Switch on to the electric planet
If we're going to halt global warming, we need to switch to cleaner energy sources, writes Alan Finkel.
No one seriously – or at least, no one serious – believes the Earth does not have a problem with relentlessly increasing atmospheric carbon dioxide levels. It is a depressing prospect to most people, but to an engineer it’s a challenge, and one of such scale that it requires a transformational solution.
It is clear we cannot continue as we are, burning coal to generate most of our electricity, and using petrol to run most of our vehicles. Nor does the false hope of a hydrogen economy hold the answer. Extracting hydrogen from methane, the cheapest source, generates lots of carbon dioxide as a by-product, which rather defeats the purpose. Using electricity to split water molecules to obtain hydrogen is perfectly clean, but inefficient.
The only way to meet the energy demands of the future without sacrificing standards of living or undermining the economy is to supply the vast majority of energy requirements by electricity, a vision I like to call the “Electric Planet”.
The transformation to an Electric Planet takes place in two steps – the first, to replace our existing electricity supply with clean electricity, the second, to generate a lot more of it to replace the fossil fuels that we currently use for transportation and heating.
Step one alone would wipe out 33% of the greenhouse gas emissions if implemented in the United States.
For step two, start by converting all the cars and some of the heavier vehicles to run on clean electricity, thereby cutting emissions by another 18%. To go further, generate even more clean electricity and replace a modest two-thirds of the fossil fuel burned for industrial, commercial and residential heating to save a further 20%. These savings combined would deliver more than 70% reduction in greenhouse gas emissions.
The toughest challenge is to generate all the clean electricity required, as renewable sources alone are not enough.
Conversion to the Electric Planet need not be traumatic, either, as it is little more than an extension of what we already know, building on the existing transmission and distribution systems.
If the shift were not rushed, it would not be significantly more costly than business-as-usual nor compromise our high living standards. Coal-fired electricity generators can be closed down and replaced with clean alternatives as they reach the end of their design life; electric cars can replace internal combustion engine cars as consumers upgrade their vehicles.
Electricity is an extraordinarily efficient way to distribute energy. For example, if a balloon of natural gas were used to fuel a car it might keep it going for, say, one kilometre. But if the same balloon of natural gas were used to generate electricity to run an electric car it would keep going for three kilometres!
Other problems are overstated. Losses due to transmission and distribution are less than 7% on average, and the environmental impacts of manufacturing batteries are small compared with the mitigated carbon dioxide emissions.
The toughest challenge is to generate all the clean electricity required, as renewable sources alone are not enough. Wind and solar electricity have many dips that must be smoothed out. Hydro helps, but there just isn’t enough of it. Geothermal, and coal with carbon capture and storage have theoretical potential but neither is commercially proven and prospects for a significant contribution are low. Biomass is useful, but can conflict with agricultural land-use.
Nuclear can generate massive quantities of clean electricity but it will not make a contribution above its current levels in the next 30 years because of rising construction costs, licensing delays, politics, proliferation, waste management and safety concerns, and the long design cycle. If these problems can be overcome, nuclear will make a hugely important contribution in the second half of the century.
That leaves natural gas: it is not perfect but it has a significantly lower carbon emissions profile than oil or coal. In the world of engineering, we look for best possible outcomes, not perfection. Gas today already enables a very good outcome, and it is likely that extraction and generation will both become more efficient. Gas makes large-scale solar and wind electricity generation practical by providing the electricity when the sun is not shining and the wind not blowing. The combination of renewables and gas allows the economic delivery of an expanded electricity supply that, while not zero-emission, would be very low. While we won’t quite achieve a 70% reduction we’ll get close.
The engineering might well be the easy part. To achieve the Electric Planet by 2050 we need to agree on the vision and set in motion an international strategy now.
Even if the politics looks harder than the science, we mustn’t be deterred. Earth is the best planet we have. We should invest in its future.