To green the UK's electricity system, this is what we need a whole lot more of. Offshore wind turbine at Burbo Bank, Liverpool Bay, England. Photo: Danish Wind Industry Association / Vindmølleindustrien via Fliclr (CC BY-NC).
How the UK can get almost all its power from renewables - without new nuclear
Damian Kahya / Greenpeace Energydesk
21st September 2015
The government claims that we need nuclear 'baseload' power to keep the lights on, writes Damian Kahya. But a new study shows reliable, low carbon energy can be provided by combining diverse green technologies including efficiency, large scale renewables, 'smart grid', energy storage and rarely used fossil fuel backup.
Most of our power capacity, 55GW, would be in offshore wind farms, more than twice as much as currently exists or is consented. This would amount to a world-leading revolution and would be roughly in line with the CCC's 'high renewables' estimates.
The UK could generate more than 80% of its electricity from wind, solar and tidal power within 15 years and keep the lights on.
And it's all possible thanks to advances in storage and smart technology, and falls in the costs of renewables, according to a new study
The analysis comes as experts and politicians remain divided over how and whether the UK can cut its emissions, following the example of countries like Sweden and Denmark.
The UK government is keen to put its efforts into large-scale projects such as the Hinkley Point C nuclear plant. Just today the Chancellor, George Osborne, announced a £2 billion loan guarantee for the project - a first instalment on a promised £17 billion loan guarantee package.
In the opposite corner, the chief executive of the UK's National Grid recently said in an interview that "the idea of large power stations is outdated."
The study by consultants Demand Energy Equality (DEE) for Greenpeace, '2030 Energy Scenarios', is one of the first to look at whether the UK could meet its targets to reduce emissions and tackle climate change through renewable energy, efficiency, batteries and smart technology.
It meets a target for carbon emissions of 50g for every kWh of energy produced - in line with the advice of the government's independent climate committee.
It's a tricky question, particularly because of concerns that getting much more than half our power from renewables would be inefficient, needing huge amounts of backup power for when the wind doesn't blow or the sun doesn't shine.
The report suggests it is possible to avoid these pitfalls - though it isn't easy.
Eleven years of weather data analysed
The study's authors used hourly weather data for 11 years and modelled how national demand could be met, down to the household level, if the UK were relying on renewables - chiefly wind, solar, and tidal power - for more than 80% of its electricity.
To make things even more complex the study also assumes we use electricity not just for traditional purposes, but also for transport and heat - as more people begin to drive electric cars and use electricity instead of gas to heat their homes.
The DEE study did not include a full technical cost modelling exercise - partly because the cost of renewable energy keeps changing.
However, the rapidly falling cost of onshore wind, solar and offshore wind - along with the high cost of alternatives such as nuclear and clean coal - mean that the costs would be similar to other cost-effective ways of decarbonising the power sector using a different mix of technologies.
A comparison of the scenario in the study with a 'high renewables scenario' done by energy analysts Poyry for the government's independent climate advisors, the Climate Change Committee, indicates that the costs would not be very different.
It is likely that levels of investment would now be lower than those estimated when the Poyry scenario was published four years ago because of the changing costs of different technologies - in particular the falling costs of renewables.
So here are four important steps to delivering renewables in the UK ...
1. Use less energy - especially for heat
Cutting emissions isn't just about reducing the amount of coal and gas burnt to produce electricity - it's also about reducing the amount of gas used to heat our homes.
But that doesn't just mean more insulation, it also means a gradual switch towards electric heating through heat pumps and underfloor heating. (It also means a shift towards electric cars.)
That may lead to warm feet and quiet journeys but the problem is it means we will need more electricity, particularly at peak demand times.
This is why the report suggests demand for energy to heat our homes needs to fall by more than half over the next 15 years. The government's own scenarios only envisage this happening by 2050. But the devices we already power with electricity also need to become more and more efficient - bringing down this 'traditional' power demand.
The second part - falling demand for power from our TVs, fridges etc - is happening already, and the report suggests it will continue at the current trend.
But the first part - a dramatic reduction in the need for heat through a revolution in home insulation, which would save people lots of money - may not happen without a change in government priorities.
That fall in home heat demand would allow technology like heat pumps to provide a quarter of our heating, but rolling out this technology at that scale in the next 15 years would be challenging.
Ironically if that didn't happen it would make it easier to power the UK with renewables, but it would also mean emissions would be higher. Given the current state of government policy many now view this outcome as more realistic.
2. Build lots of wind turbines and solar panels
The report's targets for onshore renewables are actually fairly modest. It suggests a 47% increase from the number of onshore wind turbines that were built or approved for building at the end of 2014.
It also proposes a target for solar panels only a bit larger than one once put forward by a Conservative minister (before they went off the idea).
When it comes to oceans, though, it's ambitious. Most of our power capacity, 55GW, would be in offshore wind farms located around the UK, building more than twice as much as currently exists or is consented.
This would amount to a world-leading revolution in technology and would be roughly in line with the 'high renewables' estimates from the government's climate advisers.
3. Combine power generation with heating
In order to reduce the UK's reliance on imports from other countries the report still uses some gas backup. But conventional gas plants create a lot of heat, which is partially lost. The report suggests rolling out a fleet of new gas plants which would combine power generation with industrial or district heating.
They would sometimes operate alongside pumped-storage facilities - where water is pumped uphill when there is too much power and allowed to flow down when there's too little - to help provide backup if the weather doesn't deliver all we need.
Conventional plants would remain on the system, but would be barely used, running just 2.1% of the time.
4. Smart technology
One big difference between this study and others before it is that it takes account of future changes in technology which - put simply - means we can use less kit to power the same number of homes. Most or all of the technology already exists but hasn't been deployed much.
In particular the study looks at how smart meters, batteries and demand-side management can be used to reduce the need for extra gas power stations at key moments (remember that hourly weather monitoring?).
That means, for example, smart fridges which would turn down slightly during a dark, still winter's evening, or perhaps when everyone turns on the kettle at half time during the football. Or home or grid-scale batteries which could store excess renewable energy ready to be used if the wind stops blowing.
This is all much cheaper and more efficient than building whole new power plants just to meet extra demand during these relatively short peak periods.
Essentially, what this report shows with unprecedented accuracy is that, contrary to popular belief, renewables can keep the lights on.
The report: '2030 Energy Scenarios' was written by Dr. Daniel Quiggin & Max Wakeﬁeld of Demand Energy Equality (DEE) for Greenpeace.
Damian Kahya is an author at Greenpeace Energydesk.
This article was originally published on Greenpeace Energydesk, which is editorially independent of Greenpeace.
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