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Home Energy Magazine Online September/October 1999
trends
in energy
Gas vs. Electric:An Equal Playing Field at Hand?
| Table 1. Cost of Delivered Heat by Fuel Type |
| Fuel Type |
Price |
$/Mbtu of Heat Supplied |
| Electricity1 |
8¢/kWh |
23 |
| Gas2 |
70¢/therm |
10 |
1. Assumes resistance heat. A heat pump is able to deliver
as much as 3 times the heat for the same amount of electricity (or the
same heat at 1/3 the cost).
2. Assumes 70% efficiency of conversion. Most gas appliances exceed
this. |
The Department of Energy (DOE) is quietly exploring
solutions to the site/source energy problem or, more specifically, to the
way electricity is compared to other fuels. This controversy has undermined
the credibility of the Home Energy Rating System (HERS) and has hindered
its widespread deployment. The problem arises because electricity generation
is only about 30% efficient, and the energy consumed at the power plant
and in transit to homes is ignored by many DOE procedures. At present,
the HERS rating considers only site energy consumption; that is, the energy
measured by the electric or gas meters. It excludes the energy that is
lost in electricity generation, transmission, and distribution (about two-thirds
of the total energy). Ignoring these energy losses makes electric-resistance
heating appliances appear more efficient than gas appliances. This means
that a house could improve its HERS rating merely by replacing the gas
furnace and water heater with electric counterparts, even though the energy
costs and total source energy (including that consumed at the power plant
and in energy transportation) would increase with the electric system.
It's too early to predict the outcome, but clearly
the California Home Energy Efficiency Rating System (CHEERS) offers an
attractive model to follow. In the CHEERS rating, the fuels are weighted
according to their relative costs to consumers (the cost per kWh versus
the cost per therm--see Table 1). Since the consumer
cost of electrical energy made by resistance heat at the meter is roughly
three times greater than that of gas energy, this is nearly the same as
a source energy adjustment.
On another front, researchers at the Florida
Solar Energy Center have come up with a new way to consider electric and
gas energy on an equal basis. FSEC deputy director Philip Fairey feels
that this method "solves the last remaining technical inequity that has
been brought to the table" in the debates about HERS effectiveness.
"The equations to calculate the point score were
normalized to account for the differences in potential for improvements,"
Fairey explains. "For the end uses of heating and water heating, we created
a standard for electric and gas, used the National Appliance Energy Conservation
Act minimum standard and a set of best-available technologies as the end
points in the standard, and then normalized the standards to each other."
"This solution transcends the problem," says
David Goldstein of the Natural Resources Defense Council, "because it doesn't
use either gas or electric, but uses a point score. The score is fuel neutral."
According to Goldstein, the Residential Energy Services Network is currently
discussing adoption of this technique, and the National Association of
State Energy Officials (NASEO) has tentatively approved using it. (NASEO
will soon vote on whether to make that approval final.) Although the states
are not obligated to adopt these guidelines and will make their decisions
individually, Goldstein says, "most states will probably go along with
the guidelines. It's an ingenious approach."
If a change in policy occurs, DOE programs that
would also be affected include the appliance standards program and the
EnergyGuide labels. Currently, both programs treat gas and electric appliances
separately. If they were compared within the same category--and legislation
might be required for this--most gas appliances would get far better ratings.
For example, if an EnergyGuide label showed gas and electric water heaters
on the same scale of annual cost of operation, few electric water heaters
would appear on the low-cost end. However, an electric heat pump water
heater might appear better than both gas and electric resistance water
heaters, which would encourage manufacturers to build them and consumers
to buy them.
Such a change could have an enormous impact on
consumer decisions, leading to more purchases of gas-fired furnaces, water
heaters, and clothes dryers. This could also spur new advances in electric
technologies, such as heat pump water heaters, as manufacturers seek to
improve the standing of electric heating.
Three factors appear to be spurring DOE into
action. First, there is a desire to rationalize some of the economic assumptions
inside DOE's regulatory programs. Second, the White House needs to reduce
CO2 emissions, and it wants to ensure that internal regulations
are consistent with that goal. Finally, the electricity industry--the main
opponent to changes in the current situation--is relatively weak and divided.
Restructuring has created many new firms and, with them, less opposition
to industry reform. Meanwhile, the gas industry remains strongly united.
The RAND Corporation is currently conducting
a study for the Department of Energy's Office of Energy Efficiency and
Renewable Energy. According to RAND researcher Mark Bernstein, the study
will discuss how HERS may be affected by a change in approach. Results
of the study may influence DOE's decision; they were not available at press
time.
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