<p>Volcanic eruptions effectively inject large quantities of aerosols in the upper layers of the atmosphere, increasing Earth's albedo and reducing the intensity of the solar radiation reaching the surface. Such reduction would indeed lower the solar energy available to solar panels.</p>

<p>These effects of volcanic eruptions have been studied by <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008JD010239" rel="nofollow noreferrer">Gao et al. (2008)</a> and <a href="https://www.earth-syst-sci-data.net/5/187/2013/" rel="nofollow noreferrer">Crowley and Unterman (2013)</a>. Both studies were combined by the <a href="http://www.climatechange2013.org/report/full-report/" rel="nofollow noreferrer">IPCC Working Group I during the assessment report 5 (2013)</a>, and summarized on the figure 8.18 (<a href="http://www.climatechange2013.org/images/report/WG1AR5_Chapter08_FINAL.pdf" rel="nofollow noreferrer">Chapter 8</a>), together with other climatic forcings:</p>

<p><a href="https://i.sstatic.net/14geX.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/14geX.png" alt="enter image description here"></a></p>

<p>You can see that the largest drop in effective radiative forcing happens in 1815 as a consequence of the <a href="https://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora" rel="nofollow noreferrer">Tambora eruption</a>.</p>

<p>Unfortunately, that event goes out the scale of the plot. However, the data is available on Table AII.1.2 of <a href="http://www.climatechange2013.org/images/report/WG1AR5_AnnexII_FINAL.pdf" rel="nofollow noreferrer">Annex II</a>, were we can see that the minimum value indeed happens in 1815 and reaches –11.629 W/m².</p>

<p>Considering the typical amount of energy received from the Sun under clear skies at seal level is roughly <a href="https://en.wikipedia.org/wiki/Solar_irradiance#Irradiance_on_Earth&#39;s_surface" rel="nofollow noreferrer">1,000 W/m²</a>, the irradiation drop produced by Tambora would represent a drop of about 1% on the energy reaching the Earth's surface. Of course, much larger local effects could be observed due to transient and more localized dense ash clouds.</p>

<p><strong>Therefore, at a global scale, if a new <a href="https://en.wikipedia.org/wiki/Year_Without_a_Summer" rel="nofollow noreferrer">"year without summer"</a> where to happen, photovoltaic energy output would drop by ~1%.</strong></p>

<p>Of course, larger effects would take place if the eruption happens to be close to the most important areas for photovoltaic energy production.</p>

CC BY-SA 4.0
2019-02-10T02:22:11.410Z
@gansub I was also somehow surprised by the low number. A possible flaw of my answer is that the value used is the drop in radiative forcing, which is not exactly the same that the drop in energy reaching the surface. As all the energy captured by the atmosphere is still part of the radiative forcing but won't be available to solar panels. However, I don't think the difference will be too significant, as the ash is pretty short lived, and at a whole year timescale won't affect much. On the other hand, aerosols last very long and are accounted in this answer.
Camilo Rada
CC BY-SA 4.0
2019-02-10T02:24:27.000Z
@gansub also the climate is very sensitive to forcing. Note that all the CO2 produce a change in the forcing of just 0.1%, and that makes a big difference specially in the long run.
Camilo Rada
CC BY-SA 4.0
2019-02-10T02:35:26.173Z
@gansub I just found here a very similar question, and it arrived to a very similar answer (1.3% on the four months after the 1991 eruption  of Pinatubo): https://earthscience.stackexchange.com/questions/8787/would-a-global-cooling-event-disable-solar-energy-usage?rq=1
Camilo Rada
CC BY-SA 4.0
2019-02-10T02:45:29.673Z
@gansub Yes, the areas affected by the monsoon have pretty bad PV potential. Look here: https://globalsolaratlas.info/
Camilo Rada
CC BY-SA 4.0
2019-02-09T17:27:01.790Z
2019-02-11T14:45:04.200Z
2019-02-11T14:45:04.200Z
Camilo Rada
<p>Are there any estimates for the reduction of global solar insolation at the Earth's surface that a Tambora scale eruption would bring? </p>

<p>If our electrical power generation became heavily reliant on solar pv would it bring about a substantial reduction in output capacity?</p>

CC BY-SA 4.0
2019-02-10T02:29:33.263Z
related question (maybe even a duplicate?) https://earthscience.stackexchange.com/questions/8787/would-a-global-cooling-event-disable-solar-energy-usage?rq=1
Camilo Rada
<atmosphere><climate><volcanology>
The Tambora eruption caused the "Year without a summer". How much would such an eruption today affect the output of solar pv on a global scale?
Mike H
# The Tambora eruption caused the "Year without a summer". How much would such an eruption today affect the output of solar pv on a global scale?

