Exhibit 99.410

                     NEGATIVE ZONAL MARKET CLEARING PRICES

WHAT ARE THE ZONAL MARKET CLEARING PRICES

PX's Zonal Market Clearing Prices (MCPs) are intended to capture the geographic
variations in the marginal energy prices in California at those times when
transmission system is congested and energy cannot freely flow between all
zones. At times when congestion exists in the ISO controlled grid, the PX, like
all other Scheduling Coordinators in California, must pay the ISO congestion
charges. Hence, the PX needs to settle with its participants based on zonal MPCs
in order to stay revenue neutral.

In a typical day-ahead market, the PX energy auction process clears the energy
market hourly by matching generation/import bids with demand/export bids for
that hour. In this process, the PX determines portfolio energy schedules for
its market participants as well as a single "Unconstrained" Market Clearing
Price for all of California as well as its ties without regard for transmission
system constraints. The PX then submits these schedules to the ISO as the
Initial Preferred Schedule (IPS). The IPS includes energy schedules for
individual scheduled resources along with the optional Schedule Adjustment Bids
(SAB) for these resources.

The ISO studies the impact of all schedules that it receives for potential
transmission congestion. If congestion is detected across any transmission
path, the ISO will alter the schedules at the two ends of the path to relieve
the congestion. The ISO relies on the SABs to determine which schedules to
modify, and by how much, in order to relieve congestion at lowest possible
cost. The congestion charges for each congested transmission path are directly
dependent on SABs of the schedules across the congested path. If there are
insufficient SABs for energy schedules across a congested path, the ISO
modifies the schedules on a pro-rata basis and assigns an administrative
congestion price for that path.

The PX receives the final energy schedules and congestion charges from the ISO.
In order to pay ISO's congestion charges and stay revenue neutral, the PX
calculates zonal MCPs according to the following three principals:

1. Difference in zonal MCPs between two zones is equal to congestion charges
   determined by the ISO for the same two zones; and

2. Zonal MCP for each zone is equal to or greater than the marginal energy price
   in that zone; and

3. No zonal MCPs could be negative - this principal is not needed for revenue
   neutrality.

EXAMPLE OF ZONAL MARKET CLEARING PRICES
Consider the energy market for hour 22 (9 to 10 PM) of March 11, 1998. The ISO
discovered congestion along California-Oregon Intertie (COI) due to abundance
of low cost imports from the Pacific Northwest. The ISO congestion management
relieved the congestion by curtailing imports from zone known as NW1. The
attached figure is intended to demonstrate the scenario in this example. In
this scenario, the IPS is the result of the PX energy auction. The Final
schedule is developed based on modifications to the IPS by the ISO in order to
relieve congestion on COI. Since there were not sufficient SABs for import
schedules from NW1 (across COI), the ISO has curtailed some imports from NW1
and assigned the administrative charge of $100 for congestion charge across COI.

According to the present method of calculating zonal MCPs, with a zero price
floor on zonal MCPs, the zonal MCPs become Zero for the NW1 and $100.00 for all
other zones including California. In this scenario, the MCP in California
becomes substantially higher than the marginal energy price in California. The
large zonal MCP in California lends itself to high

energy payments and a major windfall for all generators in and imports into
(other than those from the NW1) California. This condition is shown in the
attached figure under the existing zonal MCPs solution.

Finally, it is rather straightforward to create a similar scenario by congesting
any tie into California. Hence, gaming can readily develop in which the PX or
other ISO market participants could create and take advantage of high energy
payments in California.


WHAT IS THE IMPACT OF ALLOWING NEGATIVE MCPs

The principal of maintaining a zero price floor for zonal MCPs is not needed for
the PX revenue neutrality. Should this constraint be removed, the price within
California will become equal to the marginal energy price in California,
$24.67/MWh in this example - see the values under the new zonal MCPs solution in
the attached figure. And since the PX must pay the ISO for congestion charges,
the zonal MCP for NW1 will be set at -$75.33/MWh.


HOW TO PROTECT AGAINST NEGATIVE MCPs

Negative MCPs entail net energy payments by the PX market participants in order
to schedule their energy import into California. However, any market participant
could readily avoid paying for importing (or generating) energy into California
by providing SABs with its import (generation) schedule(s). Furthermore, if
sufficient SABs are provided by the PX market participants, it is likely that
the ISO can determine congestion charges economically based on actual marginal
energy prices; and hence avoid assigning the administrative charge of $100 for
congestion charges.

Finally, negative market clearing prices are a strong disincentive for gaming
and a very strong incentive for market participants to provide SABs with their
energy schedules.


AT THIS TIME, THE PX IS CONSIDERING DIFFERENT OPTIONS FOR POSTING NEGATIVE
ZONAL MARKET CLEARING PRICES.

                        INITIAL PREFERRED SCHEDULE (IPS)











                                 FINAL SCHEDULE