Why I am a double atheist

28 11 2017

For years and years – at least 15 – I argued with Dave Kimble over his notion that solar energy production was growing far too fast to be sustainable, let alone reduce greenhouse emissions.  I eventually had to relent and agree with him, he had a keener eye for numbers than me, and he was way better with spreadsheets!

The whole green technology thing has become a religion. I know, I used to have the faith too….. but now, as you might know if you’ve been ‘here’ long enough, I neither believe in god nor green tech!

This article – to which you will have to go to for the references – landed in my newsfeed…….  and lo and behold, it says exactly the same thing Dave was saying all those years ago…….:

How Sustainable is PV solar power?

How sustainable is pv solar power

Picture: Jonathan Potts.

It’s generally assumed that it only takes a few years before solar panels have generated as much energy as it took to make them, resulting in very low greenhouse gas emissions compared to conventional grid electricity.

However, a more critical analysis shows that the cumulative energy and CO2 balance of the industry is negative, meaning that solar PV has actually increased energy use and greenhouse gas emissions instead of lowering them.

The problem is that we use and produce solar panels in the wrong places. By carefully selecting the location of both manufacturing and installation, the potential of solar power could be huge.

There’s nothing but good news about solar energy these days. The average global price of PV panels has plummeted by more than 75% since 2008, and this trend is expected to continue in the coming years, though at a lower rate. [1-2] According to the 2015 solar outlook by investment bank Deutsche Bank, solar systems will be at grid parity in up to 80% of the global market by the end of 2017, meaning that PV electricity will be cost-effective compared to electricity from the grid. [3-4]

Lower costs have spurred an increase in solar PV installments. According to the Renewables 2014 Global Status Report, a record of more than 39 gigawatt (GW) of solar PV capacity was added in 2013, which brings total (peak) capacity worldwide to 139 GW at the end of 2013. While this is not even enough to generate 1% of global electricity demand, the growth is impressive. Almost half of all PV capacity in operation today was added in the past two years (2012-2013). [5] In 2014, an estimated 45 GW was added, bringing the total to 184 GW. [6] [4].

Solar PV total global capacitySolar PV total global capacity, 2004-2013. Source: Renewables 2014 Global Status Report.

Meanwhile, solar cells are becoming more energy efficient, and the same goes for the technology used to manufacture them. For example, the polysilicon content in solar cells — the most energy-intensive component — has come down to 5.5-6.0 grams per watt peak (g/wp), a number that will further decrease to 4.5-5.0 g/wp in 2017. [2] Both trends have a positive effect on the sustainability of solar PV systems. According to the latest life cycle analyses, which measure the environmental impact of solar panels from production to decommission, greenhouse gas emissions have come down to around 30 grams of CO2-equivalents per kilwatt-hour of electricity generated (gCO2e/kWh), compared to 40-50 grams of CO2-equivalents ten years ago. [7-11] [12]

According to these numbers, electricity generated by photovoltaic systems is 15 times less carbon-intensive than electricity generated by a natural gas plant (450 gCO2e/kWh), and at least 30 times less carbon-intensive than electricity generated by a coal plant (+1,000 gCO2e/kWh). The most-cited energy payback times (EPBT) for solar PV systems are between one and two years. It seems that photovoltaic power, around since the 1970s, is finally ready to take over the role of fossil fuels.

BUT the bit that caught my eye was this…..:

A life cycle analysis that takes into account the growth rate of solar PV is called a “dynamic” life cycle analysis, as opposed to a “static” LCA, which looks only at an individual solar PV system. The two factors that determine the outcome of a dynamic life cycle analysis are the growth rate on the one hand, and the embodied energy and carbon of the PV system on the other hand. If the growth rate or the embodied energy or carbon increases, so does the “erosion” or “cannibalization” of the energy and CO2 savings made due to the production of newly installed capacity. [16]

For the deployment of solar PV systems to grow while remaining net greenhouse gas mitigators, they must grow at a rate slower than the inverse of their CO2 payback time. [19] For example, if the average energy and CO2 payback times of a solar PV system are four years and the industry grows at a rate of 25%, no net energy is produced and no greenhouse gas emissions are offset. [19] If the growth rate is higher than 25%, the aggregate of solar PV systems actually becomes a net CO2 and energy sink. In this scenario, the industry expands so fast that the energy savings and GHG emissions prevented by solar PV systems are negated to fabricate the next wave of solar PV systems. [20]

Which is precisely what Dave Kimble was saying more than ten years ago.  To see his charts and download his spreadsheet, go to this post.

His conclusions are that “We have been living in an era of expanding energy availability, but Peak Oil and the constraints of Global Warming mean we are entering a new era of energy scarcity. In the past, you could always get the energy you wanted by simply paying for it. From here on, we are going to have to be very careful about how we allocate energy, because not only is it going to be very expensive, it will mean that someone else will have to do without. For the first time, ERoEI is going to be critically important to what we choose to do. If this factor is ignored, we will end up spending our fossil energy on making solar energy, which only makes Global Warming worse in the short to medium term.”