner energies as well, and wreak economic havoc.

Residents also worry that electromagnetic fields from the power lines can cause cancer. Some demographic studies show a correlation, though others do not. And tests on animals and cells have generally shown no danger. After a thorough review, the World Health Organization has concluded there is no evidence these lines cause cancer.

The New Jersey portion of this line will be built by PSE&G, entirely along the existing right of way. The holdup now is the National Park Service, which has dragged its feet for three years in an act of bureaucratic sabotage. The line would travel a few miles across the Delaware Water Gap, along the same route as the existing line. That’s should not take three years to sort out.

Interior Secretary Ken Salazar recently put this project on a fast track, as part of an economic stimulus push, so perhaps there is hope.

PSE&G estimates the project will create roughly 1,750 construction jobs for an average of two years. And it will lower electric bills by reducing congestion on the grid by an estimated $233 million per year.

Those who purchased homes along the existing line took a risk, and typically got a discount for it. It is a pity they will have to cope with an even taller line now.

But the larger public interest is clear: The sooner construction starts, the better.