The world’s energy, measured and calculated for you.
Simulate solar panels with real satellite weather, size a battery, compare a heat pump with your gas boiler, or see how any country makes its electricity. Every result is a link you can share, and whoever opens it can change the numbers.
Most-used calculators
All 60 →Solar panel output & payback
Simulates every hour of a full year at your exact location using NASA satellite weather, then turns the energy into savings, payback time and CO₂ avoided.
live data Batteries & storageSolar battery size & payback
Simulates your solar panels, your household’s hourly demand and a home battery for all 8,760 hours of a real year at your location, then finds the battery size that actually pays off.
live data WindWind turbine energy & payback
Pick a site and a turbine: we download a full year of hourly NASA wind at 50 m, shear it to your hub height, correct for air density and losses, and turn it into kWh, capacity factor, revenue and payback.
live data Heating & gasHeat pump running cost
Models an air-source heat pump month by month for your climate: heat demand, COP at every outdoor temperature and flow temperature, electricity use, running cost versus your current boiler and CO₂ saved.
EV & transportEV charging cost
What does it cost to charge an electric car? Enter your battery, efficiency and mix of home, public AC and rapid DC charging to get the cost per charge, per 100 km and per month, including charging losses, compared with a petrol car.
Home energyElectricity bill calculator
Build your household electricity bill from the appliances you actually use (or from your kWh), with flat, tiered or day/night tariffs, standing charge, levies and VAT. See which devices drive the cost.
Carbon & climateCarbon footprint
Home energy on your own country's grid, heating, car, flights, diet and shopping, in tonnes CO₂e per person. Compares the result with your country, the world and the 1.5 °C target, and ranks the actions that cut most for you.
Energy financeLCOE calculator
Capex, fixed and variable O&M, fuel and heat rate, capacity factor, lifetime, WACC, construction time, degradation and carbon price → the levelized cost per MWh, broken down by component and compared across 11 technologies.
SolarHow many solar panels?
Turns your yearly kWh (or monthly bill) into the number of panels, system size and roof area you need, using NASA satellite sunshine for your exact location, your panel model and roof orientation.
Leaderboards
All rankings →Most renewable grids
Countries generating ≥5 TWh/yr · %
Solar champions (share)
Countries generating ≥5 TWh/yr · %
Wind leaders (share)
Countries generating ≥5 TWh/yr · %
Cleanest electricity
Countries generating ≥5 TWh/yr · g/kWh
Country energy profiles
All 214 countries →Want them side by side? Compare Germany and France, or any countries you like.
Real weather, not rules of thumb
Solar and wind tools download hourly NASA satellite data for your exact coordinates and simulate the whole year.
Links that stay alive
Share a calculation and the recipient sees your exact inputs and can tweak them. Useful for installers, their clients, and settling arguments.
Reports with a letterhead
Turn any result into a clean, branded A4 report with charts, inputs, method and a QR code back to the live version.
Open data, cited
Ember, Energy Institute, NASA POWER, WRI, Global Energy Monitor and the Global Solar & Wind Atlas. Every number can be traced to its source.
Learn the essentials
All guides →Are Electric Cars Really Greener? A Life-Cycle Analysis
Battery manufacturing, grid mix, mining and recycling: what life-cycle studies show about EV vs petrol and diesel CO₂, with breakeven distances by country.
SolarAre Solar Panels Worth It? Payback, Savings and When They Aren't
A numbers-first guide to whether home solar pays: costs, payback periods, self-consumption, export tariffs, batteries and the cases where it doesn't.
HeatingHeat Pumps Explained: COP, SCOP and Real-World Costs
How heat pumps work, what COP and SCOP really mean, typical running costs versus gas, sizing rules and when a heat pump pays back. Worked examples included.
Batteries & storageHome Battery Storage: How to Size, Choose and Judge the Payback
How home batteries work, how many kWh you really need, LFP vs NMC, round-trip losses, cycle life and when a battery pays back, with worked examples.
SolarHow Solar Panels Work: From Photon to Plug
How a solar panel turns sunlight into household electricity: the photovoltaic effect, cells, modules, inverters, losses and real-world yields explained.
Energy basicsLCOE Explained: How to Compare the Cost of Electricity from Any Source
Levelised cost of electricity explained: the formula, discount rates, capacity factor, worked solar and gas examples, typical ranges and what LCOE leaves out.