Energy sources fall into one of two categories: free or inexpensive fuels that must be harnessed using quite costly technology, or costly fuels that can be harnessed at relatively little expense.

The first category includes nuclear power, and renewable energy sources like wind, sunlight and flowing water. The second includes fossil fuels such as coal, oil and natural gas.

The challenge in detail

To tackle impending climate change, the world needs urgently to shift to low-carbon energy sources such as nuclear and wind power. By 2020, these are expected to be among the most affordable electricity-generating technologies.

The challenge

High-carbon energy sources such as fossil fuels could become more costly due to an increase in global demand, shortage of supply, or taxes on greenhouse gas emissions. Carbon Capture and Storage (CCS) might reduce emissions from power stations and limit the effects of these taxes – but CCS technology itself is expected to increase the cost of generating electricity using these energy sources.

Low-carbon technologies that might present a solution to climate change, e.g. offshore wind farms or solar photovoltaic (PV) panels, are relatively recent developments. 

What's being done?

What’s being done?

The cost of new electricity-generating technologies tends to fall over time.

Designs can be improved and made more efficient. Construction processes will be streamlined and the volume of labour reduced as the industry gains experience. Operators learn to run their equipment in the most efficient way – minimising costs and maximising income.

What it means for the UK

What it means for the UK

In 2009, about 60% of UK electricity was generated from fossil fuels – mainly coal and gas (calculated from data presented here). But to achieve our 2050 greenhouse gas emissions targets, almost all UK electricity will need to be generated from a mix of nuclear power, renewable energy, and fossil fuels equipped with Carbon Capture and Storage (CCS) technology.

CCS traps greenhouse gases and stores them underground, but is expected to increase both the upfront and operating costs of fossil fuel-burning power stations.

This shift to an energy mix will require major investment in new electricity-generating capacity: from microgeneration projects such as household solar panels to large power stations. The UK Government estimates that as much as £110 billion of investment in generating and transmission equipment could be required by 2020.

How the UK is responding

How the UK is responding

Using a mix of energy sources and technologies to generate electricity should enable the UK to maintain its supply of affordable and low-carbon electricity. Nuclear power is expected to play a major role in this, and is already cost-competitive with other low-carbon generating technologies (and with higher-carbon generating technologies once the true cost of emissions is counted).

Onshore wind will also be a major player, although how much energy can be harnessed in this way is limited by social and geographical factors.

Offshore wind capacity will also increase and its costs are expected to fall over time.

Newer and more expensive technologies – such as Carbon Capture and Storage (CCS) – may become more affordable as the industry gains experience of using them.

The affordability challenge for each energy source

Each energy source brings different costs of harnessing power and transforming it into clean and reliable electricity. When we consider affordability, we must take all of these costs into account.


Fast-flowing water to generate hydroelectricity costs nothing at source, but dams are expensive to build and the ideal sites have already been exploited.


Surrounded by the sea on all sides, the UK is well located to exploit the power of waves and tide. But marine technologies are still in their early stages and need significant financial investment.


Sunlight in the UK is often not constant or strong enough to easily harness and store its energy. Our climate is less than ideal, and solar panels are expensive to manufacture and install.


Wind is clearly unpredictable – we cannot rely on wind power alone to generate energy. Building onshore turbines is often constrained by environmental concerns, and moving offshore is expensive and complex.


The UK relies on imported coal, which makes us vulnerable to changing market prices. To reduce greenhouse gases and reach carbon emissions targets, our coal-fired power stations of the future must incorporate CCS technology.


As the UK uses more gas, natural reserves across the world will decline faster. We also rely on imported gas, which makes us vulnerable to changing market prices.


The costs of building and decommissioning nuclear power stations can make nuclear energy look expensive. But nuclear power stations have relatively low operating costs and long working lives.

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Our energy approach

We want to bring affordable and low-carbon energy to all. With our experience, we can help the UK move toward a more sustainable energy future.

The energy mix

The UK is supplied by a variety of electricity generation sources, which we call the energy mix. Each energy source has its advantages and disadvantages.

Future energy

The UK’s electricity demand could exceed supply within the next decade, creating an energy gap. Find out how we plan to lead energy change to create a stable energy future.