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GEOTHERMAL ENERGY
Overview
Global Highlights
What’s Happening in BC?
What Does it Cost?
Environmental Matters
Technical Matters
Social, Economic & Political
Matters
Can I Do It at Home?
Links
Overview
High-temperature hydrothermal energy has been used for electric
power generation since 1909, and is presently used in over
20 countries around the world.
Power generation requires a high-temperature geothermal
resource, in the form of steam or hot water reservoirs with
temperatures higher than 170 C. These types of geothermal
resource are generally limited to recent volcanic terranes,
such as those found near tectonic plate boundaries (west
coast of North America, Iceland, New Zealand, Japan). Energy,
in form of steam from high temperature geothermal reservoirs
situated close to the surface (500m - 2,000m), is transformed
into electricity by steam-driven turbines - similar to oil
and gas generated power.
Although Canada does not currently have an operating geothermal
energy power plant, there have been extensive studies at
Mount Meager, along the Lillooet River, north of Whistler,
B.C.. The BC Ministry of Energy and Mines map (see links)
shows areas around BC that have varying degrees of geothermal
energy potential. Low hydro-electric power and fossil fuel
prices have reduced the economic incentive to develop the
resource; however, there has been recent renewed interest
in the Mount Meager Area.
Global Highlights
- There are currently 9600 MW of geothermal energy produced
globally
- Geothermal is commercially viable in 24 countries around
the world
- US geothermal plants along the West coast produce 2800
MW of electricity
- The Philippines is the second largest producer of geothermal
energy worldwide, with 1900 MW. According to the Philippine
Department of Energy, an additional eight geothermal
power plants will come on line by 2010, with a further
621 MW of capacity. (See www.doe.gov.ph )
What’s Happening in B.C.?
British Columbia has better prospects for geothermal development
than any other province in Canada. The many hot springs found
around the province mark some of the geothermal deposits.
Most have been used only for local or recreational purposes.
Meager Creek, near Pemberton, has substantial amounts of
hot water below ground, and may offer prospects for geothermal
electrical power. Mount Cayley and Mount Garibaldi have also
been explored.
In March 2004, the BC government started accepting bids
from geothermal energy companies that want to develop the
resource potential in the Meager Creek and Kinbasket Lake
(near Valemount, BC) areas. Western GeoPower Corp. has as
its mission statement: "To develop the Meager Creek
Project as Canada’s first commercial geothermal generating
facility for electricity", so geothermal energy may
soon become part of BC’s commercial electricity portfolio.
In June 2004, the BC government granted drilling permits
for two deep production wells to confirm the commercial
viability. South Meager has been classified as a "high
temperature" geothermal field with maximum temperatures
to
date up to 275 deg C . The site has a potential development
capacity of 200 MW.
What Does it Cost?
Geothermal energy is considered to be one of the cheapest
forms of large-scale grid-tied energy. The levelized cost
of geothermal energy ranges from 3.3-3.9 US cents per kWh,
compared to 5.0-6.4 US cents for wind energy and 7.3-8.7
US cents for biomass (US Department of Energy, Office of
Utility Technologies). "Levelised cost" means the
average cost of power production over the life of a power
plant, taking into account all capital expenses and operating
and maintenance costs, plus fuel costs for power plants that
rely on external fuel sources.
For the Meager Creek Geothermal Project in B.C., the estimated
long-run marginal cost of geothermal energy is 5.9 CDN cents
per kWh, compared to BC Hydro’s current long-run marginal
cost of 5.5 CDN cents.
Advances in technology have reduced geothermal electricity
generation costs by over 25% in recent years. Generation
costs are expected to drop a further 20% between 2000 and
2020, while operation and maintenance costs are expected
to drop by 30% by 2020. (Western GeoPower Corp, 2003)
Environmental Matters
Geothermal energy production can have more or less environmental
impact, depending on the siting of the generation facilities
(the area of land required and amount of noise generated
in construction and operation) and the extent to which water
resources are re-circulated into the hot water reservoirs
to prevent the land subsidence resulting from a decrease
in reservoir pressure.
Geothermal fluids contain dissolved gases, mainly carbon
dioxide (CO2) and hydrogen sulfide (H2S),
small amounts of ammonia, hydrogen, nitrogen, methane and
radon, and minor quantities of volatile species of boron,
arsenic, and mercury. Geothermal power provides a significant
environmental advantage over fossil fuel power sources in
terms of air emissions because its production releases no
nitrogen oxides (NOx) or sulfur dioxide
(SO2), and much less CO2 than fossil-fuelled
power. The reduction in nitrogen and sulfur emissions reduces
acid rain, and the reduction in CO2 emissions
reduces the contribution to global climate change. CO2 emissions
can vary from plant to plant, depending on the characteristics
of the reservoir fluid and the type of power plant. A typical
100 MW plant will reduce CO2 emissions by 600,000
tonnes/yr, and NOx and SO2 emissions by 120,000
tonnes/yr compared to a natural gas plant of equal size.
(Western GeoPower Corp, 2003)
Technical Matters
Geothermal plants are very efficient, operating at 95-98%
availability on a consistent basis. Thus, geothermal power
has a tremendous advantage over most other renewable resources,
in that it produces "base load" electricity. Utility-scale
geothermal power production employs three main technologies:
dry steam, flash steam and binary cycle systems. The technology
employed depends on the temperature and pressure of the geothermal
reservoir. Unlike solar, wind, and hydro power, a geothermal
power plant can operate independently of fluctuations in
daily and seasonal weather.
Social, Economic & Political Matters
Geothermal energy’s three main advantages are its low price,
its consistent supply, and the fact that it is a clean, renewable
source of energy. Unlike natural gas, which will cost more
in the future as supplies run short, geothermal energy will
cost less in the future as industry efficiency increases.
Price stability is very important for industry, so the more
that geothermal and other sustainable energies can replace
natural gas in the BC grid, the more stable the long term
price becomes.
These are some policies which will promote the use of geothermal
energy in BC:
- Placing an environmental tax on fossil fuels such as
coal and natural gas, to account for the harm done by
CO2 emissions, and local air pollution.
- Providing geothermal energy producers with a guaranteed
price of 7 cents/kWh for the first 5,000 MW of geothermal
energy until 2015.
Can I Do It at Home?
No. This section focuses on grid-tied geothermal generation.
For another type of geothermal energy, see Ground
Source Heat Systems.
Links
Credits
Compiled by Jamie Cowan, for the BC Sustainable Energy Association
Text updated September 4, 2004
Links updated September 7, 2007
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