The hard realities of an energy system based on renewables will soon be with us, causing far more problems than are realized. Renewables don’t offer a quick fix, and we need to get the transition from “black” to “green” technologies right to avoid some costly—and ridiculous—anomalies.

While global CO2 emissions flattened out between 2014 and 2016, they started to increase again in 2017 (up 1.6%) and are predicted to have been up 2% in 2018. The increasing use of oil and gas, and the ongoing use of coal—to support economic growth in developing countries in particular—have been identified as the main causes. There is mounting pressure for governments to move more quickly and be more radical in their responses. Formal revisions of national emissions-reduction targets will be made in 2020. In the meantime, the United Nations is subject to active international campaigns to introduce much tougher CO2targets.

Bridging to Sustainable Energy

We can all agree that the future needs to be based around sustainable energy technologies. But there needs to be a more open-eyed and systematic evaluation of the full costs—both financially and in terms of the carbon footprint—of different energy generation options. Fundamental to the issue is the actual whole-life costs of introducing more renewables. For example, the full range of environmental impacts from creating a new renewables infrastructure must be considered, including the mining and industry involved in supplying vast amounts of minerals and metals.

Most significantly, calculations need to include costs of creating buffer storage. All we’re seeing at the moment is the carbon-emissions benefits from introducing renewables as a minority of energy supplies, all done at a reasonable cost. But this will quickly change when renewables start to form a majority of the energy supply, because suddenly, supplies will be at the mercy of the intermittent nature of renewables and the demand for storage.

There are, as yet, no technological answers to the need for mass battery storage. A London School of Economics study suggests that the UK alone would require all the available resources of lithium on the planet to provide the necessary battery buffer for its needs. Whatever technologies and methods are used will mean large increases in costs to energy customers.

Other cost issues need to be considered, such as the actual carbon footprint involved in the increased use of natural gas by many developed-economy governments as a means of reducing carbon emissions. The process in itself is cleaner, but what about the potential for pipeline leakages of methane, which has a warming effect that’s estimated to be 28 to 36 times that of carbon dioxide? In the U.S. between 2010 and 2017, the natural gas network leaked 17.5 billion cubic feet of methane, constituting a similar impact to that of one large coal-fired power station for a year. Leaks have reached a level of 2.3%, and if they reach 3%, the study claims there will have been no environmental benefits at all in moving from coal to gas power plants.

Some “bridging” alternatives to conventional power stations can involve unforeseen problems. Burning wood pellets is categorized by the U.S. Environmental Protection Agency as a renewable energy, for example, and has misleadingly been counted as being “zero carbon” in Europe, with the impact assumed to be balanced out by the planting of new trees. The UK has become one of the world’s largest importers of wood pellets—coming mostly from the U.S., Canada, and Latvia—for use as bioenergy feedstock. Chatham House has called this approach a “disaster” in terms of climate change because of the simple fact that the large trees used for pellets release huge amounts of carbon when burned and it can take up to 100 years for an area of woodland to have reached the stage where it can soak up that carbon.

CCS Is a Sound Solution

Being more realistic about the whole costs of renewables isn’t an attempt to undermine their long-term importance. But it’s critical for the transition period that governments and their policymakers understand the full picture and avoid making a headlong rush for renewables without considering the sustainability of the transition. In particular, that requires an open mind when choosing the most-effective and workable transition technologies.

A prime example is carbon capture and storage (CCS). CCS has tended to be marginalized in recent years due to the obvious additional costs and loss of efficiency in power generation. But in this clear-eyed context, CCS is a workable option in terms of balancing financial costs and meeting carbon reduction targets.

Rather than focusing on the negative, frightening messages around climate change, there are many reasons to feel optimistic, because of new CCS technologies in particular. Our recent research, for instance, has demonstrated the real potential for reducing global CO2 emissions by 8% just through the use of CCS to decarbonize the iron and steel industry economically, hitting 2050 carbon targets by 2030. This wouldn’t be possible if there was a sole reliance on renewables. Introducing more CCS, just as one transition technology, will create jobs, encourage more investment, and allow a genuinely sustainable basis for a future of renewables. ■

—Vasilije Manovic, PhD is Professor of Carbon Systems Engineering at Cranfield University (www.cranfield.ac.uk).