Ten facts about solar thermal power
- Solar thermal power plants are a lot like conventional power plants - with one major difference
thermal power plants, often also called Concentrating Solar Power (CSP)
plants, produce electricity in much the same way as conventional power
stations. The difference is that they obtain their energy input through
concentrated solar radiation, rather than fossil fuels, and then
convert it to high-temperature steam or gas to drive a turbine or motor
engine. This difference means that no pollutants are emitted in
producing the electricity.
- A solar thermal power
plant built on about 1% of the surface of the Sahara Desert would be
sufficient to satisfy the entire world's electricity demand.
energy arrives on the earth at a maximum power density of about 1
kilowatt per square meter. However, solar "productivity" is limited by
certain geographical factors, including cloud cover and atmospheric
humidity. In sunny, arid locations, one square kilometer of land can
generate as much as 100 gigawatt hours (GWh) of electricity per year
using solar thermal technology, enough power for 50,000 households..
thermal power plants reduce air pollution: The solar energy falling on
an area the size of a basketball court is equivalent to 650 barrels of
oil a year
…or, in other words, each square meter of CSP
concentrator surface is enough to reduce annual consumption of 200 to
300 kilograms (kg) of carbon dioxide. In addition, the "energy payback"
time of CSP systems, taking into account the energy expended in their
manufacture, is about five months, which compares well with their
useful life of approximately 30 to 40 years. Most of the CSP solar
field materials can be recycled.
- Solar thermal power is reliable and available when needed most - during peak demand hours
most developed countries, the peak demand period - during the hottest
part of the day, when air conditioners are running in the office and
home - coincides with the period of time when the solar thermal power
plant is at peak production. In addition, solar thermal power, as
predictable and reliable as the sun shining in the desert, is a
renewable alternative to natural gas "peakers", as opposed to other
forms of renewable energy, which are either baseload or intermittent.
- Solar thermal power plants can be built (relatively) quickly
power plants can generally be built in their entirety within a few
years and can follow demand more closely than most conventional power
projects. This is primarily because solar plants are built almost
entirely with modular, commodity materials and thus have short
development and construction times. In contrast, many types of
conventional power projects, especially coal and nuclear plants,
require long lead times, and this causes significant disparities
between the demand and the supply.
- Solar thermal power plants are big - but relative to other types of power plants - they're space efficient
plants seem to use a lot of land, but when looking at electricity
output versus total size, they use less land than hydroelectric dams
(including the size of the lake behind the dam) or coal plants
(including the amount of land required for mining and excavation of the
coal). While all power plants require land and have an environmental
impact, the best locations for solar power plants are on land, such as
deserts, for which there might be few other uses.
thermal power can be used with energy storage systems or
combined with other energy sources to provide all day power
plants can be designed for solar-only or for hybrid operation, as in
California where gas-fired boilers provide steam to back-up
solar-generated steam. Thermal energy storage systems, including molten
salt, can extend the operational time of solar thermal power plants,
sometimes with six to 12 hours of storage. In addition, solar thermal
power can complement other renewable energy sources, such as wind,
which are available during off-peak hours.
- Solar thermal power plants create permanent jobs and are good for the local economy
are two main reasons why solar thermal power plants offer an economic
advantage: (1) they are labor intensive, so they generally create more
jobs per dollar invested than conventional electricity generation
technologies, and (2) they use primarily indigenous resources, such
that most of the energy dollars can be kept at home. Most importantly,
there is no need to import the energy source (i.e., sunshine) and spend
local funds outside of the region.
- Solar thermal plants produce electricity whose current and future costs are known with certainty
produced from solar thermal power plants is a fixed-cost generation
resource, generally sold through long term (20 or 30 year) power
purchase agreements in which the cost to the consumer is known in
advance. Additionally, a diversified portfolio of energy sources,
including solar thermal, decreases consumers' exposure to market
fluctuations, including the volatile cost of natural gas (which solar
thermal typically replaces in the portfolio). The reduced demand for
natural gas itself will lead to lower prices.
thermal power can be cheaper than power from fossil fuels when all cost
externalities are considered (and even when they're not)
many of the costs of fossil fuels are well known, others (pollution
related health problems, environmental degradation, the impact on
national security from relying on foreign energy sources) are indirect
and difficult to calculate. These are traditionally external to the
pricing system, and are thus often referred to as externalities.
According to the Stern Review, published in October 2006 by H.M.
Treasury, global warming is the result of colossal market failure,
i.e., failure to price fossil fuel's externalities correctly. A
corrective pricing mechanism, such as a carbon tax, could lead to
renewable energy, such as solar thermal energy, becoming cheaper to the
consumer than fossil fuel based energy.
Even without pricing
cost externalities, the cost of solar thermal power is going down.
Currently, the cost of solar thermal produced energy can be close to 12
cents (US) per k/Wh. However, many economists and investors predict
that this price will continuously drop over the next ten years with
increased installed capacity, to 6 cents per kW/h, as a result of
technological improvements, economies of scale and volume production.