Solar Power: Thinking global: Acting Local

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Regular readers will know I am currently experiencing the power of combining solar photovoltaic (PV) panels with domestic scale batteries: My house has been ‘off-grid’ for the last 3 weeks of a rather dull UK spring. It feels transformative.

I have also been reading two books which look at the impact of this combination – and other renewable energy technologies – at the scale of the UK and the world.

Both books are responding from different perspectives to some epochal changes in the reality of electricity generation.

I’ll say more about what the books have in common at the end, but let’s look briefly at each one first.

A UK ‘manifesto’

Andrew Crossland runs the site MyGridGB which is an excellent place to find current and historical data about the electricity supply in the UK.

On the site he has developed ‘a manifesto’ for low carbon electricity – and the book is essentially a wider, contextualised exposition of this manifesto.

The manifesto is a detailed plan for how get from where we are now – where (averaged over a year) each unit of electricity causes the emission of about 200 grams of carbon dioxide [gCO2/kWh]) – to a situation in 2030 where (averaged over a year) each unit of electricity would cause the emission of less than 100 gCO2/kWh.

Such an achievement would be impressive.

The manifesto assumptions are:

  • 3.2GW of new nuclear power stations (i.e. Hinkley Point C)
  • 3 x the amount of wind generation
  • 3 x the amount of solar generation (10 million solar homes)
  • 1.5 x more power available biomass, but I only dispatch biofuel when wind and solar are low so that we don’t waste this resource.
  • No coal
  • 48.6 GWh of electricity storage (3 x more capacity than Dinorwig and Cruchan)

These developments are technically achievable and affordable – they don’t require any ‘magical’ steps. The most difficult steps are likely to be completion of Hinkley Point C by 2025 and new storage facilities.

Based on his manifesto Andrew Crossland reckons that we could reach 44 gCO2/kWh by 2030 if we chose to do so.

His manifesto considers the UK situation year-by-year and hour-by-hour throughout each year to make clear that it really would work. Electricity really would be made available with no gaps using realistic market mechanisms that are not so different from how the grid operates now.

Aside from massively increased renewable generation (from both large-scale ‘farms’ and millions of microgenerators such as myself) the key difference is that thermal generation [using biomass and gas] is used only after all low-carbon options have been deployed [‘dispatched’ in the jargon]. These thermal sources just cope with peaks and gaps rather than supplying the baseload as they do now.

A Global ‘manifesto’

In contrast to Andrew Crossland, Varun Sivaram offers a global perspective, considering in particular generation in China and India.

His background was in research into new technologies for solar generation. Technologies potentially cheaper and/or more efficient than the silicon solar cells that dominate the market.

The silicon solar panels on my roof (1.7 m x 1 m) have a peak power of about 330 W and cost about £120. But they are only about 20% efficient.

Dr. Sivarum cannot hide his sorrow that the cool technologies he worked on – with much higher efficiencies – are unlikely to be implemented while silicon solar cells are so cheap. And getting cheaper.

But focusing on this relentless reduction in price, and slow increase in efficiency, Dr Sivarum foresees the point where there is so much solar (and renewable) generation, that even though its costs are low, the price people are prepared to pay for it is zero.

This is a point to which the market eventually drives itself: it is in everyone’s interest to harvest renewable energy – but the last person to the party has no-one to whom they can sell their electricity.

Renewable saturation

We are far from ‘renewable saturation’ at the moment. But the nature of renewables, and the structure of a grid which exploits them, makes the situation inevitable. Both books ask us to plan for the eventuality.

The variability of renewable generation means that in order to generate enough to cope with normal requirements we need to overprovide capacity.

This means there will be occasions where renewable generation exceeds total demand. At this point we have three options:

  1. Store as much as we can – but storage is limited and expensive.
  2. Find a market for ‘free electricity’ which is only intermittently available.
  3. Pay renewable generators not to generate.

Basically, we need to come to terms with the fact that in order to have low-carbon electricity, we need a grid built around renewables and their remarkable cheapness. And that coping with their variability is the price we have to pay for this.

But as a consequence of the variability of renewables there will be hours, and occasionally days, or even weeks, or conceivably even years, when the renewables simply don’t turn up.

And similarly there will be hours, and occasionally days, or even weeks, when gas and biomass are not required: but we still need to pay them to be ready to generate at short notice.

Its a new world

Both books make clear that we are in a new world for electricity generation. But that the central problems are not technological: the key challenge is to create economic environments that support the transition to renewable energy.

The combination of ever cheaper wind, solar and batteries creates a 21st Century landscape dramatically different from the last Century.

Although renewable generation using wind favours large-scale investments, the combination of solar generation and batteries is accessible and can contribute meaningfully at the domestic scale.

For example, instead of building a new pumped-storage site like Dinorwig, we could deploy domestic batteries like my Powerwall.

  • Dinorwig cost £424 million pounds in 1974 – around £4.24 billion in 2020 pounds
  • £4.24 billion is enough to buy and install around 500,000 Powerwalls, either in neighbourhood facilities, on renewables sites, or in homes
    • Dinorwig has a storage capacity of 9.1 GWh compared to batteries with a capacity of 6.75 GWh using current technology.
    • Dinorwig has a peak power of 1.7 MW compared to batteries which would have massive peak power of 2500 MW.
    • Dinorwig can go from off to full power about 17 seconds: batteries could respond in milliseconds.
    • Dinorwig is owned and operated by a single company: 500,000 batteries might have 500,000 owners and operators!
  • Also batteries would begin having an effect day-by-day as they were installed and would not require 10 years wait.

Such a large deployment of batteries may seem ambitious, but electric car sales in the UK are already 60,000 per year, and each car has a battery many times larger than a Powerwall. It’s not crazy to think that some fraction of these cars could participate in grid-scale energy storage.

Overall it was good to hear from both authors, that the ‘hardware’ for a low-carbon grid supply of electricity already exists – and just gets better and cheaper year-on-year. The challenge is the ‘software’.

We need to devise ways to make sure that investors can make money from the long term investments required to build a stable grid with low carbon dioxide emissions. But additionally, the electricity market will have millions of participants who are not just consumers.


At the end of his book Andrew Crossland laments the lack of ambition shown by policymakers in the 1990s that resulted in the death of the UK nuclear industry. He urges policymakers now to be bold, urging them to see the possibilities for new and better ways of doing things.

I support that call wholeheartedly.

5 Responses to “Solar Power: Thinking global: Acting Local”

  1. Sustain blog Says:

    Solar Power: Acting Local but thinking global is the way. Thank you 😊

  2. PeterG Says:

    I am still amazed (but not surprised given our government’s general myopia) that we are allowing new houses to be built in the UK which are not carbon neutral.

    • protonsforbreakfast Says:


      Indeed. I actually wrote a whole section about the housing market at the end of that article. But I deleted it because the article was already too long.

      But yes. The deleted part suggested 3 things if I remember correctly

      1. Passivhaus level insulation
      2. Houses built in the correct orientation with entire roofs of solar panels (not just decorative inlays)
      3. Domestic Batteries

      It would be a few thousand pounds extra per house which would not be funded by the government. The problem – which is why I didn’t write more – is that the UK housing market is totally dysfunctional. And the government is sensitive to those ‘winners’ in the market [homeowners and builders] but contemptuous of the millions of people who lose out.

      Deep Breath. Deep Breath.

      Best wishes


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