We can have 100% renewable energy and still have ‘baseload’ power

With a review of the proposed Hinkley Point C power station in Somerset due next month and the promise of a detailed strategy on the UK’s broader energy policy by the end of the year, this second of three blogs this week looks at ‘baseload’ power.

 

Let’s first remind ourselves of the longer-term perspective in terms of the UK’s low-carbon transition:

“The UK’s fifth carbon budget, recently passed into law, will require the power sector to be largely decarbonised by 2030. Meanwhile, the Paris Agreement on climate change means the UK has pledged, along with almost 200 other nations, to almost completely decarbonise all energy use soon after mid-century.” – Carbon Brief

That means we need to get almost all our electricity from zero- or low-carbon sources by 2030 and start making inroads into other sectors by then too; such as electrification of transport, heating and cooling systems and reduced emissions from industry, agriculture etc.

Focusing first on the electricity generation sector, which makes up the highest proportion of GHG emissions and will underpin the electrification of other sectors therefore clearly makes sense.

So can it be done? There are two main perceived challenges:

  1. Can we install enough to meet current and growing demand for electricity within the time frame needed?
  2. Whether renewable energy alone can provide sufficient ‘baseload’ power

‘Baseload’ power

‘Baseload’ (24-hour per day) demand has become widely-accepted as one of the challenges faced as we transition to 100% renewable energy.  After all, the wind doesn’t blow all the time and there’s no sunlight at night.

Gas-fired ‘peaking’ plants are often used to buffer the intermittency of industrial-scale wind and solar inputs to the grid. As such, it is argued that we may need substantial amounts of grid-level energy storage as well as a major grid overhaul as wind and solar power become more dominant in the share of electricity generation. But will this really pose a challenge? Here are four reasons why it shouldn’t…

#1 Addressing intermittency from wind energy

Wind power is currently the cheapest and most abundant source of renewable energy in the UK, but is said to present the challenge of dealing with the intermittency of wind speed.  Nevertheless, as of 2014, wind already supplied 39% of Denmark’s electricity generation.

Although the output of a single wind farm will fluctuate greatly, the fluctuations in the total output from a number of wind farms geographically distributed in different wind regimes will be much smaller and partially predictable.  Additionally, over the longer term (month by month) in many regions, peak wind production matches up well with peak electricity demand.

UK wind seasonality

Monthly wind output vs. electricity demand in the UK (UK Committee on Climate Change 2011).

#2 Distributed energy resources (DER) and home and business storage

Secondly, storage will play an increasing role. Distributed Energy Resources (DER), such as roof-top solar, are small-scale power generation sources located close to where electricity is used (e.g. a home or business) and provide an alternative to or can supplement power that comes from the grid. DER is a faster, less expensive option to the construction of large, central power plants and high-voltage transmission lines. Furthermore, it offers consumers the potential for lower cost and energy independence.

Alongside DER, batteries will play a key role. Batteries won’t only replace petrol tanks in cars over the next decade or two, they will also make it into our homes and businesses to store electricity from rooftop solar panels or from the grid. The electric car company Tesla announced its entry into this market last year, unveiling a suite of low-cost solar batteries for homes, businesses and utilities; “the missing piece”, it said, in the transition to a sustainable energy world.

Wall-mounted, with a sleek design, the lithium-ion batteries are designed to capture and store up to 10kWh of energy from wind or solar panels. The reserves can be drawn on when sunlight is low, during power cuts or at peak demand times, when electricity costs are highest. The smallest “Powerwall” is 1.3m by 68cm, small enough to be hung inside a garage or on an outside wall. Up to eight batteries could be “stacked” in a home.

The batteries will initially be manufactured at the electric car company’s factory in California, but will move production to its planned “gigafactory” in Nevada when it opens in 2017. The Nevada facility will be the largest producer of lithium-ion batteries in the world and it is hoped its mass-production scale will help to bring down costs. It is not the only battery storage system on the market, but the Powerwall boasts a relatively high storage capacity, a competitive price, and the heft of investment and excitement generated by Musk’s vision.

