Comparison of Energy Sources
What sort of energy source is used for a particular purpose should in the end be reflected in the price of the energy generated by the source.
The World's Fossil Fuels are a finite resource that will be consumed within 500 years at present and projected future rates of consumption. In addition these are often accompanied by substantial pollutants and of course their major waste by-product, carbon-dioxide gas, is the major Greenhouse emission of concern.
There is general consensus within the Scientific Community that a new phase of global warming induced by carbon-dioxide emissions is currently underway and that the World's temperature will rise significantly within the next century. There is still substantial debate about the climatic consequences of this temperature rise although there is little doubt that the world's climate will be different in 100 years time if we continue to increase our rate of consumption of fossil fuels. Given that there is no clear consensus on the outcome of the global warming and that some of the consequences are very dire indeed
, the safe course of action is to limit the amount of Global Warming and hence to limit the amount of Greenhouse gas emission.
To date the cost of the carbon-dioxide emissions from Fossil fuels has not been priced into to their use.
Recently Carbon Dioxide Sequestration
has emerged as potential solution to the global warming problem. This is the process of trapping Carbon in the bio-sphere instead distributing it within the atmosphere. There are now a number of methods proposed to achieve this which range from developing new bio-masses
(forests, algae) to injection of C02 into Deep Oceans
or storing in underground reservoirs
including Natural gas and Petroleum fields
. Many of these may be implemented within 20 years and could potentially be paid for via a carbon tax. A document providing an overview of various CO2 sequestration options is available here
. This study estimates that 80 years worth of current CO2 production could be stored at a cost of about 50 Euros (80 AUD) per tonne CO2 stored.
Oil is the most precious and least abundant of the world's fossil fuels. Never-the-less the amount of Oil on the Earth is likely at least the range of several trillion barrels of Oil once non-conventional sources of Oil are considered. These include the Heavy Oil deposits of South America, the Oil sands of Western Canada and shale Oil found through out the World. In addition as the price of Oil increases, previously abandoned fields become economic to re-extract. Consequently despite constantly increasing Oil production throughout the world, there is likely at least a century of usable Oil available in the world. A more useful question is: At what price will petroleum and gasoline be widely displaced as the fuel of choice for transport? It has already been largely displaced as a fuel for Electricity. For a period from 2006 until 2008 the world demand from Oil was such that OPEC could no longer control its price
and output from the most readily refined petroleum had peaked
. In July, 2006, the Australian Broadcasting Commission televised an excellent documentary about high Oil prices. You can download it from here
. The Chicago tribune have produced an excellent series on Peak Oil in their July 29th, 2006 edition. You can find it here
Recent updates on upcoming large scale projects
combined with a projected increase in supply from Iraq imply that oil production could continue to grow until 2018
, given sufficient demand.
Coal is the most abundant fossil fuel. It is found throughout the world and current proven reserves are sufficient for at least 300 years of exploitation. Although coal is cheap, it is dangerous to mine
(thousands of miners die every year all over the world) and is bulky and expensive to transport. Because coal has relatively low energy content for its weight, a lot of it is required to produce a given amount of electricity. For example, A 1000 MW coal power station requires about 8,600,000 kg of coal per day, compared to 74 kg per day of uranium for the equivalent sized nuclear power plant
. In addition coal-based power plants produce vast amounts of pollutants, including radioactivity, in addition to the C02 emissions which contribute to global-warming.
Natural Gas reserves are intermediate between Coal and Oil. It is currently the most favoured fuel source for new electricity production with the USA. Natural gas combined-cycle
generators can reach 60% efficiency for converting heat energy into electricity. Natural gas also produces 40 -50 % fewer CO2 emissions for the same amount of electricity generated as Coal. However the price of Natural Gas is steadily rising and the costs associated with sequestration of the generated CO2 are not yet included in the price of electricity passed on the consumer. The following table from a comprehensive study
of the cost of electricity production from coal and gas in the USA without sequestration charges or other pollution charges shows the price sensitivity of natural gas production. All prices for Natural Gas are shown in units of thousand Cubic Feet (MCF).
The following table shows the effects of a Carbon tax to pay for sequestration.
The price of Natural Gas delivered via long-term contracts as Liquified Natural Gas (LNG) is typically around $6 per MCF.
