<story><title>China solar module prices keep diving</title><url>https://www.pv-magazine.com/2023/06/23/china-solar-module-prices-keep-diving/</url></story><parent_chain><item><author>ianburrell</author><text>The problem is that there is no standard for house-scale DC power. It has to be higher voltage than 12V or 48V that are used off-grid. There are no standard plugs or sockets, and it has to be different than AC.&lt;p&gt;The big problem is that everyone has AC sockets, and it isn&amp;#x27;t worth the trouble to switch. It is going to be huge expense to buy new appliances for potential small efficiency gain. The in-wall voltage is going to mean that need adapters for other DC uses.&lt;p&gt;A better approach is to have a standard for DC power between AC side, batteries, and solar panels. Then have a single big inverter between AC and DC. It also makes possible to have DC-only in places like cabins that aren&amp;#x27;t connected to the grid.&lt;p&gt;Finally, many houses and apartments can&amp;#x27;t add batteries or solar panel. Not everyone has space like a basement. Like there is efficiency advantage like with utility solar, it might make sense to put batteries in substations where can use containers.</text></item><item><author>yazaddaruvala</author><text>&amp;gt; In practice, inverters probably also need partial redesign&lt;p&gt;I&amp;#x27;d also love for appliances to entirely adopt DC.&lt;p&gt;- Homes should run on batteries.&lt;p&gt;- Batteries should be trickle charged from the grid with a cheap rectifier.</text></item><item><author>philipkglass</author><text>The ratio of DC panel wattage to AC inverter wattage is called the inverter loading ratio, and it has been creeping up over time in utility scale solar farms. The reasoning is indeed to give more of a plateau shape to AC output (which is limited by transmission line capacity) and to perform more steadily under hazy or partly cloudy conditions. In theory, this ratio could go up a lot if panel prices continue to decline faster than inverter prices.&lt;p&gt;In practice, inverters probably also need partial redesign for a high loading ratio. Higher ILRs in large solar farms has appeared to contribute to faster inverter failures in recent years.</text></item><item><author>aitchnyu</author><text>I have almost 5kw of panels and a 5kw inverter. If solar panels get cheaper than dirt, will future 5kw inverters allow 10 kw of panels, so that the power vs time graph is a wide &amp;quot;plateau&amp;quot; instead of a thin &amp;quot;hill&amp;quot;?</text></item></parent_chain><comment><author>nine_k</author><text>Low-power 12V or 24V DC is very doable around the house, for small-scale LED lighting, etc. But if you limit yourself to small connectors and thus reasonably low currents  (like 10A, as I did), it&amp;#x27;s 120W or 240W per connector at the very top.&lt;p&gt;Serious power, in the kilowatt range, would require much higher voltage, and still much bulkier connectors and thicker conductors. OTOH 400V DC should be comparable in this regard with 220V AC, which has a 380V amplitude. The 400V DC standard is relatively widespread and well-supported by existing industrial equipment. Connectors are comparable in size to the (grounded) Euro plugs.</text></comment>
<story><title>China solar module prices keep diving</title><url>https://www.pv-magazine.com/2023/06/23/china-solar-module-prices-keep-diving/</url></story><parent_chain><item><author>ianburrell</author><text>The problem is that there is no standard for house-scale DC power. It has to be higher voltage than 12V or 48V that are used off-grid. There are no standard plugs or sockets, and it has to be different than AC.&lt;p&gt;The big problem is that everyone has AC sockets, and it isn&amp;#x27;t worth the trouble to switch. It is going to be huge expense to buy new appliances for potential small efficiency gain. The in-wall voltage is going to mean that need adapters for other DC uses.&lt;p&gt;A better approach is to have a standard for DC power between AC side, batteries, and solar panels. Then have a single big inverter between AC and DC. It also makes possible to have DC-only in places like cabins that aren&amp;#x27;t connected to the grid.&lt;p&gt;Finally, many houses and apartments can&amp;#x27;t add batteries or solar panel. Not everyone has space like a basement. Like there is efficiency advantage like with utility solar, it might make sense to put batteries in substations where can use containers.</text></item><item><author>yazaddaruvala</author><text>&amp;gt; In practice, inverters probably also need partial redesign&lt;p&gt;I&amp;#x27;d also love for appliances to entirely adopt DC.&lt;p&gt;- Homes should run on batteries.&lt;p&gt;- Batteries should be trickle charged from the grid with a cheap rectifier.</text></item><item><author>philipkglass</author><text>The ratio of DC panel wattage to AC inverter wattage is called the inverter loading ratio, and it has been creeping up over time in utility scale solar farms. The reasoning is indeed to give more of a plateau shape to AC output (which is limited by transmission line capacity) and to perform more steadily under hazy or partly cloudy conditions. In theory, this ratio could go up a lot if panel prices continue to decline faster than inverter prices.&lt;p&gt;In practice, inverters probably also need partial redesign for a high loading ratio. Higher ILRs in large solar farms has appeared to contribute to faster inverter failures in recent years.</text></item><item><author>aitchnyu</author><text>I have almost 5kw of panels and a 5kw inverter. If solar panels get cheaper than dirt, will future 5kw inverters allow 10 kw of panels, so that the power vs time graph is a wide &amp;quot;plateau&amp;quot; instead of a thin &amp;quot;hill&amp;quot;?</text></item></parent_chain><comment><author>seanmcdirmid</author><text>Didn’t utilities in NYC offer DC service for a long time? See &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;archive.nytimes.com&amp;#x2F;cityroom.blogs.nytimes.com&amp;#x2F;2007&amp;#x2F;11&amp;#x2F;14&amp;#x2F;off-goes-the-power-current-started-by-thomas-edison&amp;#x2F;&quot; rel=&quot;nofollow noreferrer&quot;&gt;https:&amp;#x2F;&amp;#x2F;archive.nytimes.com&amp;#x2F;cityroom.blogs.nytimes.com&amp;#x2F;2007&amp;#x2F;...&lt;/a&gt;&lt;p&gt;Old buildings had elevators, lights, and so on, that operated on DC.</text></comment>