In June 2019, the UK became the first major economy in the world to pass laws to end its contribution to global warming by 2050. The target will require the UK to bring all greenhouse gas emissions to net zero by 2050. To do this, we need to rapidly ramp up renewable energy sources, halt fossil fuel use, and offset any remaining emissions. The recent release of 2020 energy data from BEIS revealed that good progress is being made in the electricity sector (Figure 1). This month, the blog looks into the road to net zero - what progress we have made since the turn of the century, and what you can do to help make net zero a success.
Net Zero
Net zero means that the UK’s total greenhouse gas (GHG) emissions would be equal to or less than the emissions the UK removes from the environment. Carbon dioxide (CO2) is the largest contributor to GHG emissions globally, and is generated primarily from the burning of fossil fuels: coal, oil and gas.
A key route to achieving net zero is, therefore, to stop burning fossil fuels, and where this is not possible, offset the resulting emissions through carbon capture methods. In order to reduce our reliance on fossil fuels, we must rapidly ramp up renewable energy sources, such as wind power, solar power, tidal power. Other energy sources may also play an important role going forward, such as nuclear power and biofuel.
The UK reached peak CO2 emissions in the 1970s, and has since been on a general decline to 2020 levels of 329.58 million tonnes (405.5 million tonnes carbon dioxide equivalent of total GHG emissions). In 2020 CO2 emissions were half of the 1971 peak of 660 million tonnes (Figure 2). To achieve net zero, emissions net emissions of green house gases need to be need to zero or in deficit.
Changing Energy Usage
Much progress has been made to reduce emissions in the last decade. This has been driven by a reduced reliance on fossil fuels for electricity generation through a significant drop in the number of coal- and oil- powered power stations, and a rapid expansion in renewable energies (primarily wind energy) in the last decade (Figure 3).
Figure 4a shows the changing source of electricity over my life time. Coal (the largest GHG emitter out of all energy sources) has been all but eliminated from the energy mix in the UK in recent years. Gas has filled the gap that coal has left. Although Gas (green) is also a fossil fuel, it produces significantly fewer GHG emissions than coal (grey) on combustion. Our dependency on imports (pink), nuclear (lilac) and hydroelectric (dark blue) have remained fairly constant, however the clear expansion of renewable energies: wind (light blue), solar (yellow), and other renewables such as biofuels, tidal and wave (orange) is clearly seen in the graph. As these continue to expand, our need for gas power stations will continue to decline.
However, the change in electricity generation over time only accounts for a small portion of overall energy consumption in the UK. Figure 4b shows the total primary energy consumption in the UK over the same timeframe. Primary Energy includes energy used for heating, transport, and industry amongst other energy uses. As with electricity consumption, coal has rapidly declined in the last two decades, however oil and gas still play a very significant role in energy supply. When we examine the percent contribution of fossil fuels, renewables, and other energy sources to primary energy (Figure 5), it can be seen that fossil fuels still make up over three quarters of the energy used in the UK as of 2020.
Fossil Fuels in our Energy Mix
Why is our primary energy oil- and gas-dominated? Although we use a significant amount of gas for electricity generation (around 30%), we also rely heavily on gas for domestic heating and cooking in the UK (around 35%) (Figure 6). Gas is also used in industry and services (such as agriculture). The vast majority of oil used in the UK is used in transportation: petrol, diesel, jet fuel. Diesel - primarily used for heavy goods vehicles - made up 35% of all oil used in the UK in 2019.
Heating and transport activities are very challenging to decarbonize compared to electricity generation, and so the use of oil and gas are very likely to remain an important part of our energy mix for some time.
On a side note - data shown in Figure 6 are taken from 2019 rather than 2020 since the Covid-19 pandemic caused a temporary shift in energy usage in the UK with the shut down of industry, a fall in transportation of people and goods, and a move to at home working and lockdowns. This resulted in a significant drop in primary energy usage, as can be seen in Figure 4b.
How can we contribute to net zero?
It is clear that very good progress has been made on the road to net zero 2050 - particularly in the last 10 years with rapid expansion of the renewables energy market contributing to decarbonizing our electricity supply. However, significant challenges lie ahead in removing emissions from domestic gas usage (for heating and cooking) and transportation fuels.
Even before Covid-19, the total amount of energy the UK uses has been falling year by year (Figure 7). Primary energy demand has shown a general decline from a peak in 2005 of 2692.53 TWh to 2091.3 Twh in 2019. Much of this decline has been driven by increased efficiencies in industry, transportation and homes. When this decline in energy usage is combined with the expansion of 'green' renewable energy sources, CO2 emissions drop at a dramatic rate (Figure 7). Renewable energies have an important role to play in net zero - but it is the continued reduction in primary energy consumption that will be the key to its success.
We all have a responsibility to contribute to reducing energy consumption. Doing so is actually very easy to achieve. Here are three suggestions of actions that you can take to maximise the reduction in GHG emissions in the UK.
1. Stop using Amazon Prime. Diesel - primarily used for heavy goods vehicles - made up 35% of all oil used in the UK in 2019. Reducing the amount of oil used for transportation is the fastest way to reduce our GHG emissions. Unfortunately, we have gotten used to clicking a few buttons and expecting our newly purchased item to arrive within hours, no matter where in the country (or World) it is from. The logistics to achieve this are incredibly wasteful, and in most cases, completely unnecessary. Shop local where possible. When you cannot avoid internet shopping, do not support rapid delivery so that goods can be moved using slower but more efficient means using fewer HGVs, or other greener means of transport such as trains.
2. Avoid car use where possible. 35% of all oil in the UK is used as diesel, and 17% used as petrol for cars. Reducing our use of private vehicles for travel would vastly reduce the volume of oil-generated GHG emissions. There are many small ways to contribute to this action. For short journeys, opt to walk, cycle or take the bus. For longer journeys consider the train. Preferably, if you do not regularly need access to a car, look to opt into a car share scheme rather than private ownership.
3. Turn down the thermostat. After transportation, the next largest use of fossil fuel in the UK is for domestic gas uses - heating and cooking. There are many ways to reduce our gas consumption in the home including the (often costly) investment of insulation, and double glazing. Where this is not possible, look for other ways to increase the efficiently of home heating such as the installation of curtains and draft excluders, or targeted heating in rooms that are being used rather than heating the whole house. And always keep a jumper to hand!
The last 20 years have shown that rapid changes to our energy system is possible, and excellent progress has been made to decarbonise our UK electricity supply. However, removing fossil fuel emissions from transportation and domestic heating uses remains a challenge. Energy efficiency will play and important role in this, however reduction in primary energy demand is going to be key to the success of net zero 2050. For this, we all need to contribute, and each and every person really can impact our GHG emissions.
All data used in this study was sources from BEIS and the Our World in Data website.