Underground Power Lines: FACT OR FICTION??
You've heard... The rest of the story...
The utility must use the least cost method for a project

The Public Utilities Commission of Nevada (PUCN) requires that the utility use the least cost method or the additional cost cannot be recovered in rates.

No, the PUCN requires that the utility exercise prudent judgment in construction of needed facilities.

But, if the local government requires using a more expensive method (e.g. undergrounding) as a condition of issuing the Special Use Permit, then the additional cost for undergrounding can be recovered in rates. Rates take into account overall income, expenses, and allowed return to utility shareholders.

So the utility can put the cost of undergrounding in the rates to be recovered from all customers.
Undergrounding requires a new state law.

It is necessary to pass a new state law in order for the costs of undergrounding to be recovered in utility rates.

Yes, there was a proposed state law (which failed) about putting the cost of undergrounding into rates.

But the proposed law wanted to put the cost over the small area affected rather than over the whole utility district of northern Nevada. This would have unfairly burdened rural areas especially where transmission lines are concerned, so it was rejected. However, nothing currently forbids undergrounding being put in the overall rate. In fact, SPP just put in two underground lines in Reno with no prior PUCN review or approval.

So the current PUCN regulations allow recovery of underground costs.
Undergrounding is too expensive.

The recent downtown underground projects cost $2,000,000 per mile. This is eight times the $250,000 per mile cost of overhead construction.

Yes, total urban undergrounding in Reno can cost $2,000,000 per mile.

But total urban overhead is about $400,000 (not $250,000). The cost difference is $1,600,000. This can be lowered with rural construction, shorter routes and less right of way costs. Our figures show a worst case monthly cost of 1.5 cents per mile for a residential rate payer.

So 30 miles of selective undergrounding in the next 20 years will cost less than 50 cents per month for residential rate payers: the cost of one newspaper.
Undergrounding is uneconomical.

Undergrounding part of the route will make the project so expensive that it will not be a good investment of utility money.
Yes, selective undergrounding may increase the overall construction cost of a route. In the proposed Sugarloaf -Tracy project it could go from a projected $10 million to, at worst, $15 million. This $5 million can be reduced by shorter routes and less right-of-way costs. (Sierra Pacific incurred over 9 times that much in  overruns alone on the Alturas transmission line. It was projected at $102.5 million, but cost $150 million.)

But prudent investment for any utility facility is allowed to return the same amount to shareholders.

So the utility should be economically indifferent to the type of investment as long as it is prudently incurred.

120 kV is not for wheeling power.

Will the proposed 120 kV line be for local usage or will it be used to wheel power? (Wheeling power is the transfer of bulk power across the system for use by other utilities.) It is said that 345 kV is for wheeling power and that 120 kV is not used for wheeling.


Yes, most wheeling is scheduled on 345 kV lines rather than on 120 kV.


  1. until the early 1970's, all imported power into the Reno area came in on one 60 kV and two 120 kV lines. The 120 kV lines wheeled power then and still do wheel power.
  2. The proposed 120 kV line will unload power from an overloaded 345 kV line, freeing it up for potential wheeling.
  3. The 120kV system provides reliability to the total transmission system.

So though the utility does not exclusively wheel power on 120 kV lines, 120kV loops free up capacity on 345kV lines and supplement needed backup.

There is a 3 year rate freeze with the SPP merger.

Extra costs cannot be added in because of the rate freeze.


Yes, the rates are frozen for 3 more years.

But the rates have been frozen since 1994. They were frozen based on 1988 expenses and revenues. Fuel costs were higher then. Instead of lowering the rates because of lower fuel costs, last year the utility made excess earnings and consequently refunded some to customers. Even with the rate freeze, the utility usually invests about $100,000,000 in capital improvements every year. Also, construction costs are generally spread over 30 years and don't get included in rates until the system is placed in service.

So instead of 30 years, they may recover costs over just 28 or 29 years.
Underground lines generate more EMF.

Concern has been expressed about people being closer to underground lines


Yes, there is less distance from the wire.

But there are two fields - electrostatic and magnetic. Overhead wires have both. Underground wires are shielded and have no electrostatic fields. The three wires for the three phases are placed much closer together on underground than overhead. The three phases in underground thus cancel out the magnetic effect in a much shorter distance than with overhead. 

In any case, Sierra Pacific supports the position that EMF has no adverse health effects.

So with underground, there is no electrostatic field and the magnetic field does not extend out as far as overhead.
Underground transmission lines are more dangerous than overhead lines.

Some have mentioned concern about the potential danger caused by accidentally digging into the 120 kV power line,
Yes, there is danger if one digs into an underground 120 KV line.

But most new distribution lines are underground, and they are just as dangerous. Any digging now requires checking for all underground - telephone, water, gas, sewer and power. Also, the 120 kV lines have concrete above them to help remove heat - it alerts diggers that they are approaching lines. 

Contact with overhead wires causes many more problems than digging. Kites, vehicles and boom trucks do not come into contact with underground lines. (OSHA lists "Contact with overhead power lines" as an occupational fatality category - the cause of 41.6% of electric current deaths in 1996. Underground power lines did not have enough events to be a separate category.) Fires are not started by underground lines and fires do not destroy underground lines.

So overhead wires have many more dangers than underground lines.