What are the benefits of this hybrid clean energy system?
- energy production at any time of the day and year
- better use of system components
- more power in constrained area 5sqm-50sqft is roughly 1kW PV which makes anything above 10kW very hard to achieve on standard house roof
energy production at any time of the day and year
even in temperate climate abt 70% of energy from solar power is produced from march to november so you depend of government clean energy schemes and feed in tarifs if you want to have your energy whole year even more in the night when solar production is 0. Simple and clean solution is Wind power. In most european countries wind is still more prevalent energy source than PV. and to my surprise and joy I read in industry raports and production data that more than 70% of wind turbine energy production is in colder/darker months so why not marry them together? is it possible is it complicated?
better use of system components
it is so easy that it can be done even in rv, yacht, cabin. But here we will study how is working system which powers standard home. As permits for solar are easier in most countries and solar is more popular Lets make assumption that you already have solar system. But you want more energy. Good because by adding wind turbine you actually improving ROI from your solar system. How? now your solar inverter works only during the day and if you are living more to the poles than to equator it doesnt work very hard for half of the year. But if we can connect wind Turbine to your existing system this money which you spend on inverter will work for you also in night time, during storm or winter. YES WE ARE USING SOLAT INVERTERS FOR WIND!
Wind turbines taking also less space horizontally which is why they are often used on yachts or anywhere where space is constrained. from each 1sqm(10sqft) of PV we can have 200-240W of power but with wind turbine we need 1sqft of surface to set a tower for 5kW wind turbine!
types of wind+solar energy systems can we build
1. offgrid means system which can work independently to the grid. this doesnt mean you cant have grid connection in your site it just means you do not feed your production to the grid. sometimes it is named island installation because it is separated from grid. Now most popular are 24V and 48V PV based systems of so called “hybrid” inwerter(inverter which in one case has PV controller, Inverter and battery charger)this kind of inverters are just oversized UPS systems with solar controller. of course they can be connected to the grid just like your laptop or UPS in office or shop. Most of them have MPPT solar controller which allows to connect PV string with working voltage up to 450V and Voc up to 500V. They are easy to install and easy to use but because of MPPT this controllers are not suitable for Wind Turbines. Therefore if we want to build solar-wind hybrid system with these inverters we need to buy wind turbine with nominal voltage same as Battery voltage in our system and then use PWM controller to charge system battery from wind turbine without without the use of our inverter. This means we need to set current in inverter at a little bit lower range to avoid damaging battery by charging it with combined current from wind and solar or wind and grid. 24V systems are suited for wind turbines up to 1kW 2-5kW systems work better with 48V systems
2. ongrid or grid tie systems are systems which tied to grid therefore usually work with higher voltages. In popular version ist just PV inverter and solar panels in one or more strings. String voltage can be up to 1000V. We can use wind turbine with this kind of system but we need a controller that will trick the inverter into thinking that the wind turbine is a string of photovoltaic panels. There are few inverters which allows you to connect wind turbine directly Deye is one of them. But this inverter has controller based on preprogrammed wind turbine characteristics which could be troublesome if you do not know your turbine power curve or this curve was draw by marketing department 😉
if we already have PV on grid system we can have two situations: either we have all mppt inputs of our inverter in use already or not. If we have one free mppt we can connect wind turbine to controller and controller to this mppt. Vmpp of most solar inverters is between 200-800VDC so itit doesn’t matter whether we buy 220Vor 380V turbine versions. But because 380V after rectifier and without load can easily reach 1000VDC rule of thumb up to 5kW is 220V 10kW and more is 380V nominal voltage.
There are only fev Wind Turbine inverters on the market and all of them are quite expensive(deye for example is the price of 10kW wind turbine) therefore especially for most popular 2 and 3kW turbines we are using inhouse made controllers since types provided by Wind Turbine producers are unsuitable for use with PV inverter mppt input.
of course since not every turbine has aerodynamic braking we need to provide braking resistors. They could be very expensive but we can use also electric heaters both air and water types. Of course you need to calculate resistance and use type/power of heating element which is suitable to power and voltage of your turbine but you have additional benefits by doing so.
Heater both in offgrid and on grid systems could be use for central heating and water heating purposes.
To avoid shock currents all Controllers we are using have PWM of heaters/resistors. This allows not only to prolong lifespan of turntable brushes but also rotor/generator bearings and resistors themselves.
And since it is PWM we can use it both ways- if we want we can brake turbine but if we want we can just use braking resistor(all heaters are resistors ) to generate maximum amount of heat.
Last year because of price drop in offgrid mppt inverters these controllers are more often use also in off grid systems.
If they are used with PV string connected in parallel to the same mppt inverter input we need to have same voltage output from controller as is our PV string ie if PV string is 390VDC MPP we need to set up controller from our wind turbine to give output 390V too if they are to work simultaneously.
Further from equator you live its more necessary to supplement Solar with another energy source. Wind Turbines are much less frequently used because they are more demanding in installation and set up but then they they remain maintenance-free for many years. I have a lot of customers who are using their systems for more than 15yrs already.
What do you thing about wind and solar combo?