(Asked by: username_0 on 2019-02-09)

Are there any estimates for the reduction of global solar insolation at the Earth's surface that a Tambora scale eruption would bring?

If our electrical power generation became heavily reliant on solar pv would it bring about a substantial reduction in output capacity?

**Tags:** atmosphere, climate, volcanology

> **Comments:**
> **username_1**: related question (maybe even a duplicate?) https://earthscience.stackexchange.com/questions/8787/would-a-global-cooling-event-disable-solar-energy-usage?rq=1  

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## 1 answers

### Answer by username_1 on 2019-02-09. Score: 4

Volcanic eruptions effectively inject large quantities of aerosols in the upper layers of the atmosphere, increasing Earth's albedo and reducing the intensity of the solar radiation reaching the surface. Such reduction would indeed lower the solar energy available to solar panels.

These effects of volcanic eruptions have been studied by [Gao et al. (2008)](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008JD010239) and [Crowley and Unterman (2013)](https://www.earth-syst-sci-data.net/5/187/2013/). Both studies were combined by the [IPCC Working Group I during the assessment report 5 (2013)](http://www.climatechange2013.org/report/full-report/), and summarized on the figure 8.18 ([Chapter 8](http://www.climatechange2013.org/images/report/WG1AR5_Chapter08_FINAL.pdf)), together with other climatic forcings:

[![enter image description here](https://i.sstatic.net/14geX.png)](https://i.sstatic.net/14geX.png)

You can see that the largest drop in effective radiative forcing happens in 1815 as a consequence of the [Tambora eruption](https://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora).

Unfortunately, that event goes out the scale of the plot. However, the data is available on Table AII.1.2 of [Annex II](http://www.climatechange2013.org/images/report/WG1AR5_AnnexII_FINAL.pdf), were we can see that the minimum value indeed happens in 1815 and reaches –11.629 W/m².

Considering the typical amount of energy received from the Sun under clear skies at seal level is roughly [1,000 W/m²](https://en.wikipedia.org/wiki/Solar_irradiance#Irradiance_on_Earth's_surface), the irradiation drop produced by Tambora would represent a drop of about 1% on the energy reaching the Earth's surface. Of course, much larger local effects could be observed due to transient and more localized dense ash clouds.

**Therefore, at a global scale, if a new ["year without summer"](https://en.wikipedia.org/wiki/Year_Without_a_Summer) where to happen, photovoltaic energy output would drop by ~1%.**

Of course, larger effects would take place if the eruption happens to be close to the most important areas for photovoltaic energy production.

> **Comments:**
> **username_1**: @gansub I was also somehow surprised by the low number. A possible flaw of my answer is that the value used is the drop in radiative forcing, which is not exactly the same that the drop in energy reaching the surface. As all the energy captured by the atmosphere is still part of the radiative forcing but won't be available to solar panels. However, I don't think the difference will be too significant, as the ash is pretty short lived, and at a whole year timescale won't affect much. On the other hand, aerosols last very long and are accounted in this answer.  
> **username_1**: @gansub also the climate is very sensitive to forcing. Note that all the CO2 produce a change in the forcing of just 0.1%, and that makes a big difference specially in the long run.  
> **username_1**: @gansub I just found here a very similar question, and it arrived to a very similar answer (1.3% on the four months after the 1991 eruption  of Pinatubo): https://earthscience.stackexchange.com/questions/8787/would-a-global-cooling-event-disable-solar-energy-usage?rq=1  
> **username_1**: @gansub Yes, the areas affected by the monsoon have pretty bad PV potential. Look here: https://globalsolaratlas.info/  

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