<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>thelastgallon</author><text>&amp;gt; I&amp;#x27;d like to see the the energy density of petrol for comparison.&lt;p&gt;Petrol&amp;#x27;s higher energy density doesn&amp;#x27;t matter as much as people think.&lt;p&gt;Electric vehicles are around four times as efficient as petrol. In a petrol car, only 20% of the energy is converted to motion. In electric cars, this is around 80% (with some variation dependent on regenerative braking). I wrote about this extensively in a previous article: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.sustainabilitybynumbers.com&amp;#x2F;p&amp;#x2F;electrification-energy-efficiency&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.sustainabilitybynumbers.com&amp;#x2F;p&amp;#x2F;electrification-en...&lt;/a&gt;</text><parent_chain><item><author>sixstringtheory</author><text>This is a great set of charts and analysis, although I have two problems with it.&lt;p&gt;1. On the chart of energy density, I&amp;#x27;d like to see the the energy density of petrol for comparison. It&amp;#x27;s much higher, and even though extrapolation is dangerous, I&amp;#x27;d like to see how long it could take to reach parity given some of the different forecasting models they mention. Specifically regarding their mention of air travel, I&amp;#x27;d like to know what the minimum viable energy density would be for a vessel&amp;#x27;s fuel source, because my current understanding is that commercial air travel powered by electricity is not feasible.&lt;p&gt;2. They mention S-curve adoption, but that reaches a horizontal asymptote eventually, it doesn&amp;#x27;t go up forever. I&amp;#x27;d like to see more analysis on where we think we&amp;#x27;re at on the S-curve, and why. I&amp;#x27;d like to see a guess on where it levels out displayed on that chart, instead of the arrow simply pointing at the sky. If nothing else, show where the chemical limit might be based on current battery technology.&lt;p&gt;I want to displace fossil fuels and reduce pollution and slow the greenhouse effect as much as possible. I think transparency and realistic expectations need to be part of the transition. The more information available to markets, the more efficiently they can work towards the goal. I find it very difficult to get answers to these types of questions when discussing renewable energy generation and storage. I&amp;#x27;m sure part of it is my own ignorance on where to look, which is why I ask: especially here, hopefully an expert can see this and quickly point me in the right direction.</text></item></parent_chain></comment><story><title>The rise of batteries in six charts</title><url>https://rmi.org/the-rise-of-batteries-in-six-charts-and-not-too-many-numbers/</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>Spinnaker_</author><text>The mention of air travel was strange. I wasn&amp;#x27;t aware of anyone who thought long range flight would ever be electrified. At least not without some fundamental breakthrough.&lt;p&gt;S-curves are hard to predict. Basically every time someone attempts to do it, they are way off. This [0] is a neat paper that addresses the question. We&amp;#x27;ve blown past every single prediction.&lt;p&gt;[0] &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.inet.ox.ac.uk&amp;#x2F;files&amp;#x2F;energy_transition_paper-INET-working-paper.pdf&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.inet.ox.ac.uk&amp;#x2F;files&amp;#x2F;energy_transition_paper-INET...&lt;/a&gt;</text><parent_chain><item><author>sixstringtheory</author><text>This is a great set of charts and analysis, although I have two problems with it.&lt;p&gt;1. On the chart of energy density, I&amp;#x27;d like to see the the energy density of petrol for comparison. It&amp;#x27;s much higher, and even though extrapolation is dangerous, I&amp;#x27;d like to see how long it could take to reach parity given some of the different forecasting models they mention. Specifically regarding their mention of air travel, I&amp;#x27;d like to know what the minimum viable energy density would be for a vessel&amp;#x27;s fuel source, because my current understanding is that commercial air travel powered by electricity is not feasible.&lt;p&gt;2. They mention S-curve adoption, but that reaches a horizontal asymptote eventually, it doesn&amp;#x27;t go up forever. I&amp;#x27;d like to see more analysis on where we think we&amp;#x27;re at on the S-curve, and why. I&amp;#x27;d like to see a guess on where it levels out displayed on that chart, instead of the arrow simply pointing at the sky. If nothing else, show where the chemical limit might be based on current battery technology.&lt;p&gt;I want to displace fossil fuels and reduce pollution and slow the greenhouse effect as much as possible. I think transparency and realistic expectations need to be part of the transition. The more information available to markets, the more efficiently they can work towards the goal. I find it very difficult to get answers to these types of questions when discussing renewable energy generation and storage. I&amp;#x27;m sure part of it is my own ignorance on where to look, which is why I ask: especially here, hopefully an expert can see this and quickly point me in the right direction.</text></item></parent_chain></comment><story><title>The rise of batteries in six charts</title><url>https://rmi.org/the-rise-of-batteries-in-six-charts-and-not-too-many-numbers/</url></story>