The story of energy is the story of our common human history. As humanity has established itself it has sought to harness the energy resources of the planet to the benefit of civilisation. Yet the use of fossil fuel energy sources since the industrial revolution has also had a devastating impact on our planet’s health. As the author Amory Lovins has described it, oil and coal have built our civilisation, created our wealth and enriched the lives of billions. Yet we are now faced with the rising costs of these energy sources, threats to our security, economy, health and environment which now outweigh their benefits.
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Human society harnessed the power of the wind and sun for millennia. Persian and Chinese civilisations used horizontal windmills and water mills to grind grain and pull water. The use of the sail to power water craft has occurred from the earliest periods of human settlement. Seeing the potential of earths star, the sun, the Chinese, Roman and Greek empires concentrated sunlight through mirrors for domestic, religious and even military purposes. Societies as ancient as the Romans and the Pueblo Indians of North American designed their dwellings to take advantage of solar access during the winter months. Human society has long understood the potential of the sun and the wind to power technology and benefit its community.
The re-emergence of scientific discovery and endeavour in Europe in the 17th century and the commencement of the industrial revolution drove new discoveries and understanding of the potential of the power of the wind, sun and water. The late 1880’s saw the discovery of the photovoltaic process, when it was realised that that the chemical selenium, when exposed to sunlight and without any moving parts or heat, could create electricity. The French hydraulic and military engineer Bernard Forest de Belidor developed proposals for water powered turbines in the mid 1700’s.However at the same time this period saw human society move away from the use of renewable resources of the wind, water and the sun, and instead choose the newly invented, and powerful, steam engine, fired first by timber and then by coal, to drive technological advancement, economic growth and prosperity.
The industrial revolution transformed human society, mass production replaced cottage industry and feudal systems of harvest, production and distribution. The steam engine powered industrial development, large scale mechanisation and the rapid distribution of goods, products and people over large distances. Cities grew exponentially, as the great shift of human society from rural to urban centres commenced. Humanity itself was disrupted by this technological change. The new working class emerged to provide the workforce of industrialised society and with it the new politics of modern democratic societies, social movements of labour and democratisation, universal franchise, and ultimately the development of the modern welfare state.
The creation of industrial modern society led to widespread electrification of human society . The rapid acceleration of the scientific process , aided by technological advancement, particularly in the energy sector, improved human wellbeing and public health, and livings standards dramatically advanced, albeit unevenly, across the globe. Public health improvements in many of the world’s major metropolis’ have also seen pollution and squalor dramatically reduced. In Europe and North America developed nations have prospered, yet much of that prosperity has been built on the back of heavily polluting industrial processes and fossil fuel consumption.
In the latter half of the 20th century the developing world, Asia, Africa, South America and the Indian sub-continent have emerged as the new centres of technological development and economic growth. These societies are experiencing the same challenges of industrialisation that the developed nations of Europe, North America and Australasia experienced in the 18th and 19th centuries. The colocation of industrial manufacturing and fossil fuel generation plants with large areas of urban settlement has severely impacted the lives of those who live in the newly developing mega cities of China, south east Asia and India.
Wide spread utilisation of fossil fuel energy sources, particularly coal and oil has seen dramatic impacts on urban air quality and human health, and the contributions of the developing world, particularly nations such as China and India, to global greenhouse gas emissions are now projected to grow to a similar magnitude of the industrialised economies of Europe and North America
Growing understanding of the impact of global warming, and continued research and development of renewable energy technologies, combined with periods of high oil prices, such as the global oil shock of the mid 1970s’, lead to renewed development of wind and solar generation technologies. Three key technologies dominate renewable energy generation in the world today, solar, wind and hydro-electric. Other technologies are wave energy technologies, geo-thermal and bio mass generation.
The wind sector has dominated commercial renewable energy development since the 1990’s. Starting as a cottage industry designed to deliver stand alone electricity generation in isolated locations where the electricity grid was not available, wind energy turbines have grown to multi megawatt turbines delivering millions of megawatt hours of electricity generation from large scale commercial wind farms, located both on shore and at sea.
This is good news for the economics and reliability of wind energy generation. Better utilisation of available generation capacity means lower costs for the clean electricity which is generated, and it also means greater incentive economically to maximise the efficiency of the wind energy technology to further reduce costs. This has led to greater innovation in the development of wind energy technology.
Wind energy technology has dramatically increased in size and scale over the past two decades as wind companies innovate to improve the efficiency of their technologies. Taller towers and longer blades to capture greater levels of wind resource have emerged to maximise generation potential. Onshore (or land based) towers are now exceeding 150 metres from the ground level to blade tip height, and the length of the blades is now approaching 80 metres in length.
In addition the size of turbines is also increasing, from 1.5 MW to 3 MW as the new industry standard. Combined with the emergence of large scale wind farms with generation capacity of over 300MW each these changes have meant that wind is fast approaching coal and hydro power in its relative capacity factor, delivering increasingly steady and consistent electricity generation. Even more dramatic changes are emerging in off shore projects. Because wind resources are stronger and more constant in the physically uninterrupted space of the open ocean offshore wind is becoming a giant of renewable energy generation.