Also unveiled last year was a larger “Powerpack”, which is a 100kWh battery block to help utilities smooth out their supply of wind and solar energy or to pump energy into the grid when demand soars. Approximately two billion Powerpacks could store enough electricity to meet the entire world’s needs, which may seem like an insane number, but as Musk said: “this is actually within the power of humanity to do.”

#3 Reducing baseload demand

Thirdly, it is about timing. It is now widely recognised that we will need to start timing our energy usage to better coincide with the availability of sunlight and wind energy and in order to smooth out peaks in demand, and demand response technologies, such as smart grids, smart meters and smart appliances are already stepping up to the task.

Smart grids are energy networks that can automatically monitor energy flows and adjust to changes in energy supply and demand accordingly. When coupled with smart metering systems, smart grids reach consumers and suppliers by providing information on real-time consumption.

This will help to better integrate renewable energy by combining information on energy demand with weather forecasts to allow grid operators to better plan the integration of renewable energy into the grid and balance their networks.

The incentive to individuals and businesses is price driven. With smart meters, consumers can adapt – in time and volume –  their energy usage to different energy prices throughout the day, saving money on their energy bills by consuming more energy in lower price periods when renewable energy is more abundant or demand is lower. Smart grids also open up the possibility for consumers who produce their own energy to respond to prices and sell excess to the grid.

Energy companies have already started installing smart meters in homes in England, Scotland and Wales. Every home in Britain will have a smart meter installed by 2020.

Smart appliances will also play a part. Domestic appliances can offer a range of options for load-shifting, including delaying the start of washing or dishwashing cycles, intermediate interruptions of operation of appliances, or the use of refrigerators and freezers for temporarily storing energy.

#4 Renewable ‘baseload’ sources

There’s more to renewable energy than wind and solar!

Some renewable energy sources are just as reliable for ‘baseload’ energy as fossil fuels and nuclear, if not more so (coal and nuclear in particular can not be turned on and off quickly as and when required).

Types of ‘baseload’ renewables will differ depending on the particular environmental conditions around the world. For example, bio-electricity generated from burning the residues of crops and plantation forests, hydro in countries like Norway, concentrated solar thermal power with low-cost thermal storage (such as in molten salt) in countries like Spain, Morocco and Australia, and geothermal power all provide ‘baseload’ power.

Tidal

It is estimated that tidal power could generate around 20% of Britain’s requirements and Scotland and the UK generally are seen as world leaders in tidal energy research. Sunshine, wind and waves vary with the weather, but tides still rise and fall and the flow can be safely harnessed in and out. There are great practical challenges associated with this form of hydropower and only around twenty sites in the world have been identified as being ideal locations for large scale tidal power arrays, but eight of these sites are to be found in Britain.

The Severn, Dee, Solway and Humber estuaries are all potential sites for tidal energy generating barrages in the UK, while Islay and the Pentland Firth are to host tidal turbine arrays. The Pentland Firth, the narrow run of water between the north-east tip of Scotland and the Orkney islands, is possibly the best place in the world to generate electricity from the movement of the tides. It is estimated that around 8 TWh could be generated by tidal power in the Pentland Firth, representing 8% of total UK electricity consumption.

Additionally, in his autumn statement last year, George Osborne flagged up the prospect of a tidal lagoon power project in Swansea Bay, only to put it out for review when the price of oil and gas came down. The start-up cost for Swansea Bay stands at £1.3bn compared to £18bn for Hinkley Point C. The planned productive life of the lagoon would be more than 100 years compared with 60 years for Hinkley. Over the years, with rising output from larger lagoons around the coast, tidal input to the national grid could match Hinkley nuclear in cost and quantity.

Biomass

Certainly a controversial form of renewable energy, but it will play a part. Last year, Drax burned pellets made from nearly 12 million tonnes of wood, more than the UK’s entire annual wood production. 98% of their wood was imported; the vast majority from the southern US and Canada.  Whilst many NGOs claim that this is leading to forest destruction for electricity, which is disastrous for the environment and the climate, Drax insist that they  have a policy of driving fuel procurement activities through a set of sustainability principles and the pellets all come from waste cuttings, residue from sawmills, ag waste etc. and that the supply chain is independently checked and the whole process carbon neutral.

