At present, our renewable energy calculators are at beta test stage. Consequently, they are available for everybody to use, entirely free of charge. At the end of the beta test, you will be able to access the calculators free of charge on three occasions. After this, you will need to register in order to gain access to the calculators.
Registration will cost £49 per year in the United Kingdom, $69 in North America, or an equivalent amount across the rest of the world. Alternatively, private users who have purchased a copy of Introducing Renewable Energy can access the calculators entirely free of charge by entering the software license key that is included in the book.