By 2017 global offshore wind generation amounted to 18.8 GW of generation. Europe and the UK dominate this sector of wind energy development. Towers are reaching up to 160 metres in height and with blade lengths of up to 100 metres. Combined with turbine sizes of up to 8MW these offshore projects are increasingly being developed with combined generation capacity of between 500MW and 1500MW in size.
Solar energy is fast emerging as the most cost effective form of renewable energy generation. While previously more expensive than wind energy generation, photovoltaic (PV) solar cells are increasingly approaching parity in price competitiveness with wind energy generation. Bloomberg New Energy Finance forecasts that PV solar, combined with wind energy, will provide 50% of global electricity generation by 2050.
PV solar first emerged into the public consciousness in the 1970’s as a technology to power Russian and United States satellites and spacecraft, such as the Skylab and Soyuz space vehicles. It quickly emerged to be used as a demonstration technology on public buildings and some private dwellings. However its relative efficiency and cost competitiveness only began to significantly improve following the year 2000. PV solar had a capacity factor of just 10 % in 2013, improving to over 20% by 2017.
The decentralised nature of solar PV technology allows it to be installed at both an individual household level and also at a utility scale. In nations with high levels of sunshine, such as Australia, the scale of roof top solar development is amongst the largest in the world.
Utility scale solar is also rapidly developing. Australia is again a leader in the field, with large scale solar farms being rapidly developed due to declining technology costs and growing experience in the deployment of large scale solar farms. In 2018, 29 large scale solar plants , delivering the equivalent of 3GW of clean electricity generation , were approved or under development. Wholesale electricity prices from these plants were approaching $55 MWh, equivalent to wholesale prices for large scale wind energy generation in the Australian market.
Concentrated Solar Power technology is the other key technology in the solar sector. CSP technology involves utilising the heat of the sun, rather the photovoltaic process, to produce electricity. Direct sunlight is captured utilising large reflective surfaces or mirrors and directing that heat to a concentrator which transfers the heat into water or another liquid medium, creating steam. Steam then powers a turbine to create electricity. These technologies are more expensive to develop than PV solar farms but have the capacity to deliver dispatchable power when required. Steam created in the solar thermal plant can be stored as heat through storage technologies such as molten salt, which can they then be converted back to steam to power the turbines when required. Despite CSP technology being more expensive than solar PV the cost of electricity continues to decline , from $100MWh in 2017, to under $50MW in 2018.
Solar thermal plants are usually large, with plants often exceeding several hundred MW capacity in size. The Crescent Dunes and Ivanpah CSP plants in North America are amongst the largest in the world , at over 300MW in capacity. In Australia a proposed CSP plant at Port Augusta, South Australia, is planned at 150MW of capacity.
As the level of renewable energy in electricity grids continues to grow the key challenge is its integration into the electricity grids of the future, the need for dispatchability at periods of peak demand, as well as the capacity to manage the emergence of multiple distributed renewable energy sources.
To overcome these challenges earlier forms of renewable energy can help provide the solutions. Hydro electric generation, the use of turbines to capture the energy of falling water from a river or dam, is also a form of electricity storage. Abundant and cheap renewable energy from wind or solar generation can be utilised to pump water uphill into a water storage. This stored energy is then realised downhill in the form of falling water, driving turbines to generate electricity when demand requires it. In nations with an increasingly high level of renewables in their electricity grid, such as Australia, extensive studies are now underway to identify and develop new locations for pumped hydro plants to deliver the dispatchable capacity a renewable electricity grid will require.
The future grid
Another key challenge for the development of a fully renewable electricity grid is to be able to fully utilise the clean energy resources which are available. In the 19th and 20th century our electricity networks were designed to transmit electricity from where coal resources were physically located (and where coal fired generation plants were built) to the areas of electricity demand, our cities, towns and industrial centres. Yet these electricity networks were not built to anticipate the development of multiple points of electricity generation from numerous large scale solar and wind farms, and millions of roof top solar generators, nor to transmit the electricity generated to where the demand exists.
To overcome this problem new approaches are being adopted to develop new transmission networks, increasingly utilising high voltage direct current technology, to transmit renewable electricity from where there are excellent solar and wind resources, often in remote locations, to where the electricity is needed.
The final key technological development is battery storage. Distributed battery storage, at either household or grid scale is enabling renewable electricity to be stored at times where there is an excess of supply (such as the middle of the day for solar) and providing for dispatchable power to be delivered in the evening or at other times of higher demand. The first large scale adoptions of lithium ion battery storage capacity at grid scale, such as the Hornsdale Wind Farm and Power Reserve in South Australia, has proven highly successful, and extremely responsive, at addressing fluctuations in the electricity grid, and quicker and more precisely than traditional coal or gas fired generators.
Our civilisation has been presented with an existential crisis, our landscapes, water and food supplies, cities and towns are under threat from a hotter and more severe global climate driven by carbon pollution and the greenhouse effect. With the concentrations of carbon dioxide in the atmosphere exceeding 400 parts per million the Intergovernmental Panel on Climate Change has warned we have only 10 years to dramatically decarbonise our economy to avoid the worst impacts of global warming. The decarbonisation of the electricity supply sector will be a key element of any successful global effort to reduce our societies polluting impact on the atmosphere.
Simon Corbell is renewable energy and sustainability advisor for Transcendence.