A solar PV installation does not produce the same in January as in July, and a home or business does not consume the same either. Understanding how the two curves move through the year is what allows a system to be sized properly, without surprises.<\/p>\n
The deciding factor is the available irradiation: more hours of sun and a higher sun in summer, the opposite in winter. The difference between the months of highest and lowest output is considerable, and depends on latitude and on the orientation and tilt of the modules.<\/p>\n
One point surprises many people: heat does not help<\/strong>. A PV module’s efficiency falls as its temperature rises, so the day of highest output in the year is not usually the hottest, but a clear spring day with moderate temperatures.<\/p>\n That is why ventilation under the modules is not a minor installation detail: an installation that dissipates heat well runs cooler and produces more during the hours of highest irradiance.<\/p>\n In a home or building with air conditioning, consumption rises in summer just as output rises. That coincidence is favourable: energy is generated and consumed at the same time, which is when it is used most effectively.<\/p>\n In winter the opposite happens. Output falls and, if heating is electric, consumption rises. In those months the installation covers a smaller share of demand and the rest has to be bought from the grid.<\/p>\n In an industrial site with stable production all year, the seasonal mismatch is smaller and sizing is simpler.<\/p>\n It is worth being precise about expectations, because some claims in circulation do not hold up.<\/p>\n A self-consumption installation without storage does not cover all consumption<\/strong>: it does not produce at night, and in the months of lowest irradiation it produces considerably less than is used. What it does is replace a significant share of the energy purchased, and that share is calculated from the installation’s actual consumption curve.<\/p>\n The figure that should drive the decision is not the installed capacity, but the proportion of output used directly. That is the percentage that translates into full savings; energy exported to the grid is compensated at a considerably lower value.<\/p>\n Technically, any time of year will do: the installation starts producing on the day it is commissioned.<\/p>\n In practice there is a seasonality, but it lies in lead times rather than in the sun:<\/p>\n In other words, getting ahead makes sense for logistics and permitting, not because the equipment works better if installed in a particular season.<\/p>\n Annual consumption and its hourly distribution (the load curve, which the electricity supplier provides on the account holder’s request), the available area with its orientation and tilt, a shading analysis through the year, and the intended use.<\/p>\n With this information, output is estimated month by month and compared with consumption to give the expected self-consumption ratio, which is the figure used to calculate the return on investment.<\/p>\n See our residential PV installations<\/a> and commercial and industrial PV installations<\/a>, or contact us<\/a> with your annual consumption.<\/p>\n","protected":false},"excerpt":{"rendered":" A PV installation does not produce the same in January as in July, and consumption changes too. How both curves move through the year and what that means for sizing.<\/p>\n","protected":false},"author":1,"featured_media":5726,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[132],"tags":[],"class_list":["post-10927","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-energy-saving-management"],"acf":[],"_links":{"self":[{"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/posts\/10927","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/comments?post=10927"}],"version-history":[{"count":2,"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/posts\/10927\/revisions"}],"predecessor-version":[{"id":11797,"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/posts\/10927\/revisions\/11797"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/media\/5726"}],"wp:attachment":[{"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/media?parent=10927"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/categories?post=10927"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/keikengroup.com\/en\/wp-json\/wp\/v2\/tags?post=10927"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}How consumption varies<\/h2>\n
What to expect realistically<\/h2>\n
When to install<\/h2>\n
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What is needed for sizing<\/h2>\n