In previous posts we’ve looked at the impacts of global heating assuming we don’t do enough to mitigate it. We’re now going to look at some of the technological solutions, first in the area of energy generation.
Getting to “net zero” carbon emissions means drastically reducing the use of fossil fuels in energy generation, because that sector represents 25% of emissions. In BP’s 2019 Energy Report, their Chief Economist concluded: “There is a growing mismatch between societal demands for action on climate change and the actual pace of progress, with energy demand and carbon emissions growing at their fastest rate for years. The world is on an unsustainable path.”
Fortunately, substantial progress has been made in the use of renewables and the economics of these energy sources are improving rapidly. The challenge is creating the political will to implement them quickly enough.
At the end of May the UK, for the first time since the Industrial Revolution, went 2 weeks without using any coal in its power systems. Wind and (to a much lesser extent) solar power are providing 30% of the UK’s power today and are forecast to be providing 70% by 2030. However, G20 countries generally have tripled coal power subsidies. The coal industry is increasingly unprofitable in comparison with renewables, so these subsidies are more about employment support – avoiding coal miners going out of work. The issue is socio-political rather than technological.
Offshore wind projects have seen costs halve in just two years. BEIS estimates its costs as £106 per MWh; onshore is cheaper at £63 per MWh, cheaper than solar (£65) and all other sources. Again, the issues around expanding wind-power are socio-political rather than economic/technological.
A recent study found that maximizing onshore wind potential could enable Europe to generate 100 times more electricity than it currently does. That’s enough to cover energy demand for the entire world from now until 2050. But that again omits consideration of practical, political constraints.
Wind-power suffers from a number of drawbacks: wind variability, meaning that storage is needed; wind-shadow effects (adding new turbines reduces the performance of others); and local heating (wind turbines push warm air downwards).
Despite growth in recent years, solar photovoltaics power is only a small proportion of energy generation – less than 1%. However, costs of solar are falling: in Europe, the price per MWh is expected to decline to between €40 and €60 in 2025 and further decrease to as low as €20 in 2050, making it among the cheapest sources of energy. Solar systems could grow to supply 5% of global electricity consumption in 2030, rising to 16% by 2050. This would avoid the emission of 4 Gt of carbon dioxide annually.
Solar also suffers from variability of supply, but innovative approaches are looking to address this.
- Belgian scientists have combined solar panels with generating and storing hydrogen as a more efficient and cheaper solar energy storage system than batteries.
- Energy Vault is a venture that stores excess solar farm electricity by using giant cranes to lift and stack 35-metric-ton bricks, thus storing it as potential energy. When the energy is later needed, software tells the system to lower the bricks, and that spins generators to send electricity back into the grid. The system can respond within a millisecond.
- Malta is building a grid-scale energy storage technology that stores electricity from solar sources as heat inside large tanks of high temperature molten salt and as cold in large tanks of chilled liquid.
One of the oldest renewable energy sources, hydropower, is, ironically, itself being threatened by climate change. Rivers that once ebbed and flowed with seasonal regularity have grown erratic. In Brazil, record drought triggered blackouts in 2015. In California, output from dams has swung wildly from year to year. And in Europe, Spanish utility giant Iberdrola SA’s hydro output reached a record high in 2016, then plunged 57% the following year. As one energy adviser put it: “The challenge is the future doesn’t look like the past.” Quite.
Tidal power has its supporters too. Although the Government rejected subsidies for a tidal barrage in Swansea Bay, a private company is now planning to build it within 6 years. The predictability of the tides means it doesn’t have the storage challenges of wind and solar. The Institution of Civil Engineers suggest that, because the Severn Estuary has the second highest tidal range in the world, tidal power in the Severn could produce a total of about 7% of the country’s energy needs.
Geothermal energy is used in over 20 countries. The United States is the largest producer of geothermal energy in the world, and hosts the largest geothermal field, in California. The field is spread over 117 square kilometres and formed of 22 power plants, with an installed capacity of over 1.5GW. The energy source is also prevalent in Iceland where it produces 25% of the country’s energy from five geothermal power plants. Geothermal energy does emit CO2(one-sixth of the produced by a natural gas plant) It has also been associated with other emissions like sulphur dioxide and hydrogen sulphide.
Bioethanol fuel is mainly produced by the sugar fermentation process. Most bioethanol is produced from sugar cane (Brazil), molasses and corn (USA), but other starchy materials such as wheat, barley and rye are also suitable. It is a high-octane fuel, often blended with petrol to enhance performance. R&D activities focus on using lignocellulosic or woody materials, which are more abundant and less expensive than food crops and have a higher net energy balance.
However, whilst the drive for clean energy is under way, and costs are reducing, coal and natural gas are here to stay for the foreseeable future. China’s more ambitious plans include building between 300 and 500 coal fired plants between now and 2030, for instance. The World Coal Association, whilst placing a new focus on carbon capture and “clean” coal technologies, makes the point that coal power is the quickest and cheapest way “to provide access to base load electricity and is a critical building block for development”. Coal is also political: both the United States and Australian administrations are firmly pro-coal because of a combination of sentimental and employment factors; “artisanal mining” (ie informal mining by individuals) is a vital part of economies around the developing world.
Alternatives to fossil fuels exist and so the goal of “net zero” emissions is achievable. The question is whether we want it enough to make the necessary changes.
Written by Huw Williams, SAMI Principal and Jonathan Blanchard Smith, SAMI Fellow and Director
The views expressed are those of the author(s) and not necessarily of SAMI Consulting.
SAMI Consulting was founded in 1989 by Shell and St Andrews University. They have undertaken scenario planning projects for a wide range of UK and international organisations. Their core skill is providing the link between futures research and strategy.
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