What Size Solar System Do I Need?

12/14/2021

Assuming you're pondering going sun based, one of the initial steps you'll need to take is sorting out the right nearby planet group size for your home.

It's difficult to exaggerate the effect that the planetary group size has on the most common way of going sun based. The size of the planetary group will decide:

All in all, what precisely does 'planetary group estimate' mean*? What elements influence what framework size you'll require? Also how might you effectively ascertain the right planetary group size for your home? We answer that large number of inquiries in this blog.

Step by Step Instructions to Work Out Home Energy Utilization

You could include the wattage of every one of your apparatuses and gauge how long they are utilized every day, except this is exceptionally unwieldy and not precise.

For instance, a few apparatuses, like coolers, are hard to appraise. This is on the grounds that they have blower engines ready and have variable momentary power esteems.

By a wide margin the most straightforward way is to take it from last year's service charge, which typically shows the entire year's energy utilization in kilowatt-hours (kWh).

Essentially partition this figure by 12 to get the monthy utilization, or 365 for the normal day by day utilization.

The normal amnount in the US is around 30kW each day, however your own will rely upon where you reside.

How Would I Ascertain Solar Powered Chargers for My Home?


Whenever you have observed your day by day energy utilization, it tends to be utilized to measure your solar panels.

It should be said that solar panel power evaluations are not a precise impression of the genuine power age, in actuality, conditions.

Indeed, there are numerous misfortunes related with a functioning home planetary group. As much as 23% is regularly lost and should be deducted from the sunlight based exhibit power rating.

What Does Nearby Solar System Size Mean Precisely?


In the sun powered industry, the term 'solar system size' is utilized to depict a sunlight based charger framework's ability to deliver power.

A sunlight powered system framework measured 300 watts is one that can deliver 300 watts of power, while a framework estimated 6 kilowatt (6000 watts) planetary group will create 6000 watts - under standard conditions.

How about we separate the key terms utilized here:

"Standard" conditions: These are the particular conditions needed for sun powered chargers to perform at full limit, or 'pinnacle yield.' The sun based cells ought to have precisely 1000 watts of daylight for every square meter gleaming on them, and they ought to be working at a reliable temperature of 77F° (25C°). These particular conditions, reproduced in a lab, are actually called 'Standard Test Conditions (STC).'

Watts: Watts are a unit of estimating electric result. At the point when we are talking about sunlight based charger or nearby planet group size, we are alluding to watts of Direct Current (DC) electrical result. (Peruse this to comprehend the distinction between watts, kilowatts and kilowatt hours).
Since you know these terms, solar charge controller spec sheets and planetary group statements will check out.

For example, you'll see a sunlight based charger portrayed as "appraised 300 watts of DC yield at STC"; in layman's terms, we'd call it a 300-watt board. Furthermore when we put 20 boards with this wattage together to make a nearby planet group, we get a nearby planet group that is 6 kilowatts (6 kW) in size!

Since we know what the term 'nearby planet group size' gauges, we should think about the three techniques we can use to compute it.

What Factors Determine the Right Solar System Size for You?

There are five key factors that are used to calculate solar system size: 

* Usage
* Solar insolation and weather
* Roof characteristics
* System losses
* Battery storage
* Usage

The amount of energy you consume is the most important factor in determining what size solar system you need. Aim to size your solar system to offset 100% of your power consumption - this maximizes savings, as it means you won’t be buying electricity from the utility company anymore. 

As such, any calculation of solar system size will require your electricity usage figures. With the Powmr calculator, this is super easy: you just need to provide the amount of your average monthly electric bill. The Powmr calculator will do the rest, using utility rate and electricity usage pattern information for your area to extrapolate your annual electric usage. 

If using PVWatts to calculate system size, you’re going to need to dig up a year’s worth of utility bills and add up your annual electricity usage. If you’re asking a solar company, then you can just hand them the year’s bills in order to determine your household’s electricity consumption. 

Normal Solar System Size and Power Yield by Area

We realize that certifiable result for a given framework size is impacted by a few factors and is continually fluctuating. In any case, relax - it's feasible to represent climate conditions in your space dependent on many years of verifiable information, which permits us to compute normal sunlight based power yield for a given planetary group size at a particular area.

Normal nearby solar system size (power limit) in chose states

StateAverage system size Avg. daily power generation*Annual power generation
California7.33 kW31 kWh11,326 kWh
Texas10.32 kW42.3 kWh15,441 kWh
Florida10.75 kW43.6 kWh15,939 kWh

Solar insolation and weather

This factor is extremely location-dependent. If we compare peak sunlight hours (PSH) - a measurement of the average amount of sunlight (also known as solar insolation) a location receives - we see that sunny Tucson, Arizona gets 7.5 - 7.9 PSH. That is more than twice the sunlight that rainy Seattle, Washington gets - which is only 3.3 - 3.9 PSH. 

That means that, all things equal, to get the same solar system output in both locations, the system in Seattle will need to be twice the size of that in Tucson!

Any method you choose to calculate solar system size will take your location’s peak sun hours into account. PVWatts has access to the National Solar Radiation Database, which has years of solar radiation and meteorological data. 

The Powmr calculator and your local solar company get access to the same dataset through PVWatts.

Roof characteristics

The orientation (‘azimuth’) and pitch (‘tilt’) of your roof will determine the orientation and angle of your solar panels. Both factors, especially direction, can have a considerable impact on solar energy production.

A solar array facing east or west will produce approximately 15% less output than one facing south. If you can only install on an east or west-facing roof, you’ll have to increase the size of the solar system to account for that. 

System losses

You will not have access to the full DC output of your solar panels; that’s because all solar power systems experience system losses. 

There are typically wiring losses of about 2% during the transmission of DC electricity to the solar inverter. Then there’s the conversion losses that occur as the inverter changes the power from DC to AC electricity - these account for a further 3% of electricity produced. That means with a typical grid-tied solar power system, you can expect to only have 95% of power generated by the solar panels actually available for use in your home. 

Actual figures will vary based on your system design and the type of equipment used. For example, you can reduce losses by reducing your wiring or using a high-efficiency inverter. 

Battery storage

The addition of battery storage to a solar power system can also have a considerable impact on solar system size. Exactly how much it will affect the solar system size you need depends on the following factors:

Amount of backup power required

 
Do you just want to have a few hours of emergency lights? Or do you want enough solar-plus-battery storage to power your entire home for 24-48 hours if there’s an extended grid outage? 

The former won’t affect system size too much, but the latter option will require you to have a system size that’s large enough to cover your daily energy consumption and fully recharge your batteries, even on days with low solar production (i.e. a cloudy day in winter). 

Battery Efficiency

There is a small energy loss every time electricity enters or leaves a battery. The total losses you can expect to see will vary greatly, depending on what type of battery setup you opt for. 

DC-coupled battery systems, like the LG Chem Resu, have an average round-trip efficiency of roughly 95%. By comparison, AC-coupled batteries, such as the Tesla Powerwall, have lower round-trip efficiencies of around 90%. 

You will need to compensate for these losses by oversizing your solar panel system accordingly.