Within the USA, Natural Gas prices had been extremely volatile
over the past few years as production had not been able to keep pace with demand. However of March, 2009 the price has fallen to below $4.00 per thousand Cubic Feet (MCF). It is not clear whether is drop is due to the current recession or from greater utilization of unconventional gas resources
, such as Coal Seam Methane and "Tight Gas" from shale formations. World-wide, reserves of unconventional Natural Gas are estimated to be over 32,000 Tera Cubic Feet (TCF)
while conventional natural gas reserves are estimated to be 7200 TCF
. World-wide natural gas production in 2007 was slightly over 100 TCF
Australian reserves of Natural Gas have risen dramatically since 2006 through the rapid development of Coal Seam Methane, which accounted for 13% of Australian production in 2008, up 40% in 2008 over 2007
. Australia's Natural Gas reserve base (including Coal Seam Methane), is currently estimated to be 400 TCF
The cost of Nuclear Fission Power is dominated by the capital cost of construction of the plant. Proponents of next generation, (3rd generation), Nuclear Power plants were initially projected to be around $1000 - $1200 per KW (Westinghouse AP1000
, Advanced Boiling Water Reactor
, Advanced CANDU Reactor
, South Africa HTGR
). These reactors also have significant increases in Uranium efficiency and substantial increases in operating life of the plant (60 years). In addition the proponents claim a ten-fold increase in safety of operation over previous generation reactors. Electricity generated from such plants was initially projected to cost less than 3.5
US cents per KW-Hr. However recent reports imply the capital cost of these plants to be over $3500 per KW
. Additional costs for infrastructure upgrades, financing and inflation take the total expected cost to around $17 Billion for a twin unit AP1000 with 2.2 GW capacity. Electricity produced at these rates would be substantially more expensive than Eastern Australian coal powered electricity
prices of 2.3 - 4.0
US cents per KW-Hr.
Disposal of Nuclear Waste remains a topic of intense debate and controversy. However the USA, Sweden, Finland and France have well-developed programs for waste disposal funded from the sale of electricity.
Current Australian electricity prices do not include any sequestration charges. Although Australia has not signed any treaty requiring compliance with the reduction of carbon emissions, (citing National Interest reasons), we may be compelled by the international community to do so in the future.
Nuclear Fission is currently unique in that the costs of decommissioning and waste disposal are fully reflected in the price of the generated electricity.
The nuclear industry has longer-term plans to develop advanced reactors that are over 50 times more efficient in their use of Uranium and which consume a large fraction of the long-lived waste generated from current (2nd generation) reactors. In addition these plants may also be used to efficiently produce Hydrogen
for use as a transportation fuel and to de-salinate sea water
. These are the Fourth Generation
Nuclear Reactors and are not expected to be ready for deployment before 2020.
There is a large
and very vocal opposition
to Nuclear Fission power because of the radioactive material produced in the process of generating energy and from Nuclear Proliferation concerns. There are also claims that Nuclear Power is more expensive
than alternative energy generation schemes. There are also numerous websites and documents
that counter such claims and offer strong opinion
that Nuclear Power is the best energy option.
Nuclear Fusion is often proposed as the ultimate energy source. Great progress has been made in this field in the 50 years since it was first proposed. Construction has started for the next generation Fusion Test Reactor (the ITER). Its projected start date is 2016. It will be operated for the 10 years following to learn the about the Physics and Engineering required to build and operate a commercially competitive Power Plant. It is projected to produce 500 MegaWatts of energy at full power. See
The ITER Fusion project.
Like Nuclear Fission, the size of the resource (Deuterium and Lithium) consumed in generating this energy is essentially unlimited.
However much research and development still needs to be done on the project. The proponents project the Capital Cost of a commercial plant, built in 2050, generating electricity via Nuclear Fusion to be around $4000 per KW.
Solar energy has made significant progress and is displacing fossil fuel technologies from many niche applications.
These are technologies that concentrate sunlight to produce intense heat or light. Many significant technology hurdles have been overcome through ingenious design and the use of advanced materials. Nevertheless despite many years of effort these technologies produce electricity at far higher cost than coal-based production. The exceptions are when these are located in sunlight rich regions with poor access of Fossil Fuels or where the full cost of Fossil Fuels are passed on to the consumer. Solar Thermal power plants in Spain have grown significantly because of feed-in tariffs in excess of $USD 0.20 per KWHr
. These are over 5 times higher than the prices received by Australian utilities. The Blythe Solar Project
in South West California is in the final state of it's Environmental Review. It is a nominal 1 GW power facility, with a 5.5 year construction time and an expected capital cost of $6 Billion. It is expected to produce 2-3 billion KW-Hours of electricity per year. The projected cost of electricity sourced from the facility is thus well over 20 cents/KWHr.
PhotoVoltaic systems convert sunlight directly into electricity by utilizing the Quantum-Mechanical properties of light. There has been great progress at both increasing the efficiency of solar cells for use in concentrator systems
and in decreasing the cost of large array converters
The current world market for PhotoVoltaics is around 1.2 GW of peak power per year and is growing at an annualized rate of 30% per year. This amounts to some 1 billion-kilowatt-hours of electricity production once the 10% duty factor of photo-voltaic systems are taken into account. The current world consumption of electricity is around 13,000 billion kilowatt hours per year and is projected to rise to 23,000 billion kilo-watt hours per year by 2025.
