POWER August 2013 - 16

consideration.
Several companies had proposed possible
designs for the barrage. Evans Engineering
had proposed a " tidal reef " that
would use bidirectional turbines for ebb
and flow generation and a low head of
water. Rolls Royce and Atkins had also
developed a scheme for a low-head barrage
using bidirectional turbines. Hafren
Power, the firm that had most prominently
supported the project, proposed a similar
idea but replaced the 256 unidirectional
bulb turbines with 1,026 bidirectional
low-head turbines to allow the design to
operate in ebb and flood mode.
The demise of the Cardiff-Weston Severn
Barrage doesn't mean the end of hopes
to use tidal power to generate substantial
power in the UK. According to Evans
Engineering, its REEF tidal power concept
(which has now been endorsed by an Atkins-Rolls
Royce report commissioned by
the DECC) is " very much alive and well. "
The company reports that " fresh enthusiasm
and the prospect of major private
finance is pushing this proposal. " Work at
Evans is reportedly proceeding with forming
a consortium.
Vehicle-to-Grid Aggregated
Project Sells Electricity to
the Grid
A technology developed by the University
of Delaware (UD) and NRG Energy that
provides a two-way interface between
electric vehicles and the power grid earlier
this year became an official paid resource
on PJM Interconnection's regional
grid (Figure 4). One of the first of its kind,
the project proves the so-called " vehicleto-grid "
(V2G) concept can sell electricity
from electric vehicles.
The V2G concept supports widespread
adoption of electric vehicles and seeks to
support the reliability of the grid by providing
ancillary services. It essentially facilitates
bidirectional electricity transfers
to and from electric vehicles.
As UD explains, a grid-integrated vehicle
(GIV) is always " a net load to the
system over time. " It has to charge a battery
before it can deliver that same energy,
minus conversion losses, back to the
grid. The GIVs being produced in Delaware
will have the ability to charge or discharge
at a capacity of 19 kW. The GIVs will also
be aggregated together as one electric
power resource " so that grid operators
don't have to interact with thousands of
vehicles, " UD says. A UD and NRG Energy
joint venture has set up an aggregator
that monitors different energy markets
16
4. Ancillary services from a car. The University of Delaware and NRG Energy earlier
this year officially connected their eV2g project to PJM Interconnection, for the first time in the
U.S. selling electricity to a grid operator using electric vehicle-to-grid technology. Courtesy: Evan
Krape/University of Delaware
and bids into those markets according to
their aggregated vehicles' available capacity
and market price.
This February, the project became an
official participant in the PJM's frequency
regulation market. Since then, the project
has been selling power services from
a fleet of electric vehicles to the regional
transmission organization. BMW provided
the electric vehicles, Milbank Manufacturing
provided charging stations based on
UD technology, and AutoPort installed UD
control technology into the electric vehicles.
UD says the system is still in development,
however; its restricted test fleets
are not yet a commercial offering.
The project got its boost with a September
2009 Delaware law-one of the first of
its kind in the world-that requires electric
utilities to compensate electric car
owners for electricity sent back to the grid
at the same rate they pay for electricity
to charge the battery. PJM also changed
its rules for participation in the regulation
service market to decrease the minimum
amount of power needed to participate.
" We implemented new rules that recognize
and compensate faster, more accurately
responding resources, such as batteries, "
Michael J. Kormos, a senior vice president
at PJM said.
Experts note that a V2G aggregator also
benefits from open-access transmission
rules promulgated by the Federal Energy
Regulatory Commission, which requires
grid operators to purchase ancillary services
from the generator providing them at
www.powermag.com
the lowest available cost. Otherwise, the
general legal and regulatory environment is
" not optimized " to accommodate the V2G
concept, as industry experts Matt Hutton
and Tom Hutton write in a 2012 journal article
published in the William & Mary Environmental
Law and Policy Review.
Several questions remain unanswered.
For example, who is entitled to what portion
of the economic benefits-the owner
of the battery or the entity that pays for
the electricity used to charge the battery?
Another apparent hurdle is modifying
state net metering laws to accommodate
V2G (only Delaware has a net metering
statute that explicitly includes vehicles).
Still, regulatory changes needed " are not
expected to be especially controversial, "
the authors say, noting " no serious opposition
has materialized from industry
groups. " Several of the hurdles are simply
manifestations of uncertainties in the
business environment. Of the more properly
legal and regulatory impediments,
most are " expected to be surmountable, "
they say.
A number of studies point out that electric
vehicle developers must, meanwhile,
work to allay worries by potential consumers
regarding range anxiety, long charging
time, and high purchase prices. The consensus
among experts is that though customers
are willing to pay high premiums
for electric vehicles, battery costs need to
drop considerably if electric vehicles are
to be competitive without subsidies at
current U.S. gasoline prices.
POWER | August 2013

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POWER August 2013

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