The wind doesn’t always blow, the sun doesn’t always shine – so how do you get lots of power from renewable sources, and keep the lights on?
An analysis by consultants Energynautics for Greenpeace based on European weather information for 2011 and data from the International Energy Agency (IEA) suggests it is possible to get 77% of Europe’s electricity from renewable sources by 2030; through smart grids, demand management, gas backup and big changes in how our power grid works.
The model suggests that by taking a European approach (rather than planning by country) and using a (relatively) new type of power cable the cost of integrating new renewables into the grid can be significantly cut.
It means you can meet three quarter’s of Europe’s power from renewable sources for slightly more than countries are currently planning to spend on grid upgrades delivering just 37% renewable power.
The total investment currently planned amounts to less than 1% of the average European energy bill, according to the study.
The analysis also suggests that opting instead for a mixed approach – by retaining coal and nuclear power alongside renewables – could wind up costing around 2bn euros a year by 2030 making the system more expensive than an entirely renewable and gas option.
Can you reach three quarters renewables and keep the lights on?
The report suggests that by 2030 Europe’s grid will be able to absorb a renewable share of 77% (equivalent to a 45% renewable energy target) with some countries, such as Spain, getting all their power from renewable sources. The UK would be on 70%.
Around half of Europe’s power (53%) would come from wind and solar PV panels rather than other renewable sources. Yet sometimes the wind blows hard and sometimes not at all.
The solution to the problem, the report argues, is cables to import or export power between European countries.
The expansions would mostly be on top of the existing grid.
That means upgrading Europe’s grid with high voltage direct current cables which carry more power, take up less space and waste less electricity than the conventional, alternating current pylons we mostly use now.
But sometimes much of Europe is still and cloudy at the same time, a problem for the sailing ships of old and the renewable power sources of today.
Renewables which aren’t dependent on the weather, like concentrated solar power, hydro and limited amounts of biomass can fill some of the gap. The rest comes from gas which can be turned on, and off, very quickly.
To limit the amount of ‘backup’ power you need smart grids and demand management – think electric cars or fridges that adjust their power use according to the cost of electricity – to spread the load, avoiding the need for huge amounts of power all at once.
You could think of it as the Googlification of power – applying algorithms to ensure electricity is used more smartly.
Fine, but how much will it cost?
Cables are not cheap and indeed if we wanted to just stick with exactly the electricity infrastructure we already have (bit of an issue for climate change and the lights going out) we probably wouldn’t need that many of them.
But that isn’t actually an option. Coal and nuclear plants are getting very old, and some are being phased out. Clean energy, including renewable energy, is being built in an effort tackle climate change and countries are trying to ensure their power supply is secure.
The plans we already have are so expensive that – the report argues – you could get to 77% renewable power for about the same price. The trick is to decide what you want rather than build a grid to cover all options.
Right now individual nations have already come up with plans to build lots of new cables, just to meet the changes happening between now and the 2020s – which includes 37% of renewable power by 2030.
These schemes have been brought together into a European Ten Year Network Development and Regional Development Plan which, when all totted up, comes to about 104bn Euros.
The energynautics analysis takes out costs which are hard to compare, like land rights, licenses and refurbishment and comes to a total of 58bn euros.
It then runs a model of how much it will cost to build a grid that can handle 77% renewable power – but assuming you take a European approach from the start and with some big changes to how the grid is built consistent with such a big renewables share.
That means expensive but high capacity and low-wastage cables between regions and countries and batteries which can store the power from solar plants for a limited time (technology that already exists). It also assumes renewable power can be curtailed in extreme cases.
All in all it comes to 61bn euros – though obviously it would be more once you throw in refurbishment, land rights etc.
The change in technology also reduces the amount of cables needed, from a slightly dotty 52,300km by 2022 to a still very significant 26,000km by 2030.
In the picture above you can see that you need more cable with the 800kV alternating current cables, which is what we have, compared to the 188kV high voltage direct current cable that is recommended in the energynautics analysis.
But trying to go for renewables, coal and nuclear is tricky (and expensive)…
Sticking with elements of the current system in some countries – but adopting new technologies in others – is not an especially implausible outcome of the current negotiations over Europe’s energy targets.
France and Poland, for example, could remain largely powered by nuclear and coal respectively.
This poses another challenge because whilst renewable power is variable nuclear and coal power plants are – for the most part – relatively inflexible.
Unlike gas, which can be turned on and off quite quickly coal and nuclear plants can be ramped up and down by a certain amount (it varies but often around 20%) but it’s hard to turn them on and off.
That means if the wind is blowing across Europe we may not be able to use it all. So coal is burnt for no reason, gas plants, which struggle to compete with coal, are forced to seek subsidies to stay open and emissions are probably higher (depending on whether it is coal or nuclear in the mix).
The situation could be particularly difficult for Germany or countries, like the UK, with a limited ability to import and export power.
Even if – as planned – Germany develops lots of renewable energy it would find itself sandwiched between countries with high levels of inflexible power generation. That means it wouldn’t be able to export power on windy days and would instead face be forced to curtail 9.8% of its renewable generation.
The report concludes, curtailment could cost around 2bn Euros a year by 2030 assuming we are paying 50-60 Euros for each MWh of power we don’t use.
So running a mixed grid may mean fewer cables, and less up front investment, but could also wind up costing more when it comes to the whole system. You can see why inflexible power is a problem on the chart below (well…… so we’re told).