If the current rate of growth of the PV market is maintained for 20 years, it will still amount to less than 5% of electricity production by 2025. More-over much of the growth in electricity demand will take place in places where solar power is not abundant.
In Australia distributed solar voltaic power from rooftop panels could be a useful adjunct to power produced from the grid since it is most effective at the times of peak demand on the very hot days.
This is the idea behind some of the programs in the
Solar Cities initiative.
For a detailed look at solar energy in Australia see the
SA government's information page on solar power.
Furthermore, Sliver Cell
technology, developed at The Australian National University, promises a factor of 4 reduction in overall PhotoVoltaic costs.
Wind Power utilizes modern-versions of wind-mills
to produce electricity. Its use is growing world-wide
. The current installed base is is over 50 GW of peak power with a growth rate of around 10% per year.
In countries with high-cost electricity production, favourable geography and anti-nuclear policies, it is almost cost-competitive with conventional electricity generation as an additional source of power-production. Its main drawback is its intermittent availability. This means that on average it produces only about 25 -35% of its peak capacity when averaged over a year and so it requires backup for windless days. Large-scale wind use requires capital to both build the wind-powered turbines and backup facilities. Denmark uses a mix of Wind, local coal power and imported electricity from it's Nordic neighbours. Unlike Norway and Sweden, Denmark found its electricity prices increased
after a period of deregulation. Denmark also has a substantial "Green Tax" which makes it's electricity prices much higher
than France or Sweden, which have vigorously pursued Nuclear Power. Furthermore, there are reports
that suggest wind power suffers diminishing rates of return as it's fractional use within an electricity network exceeds some threshold (typically 10%) due to it's fluctuating availability
. Within Australia, Wind is the fastest-growing renewable form of electricity generation. Its use within Australia is driven from Government subsidies in the form of the Mandatory Renewable Energy Target (MRET). It is most useful as a supplement to Hydro Power which can be conserved and used on windless days during peak demand.
Electricity generated from wind power within Australia is currently more expensive than that from coal plants. The Challicum Hills wind farm
, one of the first in Victoria, cost $76 million for a 52 MW peak output. After operating for several years, the average capacity of the facility has been measured at 30%. The Capital Cost of the facility is therefore $USD 3660.00 (AUD$ 4880.0) per KW. Studies of US Wind Farms suggest the effective charge for on-going maintenance of the system works out at around 2 cents per KWHr.
Assuming a 7% interest rate, we estimate the cost of producing Wind Power from Challicum Hills to be 7.6 AUD cents per KWHr.
There is a vocal environmental opposition
to Wind Power from those who oppose the visual impact of wind-turbines on the landscape, its danger to bird life and noise. There are numerous websites
that counter such claims.
utilize various biological processes to generate hydrocarbon fuels like Methane Gas and Diesel fuel. Modern Biomass projects focus on methane gas
from refuse and biodiesel fuel from algae
and waste products.
There is intense, world-wide research into this energy source as Biodiesel could well become cost competitive as the price of conventional Oil increases. There are numerous hobbyists who create Biodiesel fuel
for their own use.
However, presently available crops are rather inefficient at converting sunlight into useful fuel which makes biomass unsuitable for large-scale electricity production. Estimates
are that providing feedstock for a 1 GigaWatt power plant for one year would require 2500 square kilometers of the best quality land. Modern biomass
projects efficiently utilize agricultural waste and provide a useful energy resource in some locations, in particular from sugar production
regions, however their potential elsewhere is limited.
energy relies on converting heat trapped underground to generate useful power. In most cases this means converting the heat to electricity via the same techniques employed by Fossil Fuel power stations. There are in addition several locations in the world where Geothermal energy is also used to provide district heating.
It is classed as a renewable resources although in some locations Geothermal energy consumes a region of heat trapped in the Earth's crust. Once consumed, the resource is exhausted. Other locations continuously generate heat from a large local Uranium concentration. There are some very large reserves of heat and these have been exploited in different parts of the world.
Geothermal has the advantage over Wind and Solar power of being available 24 hours a day. In Australia it is employed to generate 150 KW of electrical power in Birdsville
from hot water extracted from the Great Arterial Basin.
Within an Australian context, there is much interest in exploiting Hot Dry Rocks, which are both very hot (awards of 200 degrees Celsius) and within drilling distance from the surface. The idea is to inject water under high pressure at the surface, generate fractures within the heated rock, allow the water to permeate through the fractures and extract it from another hole some distance away. The water is heated as it passes through the rock and can be used to generate electricity at the surface via a conventional heat engine. This processes is known as Enhanced Geothermal energy.