Carbon Brief produced a report last year investigating the use of Biomass in the UK, and Drax in particular, which demonstrated just how tricky this argument is.  I think it’s fair to say that the jury is still out, but it was providing 5.5% of our electricity in 2015).

#5 Interconnectors

One final way to allay fears around ‘baseload’ power is by linking to other countries’ transmission systems. By doing this the National Grid can increase the diversity and security of energy supplies, facilitate competition in the European market and help the transition to a low carbon energy sector by integrating with renewable sources in other countries . Consider Norway for example, which produces almost all it’s electricity from hydro, providing access to a secure ‘baseload’ supply.

National Grid’s transmission system is already linked by interconnectors to the transmission systems of France (which derives about 75% of its electricity from nuclear energyand The Netherlands. In addition to jointly owning and operating the England-France and England-Netherlands interconnectors, National Grid are developing proposals on a number of other interconnector projects.

  1. Belgium – In February 2015 National Grid Nemo Link Limited and Elia, the Belgian Transmission System Operator, signed a joint venture agreement to move ahead with the Nemo Link – the first electricity interconnector between the two countries. When completed the interconnector will provide 1 GW of capacity – enough to power half a million homes. It’s anticipated that Nemo Link will go into commercial operation in 2019.
  2. Norway – Further plans to connect to Norway to take advantage of their immense supply of hydropower via another subsea power cable, supplying a further 1.4GW – enough to power nearly three quarters of a million UK homes. National Grid and Statnett, the Norwegian Transmission System Operator, has signed the ownership agreement which signals the start of the construction phase for the 720 km interconnector between the UK and Norway (known as NSL).
  3. France – Plans are underway to construct a second subsea power cable, which will supply enough electricity (1 GW) to power two million British homes and is intended to be up and running by 2020
  4. Denmark – the Viking Link is a proposal to build a high voltage direct current (HVDC) electricity interconnector between Bicker Fen in Lincolnshire and a substation at Revsing in southern Jutland, in Denmark. It is expected to be operational by the end of 2022.
  5. Iceland – A capacity of 1 GW is being investigated, with desk studies ongoing to establish feasible converter sites, onshore and offshore High Voltage Direct Current (HVDC) cable routes, and landing points. It is expected that the landing points for the cable will be in Northern Scotland and South East Iceland. The project is currently projected to be operational from 2027

The first two of these projects (with Belgium and Norway), in which agreements have been signed to signal the start of construction, will together provide 2.4 GW of capacity, the equivalent of more than 5% of UK power generation capacity.

European Union Case Study

The European Renewable Energy Council (EREC) prepared a plan for the European Union (EU) to meet 100% of its energy needs with renewable sources by 2050 (that’s all sectors, not just power generation), entitled Re-Thinking 2050.  In 2050, the proposed EU energy production breakdown is:  31% from wind, 27% from solar PV, 12% from geothermal, 10% from biomass, 9% from hydroelectric, 8% from solar thermal, and 3% from the ocean.

EU Renewables

EREC report breakdown of EU energy production in 2020, 2030, and 2050

Summary

Arguments that renewable energy isn’t up to the task because “the Sun doesn’t shine at night and the wind doesn’t blow all the time” it would seem are overly simplistic.

There are a number of renewable energy technologies which can supply ‘baseload’ power and the intermittency of other sources such as wind and solar can be addressed by interconnecting power plants (and even countries), which are widely geographically distributed. The use of battery storage and evening out demand through smart technology will also play a part.  Numerous regional and global case studies – some incorporating modelling to demonstrate their feasibility – have provided plausible plans to meet 100% of energy demand with renewable sources.

However, many if not most of these rely on significantly reducing the amount of energy we consume as well as switching to renewable energy sources. Energy efficiency is therefore likely to play a significant role in achieving our targets.

Can we install enough renewable energy to meet current and growing demand for electricity through the electrification of other sectors within the time frame needed?

Do we need new nuclear power stations like the one proposed at Hinkley in Somerset? 

This will be the subject of the last in this series of blogs on UK energy policy out tomorrow…

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