Anthropogenic carbon emissions, and other greenhouse gases, especially methane, have resulted in a major increase in atmospheric levels of CO2 and other greenhouse gases. This is leading to global warming, through the greenhouse effect and also acidification of the oceans. There is therefore a pressing need to reduce future emissions of CO2 and other greenhouse gases. In line with this, the UK government have a plan to become net zero by 2050; the University of Cambridge plan to become net zero by 2048. Net zero means that there is no net emission of CO2.
Reaching net zero is a major challenge, requiring a re-building of much of the national and international infrastructure related to the energy industry. The challenges fall both in the supply of energy and the demand or use of energy.
The supply needs to change from oil, gas and coal to carbon free sources, which with today’s technologies largely implies new wind and solar power. Future technologies may also unlock more of the potential energy in waves, tides and geothermal for example. Presently over 80% of the world energy is supplied by fossil fuels, with hydroelectric and nuclear being another 14%, and so the transition in the energy supply system is of a truly global scale. While the transition occurs, energy supply needs to be maintained; given the scale of the infrastructure change, it is very likely that we will continue to use a gradually diminishing, but significant inventory of fossil fuels, as the new renewable supplies come on stream. This future inventory of fossil fuels will produce a substantial mass of new carbon emissions; technologies to reduce these emissions by making the production or consumption of this fuel more efficient, while the energy transition is under way, can therefore have an important impact on overall atmospheric carbon levels, given that the residence time of CO2 in the atmosphere is of order centuries.
The demand for energy spans many different uses, but major demands include heating (for buildings), electricity for power (for use in lighting, powering computers, and other electrical goods), and energy for transport (cars, trucks, trains, ships and planes). Presently, in the UK for example, 22 million homes use natural gas for heating: transitioning to a carbon free heating system will require replacement of all the gas boilers with other systems, possibly including electrical heat pumps or hydrogen driven heating systems. Transport presently is centred on petrol and diesel powered cars and trucks, jet-fuel for planes and coke for shipping. To transition to a zero carbon system, we need new vehicles powered by carbon free energy sources. Electrical cars provide a replacement for petrol/diesel cars, but large trucks, with substantially greater mass and hence energy needs, may require alternative high density energy sources, such as hydrogen, and there are experiments under way exploring the use of hydrogen to power ships. Electricity is a direct product of wind and solar power, and so with sufficient supply of wind turbines and solar farms, the electrical systems become zero carbon. In today’s power generation system, wind and solar do not provide all the electricity, and that fraction of the electricity derived from natural gas is not carbon free; electric cars or heat pumps running on gas-derived electricity do not remove carbon emissions. Hydrogen could be generated from renewable energy using the electricity to electrolyse water, thereby making the hydrogen a zero carbon fuel.
Another major challenge of the energy transition is that as well as requiring new infrastructure for both the supply and the demand systems, the electrical grid which transmits the electricity needs a substantial upgrade and redesign if it is to carry the energy for transport and heating as well as the electricity load for its present uses. For context, in the UK, the energy used for present electricity, for heating and for transport are of comparable scale.
Owing to the enormity of these challenges, another technology which has been discussed and which is included in the IPCC and the UK Committee for Climate Change plans is the process of Carbon Capture and Storage. Carbon Capture and Storage involves the removal of carbon dioxide from the exhaust gases produced when fossil fuels are combusted. At a power station, the CO2 can be captured on a large scale, and this CO2 is then pumped underground about 1.5-2km below the surface into saline aquifers ( layers of permeable rock), where the CO2 will displace the water in the pore spaces in the rock, and then become trapped. CCS provides a means to prevent addition of CO2 to the atmosphere, while still using natural gas or other fossil fuels to generate electricity, leading to the expression clean gas. CCS is however an important technology in its own right, since there are other industrial processes which produce large fluxes of CO2, for example the process of cement manufacture. Using CCS to capture the large flux of CO2 produced at a cement factory or other such site would reduce those emissions into the atmosphere. It is also possible to grow biofuels, which absorb CO2 from the atmosphere, and then burn the fuels to produce electricity, while capturing the exhaust gases through CCS. This ultimately leads to negative emissions of CO2, and has been proposed as part of the net zero system for 2050.
Finally, an important element of the energy transition is in designing more efficient systems, from small machines, phones and computers, to larger scale efficiency of buildings and other infrastructure. Using less energy while maintaining the present functionality of the system offers huge opportunities for reduction of carbon emissions.
The BP Institute is involved in the development of many of the above solutions or topics related to the energy transition. Work is under way to reduce the frictional stresses associated with lubricants, making machines with moving parts more efficient so they use less energy in the first instance. We also have a major programme of research into carbon capture and storage, examining how much CO2 can be injected into a subsurface aquifer, where it will spread in the aquifer, and how we can monitor where the CO2 migrates within the aquifer. Other research in the BPI is directed towards designing low energy buildings, while also keeping the environment in such buildings safe and well ventilated. We have projects exploring the production of batteries with higher energy capacity, and in using aquifers to store thermal energy on a seasonal basis. Some research in the BPI is directed towards understanding the detailed processes which occur in nature as a result of the climate change; we have projects exploring the long term evolution is ice sheets in Greenland and the Antarctic, modelling deep ocean mixing with a view to providing clearer quantification of the residence time of CO2 adsorbed into the ocean, and work modelling avalanches and landslides which are becoming more frequent owing to changes in vegetation and forest fires as well as other effects.
We welcome mutually respectful debate and discussion about the important issues of climate change and the energy transition, and encourage students to sign up for the annual BPI Masterclass in December. The energy challenge requires a very wide cohort of students and faculty to engage with the multitude of problems associated with driving forward the energy transition, ranging from the science and technology to the design of new policy, and the challenges of the social and economic constraints. Please contact : firstname.lastname@example.org for more information.