Long before he became the Department for Energy and Climate Change’s chief scientific advisor, David Mackay lectured a course at Cambridge on how to perform back of the envelope calculations called ‘Order of Magnitude Physics.’ To teach the course, Prof. Mackay used a series of example calculations based on renewable energy. Little did I know that the examples he was using would later become part of a book he was writing (and little did he know of the fame and career change that it would bring) but it was listening to these lectures during my undergraduate that confirmed my ambition to work in the solar energy industry.
Already extremely concerned by the growing evidence for ‘human-caused’ climate change, Prof Mackay’s course taught me some astonishing facts, such as how the amount of solar energy delivered to the Earth is ten thousand times the total amount of energy we use over the course of a year. He made me realise that human civilisation has a huge amount of work to do to halt its greenhouse emissions, but he also gave me the hope through new technologies, we really can wean ourselves off fossil fuels without impacting our quality of lives too severely.
After a PhD and several years working in solar photovoltaics for a large company in Germany, I returned to the UK and was astonished to find that the Government has extremely low ambitions for solar energy and even more astonished that it is using David Mackay’s analysis, at least in part, to justify this. At present, the Treasury’s £360m cap on Feed-in tariffs means that support for solar PV at all scales will end by mid-2012 and limit solar PV capacity in the UK to less than 3% of Germany’s current installed base.
When I re-read Mackay’s key book ‘Sustainability Without the Hot Air,’ I find it paints a very compelling argument for solar energy. Prof Mackay repeatedly points out that solar energy can deliver far more energy than any other renewable energy technology in the UK, as illustrated by the fact that the amount of solar energy we receive in the UK is fifty times the total amount of energy we use, including transport and heating. At the time of writing, David Mackay singled out two hurdles for widespread solar adoption in the UK; cost and space. It seems as though these hurdles have been interpreted by the Government as insurmountable barriers, whereas careful re-examination of these hurdles using up-to-date figures reveals them to be significantly less onerous than Mackay first assumed.
In relation to costs, David Mackay states ”it will be wonderful if the cost of photovoltaic power drops in the same way that the cost of computer power has dropped over the last forty years.” This is exactly what has been demonstrated over the last 5 years. Jenny Chase, a solar energy analyst at the research firm Bloomberg New Energy Finance claims “In 2011 we expect an oversupply of solar panels which will put continued downward pressure on system prices.” In his book, David Mackay uses a solar electricity cost of €0.25 per kWh which is 4 times current wholesale electricity costs, but only twice the price of retail electricity, and seeing as prices have continued to fall exponentially since the time of writing in 2008 we can expect this gap to be closed fast. In fact, the cost of solar energy is falling much faster than that of any other energy technology to the point where it is the expected to compete with unsubsidized retail electricity prices in UK latitudes by 2014/2015 [1]. In contrast, the cost of nuclear energy has risen 5 fold since 1970 according to a recent study by Yale University’s Arnulf Grubler [2]. By supporting the solar industry now, it will soon be able to support itself without subsidy.
Digging deeper into the Government’s original modelling of overall ambition for PV, the Renewable Energy Association has found that a mid-range future fossil fuel price scenario was used which assumes a cost of $80 per barrel of oil in 2020 (which is unlikely considering current prices are frequently above $100). By using such unrealistic forecasts, the value of investment in solar energy is being systematically undervalued.
The second issue that Prof Mackay raises is with the amount of area required to get large amounts of solar energy. Whilst there is a vast amount of solar energy available to us in the UK, that energy is disperse, meaning you do indeed need to cover a considerable area in solar panels to cover our electricity needs. Prof Mackay points out that to get our current electricity (50 units of electricity per person per day) needs would require 200m2 per person. This is a huge amount of area, but it’s important to realise that reaching that target is highly plausible. The total amount of roof space per person in England is 47m2, domestic gardens 114m2, and roads and open spaces make up 60m2 and 2300m2 per person respectively [3], so by using a proportion of roof space and a small proportion of open space we could certainly get close to 200m2. Its important to point out that open space does not mean prime farmland, there are many brown field sites that could be put to good use. Nor do solar panels on open space prohibit the use of that land for other means. When placed in fields for example, solar arrays can still permit some animal grazing and in other countries, solar arrays are often positioned along motorway banks or as canopies above car parks.
Obviously getting between 100m2 and 200m2 of solar panels per person in the UK would be a gigantean undertaking and one that would change the look of our country, but this would be just one of a long line of gigantean undertakings that have taken place in our history. The expansion of organised farming, the construction of road and rail networks, and more recently the construction of electricity and mobile phone grids were all projects that have profoundly changed our country and its appearance. Just because the task may be large, does not make it impractical. In the UK we happily resurface 60m2 of road per person every 5-10 years.
Solar energy has already proven itself highly popular in the UK. It is one of the few technologies that can be produced effectively on a domestic scale giving power to families to generate their own electricity. Solar energy can also be deployed staggeringly quickly. In 2010 alone Germany installed 8GW of solar energy distributed among over 200,000 individual installations. That is equivalent to over two nuclear power stations, and there is no way those nuclear power stations could be built so quickly.
There is a misconception that micro-generation does not result in large amounts of energy, but multiplied thousands of times, the amount of energy we can harvest from small solar installations is enormous. The UK will of course need a balanced mix of different energy technologies, but lets give solar its rightful place alongside the other major forms of energy generation. As Prof Mackay points out; ‘to complete a plan that adds up, we must rely on one or more forms of solar power. Or use nuclear power. Or both.’
1. AT Kearney Report; ‘The True Value of Photovoltaics for Germany’ 2010
2. Arnulf Grubler, Yale University; ‘The costs of the French nuclear scale-up: A case of negative learning by doing’ Energy Policy, 2010
3. Department for Communities and Local Government, Land Use Statistics (Generalised Land Use Database) 2005, www.communities.gov.uk/publications/planningandbuilding/generalisedlanduse
Dr Toby Ferenczi