The potential reserve of Geothermal energy contained within Hot Rocks in central Australia is estimated be in excess of 300,000 PJ
which is sufficient to supply all Australia's current electrical power needs for over 400 years. However to date this type of Enhanced Geothermal power generation has not been exploited commercially.
There are a number of companies attempting to commercialize this technology in Australia. Two of the more prominent are Geodynamics
. Geodynamics has the rights to exploit large heat reserves in the Cooper Basin in South Australia and Queensland as well
as the Hunter Valley in New South Wales.
Petratherm has a variety of conventional Geothermal prospects elsewhere in the world as well as proposals for Enhanced Geothermal near mines in outback South Australia.
This is promising technology but there remain a number a barriers to it's full exploitation at large scale. Perhaps the ultimate concern is the supply of water needed to top up losses in the deep desert. Even though water is recirculated through the system some water losses occur. Over the course of a year, a one GigaWatt system with 5% water loss requires an additional estimated 40 Gigalitres
per year. To put this in perspective, this is approximately 14% of Melbourne's annual water consumption of 300 Gigalitres.
At this point in time it is difficult to estimate the cost of large scale Enhanced Geothermal power. The capital cost of Birdsville-like installations has been estimated to be $7000/KW which implies an electricity cost of 7 cents/KWHr. However this neglects the cost of supplying the top-up water and the much deeper dill holes required to tap the larger and hotter reservoirs. On the other hand economies of scale should be expected as should cost reductions through learning-by-doing as the industry matures and grows.
Hydrogen is a completely clean fuel but it must be made from some other energy source. As a fuel, Hydrogen has many benefits. It can be consumed in a Fuel Cell to make electricity very efficiently and produces only water as emissions. Three kg of Hydrogen is expected to provide a car a driving range of 400 km. The main difficulty with using hydrogen as a transportation fuel is the ability to cheaply distribute and store it
. However great progress is being made in this field. For example in January 2005, General Motors unveiled a concept car
with 5 kg of Hydrogen storage capacity and which provided a driving range of 500 km.
At present, the cheapest way to make Hydrogen is via chemical reactions on Natural Gas. Natural Gas delivered via LNG costs about $6.00 per MCU which gives Hydrogen production costs of approximately $2.00 per kg. There is already a substantial world-wide market for hydrogen gas. The main users of Hydrogen are the Petroleum and Chemical Industries. The Petroleum industry uses Hydrogen in refineries and to upgrade Heavy Oil to Petroleum suitable for refining. This latter need is expected to substantially increase the demand for Hydrogen as the production of Heavy Oil ramps up.
Hydrogen can also be made from water via either electricity driven electrolysis or via high temperature catalytic chemical reactions. There are extensive research programs to efficiently produce Hydrogen using Solar
and Nuclear Power
The supporters of all the energy sources described here have answers to problems ascribed to them. The fossil Fuel advocates are pursuing carbon sequestration projects. The Biomass, Solar and Wind Power advocates claim that costs will continue to diminish with the aid of government subsidies to ramp up production and to support continued research and development. The Nuclear Power industry advertise that their 3rd generation reactors will provide electricity at less than half the cost of the average second generation reactor and be at least 10 times safer. In addition they believe that there are now safe and reliable means to dispose of waste over the long term. Further-more the industry claim that the Fourth Generation reactors will completely burn all the 238U in natural Uranium and/or fully utilize Thorium while generating one tenth to one hundred the waste of present reactors. If perfected, there is sufficient accessible Uranium and Thorium to enable these reactors to provide enough energy to power an advanced civilization for everyone living on Earth for well over 1 million years.
Of all the energy sources discussed here, Nuclear Fission Power is the lowest-cost form of non-greenhouse energy production. The second-generation reactors currently operating at World's best-practice level consistently produce low-cost electricity with no greenhouse gas emissions at high reliability. The French decision to go all-Nuclear has paid-off handsomely and Sweden has the almost the lowest priced electricty
in Europe. Furthermore, Denmarks' Greenhouse Gas emissions per capita
are substantially greater than both France and Sweden since the Danes use coal power for the majority of their electricity needs even with their commitment to Wind Power.
In the the longer term advanced reactors, fusion-fission hybrids and accelerator driven systems that efficiently use the World's abundant Thorium and Uranium reserves have the capability to power a planet-wide advanced civilization essentially indefinitely. They also have the capability to generate energy from and dispose of the long-lived transuranic waste. However this technology will always require strict safe-guards and independent oversight.